JPH10332967A - Manufacture of optical waveguide with light emitting and receiving element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the manufacturing process and to reduce the manufacturing time and the manufacturing cost by beforehand forming a structure of an optical waveguide successively forming a core part and an upper clad layer on a lower clad layer, and thereafter, forming a recessed part housing a light emitting/receiving element on an area where the light emitting/receiving element is arranged afterward. SOLUTION: First of all, the recessed part 61 in which the core part 32 is housed afterward and the recessed part 62 in which the light emitting/receiving element 33 is housed are formed on an upper surface of glass material 41 constituting the lower clad layer 31. Then, the glass material 42 with a refractive index higher than the glass material 41 is laminated on the part excepting the recessed part 62 in the upper surface of the lower clad layer 31. Then, the laminated glass material 42 is removed remaining the part buried in the recessed part 61, and the core part 32 is formed. Then, the glass material 43 with the refractive index equal to the glass material 41 is laminated on the part excepting the recessed part 62 in the surface formed on the upper surfaces of the lower clad layer 31 and the core part 32, and the upper clad layer 30 is formed. The light emitting/receiving element 33 is fitted to the recessed part 62.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical waveguide having a light emitting element or a light receiving element.

[0002]

2. Description of the Related Art Conventionally, in a process of manufacturing an optical waveguide with a light emitting element or a light receiving element such as a PLC platform, a step of incorporating the light emitting element or the light receiving element on the optical waveguide is performed by a light emitting element or a light receiving element for a core portion of the optical waveguide. Since it is necessary to perform the positioning with high precision, a lot of time is spent, which is one of the factors that increase the manufacturing cost.

FIG. 5 shows an example of a conventional method for incorporating a laser diode on an optical waveguide. First, in order to accurately position the laser diode 33 with respect to the core 32 of the optical waveguide, the index marks 37a and 37b are used.
Are formed on the optical waveguide substrate 38 and the laser diode 33 by photolithography, respectively. next,
While irradiating infrared light from below the optical waveguide substrate 38,
The laser diode 33 is positioned with respect to the core portion 32 of the optical waveguide by aligning the positions of the index marks 37a and 37b with each other by looking through the CCD microscope from above the laser diode 33. Attach.

The above-described conventional method for manufacturing an optical waveguide with a light-emitting element or a light-receiving element requires a large number of steps, is difficult to automate, and is mainly performed by hand. Therefore, it is not suitable for mass production. However, this is time-consuming and increases the manufacturing cost.

[0005] In today's information society, it is required to transmit a large amount of information at high speed and in both directions, and for that purpose, optical communication is indispensable. Also, "Fiber to the Hom
As represented by words such as e "(FTTH), the optical communication network is going to extend to each home. A laser diode or a photodiode is directly incorporated into an optical waveguide which is a key device of the optical communication. A method of manufacturing a base (PLC platform) for hybrid optical integration has been proposed and already commercialized.

FIG. 6 shows an example of the structure of a PLC platform. The lower cladding layer 3 is formed on the optical waveguide substrate 38.
1 and an upper cladding layer 30 are sequentially stacked, and core portions 32a and 32b of the optical waveguide are disposed at an interface between the lower cladding layer 31 and the upper cladding layer 30. Core portions 32a and 32b
The light-emitting element 33 and the light-receiving element 34 are connected to one end, respectively.

As described above, the light emitting element 33 and the light receiving element 3
In the step of directly connecting the light emitting element 4 to the core portions 32a and 32b of the optical waveguide, it is necessary to precisely position the light emitting element 33 and the light receiving element 34 with respect to the core portions 32a and 32b of the optical waveguide. Required many steps. As a result, the optical waveguide with the light emitting and receiving elements becomes an extremely expensive component, and has been a great obstacle to the development of the optical communication network.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the conventional method of manufacturing an optical waveguide having a light emitting element or a light receiving element.
In a method of manufacturing an optical waveguide with a light emitting element or a light receiving element, an object of the present invention is to shorten a manufacturing process and reduce a manufacturing time and a manufacturing cost.

[0009]

According to a method of manufacturing an optical waveguide with a light emitting and receiving element according to the present invention, a core is disposed between a lower cladding layer and an upper cladding layer, and the light emitting and receiving element is mounted on the core. A method for manufacturing a connected optical waveguide with a light emitting and receiving element, comprising: a first concave portion in which a core portion is later housed on an upper surface of a first glass material constituting a lower cladding layer; A first step of forming a second concave portion to be formed, and, among the upper surface of the lower cladding layer, a portion excluding the second concave portion, a second glass material having a higher refractive index than the first glass material. The second step of laminating, the second glass material laminated in the second step, the third portion forming a core portion by removing leaving a portion embedded in the first concave portion Step and the third step, formed on the upper surface of the lower cladding layer and the core part A fourth step of forming an upper clad layer by laminating a third glass material having a refractive index equivalent to that of the first glass material on a portion excluding the second concave portion, of the A fifth step of attaching the light emitting and receiving element to the second concave portion and a sixth step of connecting an attached wiring to the light emitting and receiving element are provided.

Preferably, the formation of the first and second recesses in the first step is performed by heating the first glass material and press-molding using a mold. Alternatively, in the first step, the formation of the first and second concave portions may be performed by grinding, polishing, etching, or a combination thereof.

Preferably, in the second step, the lamination of the second glass material is performed, and the second glass material is laminated.
After heating, it is performed by press-molding using a mold and bonding to the lower clad layer.

The removal of the second glass material in the third step can be performed by grinding, polishing, etching, or a combination thereof. Also, preferably, the lamination of the third glass material in the fourth step,
After the third glass material is heated, the third glass material is press-formed using a mold and bonded to the upper surface of the lower clad layer and the core portion.

In place of the above manufacturing steps,
On the lower cladding layer, except for the region where the light emitting and receiving element is arranged later, after forming the structure of the optical waveguide in which the core portion and the upper cladding layer are formed in order, the light emitting and receiving element is later housed in the region. An optical waveguide with a light emitting and receiving element can be manufactured by forming a concave part to be formed, then attaching the light emitting and receiving element to the concave part, and further connecting an attached wiring to the light emitting and receiving element.

Preferably, the formation of the concave portion is performed by heating the lower clad layer and then press-molding the lower clad layer using a mold. Alternatively, the formation of the recess may be performed by grinding, polishing, etching, or a combination thereof.

In the above description, the light emitting / receiving element means a light emitting element such as a laser diode or a light receiving element such as a photodiode.
According to the method for manufacturing an optical waveguide with a light emitting and receiving element of the present invention,
Unlike the conventional manufacturing method, a step of forming index marks for positioning the light emitting and receiving elements with respect to the core portion of the optical waveguide on the optical waveguide substrate and the light emitting and receiving elements, and a CCD.
As a result of eliminating the step of mounting the light emitting and receiving elements on the optical waveguide substrate while looking through a microscope or the like, the manufacturing process is greatly reduced, and the manufacturing time and cost can be reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the structure of a press forming apparatus for an optical element used in a method of manufacturing an optical waveguide with a light emitting and receiving element according to the present invention will be described. FIG. 4 shows a schematic configuration diagram of a press forming apparatus for this optical element.

A fixed shaft 2 extends downward from an upper portion of the frame 1, and an upper die assembly 4 is attached to a lower end thereof via a heat insulating cylinder 3 made of ceramic. The upper die assembly 4 is attached to a metal die plate 5, a ceramic upper die 6 disposed below the die plate 5, and a lower side of the die plate 5, and supports the upper die 6 from the surroundings. And a fixed die 7 forming a part of the mold.

A driving device 8 is arranged below the frame 1 and a moving shaft 9 is mounted above the driving device 8 via a load detecting device 8b. The moving shaft 9 is
, Extends upward through the intermediate plate 1 a located above, and faces the fixed shaft 2. The driving device 8 incorporates a screw jack, converts the rotational motion of the servomotor 8a into a linear motion thrust, and drives the moving shaft 9 up and down. The speed, position and torque of the moving shaft 9 are controlled in accordance with a program previously input to the control device 28.

A lower mold assembly 11 is attached to the upper end of the moving shaft 9 via a ceramic insulation tube 10. The lower die assembly 11 is a metal die plate 1
2, a lower die 13 made of ceramic disposed on the upper surface of the die plate 12 and a movable die 14 attached to the upper side of the die plate 12 and supporting the lower die 13 from the periphery and forming a part of the die. I have.

A bracket 15 which is moved up and down by a driving device (not shown) is mounted around the fixed shaft 2 so as to be vertically movable. Bracket 1
5, a transparent quartz tube 16 is attached to the lower surface, and the transparent quartz tube 16 is paired with the upper die assembly 4 and the lower die assembly 11 which form a pair.
Surrounds the By bringing the lower end of the transparent quartz tube 16 into contact with the intermediate plate 1a, a molding chamber 17 having airtightness is formed around the upper die assembly 4 and the lower die assembly 11.

An outer cylinder 18 surrounding the transparent quartz tube 16 is mounted on the lower surface of the bracket 15, and a lamp unit 19 is mounted inside the outer cylinder 18. The lamp unit 19 includes an infrared lamp 20, a reflection mirror 21 disposed behind the infrared lamp 20, and a reflection mirror 2.
The upper die assembly 4 and the lower die assembly 11 are configured to be heated from the surroundings.

An inert gas is introduced into the fixed chamber 2, the moving shaft 9 and the bracket 15 into the molding chamber 17, or a gas supply path 23 for cooling the upper mold assembly 4 and the lower mold assembly 11 is provided. 24 and 25 are respectively formed,
An inert gas is supplied to the molding chamber 17 at a predetermined flow rate via a flow rate controller (not shown).
The inert gas supplied to the inside of the molding chamber 17 is exhausted from an exhaust port 26 formed in the intermediate plate 1a. The lower die assembly 11 is provided with a thermocouple 27 for temperature detection.

(Example 1) Next, a method of manufacturing an optical waveguide with a light emitting and receiving element using this press molding apparatus will be described.

FIG. 1 shows the structure of an optical waveguide with light emitting and receiving elements manufactured in the following example. This optical waveguide with a light emitting and receiving element is a PLC platform.
In the figure, 32 indicates a core portion, and 33 indicates a laser diode. A core 32 is formed at the interface between the upper cladding layer 30 and the lower cladding layer 31, and a laser diode 33 is connected to an end of the core 32. The laser diode 33 is connected to an auxiliary wiring 35 for giving a signal from outside.

FIG. 2 shows a manufacturing process of the above-mentioned PLC platform. (A) First step; see FIGS. 2A and 2B First, the lower cladding layer 31 of the optical waveguide is formed. That is,
A glass material 41 having two flat surfaces, for example, BK-7 (manufactured by Sumita Optical Glass Co., Ltd .; refractive index n _d 1.5163, transition point Tg)
553 ° C., yield point At 614 ° C.), and set between the upper die 6a and the lower die 13a of the press forming apparatus (FIG. 4). On the lower surface of the upper mold 6a, a convex portion 51 corresponding to the core portion 32 (FIG. 1) of the optical waveguide, and a laser diode 33
A projection 52 corresponding to (FIG. 1) is formed. on the other hand,
The upper surface of the lower mold 13a is formed as a flat surface.

After the glass material 41 is heated to a temperature equal to or higher than the yield point, the glass material 41 is press-formed using the upper mold 6a and the lower mold 13a. 61 and a concave portion 62 which will be a seat for accommodating the laser diode later are transferred. In this example, the heating temperature is 690 ° C. and the pressing force is 500 kg.
f.

(B) Second step; see FIGS. 2C and 2D Next, the concave portion 61 is filled with a glass material constituting the core portion 32 (FIG. 1). That is, in the first step, the concave 6
On both sides of the glass material 41 on which the laser diodes are housed, a glass material 42 having a flat surface on both sides, for example, KZF2
(Manufactured by Sumita Optical Glass Co., Ltd .; refractive index Nd 1.5294, transition point Tg 445 ° C., sag point At 501 ° C.), and set in a press molding apparatus. Both the upper mold 6b and the lower mold 13b used in this step have a flat molding surface.

The glass material 42 forming the core portion 32 (FIG. 1) has a refractive index higher by about 0.3 to 3% than the glass material 41 forming the lower cladding layer 31, and The transition point is required to be lower than that of the glass material 41 for the purpose of being buried in the concave portion 61 formed in the first step by press molding. The above material KZ
F2 has a refractive index higher by 0.86% than BK-7,
The transition point is 112 ° C lower.

In this state, after the glass material 42 is heated to a temperature equal to or higher than the yield point, the glass material 42 is joined to the lower clad layer 31 by performing press molding using the upper mold 6b and the lower mold 13b. . Thereby, the glass material 42 is buried in the concave portion 61 previously formed in the first step, while the concave portion 62 is left as it is. In this example, the heating temperature is 520 ° C. and the pressing force is 500 kgf.
It is.

(C) Third step: see FIG. 2E Next, the core part 32 is formed. That is, the lower cladding layer 31
The glass material 42 bonded on the substrate is removed by grinding and polishing while leaving only the glass material 42 embedded in the concave portion 61, thereby forming the core portion 32 of the optical waveguide.

(D) Fourth step; see FIGS. 2F and 2G Next, the upper cladding layer 30 (FIG. 1) is formed. That is, the glass material 43, for example, BK-7 (manufactured by Sumita Optical Glass Co., Ltd .; refraction) is formed on the lower clad layer 31 from which the glass material 42 has been removed while leaving the core portion 32 in the previous step, except for the concave portions 62. Rate n _d 1.5163, transition point Tg 553 ° C, yield point A
(t 614 ° C.) and set in a press molding apparatus.
Upper mold 6c and lower mold 13c used in this step
Are both provided with a planar molding surface.

In this state, the upper clad layer 30 is joined to the lower clad layer 31 by heating the glass material 43 to a temperature equal to or higher than the yield point and then performing press molding using the upper mold 6c and the lower mold 13c. You. At this time, the recess 62
Is left as it is. In this example, the heating temperature is 6
At 90 ° C., the pressing force is 500 kgf.

(E) Fifth step; see FIG. 2H Next, a laser diode 33 is attached. That is, the laser diode 33 is mounted in the concave portion 62 formed in the first step, and the laser diode 33 is further mounted.
Is connected to an auxiliary wiring 35 for supplying an electric signal from outside.

Through the above steps, the PLC platform in which the core 32 is arranged between the lower cladding layer 31 and the upper cladding layer 30 and one end of the core 32 is connected to the laser diode 33 is completed.

When the transmission loss of the PLC platform manufactured by using the above method was measured, it was 1.3 μm.
, A measurement result of, for example, 1.5 db / km or less was obtained. This value sufficiently satisfies the specification as a PLC platform. The value of the transmission loss varies depending on the refractive index of the glass material, the amount of absorption in the near infrared region, the surface accuracy of the outer peripheral surface of the core, the surface accuracy of the interface between the light emitting / receiving element and the core, and the like.

In the above example, the lower cladding layer 3
1, the step of forming the concave portions 61 and 62 on the substrate 1, the step of filling the concave portion 61 with the glass material 42 constituting the core portion 32 later, and the step of bonding the upper clad layer 31 to the lower clad layer 31 Is heated and press-molded, but the present invention is not limited to this. For example, the formation of the concave portions 61 and the concave portions 62 in the lower cladding layer 31 may be performed by etching or machining. Further, when the concave portion 61 is filled with the glass material 42 or when the upper clad layer 30 is laminated on the lower clad layer 31, the flame volume method (FHD), the physical vapor deposition method (PV)
D), the glass layer can also be deposited using a method such as chemical vapor deposition (CVD).

Example 2 Another example of the manufacturing process of the PL platform will be described with reference to FIG. The press forming apparatus shown in FIG. 4 is also used in this manufacturing process.

(A) First step; see FIG. 3A First, an optical waveguide structure in which a core 32 is disposed between a lower cladding layer 31 and an upper cladding layer 30 is prepared. That is, after bonding the second glass material to the lower cladding layer 31 made of the first glass material by press molding, the second glass material is processed to form the core portion 32. Next, a third glass material is bonded onto the lower cladding layer 31 on which the core portion 32 is formed by press molding to form an upper cladding layer 30.
To form At this time, of the lower cladding layer 31,
The core portion 32 and the upper cladding layer 30 are formed in a portion other than a region where the laser diode 33 and the connection wiring 35 are arranged in a subsequent process. The end surface 39A and at least one side surface of the lower cladding layer 31 (FIG. 3)
(The back side or the near side in (a)) 39B is the core part 3
It serves as a reference plane for positioning the laser diode 2 and the laser diode 33.

As the second glass material constituting the core portion 32, for example, KZF2 (manufactured by Sumita Optical Glass Co., Ltd .; refractive index Nd 1.5294, transition point Tg 445 ° C., sag point At 501 ° C.) , 31 as the first and third glass materials, for example, BK-
7 (manufactured by Sumita Optical Glass Co., Ltd .; refractive index n _d 1.5163, transition point Tg 553 ° C., yield point At 614 ° C.) can be used.

(B) Second step; see FIGS. 3 (b) and 3 (c) The optical waveguide formed in the previous step is set in a press molding apparatus (FIG. 4). The upper mold 6d used in this step has a convex portion 54 corresponding to the laser diode 33, and the lower mold 13d has a reference surface of the lower cladding layer 31 for positioning the optical waveguide with respect to the lower mold 13d. 39
A, and the projections 56A and 56B corresponding to 39B are provided.

The optical waveguide manufactured by the first step is
When setting on the lower mold 13d, the reference surfaces 39B, 39
B, the protrusions 56A, 56B formed on the lower mold 13d.
Place according to Also, the center axis between the upper and lower molds of the press forming apparatus is adjusted in advance.

In this state, the lower clad layer 31 is heated to a temperature equal to or higher than the yield point and then press-formed using the upper mold 6d and the lower mold 13d, whereby the laser diode 33 is accommodated in the lower clad layer 31. A concave portion 62 serving as a seat is formed. In this example, the pressing temperature is 690 ° C., and the pressing force is 500 kgf.

(C) Third step; see FIG. 3 (d) A laser diode 33 is mounted in the concave portion 62 formed in the previous step. The connection wiring 35 for giving an electric signal is formed.

Through the above steps, a PLC platform in which the core 32 is arranged between the lower cladding layer 31 and the upper cladding layer 30 and one end of the core 32 is connected to the laser diode 33 is completed.

In the above, an example has been described in which an embedded PLC platform is manufactured as an optical waveguide with a light emitting and receiving element. However, the manufacturing method of the present invention is applicable to other types of PLC platforms, such as a strip type and a lens type. It is also applicable to the manufacture of PLC platforms.

In the above, an example in which a laser diode is used as a light emitting element has been described, but the present invention is not limited to this. For example, a light receiving element such as a light emitting diode and a photodiode may be used.

In the above, B is used as the glass material.
Although an example using K-7 and KZF2 has been described,
The glass material is not limited to the above examples as long as the refractive index can be used as an optical waveguide.

[0048]

According to the method of manufacturing an optical waveguide with a light emitting and receiving element of the present invention, the step of positioning the light emitting and receiving element with respect to the core portion, which has been conventionally performed, is eliminated, thereby simplifying the manufacturing process. This has the effect of shortening the manufacturing time and reducing the manufacturing cost.

[Brief description of the drawings]

FIG. 1 shows a PLC manufactured based on the manufacturing method of the present invention.
The figure which shows the structure of a platform, (a) is a top view,
(B) shows a cross-sectional view of the AA section.

FIG. 2 is a view showing an example of a process of manufacturing a PLC platform based on the manufacturing method of the present invention, (a) to (h).
Represents an outline of each step.

FIG. 3 is a diagram showing another example of a process of manufacturing a PLC platform based on the manufacturing method of the present invention, (a) to (d).
(D) shows the outline of each step.

FIG. 4 is a view showing a structure of a press forming apparatus for an optical element used in the manufacturing method of the present invention.

FIG. 5 is a diagram illustrating a conventional method of manufacturing a PLC platform.

FIG. 6 is a diagram showing an example of the structure of a PLC platform.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Frame, 2 ... Fixed shaft, 4 ... Upper mold assembly, 5 ... Die plate, 6 ... Upper mold, 7 ...
Fixed die, 8 ... drive device, 8a ... servo motor, 8b ... load detector, 9 ... moving axis, 11 ...
・ Lower die assembly, 12 ・ ・ ・ die plate, 13 ・ ・ ・
Lower die, 14: moving die, 15: bracket, 1
6 ... transparent quartz tube, 17 ... molding chamber, 19 ... lamp unit, 20 ... infrared lamp, 23, 24,
25 ... gas supply path, 27 ... thermocouple, 28 ...
Control device, 30 ... upper cladding layer, 31 ... lower cladding layer, 32, 32a, 32b ... core part, 33 ...
.Light emitting element (laser diode), 34 ... light receiving element,
35: connection wiring, 37a, 37b: index mark, 38: optical waveguide substrate, 39A, 39B
··Reference plane.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hidetoshi Kitahara 2068-3 Ooka, Numazu-shi, Shizuoka Pref. Toshiba Machine Co., Ltd. Numazu Office

Claims (9)

[Claims] 1. A method of manufacturing an optical waveguide with a light emitting and receiving element, wherein a core is disposed between a lower cladding layer and an upper cladding layer, and a light emitting and receiving element is connected to the core. A first step of forming a first recess in which a core portion is later housed, and a second recess in which a light emitting and receiving element is later housed, on the upper surface of the first glass material constituting the layer, Of the upper surface of the part except the second recess,
A second step of laminating a second glass material having a higher refractive index than the first glass material, and embedding the second glass material laminated in the second step in the first recess. A third step of forming a core portion by removing the remaining portion, of the surface formed on the upper surface of the lower cladding layer and the core portion in the third step, except for the second concave portion A fourth step of laminating a third glass material having a refractive index equivalent to that of the first glass material to form an upper cladding layer, and a fifth step of attaching the light emitting and receiving element to the second concave portion And a sixth step of connecting an attached wiring to the light emitting and receiving element. A method for manufacturing an optical waveguide with a light emitting and receiving element, comprising: 2. The method according to claim 1, wherein in the first step, the first and second recesses are formed by heating the first glass material and then press-molding the first glass material using a mold. The method for manufacturing an optical waveguide with a light emitting and receiving element according to claim 1. 3. The light emitting and receiving device according to claim 1, wherein in the first step, the formation of the first and second concave portions is performed by grinding, polishing, etching, or a combination thereof. A method for manufacturing an optical waveguide with an element. 4. In the second step, the second glass material is laminated by heating the second glass material, press-forming using a mold, and bonding the second glass material to the lower cladding layer. The method according to claim 1, wherein the method is performed. 5. The device according to claim 1, wherein in the third step, the removal of the second glass material is performed by grinding, polishing, etching, or a combination thereof. Manufacturing method of optical waveguide. 6. The step of laminating the third glass material in the fourth step, wherein the third glass material is heated and then pressed using a mold to form the lower clad layer and the core portion. The method for producing an optical waveguide with a light emitting and receiving element according to claim 1, wherein the method is performed by bonding to an upper surface. 7. A method of manufacturing an optical waveguide with a light emitting and receiving element, wherein a core is disposed between an upper cladding layer and a lower cladding layer, and the light emitting and receiving element is connected to the core. A first step of sequentially forming a core portion and an upper clad layer on the layer, excluding a region where the light emitting and receiving element is arranged later, and forming a concave portion in which the light emitting and receiving element is to be housed later in the region An optical waveguide with a light emitting and receiving element, comprising: a second step, a third step of attaching a light emitting and receiving element to the recess, and a fourth step of connecting an attached wiring to the light emitting and receiving element. Manufacturing method. 8. In the second step, the formation of the concave portion includes:
The method for producing an optical waveguide with a light emitting and receiving element according to claim 7, wherein the lower clad layer is formed by press molding using a mold after heating. 9. In the second step, the formation of the concave portion
The method according to claim 7, wherein the method is performed by grinding, polishing, etching, or a combination thereof.