JP2002289971A - Semiconductor optical element and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor optical element, capable of realizing a precise composition distribution and a film thickness distribution of a waveguide in each array of a micro-array waveguide manufactured by a selective growth. SOLUTION: The method for manufacturing the semiconductor optical element comprises the steps of providing, in addition to a plurality of stripe-like growth regions 1 to become an optical waveguide, a dummy growth region 6 between the stripe-like growth regions and at a part or all of the outside, changing the shape of the region 6 in the array or between the arrays, and changing the composition of a semiconductor multilayer structure formed on the region 1 and a layer thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor optical device having a semiconductor optical waveguide array and a method of manufacturing the same, and more particularly to a semiconductor optical waveguide array having a reduced array size and a method of manufacturing a semiconductor optical device having the same.

[0002]

2. Description of the Related Art In order to commercialize a wavelength division multiplexing (WDM) optical communication system, a technology for realizing a wavelength tunable light source such as a multi-wavelength light source or a wavelength selective light source, which is one of the key devices of the system, at low cost. It needs to be developed. As one form of the wavelength selection light source, it is considered that a plurality of light sources having mutually different wavelengths are monolithically integrated on one chip. As an example, a different wavelength semiconductor laser array has been developed. One of the typical methods for fabricating conventional different wavelength semiconductor laser arrays is described in IEE Electronics Lett.
ers Vol. 28, No. 9, pp. 824-825 (hereinafter referred to as reference (1)). in this way,
In order to oscillate each semiconductor laser constituting the array at a different wavelength, a diffraction grating having a different period is formed for each semiconductor laser, and the semiconductor laser is oscillated at a Bragg wavelength corresponding to each diffraction grating period. However, in this method, since the gain peak wavelength of the multiple quantum well (hereinafter abbreviated as “MQW”) active layer is constant in the array, the Bragg wavelength of the semiconductor laser determined by the gain peak wavelength and the period of the diffraction grating is determined. There is a problem that the difference (hereinafter abbreviated as “detuning amount”) shifts and laser characteristics such as optical output and threshold current are deteriorated. It was difficult to obtain good laser characteristics.

This problem is described in Japanese Patent Application Laid-Open No.
(2)) can be solved by the method for manufacturing a different wavelength semiconductor laser array disclosed in (2). This method uses selective growth for crystal growth of an MQW active layer that generates a gain of a semiconductor laser. Selective growth refers to the characteristics of a semiconductor multilayer structure selectively grown in a stripe-shaped growth region sandwiched between dielectric films formed in advance on a substrate, specifically, layer thickness, gain peak, PL emission wavelength, etc. Can be changed by the width of the dielectric film (hereinafter abbreviated as “selective growth mask”). FIG. 21 shows a specific example of a selective growth mask pattern, and FIG. 22 shows an example of a PL wavelength change obtained from the multilayer structure when a semiconductor multilayer structure is formed on a mask pattern with a changed selective growth mask width Wm. Is shown. By thus increasing the width of the selective growth mask, the PL emission wavelength (gain peak) becomes longer. Although not shown here, the layer thickness also increases at the same time. By using this method, the gain peak wavelength of the MQW active layer can follow the oscillation wavelength of each semiconductor laser determined by the diffraction grating period.

Further, by utilizing the feature of selective growth, it is possible to easily monolithically integrate functional regions having different emission wavelengths in the stripe longitudinal direction. FIG. 23 shows an example of a selective growth mask pattern for integrating two functional regions whose PL emission wavelengths are λ1 and λ2. The combination of mask widths differs depending on the growth pressure. For example, at a growth pressure of 20 kPa, it is 10 μm in the region of λ1 and 4 μm in the region of λ2. In this case, the PL wavelength profile of the growth layer at the boundary of the functional region changes as shown in FIG. This PL wavelength profile can be largely changed by changing the growth pressure. FIG. 24 shows a PL wavelength profile when the growth pressure is increased to 98.6 kPa and two functional regions of the same λ1 and λ2 are integrated. By increasing the growth pressure in this way, a steep PL wavelength profile can be obtained. This is because the diffusion length of the raw material species in the reaction tube was shortened by increasing the growth pressure. By selecting the selective growth region width Wo to be about 1.5 μm, the single transverse mode condition can be satisfied with the same size in the optical waveguide formed by the grown semiconductor multilayer structure. Since the optical waveguide can be formed without etching the semiconductor, it is effective in improving the yield. In addition, since the side surface of the crystal to be selectively grown becomes a smooth crystal surface, compared with the optical waveguide having the unevenness formed by the conventional etching. Thus, an array optical waveguide with low loss can be formed.

When the optical waveguides formed by such selective growth are arranged in an array, the array interval is set to 10 μm.
When it is set to the degree, the semiconductor laser can be integrated at a high density, and the yield of array elements per wafer can be greatly increased. This can be realized by a method of manufacturing a semiconductor optical waveguide array and an array-structured semiconductor optical device disclosed in Japanese Patent Application Laid-Open No. 2000-012952 (hereinafter referred to as Document (3)). FIG. 25 shows a standard selective growth mask of Reference (3). A plurality of stripe-shaped growth regions 1 are arranged in an array, and the regions between the growth regions are covered with a dielectric film mask (inner SiO ₂ mask 2, width Wa). Also, two outer masks (outer SiO ₂ mask 3 and outer SiO ₂ mask 4) are arranged on the outermost sides, respectively, and their widths W _m1 and W _{m 2} are larger than Wa. FIG. 26 shows a growth pressure of 20 kP on this selective growth mask.
Fig. 3 shows a PL wavelength obtained from a semiconductor multilayer structure grown in a. The characteristics of each stripe-shaped growth region in the array grown by this mask are controlled by the width of two outer masks arranged outside the array, and by setting the two widths to different values, the characteristics of the stripe-shaped growth region are changed. It is possible to make a distribution. This growth is referred to as microarray selective growth in reference (3). Reference (3) discloses that in the case where functional regions having different PL wavelengths in the longitudinal direction are integrated in the stripe-shaped growth region of the semiconductor optical waveguide array, FIG.
The characteristics in the longitudinal direction are changed by using a mask pattern as described above. At this time, in the functional region having a short PL wavelength, a desired wavelength cannot be set only by the outer mask width. Therefore, the width of the mask arranged on both sides of each stripe-shaped growth region 1 is reduced. As a result, a new growth region is generated between all the stripe-shaped growth regions. The growth region is called a dummy growth region. At this time, the width and the interval of the dummy growth region 6 in the semiconductor optical waveguide array having the dummy growth region 6 are constant in the array, and the distribution of the PL wavelength in the stripe growth region 1 in the array is controlled by the outer mask width. I was

However, the method disclosed in this reference (3) may not be able to cope with the formation of a structure necessary for manufacturing an element. For example, when an array waveguide having different PL emission wavelengths and a multiplexer are monolithically integrated by selective growth, the PL wavelength distribution of the growth layer at the boundary portion must be sharply reduced in order to sufficiently reduce the optical waveguide loss in the multiplexer. It is important to change to To achieve this, it is effective to increase the growth pressure to shorten the diffusion length of the raw material species in the reaction tube and realize a steep PL wavelength profile in the longitudinal direction, as described above. However, in this case, it is impossible to control the composition distribution and the layer thickness distribution of the stripe-shaped growth region in the array by the width of the outer mask arranged outside the array while keeping the width and interval of each growth region. is there. It is explained as follows. When the selective growth is performed by the metal organic chemical vapor deposition method, since the diffusion length of the raw material species changes by changing the growth pressure, the influence range of the selective growth mask changes. This state is schematically shown in FIG. When the growth pressure is low, the diffusion length of the raw material species is long. Therefore, when the raw material species in the gas phase on the mask diffuses over a wide range, the influence of the selective growth mask extends far. Therefore, it was possible to change the characteristics (layer thickness, gain peak, PL emission wavelength) of the entire array of the stripe-shaped growth regions by the width of the two outer masks located relatively far away. However, when the growth pressure is increased, the diffusion length of the raw material species becomes shorter, so that the influence of the outer mask is less likely to reach the growth region near the center.

The results of an experiment performed under such conditions will be described below. FIG. 28 shows a mask pattern for producing eight optical waveguide arrays by the method according to the literature (3). Here, the opening width Wo of the stripe-shaped growth region 1 is set to 1.5.
μm, the opening width of the dummy growth region 6 was 1.5 μm, and the stripe interval was 10 μm. The growth pressure is 98.6, which is higher than 9.33 to 40 kPa shown in the embodiment of Reference (3).
kPa, 8-layer MQW structure (well: 1.5 μm composition compressively strained InGaAsP, barrier: 1.24 μm composition InG
aAsP) was prepared. FIG. 29 shows the PL wavelength distribution obtained from each stripe-shaped growth region. Even if the widths W _{m, out1} of the two outer masks are changed to 2 μm, 4.5 μm, and 8 μm, and the widths W _{m , out2} are changed to 15 μm, 11.5 μm, and 8 μm, they are located near the center of the array. For the stripe numbers 3, 4, 5, and 6, the PL wavelength can hardly be changed. Therefore, it has been difficult to create a PL wavelength distribution that changes linearly from one side to the other.
This phenomenon occurs even when the growth pressure is low, even when the distance between the stripe-shaped growth regions in the array is large or the number of stripes is large, the center and outermost stripes are longer than the diffusion length of the source species in the reaction tube at the growth pressure. This also occurs when the distance between the stripe-shaped growth regions is long, and in such cases, it is difficult to control the composition distribution and the layer thickness distribution in the array of the stripe-shaped growth regions using only the outer mask. As described above, when the growth pressure is high and the array region width is wide, it is difficult to obtain a desired in-array wavelength distribution even if a mask pattern having the dummy growth region 6 as shown in FIG. 28 is used. .

On the other hand, when there is a dummy growth region between all the stripe-shaped growth regions regardless of the growth pressure, if an error occurs in the opening width and the mask width in the mask manufacturing step (process), the stripe-shaped growth region Large variations in the composition and layer thickness of the This is particularly noticeable in the case where the number of dummy growth regions is large or the width is narrow as shown in region 1 in FIG. 27 under the growth condition where the growth pressure is high and the mask width is sensitive to a change in mask width. In the mask pattern of FIG. 28, in order to increase the PL wavelength of the stripe-shaped growth region 1, the mask width on both sides of each stripe-shaped growth region 1 is increased (that is, the dummy growth region width 6 is reduced). FIG. 30 shows a PL wavelength shift obtained from the stripe-shaped growth region 1 located inside the array (Ch. 4) in the case of the above-mentioned case. From this graph, it can be seen that when trying to control the PL wavelength within a certain range, the dummy growth region may need to be narrowed. For example, in the measurement result of FIG.
In order to obtain a PL wavelength of 1.0, the width of the dummy growth region is set to 1.0.
It is necessary to be μm. On the other hand, it can be seen from this graph that as the width of the dummy growth region becomes smaller, the amount of change in the PL wavelength becomes larger. That is, when the dummy growth region becomes narrow,
There is a problem that the amount of change from the set value of the PL wavelength becomes large with respect to the same manufacturing error of the selective growth mask.

[0009]

As described above, in the conventional method of manufacturing a semiconductor optical waveguide array by selective growth, the composition and layer thickness distribution of the waveguide in the array are controlled by the width of the outer mask disposed outside the array. Therefore, the influence of the outer mask needs to reach the selective growth portion near the center of the array. Since this condition depends on the magnitude relationship between the diffusion length of the source species depending on the growth pressure and the width of the semiconductor optical waveguide array region, it is necessary for an arbitrary optical waveguide array especially when the growth pressure is fixed under other conditions. It has been difficult to realize the PL wavelength distribution and to arbitrarily set the composition and the layer thickness distribution of each waveguide in the array.

The present invention has been made in view of such circumstances, and the outer mask is formed over the entire array due to a high growth pressure, a large waveguide spacing of the semiconductor optical waveguide array, or a large number of arrays. It is an object of the present invention to provide a method for manufacturing a semiconductor optical device which can realize a more precise composition distribution and layer thickness distribution in each of the waveguides in an array when the influence of (1) is not exerted. At the same time, it is an object of the present invention to provide a method for manufacturing a semiconductor optical device capable of reducing a composition variation, a layer thickness variation and a PL wavelength variation caused by a mask fabrication error.

[0011]

In order to solve the above-mentioned problems, the invention according to claim 1 provides a quantum well layer or a quantum well layer in a stripe-shaped growth region formed on a semiconductor substrate between dielectric thin films. In a method of manufacturing a semiconductor optical device having a semiconductor optical waveguide array obtained by selectively crystal-growing a semiconductor multilayer structure including a bulk layer, a semiconductor optical waveguide array includes a plurality of the stripe-shaped growth regions and a dummy. By providing a growth region between the stripe-shaped growth regions and outside or all of the stripe-shaped growth regions, and changing the shape of the dummy growth region in the semiconductor optical waveguide array or for each semiconductor optical waveguide array Changing the composition and the layer thickness of the semiconductor multilayer structure formed in the stripe growth region. A method for manufacturing a semiconductor optical device characterized. According to a second aspect of the present invention, in the first aspect of the present invention, the crystal growth is performed in such a manner that a source species in a reaction tube is varied with respect to a distance between a center and an outermost stripe-shaped growth region constituting the semiconductor optical waveguide array. Is performed under the condition that the diffusion length is short. According to a third aspect of the present invention, in the first or second aspect, the dummy growth region is formed in a stripe shape, and either or both of the width and the position of the dummy growth region are changed at each location. Thereby, the composition distribution and the layer thickness distribution in the array of the semiconductor multilayer structure formed in the stripe-shaped growth region are controlled. The invention according to claim 4 is the invention according to claim 1.
In the invention according to the second aspect, the dummy growth region is formed in a rectangular shape, and the position, period, and shape of the dummy growth region are changed at each location, thereby forming the dummy growth region in the stripe-shaped growth region. It is characterized in that the composition distribution and the layer thickness distribution in the array of the semiconductor multilayer structure are controlled. The invention according to claim 5 is the invention according to claim 1, 2, 3, or 4.
In the invention according to any one of the above, the width of the two outermost dielectric thin films out of the plurality of dielectric thin films is set to a different width according to a change in the dummy growth region, whereby the stripe shape is obtained. The composition distribution and the layer thickness distribution in the array of the semiconductor multilayer structure formed in the growth region are controlled. The invention according to claim 6 is based on claim 1,
In the invention described in any one of 2, 3, 4, and 5, the intervals between the stripe-shaped growth regions constituting the semiconductor optical waveguide array are made uneven, and the dummy growth is performed in a region where the intervals between the stripe-shaped growth regions are wide. By arranging the regions, the composition distribution and the layer thickness distribution in the array of the semiconductor multilayer structure formed in the stripe-shaped growth region are controlled. The invention according to claim 7 is the invention according to any one of claims 1, 2, 3, 4, 5, and 6, wherein a width and an interval of the plurality of stripe-shaped growth regions,
By changing the position of the dummy growth region, the shape, and any or all of the width of the two outermost dielectric thin films in the longitudinal direction of the stripe,
The composition distribution and the layer thickness distribution in the array of the semiconductor multilayer structure formed in the stripe-shaped growth region are changed in the longitudinal direction. The invention according to claim 8 is the invention according to any one of claims 1, 2, 3, 4, 5, 6, and 7, wherein the plurality of stripe-shaped growth regions, the dummy growth regions, and the outermost position are located. By changing the shape of any or all of the two dielectric thin films in a curved shape, the direction of guided light is changed in a curved manner in the substrate plane. According to a ninth aspect of the present invention, a dummy optical waveguide that does not guide light is formed on a part or all of the semiconductor optical waveguide array, and the width of the dummy optical waveguide is different from each other. It is a semiconductor optical device. According to a tenth aspect of the present invention, in the ninth aspect, the shape of any or all of the plurality of optical waveguides and the dummy optical waveguides in the semiconductor optical waveguide array is changed into a curved shape, and the guided light is transmitted. Is characterized in that the direction changes in a curved manner within the substrate plane. According to an eleventh aspect of the present invention, in any one of the ninth and tenth aspects, an electrode is formed on any or all of the plurality of optical waveguides in the semiconductor optical waveguide array and operates as an active element. . According to a twelfth aspect of the present invention, in the invention of the eleventh aspect, a light reflecting mechanism by a diffraction grating is provided near the upper and lower portions of the plurality of optical waveguides in the semiconductor optical waveguide array, and the optical gain is increased by current injection. It is characterized in that it is caused to cause laser oscillation. According to a thirteenth aspect of the present invention, in the invention according to the twelfth aspect, the period of the diffraction grating arranged only in the vicinity including the upper and lower portions of the plurality of optical waveguides in the semiconductor optical waveguide array is different from each other in one array. It is characterized by being different for each wave path. According to a fourteenth aspect of the present invention, in the invention according to any one of the ninth, tenth, eleventh, and twelfth aspects, the plurality of optical waveguides in the semiconductor optical waveguide array are replaced by one optical waveguide or the number of arrays. An optical function area for connecting to a different array of optical waveguides is integrated, and a part of the input / output end of the optical function area is connected to one of the dummy optical waveguides in a plurality of optical waveguides in the semiconductor optical waveguide array. Connected to the unit. According to a fifteenth aspect, in the invention according to the fourteenth aspect, the optical function region is an array-like optical function region having the dummy optical waveguide having a waveguide width smaller than an array interval of the semiconductor optical waveguide array. One end of the array-like optical function region has an array region including a plurality of semiconductor lasers oscillating at different wavelengths having the dummy optical waveguide having a waveguide width smaller than the array interval of the semiconductor optical waveguide array. Connected, the other end of the array-shaped optical function area, an optical multiplexer area for multiplexing light emitted from the array-shaped optical function area, and a single waveguide for extracting the multiplexed light. By being connected and integrated in the axial direction,
It is characterized in that light of different wavelengths can be selected and extracted.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the characteristics of each stripe-shaped growth region are controlled not only by the outer mask but also by the width of a dummy growth region formed between each growth region. Figure 1
FIG. 3 is a view showing a mask used for selective growth by metal organic chemical vapor deposition in the present invention. In FIG. 1, reference numeral 1 denotes a stripe-shaped growth region, and its width is W _O. Reference numeral 2 denotes an inner SiO ₂ mask, and reference numeral 3 denotes an outer SiO ₂ mask. Reference numeral 6 denotes a dummy growth region provided between the stripe-shaped growth regions and a part or all outside thereof. When the dummy growth region 6 is present, the source species diffused in the vapor phase on the selective growth mask adjacent thereto is consumed by crystal growth, so that the source species reaching the adjacent stripe-shaped growth region is reduced. When the width of the dummy growth region is changed, the amount of the raw material species consumed there changes, so that the amount of the raw material species reaching the adjacent stripe-shaped growth region changes. As a result, the characteristics of the stripe-shaped selective growth region change. Can change.

The present invention is particularly effective when crystal growth is performed under the condition that the diffusion length of the raw material species in the reaction tube is short with respect to the distance between the center and the outermost stripe-shaped growth region constituting the array. In this case, since the influence of each dummy growth region affects only a few stripe-like growth regions adjacent to each other, individual control of stripes constituting an array, which was difficult in the related art, becomes possible. It can be realized. In particular, FIGS.
10, 18 and 19 of the laser array element shown in FIG.
In the mask pattern for selectively forming the active layer when the optical device including the DFB laser array portion shown in (1) is manufactured, dummy growth regions are formed in stripes as shown in FIGS. By changing either or both of its width and position at each location, the stripe-like growth located inside the array cannot be individually controlled by the conventional mask pattern shown in FIG. 27 when the growth pressure is high. The composition and layer thickness of the semiconductor multilayer structure formed in the region, for example, the stripe-shaped growth regions of stripe numbers 3, 4, 5, and 6 in the experimental result of FIG. 29 can be changed.

Further, as in the case of the DFB laser region in FIGS. 2, 6 and 8, the width of the outermost two dielectric thin films of the plurality of dielectric thin films is changed according to the change in the shape of the dummy growth region. When the widths are different, it is possible to control the semiconductor multilayer structure formed in the outermost stripe-shaped growth region. As a result, as shown in FIG.
The L wavelength can be controlled to change continuously in the array. Also, as shown in FIG. 5, the PL wavelength distribution can be similarly controlled by making the dummy growth region of the DFB laser region rectangular and changing the position, period, and shape of the dummy growth region at each location. Can be. By using these methods, the PL wavelength distribution which could not be realized even under the condition where the growth pressure is low, for example,
As shown in FIG. 7, a distribution can be realized in which the array is changed stepwise from one side to the other side. Further, when fabricating an optical device in which a DFB laser array as shown in FIG. 20 is integrated, in a mask pattern for selectively forming a DFB laser array region in FIG. 15, a stripe-shaped growth region constituting a semiconductor optical waveguide array is formed. By controlling the composition and layer thickness distribution of all the stripe-shaped growth regions in the array while reducing the number of dummy growth regions by arranging the dummy growth regions in regions with a wide stripe spacing, with uneven spacing. Becomes possible. In this case, by reducing the number of dummy growth regions and increasing the width, fluctuations in the composition distribution and layer thickness distribution in the array when the width of the stripe-shaped growth regions fluctuate can be reduced.

When manufacturing an optical device in which a DFB laser array and an electroabsorption (EA) switch are monolithically integrated as shown in FIG. 19, a mask for selectively forming the DFB laser array region and the EA switch region in FIG. In the pattern, by changing the width of the plurality of dummy growth regions and the width of the two outermost dielectric thin films in the longitudinal direction of the stripe, the PL wavelength obtained from the stripe growth region as shown in FIG. It can be changed between the DFB laser area and the EA switch area. This makes it possible to integrate an array structure of a plurality of optical function areas in the longitudinal direction. Further, as shown in FIG. 10, when the interval between the stripe-shaped growth regions is different between the input portion of the DFB laser array region and the input portion of the optical multiplexer region, and when an optical element having a bent waveguide region connecting both is manufactured, FIG.
In the mask pattern of (1), by changing the stripe-shaped growth region in a curved manner, it becomes possible to change the direction of guided light in a curved manner in the substrate plane and to change the interval between the stripe-shaped growth regions. . At this time, when the width of the dummy growth region is changed within the array in the bent waveguide portion, the composition and the layer thickness of the bent waveguide array portion can be controlled. With reference to the attached drawings below,
An embodiment in which the composition distribution and the layer thickness distribution in the array, both of which could not be realized by the prior art, will be described in detail.

(Embodiment 1) This embodiment is an embodiment in which the present invention is applied to a microarray semiconductor laser having a different refractive index from one side to the other side. The microarray semiconductor laser of the present embodiment uses an optical waveguide array that is changed by about 90 nm in PL wavelength from one side to the other side and controlled to have an inclined refractive index. FIG. 16 shows a schematic diagram thereof. FIG. 2 shows the selective growth mask used in this embodiment. The mask is a SiO ₂ film deposited by CVD method,
Fabrication was performed by patterning. The interval between the stripe-shaped growth regions 1 was 15 μm, and the width Wo was 1.5 μm. Longer PL wavelengths from the left side toward the right side, to increase the refractive index, and a dummy growth region 6 in a stripe shape, and inserted into the center between each of the stripe-shaped growth region, and gradually narrowing the width W _D . The width of the dummy growth region is
5.5 μm, 5.0 μm, 4.5 μ, 4.0 μm, 3.
5 μm, 3.1 μm, 2.7 μm, 2.3 μm, 2.0
μm. The outer masks 3 and 4 are arranged outside the array (Ch. 1).
And Ch.8) greatly affect the composition and layer thickness, so that it is necessary to set an appropriate mask width for each. Here, the width of the outer mask 3 was 5.05 μm, and the width of the outer mask 4 was 10.8 μm. At the growth pressure of 98.6 kPa and the growth temperature of 625 ° C., eight MQW layers (compressed strain InGaAsP having a well composition of 1.5 μm, well having a composition of InGaAsP having a composition of 1.5 μm and a barrier of 1.2 μm) were formed on the InP substrate 99.
P) was selectively grown. FIG. 3 shows the resulting PL wavelength distribution. In this way, the PL wavelength could be changed almost linearly by 90 nm on the left and right.

On this optical waveguide array, SiO ₂ is formed again so that the width Wo of the stripe-shaped growth region of the selective growth mask is from 1.5 μm to 6 μm in the entire region, and the dummy optical waveguide is completely coated. . Using this mask, a 2.0 μm thick p-InP buried cladding layer,
μm p ⁺ -InGaAs contact layer with a growth pressure of 10 kPa
Grew up. Here, by making the growth pressure low, it was possible to obtain substantially the same layer thickness in each selective growth portion even without the dummy growth region. After that, Si
An O ₂ film was formed, a current injection window was formed, and a Cr / Au upper p electrode and an AuGeNi lower electrode were formed by sputtering. Finally, cleavage was performed so that the laser area became 400 μm. In this way, the chip size of the entire array becomes 120
A microarray semiconductor laser of μm × 400 μm was manufactured. The laser array was able to distribute the oscillation wavelength from 1480 nm to 1570 nm in all channels, and showed a very uniform and excellent characteristic of a threshold current of 6 ± 1 mA.

(Embodiment 2) This embodiment is an embodiment in which the present invention is applied to a DFB semiconductor laser array having a microarray structure having different refractive indexes from one side to the other side. In the microarray semiconductor laser of this embodiment, since three types of DFB semiconductor laser arrays are manufactured from one wafer, the number of each stripe-shaped growth region in each array is set to 8, and for simplicity, each PL wavelength is kept constant. Element 1 is 1547 nm and element 2 is 1556 n
m, the target of the element 3 was 1564 nm. FIG. 4 shows a schematic diagram thereof. FIG. 5 shows the selective growth mask used in this embodiment. The mask is a SiO ₂ film deposited by CVD method,
Fabrication was performed by patterning. The interval between the stripe-shaped growth regions 1 was 10 μm, and the width Wo was 1.5 μm. The dummy growth region 6 was rectangular and inserted at the center between the respective stripe growth regions. For simplicity, the period is changed between the three types of arrays without being changed in the array. The rectangle of the dummy growth region 6 has a width of 2.5 μm and a length of 6.
The period was set to 8.0 μm for the element 1, 8.6 μm for the element 2, and 9.1 μm for the element 3. Since the outer masks 3 and 4 greatly affect the composition and layer thickness on the outer side of the array (Ch. 1 and Ch. 8), it is necessary to set appropriate mask widths respectively. Here, the widths of the outer masks 3 and 4 are made equal, that is, 7.0 μm for element 1 and 7.3 for element 2
μm, and 7.5 μm for the element 3. In each of the semiconductor lasers, the oscillation wavelength of the element 1 is 1529 to 1537.
nm, 1538-1546 nm for element 2, 15 for element 3
In order to set the wavelength to 47 to 1555 nm, the diffraction grating period is set to 229.9 to 239.9 nm for the element 1 and 240.0 to 240.0 nm for the element 2.
-241.0 nm, 241.1-242.1 n for element 3
m. This diffraction grating pattern was transferred to the InP substrate 99 by ordinary wet etching, and the selective growth mask of FIG. 5 was formed thereon so that the stripe-shaped growth region overlapped the diffraction grating.

A growth pressure of 9 is applied to the selective growth mask.
At 8.6 kPa and at a growth temperature of 625 ° C., eight MQW layers (1.5 μm compositional compressive strained InGaAs) were formed on the InP substrate 99.
P and a barrier were selectively grown of 1.2 μm composition InGaAsP). As a result, the mask pattern was changed in one growth 3
PL wavelength is set to 1
546 μm, 1557 μm, 1556 μm, and the error could be controlled to ± 2 nm, respectively. With respect to this optical waveguide array, the width Wo of the stripe-shaped growth region of the selective growth mask is set from 1.5 μm to 5.5 μm in the entire region.
SiO ₂ was formed again to completely cover the dummy optical waveguide. Using this mask, a 2.0 μm thick p-InP buried cladding layer and a 0.3 μm thick p ⁺ -InGaAs contact layer were grown at a growth pressure of 10 kPa. Here, by making the growth pressure low, it was possible to obtain substantially the same layer thickness in each selective growth portion even without the dummy growth region. Thereafter, a SiO ₂ film was formed on the entire surface, a window for current injection was formed, and a Cr / Au upper p electrode and an AuGeNi lower electrode were formed by sputtering. Finally, the laser region 400
Cleavage was performed so as to be μm. In this way, three types of microarray semiconductor lasers having a chip size of the entire array of 120 μm × 400 μm were produced. In the laser array, the oscillation wavelength in all channels is 152
9.1 nm to 1537.2 nm;
0 nm to 1546.1 nm, 1546.9 n for element 3
m to 1554.9 nm, and the threshold current was 8 ± 1 mA.

(Embodiment 3) This embodiment is an embodiment applied to a DFB semiconductor laser array having a microarray structure according to the present invention. FIG. 17 shows a schematic diagram thereof. The semiconductor laser array having the microarray structure according to the present embodiment is a semiconductor laser array having one LDB oscillation wavelength given to two LDs and having an oscillation wavelength inclined from one to the other in order to increase the absolute wavelength accuracy. FIG. 6 shows the selective growth mask used in this embodiment. The width Wo of the stripe-shaped growth region 1 was 1.5 μm. Same P for two lasers
While realizing the L wavelength, the whole has an oscillation wavelength inclined from one side to the other, so that the dummy growth region 6 is formed in a stripe shape, its position is shifted from the center, and the width is increased from one side to the other side. . The stripe interval is 20μ
m, and the number of stripes was 8. Excluding the outer mask width, there are 16 masks in total, each having a width of 4.9μ.
m, 4.8 μm, 4.8 μm, 4.7 μm, 5.7 μm
m, 5.55 μm, 5.55 μm, 5.3 μm, 6.5
μm, 6.25 μm, 6.25 μm, 5.9 μm, 7.
They were 3 μm, 6.9 μm, 6.9 μm, and 6.6 μm.
The width of the dummy growth region 6 can be calculated from the width 1.5 μm of the stripe-shaped growth region 1 and the stripe interval, and is 9.7 μm, 8.9 μm, 8.1 μm,
7.4 μm, 6.7 μm, 6.0 μm, 5.3 μm,
4.7 μm. The outer mask width is 7.1 μ each.
m, 12.3 μm. That is, Ch. Left of 1, C
h. 2 and 3, Ch. 4 and 5, Ch. 6 and 7, Ch. This means that the position of the dummy growth area on the right side of 8 has been moved from the center to the left. In order to set the oscillation wavelength of each semiconductor laser to 1500 to 1580 nm, the diffraction grating period was changed from 240 nm to 250 nm for every two LDs. This diffraction grating pattern is transferred to the InP substrate 99 by ordinary wet etching,
Further, the selective growth mask of FIG. 6 was formed thereon so that the stripe-shaped growth region overlapped the diffraction grating.

A growth pressure of 9 is applied to the selective growth mask.
8.6kPa, growth temperature 625 ℃, 8 layers of MQW on InP substrate 99
A layer (a well having a 1.5 μm composition compressively strained InGaAsP and a barrier having a 1.2 μm composition InGaAsP) was selectively grown. The resulting PL wavelength distribution is shown in the graph of FIG. As described above, it was possible to change each of the two stripe-shaped growth regions at an interval of 25 nm while maintaining the same PL wavelength in the two adjacent stripe-shaped growth regions. With respect to this optical waveguide array, the width Wo of the stripe-shaped growth region 1 of the selective growth mask is set to 1.5 μm.
SiO ₂ is formed again so as to be 6 μm in the entire region from m to completely cover the dummy optical waveguide. Using this mask, a 3.0 μm-thick p-InP buried cladding layer and a 0.3 μm-thick p ⁺ -InGaAs contact layer were grown at a growth pressure of 10 μm.
It grew at kPa. Thereafter, an SiO ₂ film is formed on the entire surface, a window for current injection is formed, and a Cr / Au upper p electrode, A
A uGeNi lower electrode was formed by a sputtering method. Finally, it was cleaved and the end face was coated with a low reflection coating. This semiconductor laser array has an oscillation wavelength of 150 for each group.
0, 1525, 1550, 1575 nm, and within each group, the oscillation wavelength error is ± 0.8 nm.
Could be within. The threshold current was also very uniform at 6 ± 1 mA, showing good characteristics.

(Embodiment 4) This embodiment is an embodiment applied to a wavelength selective light source having a semiconductor laser array having a microarray structure according to the present invention. The wavelength selection light source having the semiconductor laser array having the microarray structure according to the present embodiment is D
It has a microarray structure with a stripe interval of 10 μm and four stripes designed to keep the oscillation wavelength and the detuning amount (the difference between the oscillation wavelength and the gain peak (PL emission wavelength)) constant in the FB-LD region. . In addition, it has an MMI optical multiplexer area, an optical amplifier area, and an optical modulator area. FIG. 18 shows the element configuration. FIG. 8 shows the selective growth mask used in this embodiment. The width Wo of the stripe-shaped growth region was 1.5 μm. Microarray DF
In order to increase the PL wavelength and increase the refractive index from channel 1 to channel 4 in the B semiconductor laser region 11, the dummy growth region 6 is formed in a stripe shape, and is positioned at the center between the stripe growth regions and gradually narrowed. I have. Here, in order from the left, 1.55 μm, 1.5 μm, 1.46 μm
m, 1.43 μm, and 1.40 μm. Outer mask 3
And 4 are PL wavelengths (refractive index) of the growth region outside the array
In consideration of the above, the outer mask 3 is set to 7.0 μm, and the outer mask 4 is set to 7.4 μm. Since the MMI optical multiplexer region 12 has a ridge buried shape, the entire growth region without using a selection mask is used here. Each of the optical amplifier region 13 and the optical modulator region 14 sets a selection mask width to obtain an appropriate PL wavelength, and Wm = 8 μm and Wm = 4.5 μ, respectively.
m. Further, in such a device having a long resonator structure, the reflected return light at the emission end causes characteristic deterioration. Therefore, the stripe is inclined by about 7 ° at the emission end as compared with the stripe. The oscillation wavelength of each semiconductor laser is set to 154.
In order to set the wavelength to 7 to 1554.5 nm, the diffraction grating period is set to 24.
It was varied from 0.0 nm to 241.0 nm. This diffraction grating pattern was transferred to the InP substrate 99 by ordinary wet etching, and the selective growth mask of FIG. 8 was formed thereon so that the stripe-shaped growth region overlapped the diffraction grating.

A growth pressure of 9 is applied to the selective growth mask.
8.6kPa, growth temperature 625 ℃, 8 layers of MQW on InP substrate 99
A layer (a well having a 1.5 μm composition compressively strained InGaAsP and a barrier having a 1.2 μm composition InGaAsP) was selectively grown. The resulting PL wavelength distribution is shown in the graph of FIG. As described above, the PL wavelength is changed from 1547.0 to 1554.5n on the left and right.
m could be varied almost linearly at 2.5 nm intervals. In addition, the MMI optical multiplexer area 1 grown at the same time
2. The PL wavelengths of the optical amplifier region 13 and the optical modulator region 14 were 1370 nm, 1563 nm, and 1477 nm, respectively, which were almost equal to the targets. Next, the width Wo of the stripe-shaped growth region of the selective growth mask is increased from 1.5 μm to DFB−
SiO ₂ is formed again so as to have a thickness of 5.5 μm in the LD array portion, and the dummy optical waveguide is completely covered. At the same time, SiO ₂ was formed so that the width of the stripe-shaped growth region was 40 μm in the MMI optical multiplexer region 12 and 6.0 μm in the optical amplifier region 13 and the optical modulator region 14. Using this mask, a 3.0 μm-thick p-InP buried cladding layer and a 0.3 μm-thick p ⁺ -InGaAs contact layer were grown at a growth pressure of 10 kPa. Thereafter, a SiO ₂ film was formed on the entire surface, a current injection window was formed, and a Cr / Au upper p electrode and a Cr / Au lower electrode were formed by sputtering. Finally, it was cleaved and a low reflection coating was applied to the end face. This semiconductor laser array has an oscillation wavelength of 1547.
1, 1549.6, 1552.0, 1554.6 nm, and the oscillation wavelength error could be kept within ± 0.1 nm. The threshold current was also very uniform at 6 ± 1 mA, showing good characteristics.

(Embodiment 5) This embodiment is an embodiment applied to a wavelength selective light source having a semiconductor laser array having a microarray structure according to the present invention. The wavelength selection light source having the semiconductor laser array having the microarray structure according to the present embodiment is D
The FB-LD region has a microarray structure with a stripe interval of 20 μm and five stripes. In addition, it has a bent waveguide area, an MMI optical multiplexer area, and an optical amplifier area. FIG. 10 shows the element configuration. FIG.
The selective growth mask used in this embodiment is shown below. The width Wo of the stripe-shaped growth region was 1.5 μm. The microarray DFB semiconductor laser region 11 has a longer PL wavelength from channel 1 to channel 4 and has a dummy growth region 6 in the form of a stripe to increase the refractive index. ing. Here, in order from the left, 7.5 μm, 7.3 μm,
7.15 μm, 7.0 μm, 6.95 μm, 6.9 μm
And The outer masks 3 and 4 are made 8.6 in consideration of the PL wavelength (refractive index) of the growth region outside the array.
μm, and the outer mask 4 was 9.1 μm. In this element, M
In order to shorten the MI length, the interval between the stripe-shaped growth regions of the MMI input section was set to 5 μm. Therefore, in order to change the stripe interval, as shown in FIG. 11, the waveguide array interval is changed in a curved manner from the emission portion of the DFB laser array to the MMI input portion. The dummy growth region 6 in the array is wide on the inside, narrow on the outside, and gradually narrowed in the stripe direction, so that there is no large difference in the PL wavelength obtained from each stripe. Since the MMI optical multiplexer region 12 has a ridge buried shape, the entire growth region without using a selection mask is used here. In the optical amplifier region 13, the selection mask width was set to Wm = 6.9 μm in order to set the PL wavelength to 1564 nm. Further, in such a device having a long resonator structure, the reflected return light at the emission end causes characteristic deterioration. Therefore, the stripe is inclined by about 7 ° at the emission end as compared with the stripe. In each of the semiconductor lasers, the oscillation wavelength of the element 1 is set to 1538.
In order to set the wavelength to 0 to 1546.0 nm, the diffraction grating period is set to 23.
It was changed from 9.0 nm to 240.0 nm. This diffraction grating pattern was transferred to the InP substrate 99 by ordinary wet etching, and the selective growth mask of FIG. 11 was formed thereon so that the stripe-shaped growth region overlapped the diffraction grating.

A growth pressure of 9 is applied to the selective growth mask.
8.6kPa, growth temperature 625 ℃, 8 layers of MQW on InP substrate 99
A layer (a well having a 1.5 μm composition compressively strained InGaAsP and a barrier having a 1.2 μm composition InGaAsP) was selectively grown. As a result, the PL wavelength could be changed from laser channels 1 to 5 as shown in FIG.
Also, the PL of the MMI optical multiplexer region 12 grown at the same time is
The wavelength is 1350 nm, and the PL wavelength in the optical amplifier region is 15
It was 65 nm, which was almost equal to the target. Next, the width Wo of the stripe-shaped growth region 1 of the selective growth mask is set to 1.5 μm.
Then, SiO ₂ is formed again so as to have a thickness of 6.0 μm in the DFB-LD array portion, and the dummy optical waveguide is completely covered. At the same time, SiO ₂ was formed so that the width of the stripe growth region was 25 μm in the optical multiplexer region 12 and 6.0 μm in the optical amplifier region 13. Using this mask, a 3.0 μm-thick p-InP buried cladding layer and a 0.3 μm thick
μm p ⁺ -InGaAs contact layer with a growth pressure of 10 kPa
Grew up. Thereafter, an SiO ₂ film is formed on the entire surface, a window for current injection is formed, and a Cr / Au upper p-electrode, Cr / Au
The lower electrode was formed by a sputtering method. Finally, it was cleaved and a low reflection coating was applied to the end face. In this semiconductor laser array, the error was within ± 0.3 nm and the error in the wavelength interval between adjacent DFB lasers was about 0.1 nm with respect to each target. The threshold current also showed good characteristics of 7 ± 1 mA.

(Embodiment 6) This embodiment is an embodiment in which the present invention is applied to an element in which an array structure semiconductor laser having different oscillation wavelengths and an electroabsorption (EA) type optical switch are respectively monolithically integrated. FIG. 19 shows a schematic diagram thereof. The modulator integrated microarray semiconductor laser of the present embodiment has a function of shifting the oscillation wavelength by 4 nm in the 1DFB semiconductor laser in the array and has eight D
It has a DFB semiconductor laser unit in which FB semiconductor lasers are arrayed, and an EA switch connected to each DFB semiconductor laser. The EA switch is connected to each connected DFB
The absorption edge was set to the shorter wavelength side by 70 nm with respect to the oscillation wavelength of the semiconductor laser. The DFB semiconductor laser was loaded with a heater to change the oscillation wavelength. For these two regions, an optical waveguide array having a stripe interval of 20 μm was used. FIG. 13 shows a selection mask used in this embodiment. 8 stripes, stripe-shaped growth region width Wo = 1.5 μm,
The stripe interval is set to 20 μm, and the DFB laser region 11
Has a width of the outer mask of 9 μm and 1
And 0.5μm, dummy growth region width W _D, in turn, 6.8
μm, 6.6 μm, 6.4 μm, 6.2 μm, 5.95
μm, 5.75 μm, 5.55 μm, 5.35 μm,
It was 5.35 μm. In order to set the detuning amount from the oscillation wavelength to 70 nm, the EA switch has Wm, out = 7 and 8.5 μm, and the dummy growth region width W _D is 11
μm, 10.8 μm, 10.6 μm, 10.4 μm, 1
0.15 μm, 9.9 μm, 9.65 μm, 9.4 μ
m, 9.15 μm. The diffraction grating period was changed from 240.0 nm to 243.5 nm in order to set the oscillation wavelength of each semiconductor laser to 1532 to 1560 nm. This diffraction grating pattern was transferred to the InP substrate 99 by ordinary wet etching, and the selective growth mask of FIG. 13 was formed thereon so that the stripe-shaped growth region overlapped the diffraction grating.

A growth pressure of 98.6 kP is applied to the InP substrate 99.
a, At a growth temperature of 625 ° C., eight MQW layers (wells are 1.5 μm compositional compressively strained InGaAsP, barriers are 1.0 μm) on the InP substrate 99.
2 μm composition InGaAsP) was selectively grown. Its MQW
The measurement result of the PL wavelength distribution obtained from the layer is shown in the graph of FIG. Thus, a substantially linear PL wavelength distribution was obtained, and a detuning amount of about 70 nm with respect to the DFB oscillation wavelength was obtained. Next, after removing the mask, the DFB-LD array section and the SiO ₂
A mask is deposited, and a 3 μm thick Fe-doped InP layer is grown. Next, an SiO ₂ mask was taken, and a p ⁺ -InP contact layer having a thickness of 3 μm and a thickness of 0.3 μm was formed on the p ⁺ -InP contact layer at a growth pressure of 1.
It grew at 0 kPa. Thereafter, an electrode and a heater wiring were formed. Finally, it was cleaved and a low reflection coating was applied to the end face. The oscillation wavelength of each laser in this semiconductor laser array is changed from 1532.1 to 155.
They could be arranged almost uniformly in the range of 9.9 nm, and the oscillation wavelength error could be kept within ± 0.2 nm. The threshold current was also very uniform at 7 ± 1 mA, showing good characteristics. These lasers could change the oscillation wavelength by about 4 nm by flowing about 100 mA to each heater, and by driving all the semiconductor lasers constituting the array simultaneously, they could be adjusted to the ITU grid. Further, by operating the EA switches attached to all the lasers, they could be used as a wavelength selection light source for selecting a wavelength to be extracted.

(Embodiment 7) This embodiment is an embodiment applied to a wavelength selective light source having a semiconductor laser array having a microarray structure according to the present invention. The schematic diagram is shown in FIG. The wavelength selection light source having the semiconductor laser array having the microarray structure according to the present embodiment is in a DFB laser region.
The number of dummy growth regions is one, the position is provided at the center, and a microarray structure with four stripes is designed to reduce the oscillation wavelength error due to the variation of the opening width generated in the opening width forming process. FIG. 15 shows the selective growth mask used in this embodiment. The width Wo of the stripe-shaped growth region used as the laser was 1.5 μm. The microarray DFB semiconductor laser region 11 of this embodiment is 4
All three stripes have the same PL wavelength, and the oscillation wavelength is changed by 7.5 nm from one to the other by changing the diffraction grating period. Here, the inner mask width is 7.5 μm, 4.4 μm, 4.4 μm, 7.5 μm in order from the left.
μm. The outer masks 3 and 4 consider the PL wavelength (refractive index) of the growth region outside the array, and
Both were 4.9 μm. Stripe spacing is channel 1
9μm between -2 and 3-4, 18μ on channel 2-3
m. As a result, the width of the central dummy stripe becomes 7.7 μm. Since the MMI optical multiplexer region 12 has a ridge buried shape, the entire growth region without using a selection mask is used here. Each of the optical amplifier regions 13 has a selected mask width Wm of 8.2 μm in order to obtain an appropriate PL wavelength.
m. Further, in such a device having a long resonator structure, the reflected return light at the emission end causes characteristic deterioration. Therefore, the stripe is inclined by about 7 ° at the emission end as compared with the stripe. The oscillation wavelength of each semiconductor laser is set to 154.
In order to set the wavelength to 7 to 1554.5 nm, the diffraction grating period is set to 24.
It was varied from 0.0 nm to 241.0 nm. This diffraction grating pattern was transferred to the InP substrate 99 by ordinary wet etching, and the selective growth mask of FIG. 15 was formed thereon so that the stripe-shaped growth region overlapped the diffraction grating.

A growth pressure of 9 is applied to the selective growth mask.
8.6kPa, growth temperature 625 ℃, 8 layers of MQW on InP substrate 99
A layer (a well having a 1.5 μm composition compressively strained InGaAsP and a barrier having a 1.2 μm composition InGaAsP) was selectively grown. The resulting PL wavelength was 1556 ± 2 nm, and could have substantially the same PL wavelength as desired. The PL wavelengths of the optical multiplexer region 12 and the optical amplifier region 13 grown at the same time were 1365 nm and 1560 nm, respectively, which were almost equal to the target. Next, the SiO _{2 is} grown so that the width Wo of the stripe-shaped growth region of the selective growth mask is changed from 1.5 μm to 5.5 μm in the DFB laser array region 11.
Is formed again, and the dummy optical waveguide is completely coated. At the same time, SiO ₂ was formed so that the width of the stripe-shaped growth region was 40 μm in the MMI optical multiplexer region 12 and 6.0 μm in the optical amplifier region 13. Using this mask, a layer thickness of 3.
0 μm p-InP buried cladding layer, layer thickness 0.3 μm
A p ⁺ -InGaAs contact layer was grown at a growth pressure 10 kPa. Thereafter, a SiO ₂ film was formed on the entire surface, a current injection window was formed, and a Cr / Au upper p electrode and a Cr / Au lower electrode were formed by sputtering. Finally, it was cleaved and a low reflection coating was applied to the end face. The semiconductor laser arrays have oscillation wavelengths of 1547.1 and 154, respectively.
9.6, 1552.0 and 1554.6 nm. The threshold current was also very uniform at 6 ± 1 mA, showing good characteristics.

In this manufacturing method, since the selective growth technique is used, different mask widths of the DFB laser array region 11 and the optical amplifier region 13 are changed for each array, so that different P
It is possible to fabricate an array of semiconductor multilayer structures having L wavelengths in one wafer. Therefore, the width of the stripe-shaped growth region and the width of the dummy growth region are intentionally set to +0.1 μm in another region of the wafer where the growth shown in this embodiment is performed.
And −0.1 μm, and simultaneously change each selection mask to −
A mask pattern changed by 0.1 μm and +0.1 μm was prepared and grown simultaneously. Also, a microarray D having four stripes, all having the same PL wavelength,
An FB semiconductor laser region is also fabricated on the wafer at the same time as the mask pattern using the conventional technology, and a device is fabricated in the same way when the aperture width fluctuates ± 0.1 μm, and the dependence on the aperture width fabrication error is examined. Was. In the prior art, the dummy growth region width W _D =
The outer SiO ₂ mask width was 1.5 μm and the width of both was 8 μm.
Comparing the two with the change in the oscillation wavelength of the semiconductor laser located inside the array, the result of the prior art was ± 1.3 μm.
About 0.5% in the case of the present invention.
It turned out to be about μm. As described above, the oscillation wavelength error due to the variation in the opening width generated in the opening width manufacturing process was significantly reduced. It should be noted that the present invention is not limited to the above embodiments, and it is clear that the embodiments can be appropriately modified within the scope of the technical idea of the present invention.

[0031]

As described above, according to the first aspect of the present invention, when the semiconductor optical waveguide array is formed by using the selective growth technique, the center and the outermost portion constituting the selective growth mask pattern are formed. By introducing dummy growth regions between the stripe growth regions and changing the width and position in the array, the composition and layers of the semiconductor multilayer structure formed in the stripe growth regions were impossible in the prior art. Individual control of the thickness becomes possible. Therefore, it is possible to provide a method for manufacturing an optical element using a waveguide array that realizes more precise composition distribution and layer thickness distribution. In particular, as described in claim 2, when performing crystal growth, the influence of the outer mask on the entire array due to a high growth pressure, a large waveguide spacing of the semiconductor optical waveguide array, or a large number of arrays, etc. If the value does not reach, a greater effect can be obtained. This effect can be obtained by forming a stripe-shaped dummy growth region and changing one or both of the width and the position of the dummy growth region at each location. Further, the same effect can be obtained by making the dummy growth region rectangular and changing the position, period, and shape where the dummy growth region is arranged, as described in claim 4. In addition to this method, claim 5
According to the described invention, it is possible to control the composition and the layer thickness of all the stripe-shaped growth regions in the array by setting the outermost mask width to a different width according to the change of the dummy growth region. . In particular, when the interval between the stripe-shaped growth regions is changed at a specific location as in the invention according to claim 6, the number of dummy growth regions is reduced and the width is increased, so that the stripe-shaped growth regions located in the array are reduced. It is possible to control the composition and layer thickness of the region. In this case, since the number of dummy growth regions can be reduced and the width can be widened, composition fluctuations, layer thickness fluctuations and characteristic fluctuations caused by mask fabrication errors for selective growth can be reduced. In this way, by connecting the semiconductor optical waveguide array of which composition and thickness are controlled in the longitudinal direction of the stripe-shaped growth region as a whole as in the invention according to claim 7, the semiconductor optical waveguide array is controlled as a whole. It is possible to manufacture a more functionalized optical integrated device. At this time, as in the eighth aspect of the present invention, the shape of the stripe-shaped growth region, the dummy growth region for controlling the stripe-shaped growth region, and the outermost two dielectric thin films are changed in a curved manner, so that light is guided. The distance between the stripe-shaped growth regions and the traveling direction of the light can be changed while minimizing the loss in the wave, and the size of the monolithically integrated optical device can be reduced.

According to the ninth aspect of the present invention, dummy optical waveguides are formed in part or all of the optical waveguide array, and the width of the dummy optical waveguides is different from each other in an arrayed optical waveguide region. In a semiconductor optical device having the same, particularly in an arrayed optical waveguide having a small array size, each stripe in the array can be individually controlled. According to the tenth aspect, any or all of the plurality of optical waveguides and the dummy optical waveguide in the semiconductor optical waveguide array change in a curved shape, and the direction of guided light is curved in the substrate plane. In this way, it is possible to change the traveling direction of the light while minimizing the loss in the waveguide of the light, and it is possible to realize an optical element that can be reduced in size. In particular, as in the eleventh aspect, by forming electrodes on any or all of the optical waveguides in the optical waveguide array and injecting current, the array portion can be operated as an active element. Further, claim 1
As described in the invention described in 2, the semiconductor laser array can be manufactured by providing a light reflection mechanism using a diffraction grating near any or all of the optical waveguides in the array, including near the top and bottom. Furthermore, by changing the period of the diffraction grating between the array waveguides, it is possible to manufacture a semiconductor laser array that oscillates at different wavelengths. According to the invention of claims 14 and 15, the semiconductor laser array thus oscillated at different wavelengths is provided with an optical functional region including another array of active elements,
To realize an optical element capable of selecting light of different wavelengths by integrating an optical multiplexing region for multiplexing light emitted from an array-like optical functional region and an optical functional region of a single waveguide. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a plan view (conceptual diagram) of a mask pattern used in the present invention and a cross-sectional view showing a selectively grown layer structure.

FIG. 2 is a plan view of a mask according to the first embodiment of the present invention.

FIG. 3 is a graph showing a PL peak wavelength obtained from an in-array stripe selectively grown on the mask of FIG. 2;

FIG. 4 is a schematic view of a DFB semiconductor laser array according to a second embodiment of the present invention.

FIG. 5 is a plan view of a mask according to a second embodiment of the present invention.

FIG. 6 is a plan view of a mask according to a third embodiment of the present invention.

FIG. 7 is a graph showing a PL peak wavelength obtained from a stripe in an array selectively grown with respect to the mask of FIG. 6;

FIG. 8 is a plan view of a mask of a wavelength selection light source according to a fourth embodiment of the present invention.

9 is a graph showing a PL peak wavelength obtained from a stripe in an array selectively grown with respect to the mask of FIG. 8;

FIG. 10 is a schematic view of a wavelength selection light source according to a fifth embodiment of the present invention.

FIG. 11 is a plan view of a mask according to a fifth embodiment of the present invention.

FIG. 12 is a graph showing a PL peak wavelength of a wavelength selective light source having a semiconductor laser array having a microarray structure according to a fifth embodiment of the present invention.

FIG. 13 is a plan view of a mask of a microarray semiconductor laser in which an EA switch according to a sixth embodiment of the present invention is integrated.

14 is a graph showing a PL peak wavelength obtained from an in-array stripe selectively grown with respect to the mask of FIG. 13;

FIG. 15 is a plan view of a mask of a wavelength selection light source having an unequally spaced DFB-laser array according to a seventh embodiment of the present invention.

FIG. 16 is a schematic view of a microarray semiconductor laser according to the first embodiment of the present invention.

FIG. 17 is a schematic view of a DFB semiconductor laser array according to a third embodiment of the present invention.

FIG. 18 is a schematic view of a wavelength-selective light source according to a fourth embodiment of the present invention.

FIG. 19 is a schematic view of a modulator integrated microarray semiconductor laser according to a sixth embodiment of the present invention.

FIG. 20 is a schematic view of a wavelength-selective light source according to a seventh embodiment of the present invention.

FIG. 21 is a diagram schematically showing a conventional selective growth mask pattern and layers grown in a stripe-shaped growth region thereof.

FIG. 22 is a graph illustrating the dependence of PL wavelength obtained from a stripe-shaped growth region grown on the mask of FIG. 21 on the SiO ₂ mask width.

FIG. 23 is a diagram schematically showing a mask pattern for integrating two different regions and layers grown in the stripe-shaped growth region in the conventional selective growth.

24 is a graph showing a PL wavelength distribution in a stripe longitudinal direction (axial direction) of a PL wavelength obtained from a stripe-shaped growth region grown on the mask of FIG. 23;

FIG. 25 is a view showing a mask pattern according to a conventional technique for obtaining a microarray waveguide by conventional selective growth.

26 is a diagram showing a distribution of PL wavelengths obtained from a stripe-shaped growth region grown at 20 kPa in the pattern of FIG. 25 in which the outer mask width is changed.

FIG. 27 is a diagram showing a mask pattern for producing two different microarray waveguide regions by selective growth in the prior art.

FIG. 28 is a diagram showing a mask pattern according to a conventional technique for obtaining a microarray waveguide by selective growth.

FIG. 29 is a diagram showing a PL wavelength distribution obtained from a stripe growth region grown at 98.6 kPa in the pattern of FIG. 28 in which the outer mask width is changed.

30 is a diagram showing the dependence of the PL wavelength obtained from the stripe growth region grown at 98.6 kPa on the pattern of FIG. 28 in the dummy growth region width.

FIG. 31 is a schematic diagram of diffusion of a source material such as In and Ga when the growth pressure is different. (a) shows the case where the growth pressure is low, and (b) shows the case where the growth pressure is high.

[Explanation of symbols]

1 ... striped growth region 2 ... inner SiO ₂ mask 3,4 ... outside the SiO ₂ mask 5 ... SiO ₂ mask 6 ... dummy growth region 11 ... DFB laser region 12 ... MMI optical multiplexer region 13 ... optical amplifier region 14 ... light Modulator area 15… Window structure area 99… InP substrate

Claims (15)

[Claims] 1. A semiconductor optical waveguide array formed by selectively crystal-growing a semiconductor multilayer structure comprising a quantum well layer or a bulk layer in a stripe-like growth region formed on a semiconductor substrate and sandwiched between dielectric thin films. In the method for manufacturing a semiconductor optical device, in addition to the plurality of stripe-shaped growth regions serving as the semiconductor optical waveguide array, a dummy growth region may be located between the stripe-shaped growth regions and outside the stripe-shaped growth regions or The composition and layer thickness of the semiconductor multilayer structure formed in the stripe growth region are changed by changing the shape of the dummy growth region in the semiconductor optical waveguide array or for each semiconductor optical waveguide array. A method for manufacturing a semiconductor optical device, comprising the steps of: 2. The crystal growth is performed under the condition that a diffusion length of a raw material species in a reaction tube is shorter than a distance between a center and an outermost stripe-shaped growth region constituting the semiconductor optical waveguide array. 2. The method for manufacturing a semiconductor optical device according to claim 1, wherein: 3. The semiconductor formed in the stripe-shaped growth region by forming the dummy growth region in a stripe shape and changing one or both of the width and the position of the dummy growth region at each location. 3. The method according to claim 1, wherein a composition distribution and a layer thickness distribution in an array having a multilayer structure are controlled. 4. The semiconductor multilayer formed in the stripe-shaped growth region by forming the dummy growth region in a rectangular shape and changing a position, a period, and a shape of the dummy growth region at each location. 3. The method according to claim 1, wherein the composition distribution and the layer thickness distribution in the array of the structure are controlled. 5. A method according to claim 1, wherein the outermost two dielectric thin films of the plurality of dielectric thin films have different widths in accordance with a change in the dummy growth region, thereby forming the dielectric thin films in the stripe growth region. 5. The method of manufacturing a semiconductor optical device according to claim 1, wherein the composition distribution and the layer thickness distribution in the array of the semiconductor multilayer structure are controlled. 6. The stripe-shaped growth by making the intervals between the stripe-shaped growth regions constituting the semiconductor optical waveguide array non-uniform and arranging the dummy growth regions in a region where the intervals between the stripe-shaped growth regions are wide. The composition distribution and the layer thickness distribution in an array of the semiconductor multilayer structure formed in a region are controlled.
6. The method for manufacturing a semiconductor optical device according to any one of 4 and 5. 7. The width and interval of the plurality of stripe-shaped growth regions, the position and shape of the dummy growth region, and the width of the outermost two dielectric thin films are set to the length of the stripe. The composition distribution and the layer thickness distribution in the array of the semiconductor multilayer structure formed in the stripe-shaped growth region are varied in the longitudinal direction by changing the distribution in the direction.
7. The method for manufacturing a semiconductor optical device according to any one of 5 and 6. 8. The method of changing the shape of one or all of the plurality of stripe-shaped growth regions, the dummy growth region, and the two outermost dielectric thin films in a curved shape, so that guided light is reduced. 8. The method according to claim 1, wherein the direction is changed in a curved manner in the plane of the substrate. 9. A dummy optical waveguide that does not guide light is formed on a part or all of the semiconductor optical waveguide array,
A semiconductor optical element, wherein the width of the dummy optical waveguide is different from each other. 10. The shape of any or all of the plurality of optical waveguides in the semiconductor optical waveguide array and the dummy optical waveguide changes in a curved shape, and the direction of guided light changes in a curved manner in the substrate plane. The semiconductor optical device according to claim 9, wherein: 11. The semiconductor optical device according to claim 9, wherein an electrode is formed on any or all of the plurality of optical waveguides in the semiconductor optical waveguide array and operates as an active device. 12. A light reflecting mechanism by a diffraction grating is provided near the upper and lower portions of the plurality of optical waveguides in the semiconductor optical waveguide array, and an optical gain is generated by current injection to cause laser oscillation. Item 12. A semiconductor optical device according to item 11. 13. The cycle of a diffraction grating arranged only in the vicinity including upper and lower portions of a plurality of optical waveguides in the semiconductor optical waveguide array, is different for each waveguide in one array. 13. The semiconductor optical device according to item 12. 14. An optical functional area for connecting a plurality of optical waveguides in the semiconductor optical waveguide array to one optical waveguide or an array of optical waveguides having different numbers of arrays is integrated, and the optical functional area is connected to the optical functional area. The part of the output end is connected to a part of the dummy optical waveguide in a plurality of optical waveguides in the semiconductor optical waveguide array. The semiconductor optical device according to any one of the above. 15. The optical function region is an array-like optical function region having the dummy optical waveguide having a waveguide width smaller than an array interval of the semiconductor optical waveguide array. The semiconductor optical waveguide array is connected to an array region including a plurality of semiconductor lasers that oscillate at different wavelengths with the dummy optical waveguide having a waveguide width smaller than the array interval of the semiconductor optical waveguide array. One end is axially connected to and integrated with an optical multiplexer region for multiplexing light emitted from the array-like optical function region and a single waveguide for extracting multiplexed light. 15. The semiconductor optical device according to claim 14, wherein light of different wavelengths can be selected and extracted.