JP5144498B2 - Single fiber bidirectional optical transceiver module and manufacturing method thereof - Google Patents

Description

The present invention relates to a single-fiber bidirectional optical transmission / reception module mounted as an optical transmission / reception function unit in an optical signal transmission / reception terminal device, which is a component of an optical communication network, and a method for manufacturing the same.

  2. Description of the Related Art Conventionally, an optical transceiver module called a BIDI (bi-directional) type has been used in a single-fiber bidirectional optical transceiver module that transmits optical signals of two different wavelengths for transmission and reception using a single optical fiber. (For example, refer nonpatent literature 1). The configuration of this BIDI type module is shown in FIG.

  As shown in FIG. 23, in the BIDI type module, a transmission TO (transistor outline) -CAN 101 equipped with a laser diode 112, a reception TO-CAN 102 equipped with a photodiode 122, and an optical fiber 141 are connected to a WDM filter 103. Is aligned and fixed to the BIDI housing 100 in which is incorporated. The transmission TO-CAN 101 and the optical fiber 141 are fixed to the mutually facing end surfaces of the BIDI housing 100, and the reception TO-CAN 102 is fixed to a surface orthogonal to the end surface to which the transmission TO-CAN 101 and the optical fiber 141 are fixed. Has been. Note that the TO-CAN is a cylindrical metal housing that houses circuit elements, and the TO-CANs 101 and 102 shown in FIG. 23 have a built-in lens.

Specifically, the transmission TO-CAN 101 includes a monitor photodiode 113 and a laser diode 112 mounted on a stem 111 and is sealed with a lens cap 114. The receiving TO-CAN 102 has a receiving IC 123 mounted on a stem 121 together with a photodiode 122 and sealed with a lens cap 124. The optical signal travels in the direction indicated by the solid line when transmitting, and proceeds in the direction indicated by the broken line when receiving the optical signal. Therefore, in the BIDI type module, an expensive active alignment process is required at least twice.
"Optical devices for PON (E-PON, B-PON, GE-PON)", [online], January 2004, Fujitsu Limited, [March 2006 search], Internet <URL: http: // telecom.fujitsu.com/jp/products/device/pdf/pon_bidi_i.pdf> H. Tanaka et.al, IEEE Photonics Technology Letters, Vol. 10, No. 3, 1998 Y. Kuhara et.al, Journal of Lightwave Technology, Vol.16, No.2, 1998 HLAlthaus et.al, IEEE Trans.On Components, Packaging, and Manufacturing Technology part B, Vol.21, No.2, 1998 H. Yoon et.al, IEEE Photonics Technology Letters, Vol. 16, No. 8, 2004

  As shown in FIG. 23, in the conventional BIDI type module, since the transmission TO-CAN 101 and the reception TO-CAN 102 are independent, at least two active alignment processes are indispensable between the optical fibers. is there. Furthermore, the number of parts is large, such as the need for the BIDI casing 100 in addition to the two TO-CAN casings 101 and 102, and cost reduction and miniaturization are difficult.

  On the other hand, in recent years, various technical attempts have been proposed to reduce the cost by integrating the functions of the BIDI type module into one TO-CAN. Non-patent documents 2, 3, 4, and 5 are given as typical examples.

  Non-Patent Document 2 proposes a configuration in which a half mirror is provided on the surface of a receiving photodiode, 50% of the transmitted light emitted from the laser diode is reflected by this half mirror, and is coupled to an optical fiber via a rod lens. doing. In this configuration, since the optical path between the laser diode and the optical fiber passes through the half mirror on the photodiode, it is possible to realize alignment between the laser diode and the optical fiber and between the photodiode and the optical fiber by one active alignment. There is. On the other hand, this configuration has the following drawbacks and is not suitable for application to an access optical communication system.

1) Since a half mirror is used and about 50% of the transmitted light is incident on the photodiode at the time of signal transmission, it is impossible to receive a signal transmitted from another place at the time of signal transmission. Therefore, it cannot be applied to communication systems such as GE-PON that are currently popular.
2) Since the half mirror reflects about 50% of the optical signal sent from other places, 3 dB degradation in reception sensitivity is unavoidable in principle.

  Non-Patent Document 3 proposes to use a translucent photodiode (HT-PD) instead of the photodiode with half mirror of Non-Patent Document 2. This proposal also has the same advantages and disadvantages as document 2, and is unsuitable for application to an actual system.

  Non-Patent Document 4 proposes a configuration in which a Si substrate processed with high accuracy using a photo process is used for a support such as a laser diode, a photodiode, a filter, or a lens. In this configuration, the high processing accuracy of the support and the high-precision mounting of the components aim to reduce the cost by optical path alignment using only inexpensive passive alignment. However, the component mounting accuracy required by this proposal is ± 2 μm or less, and it is extremely difficult to realize such high accuracy during mass production. In fact, even now, eight years after the proposal of Document 4, no mass-produced product based on this proposal has been made.

  Non-Patent Document 5 proposes that the BIDI housing is made smaller and mounted inside the TO-CAN. In this proposal, in order to reduce the size of the BIDI housing, a metal BIDI housing is not used, and a lens and a filter are fixed on the ceramic plate with an adhesive. However, when a spherical lens is fixed on a flat ceramic plate with an adhesive, the ceramic plate and the lens are in point contact, so high adhesive strength cannot be expected, and reliability sufficient to withstand practical use. It is difficult to secure. In addition, a cost reduction effect cannot be expected, for example, the number of lenses used is three, which is larger than that of the BIDI module. Furthermore, Non-Patent Document 5, unlike Non-Patent Documents 2, 3, and 4, provides technical support for overlapping a part of two optical paths between a laser diode and an optical fiber and between a photodiode and an optical fiber. No. An engineer who is familiar with the processing precision of actual photodiodes, laser diodes, ceramic substrates, ball lenses, filters, etc., can determine that it is difficult to realize the structure of Non-Patent Document 5 from a technical standpoint.

  As described above, in the conventional technical proposal and invention for integrating the functions of the BIDI type modules as described in Non-Patent Documents 2 to 5 in one TO-CAN, the laser is manufactured while suppressing the cost and the manufacturing time. It has been difficult to match a part of the optical path between the diode and the optical fiber and between the photodiode and the optical fiber with a high yield. Therefore, BIDI type modules are still widely distributed.

  From the above, a simple passive alignment method for matching the optical path between the laser diode and the optical fiber and the optical path between the photodiode and the optical fiber (hereinafter, in order to avoid confusion with other passive alignment methods, It is considered that a novel CAN type transmission / reception module can be realized by solving the problems of the BIDI type and the conventional CAN type transmission / reception module described above.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a single-fiber bidirectional optical transmission / reception module that has a low number of parts and manufacturing steps and is low in cost.

According to a first aspect of the present invention for solving the above-described problem, a single-fiber bidirectional optical transceiver module according to the present invention has a lens cap having a light transmitting portion made of a condensing lens fixed to a cylindrical or columnar metal member. A semiconductor optical transmission element, an optical signal receiving element, and at least one wavelength selection filter are mounted inside the storage body, and one optical fiber is attached to the outside of the storage body. In the single-fiber bidirectional optical transceiver module having the configuration, an emission end face of a resonator of the semiconductor optical transmission element or an emission end face of the semiconductor optical transmission element has a shape capable of specifying an emission position of laser light, and the semiconductor optical transmission element The difference between the optical path length from the emission end surface to the optical fiber and the optical path length from the light receiving surface of the optical signal receiving element to the optical fiber is small, and the semiconductor optical transmission element The optical signal receiving element and the wavelength selection filter have different supports so that the optical path between the semiconductor optical transmitting element and the optical fiber partially overlaps with the optical path between the optical signal receiving element and the optical fiber. A method of manufacturing a single-fiber bidirectional optical transceiver module fixed to the metal member via
When the semiconductor optical transmission element, the optical signal receiving element and the wavelength selection filter fixed to the support are fixed to the metal member, the support and the optical signal transmission element to which the optical signal receiving element is fixed After fixing the support body fixed to the metal member, the support body to which the wavelength selection filter is fixed is reflected through the wavelength selection filter and the reflection image of the emission end face of the semiconductor optical transmission element, The transmission image of the light receiving surface of the optical signal receiving element transmitted through the wavelength selection filter is arranged so as to be simultaneously focused at the observation position, and the reflected image of the emission end surface and the transmission image of the light receiving surface The support to which the wavelength selection filter is fixed is fixed to the metal member at a position where the two overlap each other.

According to a second aspect of the present invention for solving the above-described problem, a single-fiber bidirectional optical transceiver module according to the present invention has a lens cap having a light transmitting portion made of a condensing lens fixed to a cylindrical or columnar metal member. A semiconductor optical transmission element, an optical signal receiving element, and at least one wavelength selection filter are mounted inside the storage body, and one optical fiber is attached to the outside of the storage body. In the single-fiber bidirectional optical transceiver module having the configuration, an emission end face of a resonator of the semiconductor optical transmission element or an emission end face of the semiconductor optical transmission element has a shape capable of specifying an emission position of laser light, and the semiconductor optical transmission element The difference between the optical path length from the emission end surface to the optical fiber and the optical path length from the light receiving surface of the optical signal receiving element to the optical fiber is small, and the semiconductor optical transmission element The optical signal receiving element and the wavelength selecting filter are arranged so that an optical path between the semiconductor optical transmitting element and the optical fiber and an optical path between the optical signal receiving element and the optical fiber partially overlap, and the semiconductor optical Manufactures a single-fiber bidirectional optical transceiver module in which a transmitting element and the optical signal receiving element are fixed to the metal member via a common support, and the wavelength selection filter is fixed to the metal member via another support A way to
When the semiconductor optical transmitting element, the optical signal receiving element, and the wavelength selection filter fixed to the support are fixed to the metal member, the semiconductor optical transmitting element and the optical signal receiving element are fixed. After fixing the wavelength selective filter to the metal member, the support on which the wavelength selective filter is fixed is reflected on the reflection image of the emission end face of the semiconductor optical transmission element observed through the wavelength selective filter and through the wavelength selective filter. The transmission image of the light receiving surface of the optical signal receiving element that is transmitted through is arranged so as to be focused at the same time at the observation position, and the wavelength at the position where the reflected image of the emission end surface and the transmission image of the light receiving surface overlap. A support to which the sorting filter is fixed is fixed to the metal member.

According to a third aspect of the present invention for solving the above problems, a single-fiber bidirectional optical transceiver module according to the present invention has a lens cap having a light transmitting portion made of a condensing lens fixed to a cylindrical or columnar metal member. A semiconductor optical transmission element, an optical signal receiving element, and at least one wavelength selection filter are mounted inside the storage body, and one optical fiber is attached to the outside of the storage body. In the single-fiber bidirectional optical transceiver module having the configuration, an emission end face of a resonator of the semiconductor optical transmission element or an emission end face of the semiconductor optical transmission element has a shape capable of specifying an emission position of laser light, and the semiconductor optical transmission element The difference between the optical path length from the emission end surface to the optical fiber and the optical path length from the light receiving surface of the optical signal receiving element to the optical fiber is small, and the semiconductor optical transmission element The optical signal receiving element and the wavelength selecting filter are arranged so that an optical path between the semiconductor optical transmitting element and the optical fiber and an optical path between the optical signal receiving element and the optical fiber partially overlap, and the semiconductor optical Manufacturing a single-fiber bidirectional optical transceiver module in which a transmitting element and the wavelength selection filter are fixed to the metal member via a common support, and the optical signal receiving element is fixed to the metal member via another support A way to
When the semiconductor optical transmission element, the optical signal receiving element and the wavelength selection filter fixed to the support are fixed to the metal member, the support to which the optical signal receiving element is fixed is fixed to the metal member. After that, the support on which the semiconductor optical transmission element and the wavelength selection filter are fixed is reflected on the reflection image of the emission end face of the semiconductor optical transmission element observed through the wavelength selection filter and through the wavelength selection filter. The transmission image of the light receiving surface of the optical signal receiving element that is transmitted through is arranged so as to be focused at the same time at the observation position, and the semiconductor at the position where the reflection image of the emission end surface and the transmission image of the light receiving surface overlap. A support on which an optical transmission element and the wavelength selection filter are fixed is fixed to the metal member.

According to a fourth aspect of the present invention for solving the above-described problem, a single-fiber bidirectional optical transceiver module according to the present invention has a lens cap having a light transmitting portion made of a condensing lens fixed to a cylindrical or columnar metal member. A semiconductor optical transmission element, an optical signal receiving element, and at least one wavelength selection filter are mounted inside the storage body, and one optical fiber is attached to the outside of the storage body. In the single-fiber bidirectional optical transceiver module having the configuration, an emission end face of a resonator of the semiconductor optical transmission element or an emission end face of the semiconductor optical transmission element has a shape capable of specifying an emission position of laser light, and the semiconductor optical transmission element The difference between the optical path length from the emission end surface to the optical fiber and the optical path length from the light receiving surface of the optical signal receiving element to the optical fiber is small, and the semiconductor optical transmission element The optical signal receiving element and the wavelength selecting filter are arranged so that an optical path between the semiconductor optical transmitting element and the optical fiber and an optical path between the optical signal receiving element and the optical fiber partially overlap, and the wavelength selecting Manufactures a single-fiber bidirectional optical transceiver module in which a filter and the optical signal receiving element are fixed to the metal member via a common support, and the semiconductor optical transmission element is fixed to the metal member via another support A way to
When the semiconductor optical transmission element, the optical signal receiving element, and the wavelength selection filter fixed to the support are fixed to the metal member, the support to which the optical signal reception element and the wavelength selection filter are fixed is provided. A transmission image of the emission end face of the semiconductor optical transmission element observed through the wavelength selection filter and a reflection image of the light receiving surface of the optical signal reception element observed through the wavelength selection filter The optical signal receiving element and the support for fixing the wavelength selection filter are fixed to the metal member at a position where the transmission image of the emission end surface and the reflection image of the light receiving surface overlap each other. It is characterized by doing.

A method for manufacturing a single-fiber bidirectional optical transceiver module according to claim 5 of the present invention for solving the above-described problems is a method for manufacturing a single-fiber bidirectional optical transceiver module according to any one of claims 1 to 4. The transmission image of the wavelength selection filter has a transmittance of 10% or more and 90% for the reflection image of the emission end surface and the transmission image of the light receiving surface or the transmission image of the emission end surface and the reflection image of the light reception surface. It is the image by the light of the common visible region which becomes the following, It is characterized by the above-mentioned.

As described above, “the difference between the optical path length from the emitting end face of the semiconductor optical transmission element to the optical fiber and the optical path length from the light receiving surface of the optical signal receiving element to the optical fiber is small”. Means that the difference D between the optical path length from the emitting end surface of the semiconductor optical transmission element to the optical fiber and the optical path length from the light receiving surface of the optical signal receiving element to the optical fiber is within a range satisfying the following inequality.
D <d ÷ NA (1)
Here, d is the diameter of the light receiving surface of the optical signal receiving element to be used, and NA is the numerical aperture of the condensing lens to be used.

  By using the single fiber bidirectional optical transceiver module according to the present invention, the optical signal transmission / reception function of the BIDI module can be easily integrated in one storage body. Since the function of the BIDI type module can be mounted on one storage body, the number of parts can be reduced by about 30% compared to the BIDI type.

  Further, according to the method for manufacturing a single-fiber bidirectional optical transceiver module according to the present invention, an optical path between a semiconductor optical transmission element such as a laser diode and an optical fiber, and an optical path between an optical signal receiving element such as a photodiode and an optical fiber are provided. Since they can be easily overlapped, the processing and mounting accuracy of the semiconductor optical transmission element, the optical signal receiving element, and their supports can be relaxed. And since the optical path between the semiconductor optical transmission element and the optical fiber can be easily matched with the optical path between the optical signal receiving element and the optical fiber, the number of active alignments can be reduced to one.

  As a result, the manufacturing yield is improved, and the cost reduction of the optical module is further promoted together with the effect of reducing the number of parts and man-hours.

It is the schematic which shows the single fiber bidirectional optical transmission / reception module in embodiment of this invention. FIG. 2A is a schematic diagram showing an observation optical path in the embodiment of the present invention, and FIG. 2B is a schematic diagram showing a WDM filter surface in the embodiment of the present invention. It is a schematic diagram which shows the alignment method by the movement of the WDM filter in embodiment of this invention. It is a schematic diagram which shows the example of laser diode mounting in Example 1 of this invention. It is a schematic diagram which shows the example of receiving part preparation in Example 1 of this invention. It is a schematic diagram which shows the example of the WDM filter center alignment fixation in Example 1 of this invention. It is a schematic diagram which shows the example of sealing by the cap with a lens in Example 1 of this invention, and optical fiber alignment fixing. It is a graph which shows the code error rate characteristic by the optical transmission / reception module which concerns on Example 1 of this invention. It is a graph which shows the laser diode transmission signal waveform by the optical transmission / reception module which concerns on Example 1 of this invention. It is a schematic diagram which shows the example of laser diode carrier preparation in Example 2 of this invention. It is a schematic diagram which shows the example of receiving part preparation in Example 2 of this invention. It is a schematic diagram which shows the example of the WDM filter center alignment fixation in Example 2 of this invention. It is a schematic diagram which shows the example of sealing by the cap with a lens in Example 2 of this invention, and optical fiber alignment fixing. It is a schematic diagram which shows the example of subcarrier preparation in Example 3 of this invention. It is a schematic diagram which shows the example of laser diode mounting in Example 3 of this invention. It is a schematic diagram which shows the example of the WDM filter center alignment fixation in Example 3 of this invention. It is a schematic diagram which shows the example of sealing by the cap with a lens in Example 3 of this invention, and optical fiber alignment fixing. It is a schematic diagram which shows the example of subcarrier preparation in Example 4 of this invention. It is a schematic diagram which shows the example of component mounting in Example 4 of this invention. It is a schematic diagram which shows the example of the WDM filter center alignment fixation in Example 4 of this invention. It is a schematic diagram which shows the example of sealing by the cap with a lens in Example 4 of this invention, and optical fiber alignment fixing. It is the figure which showed an example of the light transmission characteristic of the WDM filter in Example 5 of this invention. It is a schematic diagram which shows the structure of the conventional BIDI type | mold module.

Explanation of symbols

The symbols used in the drawings are as follows. DESCRIPTION OF SYMBOLS 1 Laser diode element, 2 Photodiode element, 2a Photodiode light-receiving part, 3 WDM filter, 4 Laser diode subcarrier (support body), 5 Photodiode subcarrier (support body), 6 Filter subcarrier (support body), 7 Stem, 9-pin terminal, 10-pin terminal, 12 wire bond, 13 monitor photodiode, 14 receiver IC, 15 chip capacitor, 17 lens cap, 21 pigtail fiber, 22 subcarrier, 22a V groove, 23 surface emitting type Laser diode, 24 subcarrier (support), 41 Reflected image of laser diode end face, 42 Transmitted image of photodiode light receiving part, 43 Reflected image of surface emitting laser diode 44 Reflected image of surface emitting laser diode

  In the embodiment of the present invention, a single semiconductor optical transmission element is provided inside a package as a storage body in which a lens cap having a light transmission portion made of a condensing lens is fixed to a stem as a cylindrical metal member. A laser diode, a photodiode as an optical signal receiving element, and at least one WDM filter as a wavelength selection filter are mounted, and one optical fiber is attached to the outside of the package. That is, a package structure (One-Can type) in which an optical signal transmission / reception function can be easily integrated in one package and a manufacturing method thereof.

  The end face of the resonator of the laser diode has a shape that can specify the emission position of the laser beam, the optical path length from the emission end face of the laser diode to the optical fiber, and the optical path length from the light receiving face of the photodiode to the optical fiber, Is small, that is, within the range of the value D that satisfies the above-mentioned equation (1), the filter transmission image transmitted through the WDM filter of the photodiode light receiving unit and the reflection image of the laser diode light emitting unit are simultaneously obtained. I can observe. The laser diode, the photodiode, and the WDM filter are arranged so that the optical path between the laser diode and the optical fiber and the optical path between the photodiode and the optical fiber partially overlap.

  An outline of an example of visual alignment that is important in the present embodiment will be described based on FIGS. Here, a case where the laser diode 1 and the photodiode 2 are first fixed on the stem 7 which is a cylindrical metal member via the respective subcarriers 4 and 5 and then the WDM filter 3 is fixed will be described as an example. . In FIGS. 1 to 3, the stem 7 is formed of a cylindrical metal member, but may be a columnar metal member.

  As shown in FIG. 1, after fixing the laser diode 1 and the photodiode 2, a subcarrier 6 on which the WDM filter 3 is mounted is inserted into the space between the laser diode 1 and the photodiode 2 as indicated by an arrow.

  At this time, the reflected image 41 of the end face of the laser diode 1 as shown in FIG. 2B can be observed through the WDM filter 3 through the observation optical path 31 shown in FIG. At this time, if the laser diode 1 has an optical waveguide structure with an uneven surface such as a ridge or mesa resonator, the emission position of the laser diode light surrounded by a broken line in FIG. Can be confirmed accurately. Note that the reflected image 41 shown in FIG. 2B shows an example of a ridge waveguide. Although FIG. 2 shows an example in which the reflection image 41 of the emission end face of the resonator of the laser diode 1 is reflected on the WDM filter 3, for example, a surface emitting laser diode is applied instead of the laser diode 1. Alternatively, the reflected image of the emission end face of the laser diode may be observed.

  Further, an optical design is made so that the difference D between the optical path length from the stereomicroscope or CCD camera 11 to the photodiode 2 and the observation optical path 31 length shown in FIG. 2A is 0.5 mm or less, and FIG. When the filter subcarrier 6 is moved to the photodiode 2 side as shown in b), the filter is transmitted through the WDM filter 3 of the photodiode light receiving portion 2a as the light receiving surface of the optical signal receiving element as shown in FIG. The image 42 and the reflected image 41 of the light emitting part of the laser diode 1 can be observed simultaneously. Then, by superimposing these two images 41 and 42, the optical path between the laser diode 1 and the optical fiber and the optical path between the photodiode 2 and the optical fiber coincide with each other.

  As described above, in the visual alignment in the present embodiment, the reflected image 41 of the light emitting portion of the laser diode 1 and the filter transmission image 42 of the photodiode light receiving portion 2a can be aligned while directly observing. 1. Regardless of the mounting accuracy of the photodiode 2, the optical path alignment between the laser diode 1 and the photodiode 2 can be easily performed with a yield of almost 100%. In this embodiment, an example in which a general optical system material is used is shown.

  As described above, according to the present embodiment, optical path alignment between a laser diode and a photodiode can be performed regardless of member accuracy and chip mounting accuracy. The condition necessary for performing this visual alignment is that the laser diode 1 has an uneven optical waveguide structure that can specify the light emission position on the cavity end face, for example, an edge emitting laser diode or surface having a ridge or mesa type waveguide structure. There are only two, that is, having a light emitting laser diode (VCSEL) and that the reflected image 41 of the end face of the laser diode 1 and the transmitted image 42 of the photodiode light receiving unit 2a are simultaneously focused.

  Of the above two conditions, the cavity end face structure of the laser diode 1 may be selected from a ridge-processed type laser diode chip, and there is no particular problem. On the other hand, in order to achieve both focus, that is, to simultaneously focus the reflected image 41 on the end face of the laser diode 1 and the transmitted image 42 of the photodiode light receiving unit 2a, the optical path length from the surface of the WDM filter 3 to the surface of the laser diode 1 and the WDM filter 3 The difference D from the optical path length from the surface to the photodiode 2 is within a range satisfying the inequality shown in the above (1), for example, 0.5 mm or less if a general optical system material is used. In accordance with the optical system material or the like, an optical design is performed in which the filter transmission image 42 transmitted through the WDM filter 3 of the photodiode light receiving unit 2a and the reflection image 41 of the light emitting unit of the laser diode 1 are set to values that can be observed simultaneously. And Thereby, it is possible to make a part of the optical path between the laser diode 1 and the optical fiber coincide with a part of the optical path between the photodiode 2 and the optical fiber.

  In addition, as the optical waveguide structure having an unevenness capable of specifying the light emission position on the resonator end face of the laser diode 1 described above, it is a buried waveguide type, and a laser in which a ridge or a mesa is additionally processed for the purpose of reducing the capacity or the like A diode is also included.

  According to the single-fiber bidirectional optical transceiver module and the manufacturing method thereof according to the present embodiment, by using the visual alignment method, the optical path between the laser diode 1 and the optical fiber and the optical path between the photodiode 2 and the optical fiber are overlapped. The required processing accuracy and mounting accuracy of the laser diode 1, the photodiode 2 and their subcarriers 3 and 4 can be relaxed. As a result, the manufacturing yield is improved, and the cost reduction of the optical module is further promoted together with the downsizing of the optical module due to the effect of reducing the number of parts and man-hours.

  Thus, the difference from the inventions described in Non-Patent Documents 2 to 5 described above is that the optical design is made by quantitatively taking in the optical path length difference between the laser diode 1 side and the photodiode 2 side.

  The first embodiment of the present invention will be described below by taking specific embodiments as examples. Note that this embodiment is an example showing the effects of the present invention, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

  In this embodiment, a ridge waveguide type FP-laser diode having an oscillation wavelength of 1310 nm is used as the laser diode, and an InGaAs-type pin photodiode (hereinafter simply referred to as a photodiode) having a light receiving diameter of 80 μm is used as the receiving element. Embodiments and effects will be described by taking as an example the case where a laser diode as a semiconductor optical transmission element, a photodiode as an optical signal reception element, and a WDM filter as a wavelength selection filter are fixed on different subcarriers.

  In this embodiment, the optical path length from the WDM filter to the photodiode is designed to be 0.65 ± 0.1 mm, and the optical path length from the WDM filter to the laser diode is designed to be 0.6 ± 0.1 mm (maximum Optical path length difference: 0.25 mm).

  The assembly process of the optical transmission module in the present embodiment is shown in FIGS.

1. As shown in FIG. 4, first, the laser diode 1 and the laser diode output monitoring photodiode (hereinafter referred to as monitoring photodiode) 13 are fixed onto the stem 7 via the laser diode subcarrier 4 by gold tin solder. . The laser diode 1 is mounted by an automatic mounting machine, and the mounting accuracy may be within a circle having a radius of 100 μm centered on a specified coordinate on the stem 7, and the accuracy can be satisfied with a yield of almost 100%. Next, the laser diode 1 and the monitoring photodiode 13 are connected to the pin terminal 10 on the stem 7 by a wire bond 12.

2. As shown in FIG. 5, the photodiode 2 is fixed to the stem 7 to which the laser diode 1 and the like are fixed by gold tin solder via the photodiode subcarrier 5. The photodiode 2 is mounted by specifying coordinates with reference to the stripe electrode of the laser diode 1 already mounted by an automatic mounting machine, and gold-tin solder is used for fixing. The mounting accuracy of the photodiode 2 is within ± 25 μm with a yield of 99% or more with respect to the stripe of the laser diode 1. Next, a reception IC (transimpedance-amplifier: TIA) 14 and a chip capacitor 15 for cutting power supply noise are mounted by an automatic mounting machine, fixed with an adhesive, and connected between the pin terminal 9 and the reception IC 14. Necessary terminals are connected by wire bonds 12.

3. As shown in FIG. 6, the WDM filter 3 is fixed to the filter subcarrier 6 with an adhesive. After fixing, the filter subcarrier 6 is inserted into the space between the laser diode 1 and the photodiode 2 and aligned by the visual alignment shown in FIGS. After alignment, the WDM filter 3 is fixed together with the filter subcarrier 6 on the stem 7 by YAG welding 16. By this process, a laser diode side optical path 32 that is an optical path between the laser diode 1 and the optical fiber 21 (see FIG. 7) and a photodiode side optical path 33 that is an optical path between the photodiode 2 and the optical fiber 21 are partially shared. The common optical path 34 is provided, and superposition can be realized.

4). Lens Cap Sealing and Fiber Alignment As shown in FIG. 7, a lens cap 17 is placed on the stem 7 on which all components have been mounted and fixed by resistance welding. At this time, the lens 17a used may be an aspherical lens or a ball lens. Next, a sleeve 19 containing a 1.55 μm cut filter 18 is placed on the lens cap 17 and fixed by welding 16 using a YAG laser. Further, the laser diode 1 is energized to emit light, the pigtail fiber 21 covered with the fiber collar 20 is actively aligned, and the fiber collar 20 is welded and fixed 16 to the sleeve 19 with a YAG laser.

5. Transmission / Reception Characteristics FIG. 8 and FIG. 9 show the reception characteristics (symbol error rate characteristics) and transmission waveforms by the transmission / reception module manufactured by the above steps, respectively. The light receiving sensitivity was −28.7 dBm even when operated simultaneously with the laser diode, which satisfied the high speed passive optical network (HSPON) standard. As shown in FIG. 9, the transmission waveform passes a mask test of a high-speed optical LAN (Local Area Network) which is one of LAN communication standards. From the above results, it is clear that the optical transceiver module according to the present embodiment has a commercial level performance.

  The second embodiment of the present invention will be described below by taking a specific embodiment as an example. In this embodiment, a buried waveguide type DFB-laser diode having an oscillation wavelength of 1310 nm ridge processing is used as a laser diode, and a photodiode having a light receiving diameter of 60 μm is used as an optical signal receiving element. Embodiments and effects will be described with reference to an example in which the photodiode is fixed on the same subcarrier and the photodiode is fixed on another subcarrier.

  In this embodiment, the optical path length from the WDM filter to the photodiode is designed to be 0.55 ± 0.1 mm, and the optical path length from the WDM filter to the laser diode is designed to be 0.55 ± 0.1 mm (maximum optical path length). Difference: 0.2 mm).

  The assembly process of the optical transceiver module of this embodiment is shown in FIGS. Hereinafter, the same members as those illustrated in FIGS. 1 to 7 and described above will be described using the same reference numerals.

1. Fabrication of Laser Diode Subcarrier As shown in FIG. 10, first, the laser diode 1 and the monitoring photodiode 13 are fixed on the subcarrier 22 with gold-tin solder. The laser diode 1 is mounted by an automatic mounting machine, and the mounting accuracy can be mounted with a yield of almost 100% within ± 50 μm with respect to the designated coordinates on the subcarrier 22. Thereafter, the WDM filter 3 is inserted into the V-groove portion 22a of the subcarrier 22 and fixed with an adhesive.

2. Production of Receiving Unit As shown in FIG. 11, the photodiode 2 is fixed on the stem 7 through the photodiode subcarrier 5 by gold tin solder. The photodiode 2 is mounted by an automatic mounting machine, and the mounting accuracy may be within a circle having a radius of 100 μm centered on the designated coordinates on the stem 7, and this accuracy can be achieved with a yield of almost 100%. Next, the receiving IC 14 and the power source noise cutting chip capacitor 15 are mounted by an automatic mounting machine, and fixed using an adhesive. Finally, the terminals that need to be electrically connected are connected by wire bonds.

3. Laser diode subcarrier alignment fixing As shown in FIG. 12, the laser diode 1, the monitoring photodiode 13 and the subcarrier 22 on which the WDM filter 3 is mounted are aligned by the visual alignment shown in FIGS. And fix with gold tin solder. Through the above alignment process, a partial overlap of the optical path between the laser diode 1-optical fiber 21 (see FIG. 13) and the photodiode 2-optical fiber 21 can be realized.

4). Lens Cap Sealing and Optical Fiber Alignment Fixing As shown in FIG. 13, a lens cap 17 is placed on the stem 7 on which all components have been mounted and fixed by resistance welding. At this time, the lens 17a used may be an aspherical lens or a ball lens. Next, a sleeve 19 containing a 1.55 μm cut filter 18 is placed on the lens cap 17 and fixed by welding with a YAG laser. Further, the laser diode 1 is energized to emit light, the pigtail fiber 21 covered with the fiber collar 20 is actively aligned, and the fiber collar 20 is fixed to the sleeve 19 by welding with a YAG laser.

  The optical transmission / reception module manufactured by the above steps exhibits good transmission / reception characteristics as shown in FIGS.

  The third embodiment of the present invention will be described below by taking a specific embodiment as an example. In this embodiment, a surface emitting laser diode having an oscillation wavelength of 1310 nm is used as the laser diode, and a photodiode having a light receiving diameter of 60 μm is used as the optical signal receiving element. The photodiode and the WDM filter are fixed on the same subcarrier. The embodiment and effects will be described by taking as an example the case where the laser diode is fixed on another subcarrier.

  In this embodiment, the optical path length from the WDM filter to the photodiode is designed to be 0.55 ± 0.1 mm, and the optical path length from the WDM filter to the laser diode is designed to be 0.55 ± 0.1 mm (maximum optical path length). Difference: 0.2 mm).

  The assembly process of the optical transceiver module of this embodiment is shown in FIGS. Hereinafter, the same members as those illustrated in FIGS. 1 to 7 and described above will be described using the same reference numerals.

1. Production of Light-Receiving Section Subcarrier As shown in FIG. 14, first, the photodiode 2 is fixed on the subcarrier 22 with gold-tin solder. The photodiode 2 is mounted by an automatic mounting machine, and the mounting accuracy can be mounted with a yield of almost 100% within ± 50 μm with respect to the designated coordinates on the subcarrier 22. Thereafter, the WDM filter 3 is inserted into the V-groove portion 22a of the subcarrier 22 and fixed with an adhesive.

2. Laser diode mounting As shown in FIG. 15, first, a surface emitting laser diode 23 and a monitoring photodiode (hereinafter, monitoring photodiode) 13 are fixed on a subcarrier 24 by gold-tin solder. The surface emitting laser diode 23 is mounted by an automatic mounting machine, and each chip can be mounted with a yield of almost 100% within ± 30 μm with respect to the designated coordinates on the subcarrier 24. Next, the surface emitting laser diode 23 and the monitoring photodiode 13 are connected to the pin terminals 9 on the stem 7 by wire bonds 12.

3. Laser diode subcarrier alignment fixing As shown in FIG. 16, the subcarrier 22 on which the photodiode 2 and the WDM filter 3 are mounted is aligned by the visual alignment shown in FIGS. Fix by welding or fix with YAG laser. However, in FIGS. 1 to 3, the reflected image 41 (see FIG. 2) of the end face of the laser diode 1 is observed, but in this embodiment, the transmitted image 44 of the exit end face of the surface emitting laser diode 23 is observed. Is observed through the WDM filter 3. Here, if the periphery of the emission position of the emission end face of the surface emitting laser diode 23 is a ridge type, the emission position can be confirmed more accurately. In addition, although the filter transmission image 42 (see FIG. 3) transmitted through the WDM filter 3 of the photodiode light receiving unit 2a is observed, in this embodiment, the photodiode light receiving unit (not shown) of the photodiode 2 is used. A reflected image (not shown) reflected by the WDM filter 3 is observed. By the alignment process described above, a partial overlap of the optical path between the surface emitting laser diode 23 and the optical fiber 21 (see FIG. 17) and the photodiode 2 and the optical fiber 21 can be realized. Thereafter, the receiving IC 14 and the power source noise cutting chip capacitor 15 are mounted by an automatic mounting machine, fixed using an adhesive, and the terminals that need to be electrically connected, such as between the pin terminal 10 and the receiving IC 14, are connected by wire bonding. .

4). Lens Cap Sealing and Optical Fiber Alignment Fixing As shown in FIG. 17, the lens cap 17 is placed on the stem 7 on which all components have been mounted and fixed by resistance welding. At this time, the lens 17a used may be an aspherical lens or a ball lens. Next, a sleeve 19 containing a 1.55 μm cut filter 18 is placed on the lens cap 17 and fixed by welding with a YAG laser. Further, the laser diode 1 is energized to emit light, the pigtail fiber 21 covered with the fiber collar 20 is actively aligned, and the fiber collar 20 is fixed to the sleeve 19 by welding with a YAG laser.

  The optical transmission / reception module manufactured by the above steps exhibits good transmission / reception characteristics as shown in FIGS.

  The fourth embodiment of the present invention will be described below by taking a specific embodiment as an example. In this embodiment, a surface emitting laser diode having an oscillation wavelength of 1290 nm is used as the laser diode, and a photodiode having a light receiving diameter of 80 μm is used as the optical signal receiving element. The surface emitting laser diode and the photodiode are the same subcarrier. Embodiments and effects of the present invention will be described by taking as an example a case where the WDM filter is fixed on another subcarrier.

  In this embodiment, the optical path length from the WDM filter to the photodiode is designed to be 0.45 ± 0.1 mm, and the optical path length from the WDM filter to the laser diode is designed to be 0.5 ± 0.1 mm (maximum optical path length). Difference: 0.25 mm).

  The assembly process of the optical transceiver module of this embodiment is shown in FIGS.

1. Mounting of Surface Emitting Laser Diode and Photodiode on Subcarrier First, as shown in FIG. 18, the surface emitting laser diode 23 and the monitoring photodiode 13 are fixed on the subcarrier 24 with gold tin solder. Next, the photodiode 2 is mounted on the coordinates on the designated subcarrier with the light emitting portion of the surface emitting laser diode 23 as the reference coordinates. These chips are mounted by an automatic mounting machine, and each chip can be mounted with a yield of almost 100% within ± 30 μm with respect to the designated coordinates on the subcarrier 24.

2. Component Mounting on Stem As shown in FIG. 19, a subcarrier 24 on which a surface emitting laser diode 23, a monitoring photodiode 13 and a photodiode 2 are mounted on a stem 7 is fixed by gold tin solder. The subcarrier 24 is mounted by an automatic mounting machine. The mounting accuracy may be within a circle with a radius of 100 μm centered on the exponential coordinates on the stem 7, and this accuracy can be achieved with a yield of almost 100%. Next, the receiving IC 14 and the power source noise cutting chip capacitor 15 are mounted on the stem 7 by an automatic mounting machine, and fixed using an adhesive. Finally, the terminals that need to be electrically connected are connected by wire bonds 12.

3. WDM filter alignment fixing As shown in FIG. 20, the WDM filter 3 is adhered and fixed on a filter subcarrier 6 on which the WDM filter 3 is mounted. Thereafter, the filter-fixed subcarrier 24 is placed on the stem 7 and the visual alignment shown in FIGS. 1 to 3 described above, that is, in this embodiment, the filter transmission image transmitted through the WDM filter 3 of the light receiving portion of the photodiode 2 and Alignment is performed by superimposing the reflection image 43 of the surface emitting laser diode 23, and the YAG laser welding 16 is used for fixing. By the above alignment process, the optical paths between the laser diode 1-optical fiber 21 (see FIG. 21) and the photodiode 2-optical fiber 21 can be superimposed.

4). Lens Cap Sealing and Fiber Alignment As shown in FIG. 21, a lens cap 17 is placed on the stem 7 on which all components have been mounted and fixed by resistance welding. At this time, the lens 17a used may be an aspherical lens or a ball lens. Next, a sleeve 19 containing a 1.55 μm cut filter 18 is placed on the lens cap 17 and fixed by welding 16 using a YAG laser. Further, the laser diode 1 is energized to emit light, the pigtail fiber 21 covered with the fiber collar 20 is actively aligned, and the fiber collar 20 is welded and fixed 16 to the sleeve 19 with a YAG laser.

  The optical transmission / reception module manufactured by the above steps exhibits good transmission / reception characteristics as shown in FIGS.

  The fifth embodiment will be described below by taking a specific embodiment as an example. The present embodiment is an embodiment in which the characteristics of the WDM filter 3 are limited in the first to fourth embodiments described above.

  FIG. 22 is a diagram illustrating an example of light transmission characteristics of the WDM filter according to the present embodiment.

In this embodiment, the WDM filter 3 (see FIGS. 1 to 3) described in the first to fourth embodiments is at least a part of the visible light region (for example, the light wavelength is 760 nm to 860 nm). In the region), the transmittance was 10% or more and 90% or less. When the transmittance of the WDM filter 3 is set to the above value, the filter transmission image 42 and the laser diode 1 transmitted through the WDM filter 3 of the photodiode light receiving unit 2a when aligning by the visual alignment shown in FIGS. 1 to 3 and described above. Since both of the reflection images 41 on the end surface can be images in the visible light region, it is possible to align the transmission image 42 and the reflection image 41 while visually confirming them with a CCD camera. Further, as can be seen from FIG. 22, the transmittance of the WDM filter 3 can be 20% or more and 70% or less in a part of the visible light region (for example, a region where the wavelength of light is 760 nm to 860 nm). Thus, when the transmittance of the WDM filter 3 is set to 20% or more and 70% or less in a part of the visible light region, the photodiode is received when the alignment is performed by the visual alignment shown in FIGS. The filter transmission image 42 transmitted through the WDM filter 3 of the portion 2a and the reflection image 41 of the end face of the laser diode 1 can be observed with substantially the same light intensity, which is more desirable.

  INDUSTRIAL APPLICABILITY The present invention can be used for a single-fiber bidirectional optical transmission / reception module mounted as an optical transmission / reception function unit in an optical signal transmission / reception terminal device, which is a component of an optical communication network, and a manufacturing method thereof.

Claims (5)

One semiconductor optical transmitting element, one optical signal receiving element, and at least one inside a housing formed by fixing a lens cap having a light transmitting portion made of a condenser lens to a cylindrical or columnar metal member In the single-fiber bidirectional optical transceiver module having a configuration in which a single wavelength selection filter is mounted and one optical fiber is attached to the outside of the housing, the output end face of the resonator of the semiconductor optical transmission element or the semiconductor optical transmission The emission end face of the element has a shape that can specify the emission position of the laser beam, the optical path length from the emission end face of the semiconductor optical transmission element to the optical fiber, and the optical signal receiving element receiving surface to the optical fiber The difference between the optical path length is small, and the semiconductor optical transmission element, the optical signal receiving element, and the wavelength selection filter are light between the semiconductor optical transmission element and the optical fiber. If, so as to overlap the optical path and a portion between the optical signal receiving elements and the optical fiber, a method for producing a fiber bidirectional optical transceiver module which is fixed to the metal member through a respectively different supports,
When the semiconductor optical transmission element, the optical signal receiving element and the wavelength selection filter fixed to the support are fixed to the metal member, the support and the optical signal transmission element to which the optical signal receiving element is fixed After fixing the support body fixed to the metal member, the support body to which the wavelength selection filter is fixed is reflected through the wavelength selection filter and the reflection image of the emission end face of the semiconductor optical transmission element, The transmission image of the light receiving surface of the optical signal receiving element transmitted through the wavelength selection filter is arranged so as to be simultaneously focused at the observation position, and the reflected image of the emission end surface and the transmission image of the light receiving surface A method of manufacturing a single-fiber bidirectional optical transceiver module, comprising: fixing a support on which the wavelength selection filter is fixed to the metal member at a position where the optical fiber overlaps each other . One semiconductor optical transmitting element, one optical signal receiving element, and at least one inside a housing formed by fixing a lens cap having a light transmitting portion made of a condenser lens to a cylindrical or columnar metal member In the single-fiber bidirectional optical transceiver module having a configuration in which a single wavelength selection filter is mounted and one optical fiber is attached to the outside of the housing, the output end face of the resonator of the semiconductor optical transmission element or the semiconductor optical transmission The emission end face of the element has a shape that can specify the emission position of the laser beam, the optical path length from the emission end face of the semiconductor optical transmission element to the optical fiber, and the optical signal receiving element receiving surface to the optical fiber The difference between the optical path length is small, and the semiconductor optical transmission element, the optical signal receiving element, and the wavelength selection filter are light between the semiconductor optical transmission element and the optical fiber. And the optical path between the optical signal receiving element and the optical fiber are partially overlapped, and the semiconductor optical transmission element and the optical signal receiving element are fixed to the metal member via a common support, A method of manufacturing a single-fiber bidirectional optical transceiver module in which the wavelength selection filter is fixed to the metal member via another support,
When the semiconductor optical transmitting element, the optical signal receiving element, and the wavelength selection filter fixed to the support are fixed to the metal member, the semiconductor optical transmitting element and the optical signal receiving element are fixed. After fixing the wavelength selective filter to the metal member, the support on which the wavelength selective filter is fixed is reflected on the reflection image of the emission end face of the semiconductor optical transmission element observed through the wavelength selective filter and through the wavelength selective filter. The transmission image of the light receiving surface of the optical signal receiving element that is transmitted through is arranged so as to be focused at the same time at the observation position, and the wavelength at the position where the reflected image of the emission end surface and the transmission image of the light receiving surface overlap. A method of manufacturing a single-fiber bidirectional optical transceiver module, wherein a support to which a sorting filter is fixed is fixed to the metal member. One semiconductor optical transmitting element, one optical signal receiving element, and at least one inside a housing formed by fixing a lens cap having a light transmitting portion made of a condenser lens to a cylindrical or columnar metal member In the single-fiber bidirectional optical transceiver module having a configuration in which a single wavelength selection filter is mounted and one optical fiber is attached to the outside of the housing, the output end face of the resonator of the semiconductor optical transmission element or the semiconductor optical transmission The emission end face of the element has a shape that can specify the emission position of the laser beam, the optical path length from the emission end face of the semiconductor optical transmission element to the optical fiber, and the optical signal receiving element receiving surface to the optical fiber The difference between the optical path length is small, and the semiconductor optical transmission element, the optical signal receiving element, and the wavelength selection filter are light between the semiconductor optical transmission element and the optical fiber. And the optical signal receiving element and the optical path between the optical fibers are arranged so as to partially overlap, the semiconductor optical transmission element and the wavelength selection filter are fixed to the metal member through a common support, A method of manufacturing a single-fiber bidirectional optical transceiver module in which an optical signal receiving element is fixed to the metal member via another support,
When the semiconductor optical transmission element, the optical signal receiving element and the wavelength selection filter fixed to the support are fixed to the metal member, the support to which the optical signal receiving element is fixed is fixed to the metal member. After that, the support on which the semiconductor optical transmission element and the wavelength selection filter are fixed is reflected on the reflection image of the emission end face of the semiconductor optical transmission element observed through the wavelength selection filter and through the wavelength selection filter. The transmission image of the light receiving surface of the optical signal receiving element that is transmitted through is arranged so as to be focused at the same time at the observation position, and the semiconductor at the position where the reflected image of the emission end surface and the transmission image of the light receiving surface overlap A method of manufacturing a single-fiber bidirectional optical transceiver module, comprising: fixing a support to which an optical transmission element and the wavelength selection filter are fixed to the metal member. One semiconductor optical transmitting element, one optical signal receiving element, and at least one inside a housing formed by fixing a lens cap having a light transmitting portion made of a condenser lens to a cylindrical or columnar metal member In the single-fiber bidirectional optical transceiver module having a configuration in which a single wavelength selection filter is mounted and one optical fiber is attached to the outside of the housing, the output end face of the resonator of the semiconductor optical transmission element or the semiconductor optical transmission The emission end face of the element has a shape that can specify the emission position of the laser beam, the optical path length from the emission end face of the semiconductor optical transmission element to the optical fiber, and the optical signal receiving element receiving surface to the optical fiber The difference between the optical path length is small, and the semiconductor optical transmission element, the optical signal receiving element, and the wavelength selection filter are light between the semiconductor optical transmission element and the optical fiber. And the optical signal receiving element and the optical path between the optical fibers are arranged so as to partially overlap, the wavelength selection filter and the optical signal receiving element are fixed to the metal member through a common support, A method of manufacturing a single-fiber bidirectional optical transceiver module in which a semiconductor optical transmission element is fixed to the metal member via another support,
When the semiconductor optical transmission element, the optical signal receiving element, and the wavelength selection filter fixed to the support are fixed to the metal member, the support to which the optical signal reception element and the wavelength selection filter are fixed is provided. A transmission image of the emission end face of the semiconductor optical transmission element observed through the wavelength selection filter and a reflection image of the light receiving surface of the optical signal reception element observed through the wavelength selection filter The optical signal receiving element and the support for fixing the wavelength selection filter are fixed to the metal member at a position where the transmission image of the emission end surface and the reflection image of the light receiving surface overlap each other. A method of manufacturing a single-fiber bidirectional optical transceiver module, characterized in that: 5. A method of manufacturing a single-fiber bidirectional optical transceiver module according to claim 1, wherein a reflection image of the emission end face and a transmission image of the light reception face or a transmission image of the emission end face and the light reception are provided. Manufacturing of a single-fiber bidirectional optical transceiver module characterized in that the reflected images of the surfaces are all images of light in a common visible light region in which the transmittance of the wavelength selection filter is 10% or more and 90% or less. Method.

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