JP3533566B2 - Optical transceiver module - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical transceiver module, and more particularly to an optical transceiver module for two-way simultaneous two-way communication.

[0002]

2. Description of the Related Art A conventional example of an optical transceiver module will be described with reference to FIGS. In the field of optical communication technology, it is planned to carry out bidirectional digital communication using signal light having a wavelength of 1.31 μm and analog video broadcasting using signal light having a wavelength of 1.55 μm using one optical fiber. In this case, in the terminal that accesses the signal light, the signal light of wavelength 1.31 μm and the signal light of wavelength 1.55 μm are separated by the filter and the wavelength of 1.31 μm is used.
The signal light of μm accesses both the laser diode 9 and the photodiode 10 and has a wavelength of 1.55 μm.
The signal light of m requires a bidirectional communication module that can be introduced into the video receiver.

Here, referring to FIG. 8A, a clad 3 on which an optical waveguide 2 is formed is bonded and fixed to an optical waveguide substrate 1. The wavelength of the conventional optical waveguide 2 is 1.31μ.
A straight optical waveguide 21 for transmitting a signal light of m and a signal light of wavelength 1.55 μm and a Y-branch optical waveguide 22 for transmitting a signal light of wavelength 1.31 μm. The coupling end faces of the linear optical waveguide 21 and the Y-branching optical waveguide 22 are exposed at the end face of the clad 3, and the exposed coupling end face has a wavelength of 1.55 μm.
The dielectric multilayer filter 14 is formed to transmit the signal light of, but reflect the signal light of the wavelength of 1.31 μm. The end face of the clad 3 where the coupling end face of the Y-branch optical waveguide 22 is exposed is not at right angles to the linear optical waveguide 21, and is formed at an angle at which the reflected light from the dielectric multilayer filter 14 is introduced into the Y-branch optical waveguide 22. ing. The optical waveguide 2 is formed on the optical waveguide substrate 1, while the V-shaped groove 6 is formed on the surface of the V-shaped groove substrate 5, and since both substrates are separate bodies, a dielectric material is formed on the end surface of the optical waveguide 2. This is convenient for forming the multilayer filter 14 and facilitates its formation.

Referring to FIG. 8 (b), a V-shaped groove 6 in which an optical fiber 8 is fitted and joined and fixed to a V-shaped groove substrate 5 in cross section.
And an electrode 11 'connected to the laser diode 9 and an electrode 11' connected to the photodiode 10 are formed on the surface. The dicing groove 7 is angled corresponding to the optical waveguide substrate 1. Then, the laser diode 9 and the photodiode 10 are connected and fixed to the respective electrodes 11 '.

A method of assembling the conventional optical transceiver module will be described. The optical waveguide substrate 1 configured as described in FIG. 8A is inverted upside down,
Section V constructed as described in FIG. 8 (b)
The groove substrate 5 is aligned with each other with reference to the alignment marks 4 and 4 ', and the optical waveguide substrate 1 and the V-shaped groove substrate 5 are joined and integrated. Further, the optical fibers 8 are fitted, joined and fixed to both of the V-shaped grooves 6 in section, and the assembly is completed.

To recognize and align the alignment marks 4'formed on the optical waveguide substrate 1 and the alignment marks 4'formed on the V-shaped cross-section substrate 5 having the V-shaped cross section 6 A camera is inserted between the substrates facing each other, and the patterns of both alignment marks are simultaneously observed to perform alignment. Alternatively, a highly transmissive light such as infrared rays or X-rays is used to illuminate the alignment mark on the substrate, and the transmitted light is observed to perform the alignment. Since the optical waveguide substrate 1 and the V-shaped groove substrate 5 in cross section have a small actual thickness, infrared rays and X-rays can easily be transmitted and the alignment mark can be seen through. In the assembled optical transmission / reception module, the optical fibers 8 are in a state where their central axes face the end faces of the linear optical waveguides 21, respectively.
The laser diode 9 and the photodiode 10 face the respective branch end faces of the Y-branch optical waveguide 22.

Here, the signal light having a wavelength of 1.55 μm incident through one optical fiber 8 is sent to the linear optical waveguide 21, passes through the dielectric multilayer film filter 14 and is output to the other optical fiber 8. To be done. On the other hand, the signal light having a wavelength of 1.31 μm incident through one optical fiber 8 is sent to the linear optical waveguide 21, is reflected by the dielectric multilayer filter 14, and is introduced to the Y branch optical waveguide 22. Then, the light is received by the photodiode 10 installed opposite to the branch end face. Then, the signal light having a wavelength of 1.31 μm transmitted from the laser diode 9 is introduced into the Y-branch optical waveguide 22 via the branch end face facing the laser diode 9, and is reflected by the dielectric multilayer film filter 14 to be linearly guided. It is sent to the waveguide 21, and is output to the one optical fiber 8 facing the linear optical waveguide 21. As described above, the bidirectional communication using the signal light having the wavelength of 1.31 .mu.m and the communication using the signal light having the wavelength of 1.55 .mu.m can be carried out by one optical fiber (for details, see Reference 6- No. 250017).

In the above-mentioned conventional example, the signal light having a wavelength of 1.55 μm is transmitted and the signal light having a wavelength of 1.31 μm is reflected by the dielectric multilayer filter 14 described above.
In the conventional example, the linear optical waveguide 2 of the optical waveguide substrate 1 is used.
A slit 71 is formed corresponding to the intersecting region of the 1 and Y branch optical waveguides 22, and a film-shaped dielectric multilayer filter 14 is inserted into this slit 71 to transmit a signal light having a wavelength of 1.55 μm. It reflects signal light of 31 μm.

In the conventional example shown in FIG. 11, a laser diode 9 and a photodiode 10 are mounted on a common optical waveguide substrate 1.

[0010]

In the conventional example described above, the mutual positional relationship between the laser diode 9 and the photodiode 10 is examined. In the conventional example shown in FIGS. 8 and 9, the branch end face of the Y-branch optical waveguide 22 is shown. They are mounted on a common optical waveguide substrate 1 so as to face each other.
The two branched end faces are positioned close to each other with a very small distance therebetween. As a result, crosstalk in which light enters the photodiode 10 from the laser diode 9 may become a problem.

In both of the conventional examples shown in FIGS. 10 and 11,
The photodiode 1 faces the end surface of the linear optical waveguide 21.
0 is positioned, and the laser diode 9 is positioned so as to face one branching end face of the Y branch optical waveguide 22.
The problem of crosstalk between the laser diode 9 and the photodiode 10 is alleviated.

However, the slit 71 is formed in the optical waveguide substrate 1.
The conventional example in which the film-shaped dielectric multilayer filter 14 is inserted into the slit 71 has various problems. That is, the step of inserting the dielectric multilayer filter 14 into the slit 71 formed in the optical waveguide substrate 1 is not easy. Dielectric multilayer filter 1 for slit 71
The insertion positioning of 4 has a great influence on the optical transmission characteristics of the optical transceiver module. The thickness of the dielectric multilayer filter 14 is extremely thin, about 15 μm.
In order to insert the slit into the No. 1, the width of the slit 71 must be larger than the thickness of the dielectric multilayer filter 14, and the width of the slit 71 is about 20 μm. Therefore, the dielectric multilayer filter 14 has a play in the slit 71, and its position cannot be strictly determined at the design position. In order to improve the positioning accuracy, it is necessary to design and form the width of the slit 71, but the narrower the width, the more difficult the insertion of the dielectric multilayer filter 14 becomes.

Then, one dielectric multilayer filter 14 is used.
It is inherently difficult to satisfy both the light reflection property and the light transmission property. Since the laser diode 9 and the photodiode 10 are opposed to each other, when simultaneous bidirectional communication is attempted, light is incident on the photodiode 10 from the laser diode 9 in the optical transceiver module as described above. To prevent this, the isolation of the dielectric multilayer filter 14 needs to be about 60 dB. In order to satisfy this requirement, the film thickness of the dielectric multilayer filter 14, that is, the number of layers of the dielectric multilayer film is increased, but this is contrary to the reflection characteristic. The reflection characteristics are better when the thickness of the dielectric multilayer film is smaller. By dividing the filter into two filters, a reflection filter and an isolation filter, and using them, both the reflection characteristics and the transmission characteristics of the optical transceiver module can be satisfied, but this implementation is more difficult. In the conventional example shown in FIGS. 10 and 11, the laser diode 9 and the photodiode 10 must be positioned and mounted together with high accuracy of about 1 μm so as to face the end faces of the linear optical waveguide 21 and the Y branch optical waveguide 22. .

The present invention provides an optical transceiver module for simultaneous two-way communication with two wavelengths, which solves the above-mentioned problems.

[0015]

According to a first aspect of the present invention, there is provided an optical transmission / reception module in which a transmitting laser diode 9 and a receiving photodiode 10 are arranged at opposite positions to perform simultaneous two-way communication using two different wavelength lights. Type optical waveguide 2
3 is provided with an optical waveguide substrate 1 on the end face of which a dielectric multilayer filter 14 that reflects the transmitted light wavelength and transmits the received light wavelength is formed. A sub-mode having a multi-mode linear optical waveguide substrate 51 on which a light blocking dielectric multilayer filter 14 'for blocking a transmission light wavelength and forming a waveguide 21' is formed on the entire end surface and a receiving photodiode 10 is mounted on a side surface. The mount 52 is provided, and the branch end face of the V-shaped optical waveguide 23 is provided with the multimode linear optical waveguide 2.
The optical waveguide substrate 1 is attached and fixed to the multimode linear optical waveguide substrate 51 so as to face one end face of 1 ', and the light receiving surface of the photodiode 10 is positioned on the extension line of the optical axis of the multimode linear optical waveguide 21'. An optical transmission / reception module having the submount 52 was constructed.

According to a second aspect of the present invention, in the optical transceiver module according to the first aspect, an extension portion 511 is formed at an end of the multimode linear optical waveguide substrate 51 on the side where the optical waveguide substrate 1 is fixed, and the extension portion 511 is formed. A V-shaped groove 6 in cross section was formed in the portion 511, and a laser diode 9 was attached and an electrode for connecting to the laser diode 9 was formed.

Claim 3: Claims 1 and 2
In the optical transceiver module described in any of the above, any one of the dielectric multilayer filter and the light blocking dielectric multilayer filter formed on the end face of the multimode linear optical waveguide substrate 51 and the end face of the optical waveguide substrate 1 is used. An optical transmission / reception module was constructed in which one or both were directly formed on the end face by film formation.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the examples of FIGS. For preparing a silicon substrate and applying an etching technique and a thin film forming technique to the surface of the silicon substrate to construct the optical waveguide substrate 1 in which the optical waveguide 2 embedded in the clad 3 and the alignment mark 4 are formed, refer to the above reference. It is illustrated and described in detail in the literature. In this embodiment, with reference to this method, the optical waveguide substrate 1, the clad 3, the V-shaped optical waveguide 23, and the alignment mark 4 are similarly configured including the solder film 15. The branched end face of the V-type optical waveguide 23 is exposed at the end face of the cladding 3. A well-known technique for forming a dielectric multilayer film is applied to the exposed branch end surface of the V-shaped optical waveguide 23, and 1.31 μm light reflection / 1.
The dielectric multilayer filter 14 that transmits light of 55 μm is directly formed.

A silicon substrate is prepared as the multimode linear optical waveguide substrate 51, and a silicon anisotropic etching technique is applied to form a recess 12 in the center of one half of the substrate surface. Then, the multimode linear optical waveguide 21 ′ embedded in the overclad 33 is formed by applying the etching technique and the thin film forming technique to the other half region of the silicon substrate. Here, the multimode linear optical waveguide 21 'is the multimode linear optical waveguide substrate 5
1 is extended in the length direction, and both inner and outer end surfaces thereof are exposed at the end surface of the overclad 33. In addition, the alignment mark 4 and the solder film 15 'are provided on one side of the substrate surface 1 /.
It is formed on both sides of the region 2. Here, both end surfaces of the multimode linear optical waveguide 21 'are exposed at the end surface of the overclad 33. By applying a dielectric multilayer film forming technique to the end face of the overclad 33 where the outer end face of the multimode linear optical waveguide 21 'is exposed, a 1.31 μm optical blocking dielectric multilayer filter 14' is directly formed. ing.

Here, the optical waveguide substrate 1 on which the V-shaped optical waveguide 23 is formed is joined and integrated with the multimode linear optical waveguide substrate 51. At the time of this joining and integration, the portion of the clad 3 including the V-type optical waveguide 23 of the optical waveguide substrate 1 is fitted into the recess 12 formed in the multimode linear optical waveguide substrate 51, and the optical waveguide substrate 1 and the multimode linear Both of the optical waveguide substrates 51 are positioned relative to each other with reference to the alignment mark 4, and are joined and integrated through the solder film 15 and the solder film 15 ′. When the optical waveguide substrate 1 and the multimode linear optical waveguide substrate 51 are joined and integrated, V
The branched end face of the mold optical waveguide 23 and the inner end face of the multimode linear optical waveguide 21 'face each other with a 1.31 μm optical blocking dielectric multilayer filter 14 ′. In this case, the positioning accuracy of the optical waveguide substrate 1 with respect to the multimode linear optical waveguide substrate 51 is quite likely. Because 1.55
Since the received light of μm is input from the single-mode V-shaped optical waveguide 23 to the multi-mode linear optical waveguide 21 ′, the lateral positional accuracy is approximately multi-mode V-shaped optical waveguide 2.
If it is formed to have a core size of about 3, there is no problem, and even if a gap of 10 and several μm occurs between both optical waveguides, the optical characteristics do not deteriorate. Here, either one or both of the V-shaped optical waveguide 23 and the multimode linear optical waveguide 21 'can be a polymer waveguide.

52 is a submount, 1.55 μm
A photodiode 10 for receiving light is attached and fixed to its side surface. The submount 52 is installed by positioning the light receiving surface of the photodiode 10 on an extension line of the optical axis of the multimode linear optical waveguide 21 ′ of the multimode linear optical waveguide 51. Another embodiment will be described with reference to FIGS. 3 and 4. In this embodiment, in the embodiment of FIGS. 1 and 2, the end portion E of the multimode linear optical waveguide substrate 51 on the side where the optical waveguide substrate 1 is joined is extended to form an extended portion 511, and a cross section is formed on this surface. This corresponds to the one in which the V-shaped groove 6 is formed, the laser diode 9 is attached to this surface, and the electrode 11 ′ connected to this laser diode 9 is formed. The other configuration is the same as that of the embodiment shown in FIGS. The multimode linear optical waveguide 21 'is a polymer waveguide.

Here, referring to FIG. 5, this is a view showing the vicinity of the V-shaped optical waveguide 23 of the optical waveguide substrate 1 in the above-mentioned embodiment, which is cut out and shown. This V type optical waveguide 23
Must be formed in an optical waveguide having a single-mode propagation characteristic, so that it must be an embedded type as shown. The manner of formation is as described in the above references. The V-shaped optical waveguide 23 can be a polymer waveguide. Referring to FIG. 6, this is a diagram illustrating a multimode linear optical waveguide 21 '. This linear optical waveguide 21 'has propagated through the V-shaped optical waveguide 23 1.55 μm
Since it is an optical waveguide that guides the received light to the photodiode 10, it may be configured by a multimode optical waveguide. In order to configure this multi-mode linear optical waveguide 21 ', a silicon substrate is prepared as the multi-mode linear optical waveguide substrate 51, silicon dioxide is deposited as the cladding 3 on the surface thereof, and the cladding 3 and the cladding 3 are formed on the surface of the cladding 3. A transparent material having a larger refractive index than that of air is formed as the linear optical waveguide forming layer 30 to a film thickness of about 20 μm. Then, the surface layer with a film thickness of 20 μm is subjected to etching treatment
Only the multimode linear optical waveguide 21 ′ having a width of about 0 μm is left and formed.

Referring to FIG. 7, this is a view for explaining another embodiment of the multimode linear optical waveguide 21 '. As in the case of FIG. 6, a silicon substrate is prepared as the multimode linear optical waveguide substrate 51, silicon dioxide is formed as the cladding 3 on the surface thereof, and the cladding 3 made of silicon dioxide and the air are formed on the surface of the cladding 3. By comparison, a transparent material having a large refractive index is formed as the linear optical waveguide forming layer 30 to a film thickness of about 20 μm. Then, the linear optical waveguide forming layer 30 is subjected to a dicing cutting process to reach the surface of the multimode linear optical waveguide substrate 51 to form a cutting groove 34, and the multimode linear optical waveguide 21 'having a width of about 20 μm is separated. Form.

[0024]

As described above, according to the present invention, the optical waveguide is divided into two parts by focusing on the fact that the linear optical waveguide may be constituted by the multimode optical waveguide, and the end surface of the V-shaped optical waveguide is dielectrically divided. The optical waveguide substrate on which the body multilayer filter is formed, and the multimode linear optical waveguide substrate on which the light blocking multilayer filter is formed on the end face of the multimode linear optical waveguide. As a result, compared to the conventional example, the formation and assembly of the optical waveguide became easier, and the optical characteristics of the finished optical transceiver module were stabilized.

That is, according to the present invention, an optical waveguide substrate having a dielectric multi-layer film filter formed and adhered on the end face of a V-shaped optical waveguide, and a light blocking multi-layer filter formed on the end face of a linear optical waveguide, Since the optical transmission / reception module is configured by combining the pasted and formed multimode linear optical waveguide substrates, the complicated and difficult process of inserting the film-shaped dielectric multilayer filter into the slit as in the conventional example is unnecessary. The positional relationship between and the end face of the optical waveguide is constant.

Since the linear optical waveguide may be constituted by the multi-mode optical waveguide, the multi-mode linear optical waveguide can be easily manufactured as described with reference to FIGS. 6 and 7. You can Here, the cross-sectional dimension of the multi-mode linear optical waveguide can be designed to be about 20 × 20 μm □, which is much larger than the cross-sectional dimension of the single-mode optical waveguide of about 7 × 7 μm □. Therefore, the likelihood of positioning the end face of the V-type optical waveguide, which is a single-mode optical waveguide, opposite to the end face of the multi-mode linear optical waveguide is large, and the alignment becomes extremely easy.

Further, a dielectric multi-layered film filter is formed on the end face of the optical waveguide substrate, and a light blocking multi-layered film filter is formed on the entire end face of the multimode linear optical waveguide substrate. The optical transmission / reception module that satisfies both contradictory light reflection / transmission characteristics by assigning the role of designing the optical blocking multilayer film filter of the linear optical waveguide to the design of transmission characteristics Can be configured.

Further, the multi-mode linear optical waveguide substrate and the submount are separate bodies, and the multi-mode linear optical waveguide substrate is formed with the light-blocking multilayer film filter on the entire end face thereof, so that the multi-mode linear optical waveguide substrate is formed. The light blocking multilayer filter is interposed between the end surface of the optical waveguide substrate and the photodiode mounting end surface of the submount. Here, the light emitted from the transmitting laser diode mounted on the multi-mode linear optical waveguide substrate wraps around to the multi-mode linear optical waveguide substrate, and even if it tries to leak to the photodiode of the submount, the light blocking multilayer film Filtered out, the crosstalk problem discussed in the Problems to be Solved by the Invention is ameliorated.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an embodiment.

FIG. 2 is a diagram of FIG. 1 viewed from above.

FIG. 3 is an exploded perspective view of another embodiment.

FIG. 4 is a diagram of FIG. 3 viewed from above.

FIG. 5 is a diagram illustrating a V-type optical waveguide chip.

FIG. 6 is a diagram illustrating an example of a linear optical waveguide.

FIG. 7 is a diagram for explaining another embodiment of the linear optical waveguide.

FIG. 8 is a diagram illustrating a conventional example.

9 is a perspective view of the conventional example of FIG.

FIG. 10 is a diagram illustrating another conventional example.

FIG. 11 is a perspective view of still another conventional example.

[Explanation of symbols]

1 Optical Waveguide Substrate 10 Photodiode 11 'Electrode 12 Recess 14 Dielectric Multilayer Filter 14' 1.31 μm Light Blocking Dielectric Multilayer Filter 15 Solder Film 15 'Solder Film 2 Optical Waveguide 21 Linear Optical Waveguide 21' Multimode Linear Optical Waveguide 22 Y-branch optical waveguide 23 V-type optical waveguide 3 Clad 30 Linear optical waveguide forming layer 33 Overclad 4 Alignment mark 4'Alignment mark 5 Cross-section V-groove substrate 51 Multimode linear optical waveguide substrate 511 Extending portion 52 Submount 6 Cross-section V-shaped groove 7 Dicing groove 71 Slit 8 Optical fiber 9 Laser diode

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Kaneko 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Electric Corporation (56) Reference JP-A-11-109151 (JP, A) JP-A-11 -305054 (JP, A) JP 7-168038 (JP, A) JP 2000-98157 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02B 6/42 G02B 6 / 122 H01L 31/0232

Claims (3)

(57) [Claims] 1. An optical transmission / reception module in which a transmission laser diode and a reception photodiode are arranged at opposite positions to perform simultaneous two-way communication with light of two different wavelengths, a V-shaped optical waveguide is formed, and a transmission light wavelength is formed. It is equipped with an optical waveguide substrate that has a dielectric multilayer filter that reflects the light and transmits the wavelength of the received light on the end face, and is equipped with a laser diode for transmission, forms a multimode linear optical waveguide and blocks the wavelength of the transmitted light. It is equipped with a multimode linear optical waveguide substrate with a light-blocking dielectric multilayer filter formed on the entire end surface and a submount with a receiving photodiode attached to the side surface. Attach the optical waveguide substrate to the multimode linear optical waveguide substrate so as to face one end face of the waveguide, and fix it. Optical transceiver module, characterized in that installed the submount to position the light-receiving surface of the photodiode on the extension of the optical axis of Chimodo straight waveguide. 2. The optical transmitter-receiver module according to claim 1, wherein an extending portion is formed at an end portion of the multimode linear optical waveguide substrate on the side where the optical waveguide substrate is fixed, and a V-shaped cross-section groove is formed in the extending portion. An optical transmission / reception module, characterized in that an electrode for forming a laser diode and attaching the laser diode is formed. 3. The optical transceiver module according to claim 1, wherein the multi-mode linear optical waveguide substrate has an end face and a dielectric multilayer film filter formed on the end face of the optical waveguide substrate. An optical transceiver module, wherein one or both of the light blocking dielectric multilayer filters are directly formed on the end face.