JP2001108873A - Optical transmission module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actualize an optical transmission module suitable for mass- production, low in cost and high in reliability. SOLUTION: This optical transmission module is provided with an optical fiber having a fiber end, a ferrule wherein the optical fiber having the fiber end exposed is inserted and fixed, a substrate mounted with the ferrule and a photoelectric converting element so that the fiber end and the photoelectric converting element are arranged closely to each other, and a waveguide substrate which has an optical waveguide structure and is fixed to the substrate so that the fiber end and photoelectric converting element are optically coupled with the optical waveguide structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical transmission module applied to the field of optical communication, and more particularly to an optical transmission module for converting an optical signal into an electric signal or converting an electric signal into an optical signal.

In the field of information communication in recent years, with the advancement of information, it is necessary to increase the speed and capacity of arithmetic processing and the speed of data transmission. To realize this, optical communication is indispensable, and improvements are currently being made to expand and spread the optical communication network.

In such an optical communication network, an optical transmission module that performs photoelectric conversion (conversion from an optical signal to an electric signal) or electro-optical conversion (conversion from an electric signal to an optical signal) corresponds to the heart of an optical transmission terminal device. With the spread of optical transmission terminal devices, the production scale of optical transmission modules is expected to increase rapidly, and it is said that it is necessary to significantly reduce the manufacturing cost.

Further, in such an optical communication network, a wavelength division multiplexing method for simultaneously transmitting a plurality of optical signals having different wavelengths has been adopted in order to provide various information services.
Therefore, the optical transmission module needs a multiplexing or demultiplexing function (WDM function) for distributing optical signals of different wavelengths.

[0005] Against this background, the optical transmission module has been downsized by integrating the WDM function.
There is a strong demand for mass production and cost reduction by reducing the number of parts and simplifying the assembly process, and to ensure high reliability and long life. In addition, as a form thereof, it is essential that it can be easily incorporated into an optical transmission terminal device.

[0006]

[Prior Art] Journal of LIGHTWAVE TECHNOLAGY 1998
Vol. 16 No. 1 pp. 66-72 (Document 1) describes an optical transmission module in which a photoelectric conversion element is integrated and mounted on an optical waveguide substrate having a WDM function. In the optical waveguide substrate,
A dielectric multilayer filter that transmits 1.3 μm light and reflects 1.55 μm light is inserted into a groove formed in the optical waveguide substrate and fixed with an adhesive. With this configuration, 1.3
A WDM mechanism for splitting optical signals of μm and 1.55 μm is realized. The photoelectric conversion element is positioned and mounted with a marker on a platform formed on an optical waveguide substrate, and performs bidirectional transmission with 1.3 μm light passing through a dielectric multilayer filter. By creating an optical circuit having a WDM function and a platform on which a photoelectric conversion element is mounted on the same substrate, the number of components is reduced, and miniaturization is achieved. The assembling method employs a surface mounting technology that has a proven track record in mass production in electronic component mounting.

[0007] By the way, electric components incorporated in a communication device are usually reflow-soldered on a printed wiring board. It is desirable that the optical transmission module can be mounted on a printed wiring board in a reflow soldering step together with these electric components because of high efficiency in the assembling process. However, a conventional optical transmission module, a so-called pigtail type module with an optical fiber cord, is not suitable for this soldering process. Usually, an optical fiber cord has a nylon coating film, and since such a coating film has a heat resistance of only about 80 ° C., it is melted in a soldering process. In addition, the optical fiber cord itself causes problems in accommodation and handling at the manufacturing site, and significantly reduces the efficiency of mounting on a printed wiring board. Therefore, in order to reduce the manufacturing cost by enabling the soldering process of the optical transmission module,
It is indispensable to apply a so-called receptacle type optical transmission module that does not include an optical fiber cord.

As a conventional technique for providing a receptacle type optical transmission module capable of performing such a reflow soldering process, for example, a technique described in the following document has been known.

[0009] 47th Electronic Components and Technol
ogy Conference 1997 pp.620-625 (Reference 2)
An optical transmission module in which an optical waveguide substrate having an M function and a photoelectric conversion element are housed in a receptacle type package is described. The optical waveguide has a Mach-Zehnder optical coupler,
The multiplexing and demultiplexing of light of 1.3 μm and 1.55 μm is realized. The photoelectric conversion elements are mounted on separate substrates, respectively, and the optical waveguide and the photoelectric conversion element are optically connected by positioning and fixing the optical waveguide substrate and the substrate on which the photoelectric conversion element is mounted in a ceramic package. The optical fiber has an optical fiber structure with a ferrule in which a ferrule is attached to one end of a strand, and the strand is attached to an optical waveguide substrate with a fiber holder, and the ferrule is held and fixed by a block. A ferrule holding section by a block enables detachment from the second optical fiber. Further, in order to prevent corrosion of the photoelectric conversion element due to moisture, oxygen and the like and dew condensation on the optical coupling part, a lid is placed on the ceramic package, and the optical coupling part is hermetically sealed by adhesion and fixing. Reflow soldering of the flat lead extending from the ceramic package enables mounting on a printed wiring board.

[0010]

The biggest problem of the optical transmission terminal is cost reduction. Among the above devices, most of the cost is related to an optical transmission module having a photoelectric conversion function. For this reason, it is indispensable to secure the transmission characteristics, high reliability, and long life of the optical transmission module, and to reduce the number of members and simplify the assembly process. However, the above-described related art has the following problems.

In the optical transmission module described in Document 1, since a platform for mounting a photoelectric conversion element on an optical waveguide substrate is provided, steps related to platform formation (flat polishing, electrode / solder pad formation, etc.) in addition to optical waveguide formation are performed. And the manufacturing process becomes more complex. Therefore, the production yield of the optical waveguide substrate with a platform is liable to deteriorate, and there is a limit to cost reduction. Further, since the WDM structure using the multilayer filter has a structure in which a groove is formed to cross the waveguide and the filter film is inserted and fixed, light passing through the filter generates scattered light. This scattered light causes crosstalk between the waveguides, and may not satisfy the transmission characteristics.

The optical transmission module described in Document 2 has a structure in which an optical fiber with a ferrule has a structure in which a very easy-to-break fiber strand protrudes from the ferrule. Is liable to occur. Further, in the ferrule with an optical fiber strand after mounting, stress tends to be applied to the base of the optical fiber strand (the boundary portion between the optical fiber strand and the ferrule), and there is a possibility that the ferrule with an optical fiber connector cannot be endured. Further, the package and the lid are configured to hermetically seal the optical coupling portion, but a slit is provided on the side wall of the package for drawing out the optical fiber,
In order to achieve hermetic sealing, it was necessary to close the space at the slit portion. For this reason, a step of applying and filling an adhesive or the like in the slit portion is required, and this step has to rely on manual work. This resulted in a reduction in assembly efficiency. Further, since a package and a lid are always required for hermetic sealing, and expensive members such as ceramics are applied, there is a limit in terms of reduction in the number of parts and cost of members.

The optical fiber is attached and detached by inserting the optical fiber connector in one direction toward the side surface of the optical transmission component. Since the optical fiber connector is attached and detached after soldering the optical transmission component onto the printed wiring board, stress is concentrated on the solder connection between the optical transmission component and the printed wiring board via the lead when attaching and detaching. Take it. For this reason, there is a possibility that electrical contact failure may occur due to solder peeling due to stress or lead disconnection due to metal fatigue.

In addition, the WDM configuration using the Mach-Zehnder type optical coupler is difficult to suppress the light crosstalk between the waveguides within a certain wavelength range to a certain value or less due to its principle characteristics. There was a possibility that the transmission characteristics were not satisfied.
That is, for a one-point wavelength having a certain characteristic, crosstalk can be suppressed, but if the target wavelength range is widened, it is difficult to secure crosstalk for the entire wavelength range.

Accordingly, an object of the present invention is to solve the above-described problems and realize a low-cost and highly reliable optical transmission module suitable for mass production.

[0016]

According to the present invention, there is provided an optical transmission module including an optical fiber, a ferrule, a substrate, and a waveguide substrate. The optical fiber has a fiber end, and is inserted and fixed in the ferrule so that the fiber end is exposed. The ferrule and the photoelectric conversion element are mounted on the substrate such that the fiber end and the photoelectric conversion element are arranged close to each other. The waveguide substrate has an optical waveguide structure, and is fixed to the substrate such that a fiber end and a photoelectric conversion element are optically coupled to the optical waveguide structure.

In this optical transmission module, the optical fiber is inserted into and fixed to the ferrule, and the ferrule is mounted on the substrate. Therefore, it is easy to configure this module into a receptacle type, and the module is suitable for mass production. It is possible to provide a highly reliable optical transmission module at low cost.

For example, the ferrule includes a cylindrical first portion and a second portion obtained by cutting the cylinder to the vicinity of the optical fiber, and the substrate has a first portion on which the first portion of the ferrule is seated. A first V-shaped groove and a second V-shaped groove having a slope coplanar with one slope of the first V-shaped groove, and the second part of the ferrule has a second V-shaped groove. It touches the slope of the groove. According to this configuration, by arranging the photoelectric conversion element near the second V-shaped groove on the substrate, the fiber end and the photoelectric conversion element can be arranged very closely in parallel. As a result, the size of the waveguide substrate can be reduced, and the module can be reduced in size.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Like numbers refer to similar or similar parts throughout similar figures.

FIG. 1 is an exploded perspective view showing an optical coupling system constituting an optical transmission module in an embodiment of the present invention, FIG. 2 is a partially detailed view of FIG. 1, and FIG.
FIG. 3B is a cross-sectional view taken along the line BB ′ in FIG. 2.

In FIG. 1, reference numeral 1 denotes an optical coupling system constituting an optical transmission module. The optical fiber 14 is inserted and fixed in the ferrule 3 so that the fiber end 14A is exposed. Photoelectric conversion elements 2 and 2 'and ferrule 3
Are mounted on the substrate 4. In particular, in this embodiment, the photoelectric conversion element 2 is a laser diode as a light emitting element, and the photoelectric conversion element 2 'is a photodiode as a light receiving element.

The optical fiber 14 'is inserted and fixed in a ferrule 3', and the ferrule 3 'is mounted on a substrate 4'.

The waveguide substrate 5 has an optical waveguide structure.
Substrates 4 and 4 'are provided so that optical fibers 14 and 14' and photoelectric conversion elements 2 and 2 'are optically coupled to the optical waveguide structure.
'Is fixed to the waveguide substrate 5. The optical waveguide structure of the waveguide substrate 5 has ports 5A, 5B, 5C, and 5D to which the optical fiber 14, the light receiving element 2 ', the light emitting element 2, and the optical fiber 14' are optically coupled, respectively.

The ferrule 3 has a cylindrical first portion 3A.
And a second portion 3B obtained by cutting the cylinder to the vicinity of the optical fiber 14.

The substrate 4 has a first portion 3 A of the ferrule 3.
And a second V-shaped groove 12 having a slope coplanar with one slope of the first V-shaped groove.
And The second part 3B of the ferrule 3 is the second part.
Of the V-shaped groove 12 of FIG.

As shown in FIG. 3A, the cut surface of the second portion 3B of the ferrule 3 is attached to the wall surface of the second V-shaped groove 12 which is not in contact with the second portion 3B. If they face each other, the fiber end 14A of the optical fiber 14 can be arranged very close to the photoelectric conversion elements 2 and 2 '.

V-shaped grooves 11 and 12 can be formed by anisotropic etching using silicon as a material of the substrates 4 and 4 '. Semiconductors, ceramics, glass, or the like may be used as the material of the substrates 4 and 4 '.

As the ferrules 3 and 3 ', for example, those having a diameter of 1.25 mm made of zirconia can be used. The width of each of the V-shaped grooves 11 and 12 is, for example, 1.52
mm and 0.9 mm.

In the vicinity of the light emitting element 2, a light receiving element 6 for monitoring the backward light of the light emitting element 2 is provided. These elements 2, 2 'and 6 are electrically connected to the electrodes 16 by, for example, wire bonding.

Particularly, in this embodiment, by adopting the structure as shown in FIGS. 3A and 3B, the distance between the fiber end 14A of the optical fiber 14 and the element 2 'is about 50 .mu.m. This contributes to downsizing of the module.

Referring to FIG. 4, a perspective view of the waveguide substrate 5 is shown. Note that, in FIG. 4, the front side and the back side of the waveguide substrate 5 shown in FIG. 1 are interchanged. Port 5A and ports 5B and 5C
Are coupled by the wavelength λ1, and the port 5A and the port 5D are coupled by the wavelength λ2 (≠ λ1).
The optical filter 21 is related to the optical waveguide structure of the waveguide substrate 5.
Is provided. The wavelengths λ1 and λ2 are, for example, 1.3 μm and 1.55 μm, respectively. In this embodiment, as the optical filter 21, a dielectric multilayer filter that fits into a groove formed in the waveguide substrate 5 can be used.

The optical waveguide structure of the waveguide substrate 5 has a port 5B
And 5C and the optical filter 21 so as to be in a radiation mode (leakage mode) with respect to the wavelength λ2. That is, in a part 27 of the waveguide 23 for the wavelength λ1, the core size is changed so that the light of the wavelength λ2 is in the radiation mode. Further, a step portion 24 from which the over cladding is removed by etching is provided, and a metal film 25 is deposited on the surface thereof. Thereby, the light of the wavelength λ2 in the radiation mode is shielded, and crosstalk to the photoelectric conversion element is reduced.

Markers 22 are formed at four corners of the waveguide substrate 5, and markers 15 are also formed at corresponding positions on the substrates 4 and 4 '. Therefore, by using a transparent substrate such as a glass substrate as the waveguide substrate 5, the marker 15 can be formed.
The position of the marker 22 can be easily adjusted, and the optical axis adjustment in the horizontal direction can be omitted. Marker 22
Can be formed in the same process as the metal film 25.

The height of the optical axis of the photoelectric conversion elements 2 and 2 ′ and the optical fiber 14 is about 1 with respect to the height of the surface of the substrate 4.
In contrast to the setting of 0 μm, the waveguide substrate 5 has a core 31 having a size of 7 μm as shown in FIG.
mx 7 μm, thickness of overcladding 32 is 13.5 μm
And the core height when the waveguide substrate 5 is fixed to the substrate 4 is set to 10 μm.

As shown in FIG. 5B, the adjustment of the core height is performed in the contact fixing region 33 of the waveguide substrate 5 with the substrate 4.
After the glass film 34 having the same thickness as the core is formed at the same time as the formation of the core, an overcladding may be formed so that the thicknesses of both layers are combined to form a height adjusting layer. By setting the thickness of the over cladding 32 to 7 μm × 7 μm and 6.5 μm, the core height when the waveguide substrate 5 is fixed to the substrate 4 can be 10 μm.
Therefore, vertical optical axis alignment can be easily performed in this way, which greatly contributes to automation of module production.

Incidentally, as shown in FIG.
In order to increase the fixing strength of the ferrules 3 and 3 'to the substrates 4 and 4', blocks 7 and 7 'having V-shaped grooves corresponding to the ferrules 3 and 3' can be fixed to the substrates 4 and 4 '.

By using this optical transmission module, transmission and reception by an optical signal having a wavelength of 1.3 μm can be performed. That is, an optical signal having a wavelength of 1.3 μm output from the light emitting element 2 is reflected by the optical filter 21 via the optical waveguide structure and guided into the optical fiber 14. The optical signal having a wavelength of 1.3 μm output from the optical fiber 14 is reflected by the optical filter 21 via the optical waveguide structure and received by the light receiving element 2 ′. Furthermore, the optical fiber 1
The optical signal having a wavelength of 1.55 μm output from the optical fiber 1 is transmitted through the optical filter 21 through the optical waveguide structure, and
4 '.

Referring to FIG. 6, another configuration example of the waveguide substrate 5 is shown. Here, in FIG.
Instead of forming the optical waveguide 23 in the radiation mode (wavelength λ2), a directional coupler type waveguide filter 42 for removing light of the wavelength λ2 is provided adjacent to the optical waveguide 23. This filter 42 may be provided by a Mach-Zehnder coupler.

FIGS. 7 to 9 are views showing steps of packaging the above-mentioned optical coupling system. The support body 61 is made of a plastic molded body pre-molded on a lead frame 62, and has two side surfaces 63 and 65 serving as ferrule take-out ports. The substrates 4 and 4 'are mounted and fixed on the support 61 at predetermined positions by, for example, a positioning method using a marker. The integrated circuit chip 64 is also fixed to the support 61 at the same time. An epoxy resin can be used for fixing, and in this case, bonding can be performed by heating at about 180 ° C.

Next, a waveguide substrate 5 made of a glass substrate
The marker is positioned by visible light observation through the glass substrate from the back surface with the waveguide forming surface facing down, and fixed with a UV adhesive. After that, the ferrules 3 and 3 ′ are fixed to the substrates 4 and 4 ′, respectively, and are held by the ferrule holding lid 71.
At this time, the claw 74 of the support 61 and the ferrule holding lid 7
1 and presses the ferrules 3 and 3 ′ with a constant pressure, and the flange-shaped convex portion 72 of the ferrule holding lid 71 is fitted into the concave groove 73 of the support body 61 to open the side surface. 63
And block 65.

It is preferable to fill the inside of the support 61 with the light coupling resin 81 after the optical coupling system is incorporated in this way. The translucent resin can be cured by, for example, heating to 150 ° C.

In the molding step, as shown in FIGS. 10A and 10B, the ferrule 3 has a silicon rubber cap 9 having a flange 92 having a tapered thickness.
1 is mounted and a part 94 for holding down the ferrule of the mold 93
Flange 92 of the silicone rubber cap 91
Is clamped so that the metal is sandwiched. Thereby, the flange 92 of the silicone rubber cap 91 is in close contact with the inner wall of the concave groove of the mold 93, and the gap between the mold 93 and the ferrule 3 is closed. Thereafter, a low thermal expansion type epoxy resin is injected by a normal injection molding method, and can be shaped at, for example, 180 ° C.

The thus obtained molded article 1
As shown in FIG. 11, a recessed groove 101 is formed in 02 so that it can be attached to and detached from another optical fiber. As shown in FIGS. 12A and 12B, the claw 112 of the optical connector housing 117 is fitted into the concave groove 101, and the optical connector 113 is connected via the housing 117. The housing 117 corresponds to, for example, a commercially available MU-type optical connector, and has a C-type sleeve 114 provided therein.

By properly selecting the housing,
An adapter shape corresponding to a commercially available optical connector (SC type, MU type, etc.) can be easily obtained. A commercially available connector housing can be applied by matching the concave groove 101 on the optical transmission module side with a commercially available connector shape. Further, 117 claws 116 of the optical connector housing 117 are integrally formed on the optical transmission module side. Then, the optical connector can be directly connected.

FIGS. 13A and 13B show the attachment of the optical transmission module to the communication terminal.
The electrical lead 62 of the optical transmission module is a plug-in type plug, and a plug insertion port 122 is provided on the communication terminal device 121 side. Therefore, by inserting the lead 62 into the insertion port 122, electrical connection between the optical transmission module and the communication terminal device can be easily performed. In this case, by using the optical connector housing 117 having the protrusion 123, the protrusion 123 is inserted into the communication terminal device 121, so that the optical transmission module can be easily mechanically coupled to the optical communication terminal device 121. it can. The optical transmission module may be directly mounted on a printed wiring board in the communication terminal device by reflow soldering.

FIG. 14 shows an optical coupling system using another ferrule shape. Two optical fiber strands 132 are built in parallel in the rectangular parallelepiped ferrule 131,
On both sides thereof, a pair of holes 134 for inserting the guide rod 133 is provided. On the other hand, the optical element mounting substrate 135
Is formed with a V-shaped groove 136 for positioning the ferrule via a guide rod 133. Ferrule 131
Is positioned and fixed by the guide rod 133, and the waveguide substrate 137 is positioned and fixed using a marker (not shown) in the same manner as described above, so that the optical fiber 132 and the optical waveguide structure of the waveguide substrate 137 are optically connected. Simple coupling can be easily performed.

If a flange-like projection (not shown) is provided on the outer periphery of the ferrule 131, the flange 61 is fitted into the concave groove 73 of the support 61 shown in FIG. The open side of can be closed. Detachment from the optical connector after molding is performed in the optical connector housing 117.
This can be performed, for example, by using a commercially available MPO connector via (see FIG. 12).

FIG. 15 is an exploded perspective view showing an optical coupling system constituting an optical transmission module according to another embodiment of the present invention. Here, a substrate 51 on which the ferrule 3 and the light emitting element 2 are mounted and a substrate 52 on which the light receiving element 2 ′ is mounted are fixed to the waveguide substrate 5.

The optical waveguide structure of the waveguide substrate 5 has ports 5E, 5F and 5G to which the optical fiber 14, the light emitting element 2 and the light receiving element 2 'are optically coupled, respectively. In connection with the optical waveguide structure, for example, 1.3 μm light is reflected.
An optical filter 21 composed of a dielectric multilayer filter that transmits light of 55 μm is provided. Specifically, the optical filter 21 is inserted and fixed in a groove formed in the waveguide substrate 5. Therefore, the port 5E and the port 5F are coupled by a wavelength of 1.3 μm, and the port 5E and the port 5F are coupled.
G is coupled by a wavelength of 1.55 μm. By using this optical coupling system, transmission using an optical signal having a wavelength of 1.3 μm and reception using an optical signal having a wavelength of 1.55 μm can be performed.

In the embodiment described above, FIGS.
As shown in, a part of the ferrule 3 is cut and removed,
By mounting the photoelectric conversion elements 2 and 2 ′ in parallel with the optical fiber 14 incorporated in the ferrule 3, the pitch of the optical waveguide structure of the waveguide substrate 5 can be reduced, and the size of the waveguide substrate 5 can be reduced. Can be achieved. In addition, by separating the substrate 4 on which the photoelectric conversion elements 2 and 2 'and the ferrule 3 are mounted from the waveguide substrate 5, the process of forming the optical waveguide can be simplified, leading to an improvement in yield and a reduction in cost.

As shown in FIG.
If the thickness of 2 is the height adjustment layer of the core, the required height (thickness of the over cladding) is about 10 μm,
It is not necessary to form a thick glass film having a thickness of 30 to 40 μm unlike the related art, and the burden of the waveguide forming process can be reduced. Further, a glass film 34 having the same thickness as the core is formed simultaneously with the formation of the core in the contact fixing region 33 with the substrate 4 or 4 ′, and then the over cladding 32 is formed. By doing so, the thickness of the formed overcladding can be further reduced. There is a concern that the thickness of the over clad may increase the loss of the optical waveguide. However, as shown in FIG. 9, the transparent resin 81 filled in the support 61 acts as a refractive index matching material. It functions as overcladding and can avoid an increase in propagation loss.

The filling of the transparent resin 81 also serves to protect the optical component from the resin injection pressure at the time of molding in the next step.

The ferrule 3 having a structure having no optical fiber portion can solve the problem of stress breakage, and at the same time, can be easily handled as a part, thereby improving work efficiency.

If the substrate 4 is made of silicon, the storage groove and the like of the ferrule 3 can be easily manufactured by anisotropic etching using a semiconductor process, and it is possible to supply inexpensive components suitable for mass production. Become.

Further, if a glass substrate is used as the waveguide substrate 5, when positioning the marker with the optical component mounting substrate, it is possible to position the visible light from the back surface of the substrate through the glass substrate. Positioning and mounting can be easily realized with simple manufacturing equipment.

The structure of the optical waveguide is such that, as shown in FIG. 4, in addition to the optical filter 21, if an optical waveguide 27 in which light of a wavelength to be cross-talked is in a radiation mode is provided at an appropriate position, scattered light generated in the filter section is reduced. Crosstalk between the optical waveguides, which can be a cause, can be reduced, and transmission characteristics can be secured. Further, by removing a portion 24 of the over clad except for the vicinity of the core of the optical waveguide by etching and filling the light shielding material 25, stray light propagating in the clad can be cut, and crosstalk can be further reduced. . The marker 2 formed on the waveguide substrate 4
If a metal film is selected as the second material and the light-blocking substance 25 is added to the marker 22 and the light-blocking groove at the same time, the process steps can be simplified.

As another form of the optical waveguide, as shown in FIG. 6, in addition to the optical filter 21, a directional coupler type waveguide filter 42 for removing light of a wavelength to be crosstalked is provided at an appropriate position. , The crosstalk between the optical waveguides caused by the scattered light generated in the optical waveguide can be reduced.

As shown in FIGS. 7 to 9, the optical component mounting substrates 4 and 4
′, The waveguide substrate 5 and the ferrules 3 and 3 ′ when the optical coupling system is housed in the support 61, the ferrule holding cover 7
By providing a flange-shaped convex portion 72 on 1 and fixing the ferrules 3 and 3 ′ with the holding lid 71 and closing the open side surfaces 63 and 65 of the support with the flange-shaped convex portion 72, it is possible to reduce the number of members and processes, thereby improving efficiency. A bath filled with a transparent resin can be formed at the same time.
If the support 61 is provided with a concave portion 73 that fits with the flange-shaped convex portion 72 of the ferrule holding cover 71, the open side surface of the support 61 can be reliably closed by fitting the two. Further, when the support 61 is provided with a claw 74 that fits with the ferrule holding cover 71 and the claw 74 and the ferrule holding cover 71 main body are fitted, the ferrules 3 and 3 ′ can be held and fixed with a constant pressing force. Is possible, and the fixing accuracy of the ferrule is improved.

When the entire support 61 is molded,
By mounting an elastic cap 91 on the ferrule 3 and pressing the cap 91 with the mold die 93, it is possible to prevent the pressure at the time of fastening the die from being directly applied to the ferrule 3, and to prevent the ferrule 3 from being displaced or damaged. be able to. Also,
An elastic cap 91 is provided with a tapered flange 92,
A groove 94 sandwiching the flange 92 is provided in a portion of the mold 93 that presses the ferrule, and the flange 92 of the elastic cap 91 is brought into close contact with the inner wall of the mold groove by fitting the two. The gap between 93 and the ferrule 3 can be closed, resin leakage at the time of resin injection can be avoided, and contamination of the ferrule end surface can be prevented.

If the optical connector housing 117 can be attached or detached after mounting the optical fiber, the degree of freedom in selecting the type of the optical connector to be connected is increased, so that the common use range of the optical transmission module is expanded and the cost can be reduced. On the other hand, if the claws 116 of the optical connector housing are integrally formed with the optical transmission module 102, the number of parts and the number of assembly steps can be reduced.

As shown in FIG. 13, if the electrical lead 62 of the optical transmission module is of a pluggable plug type so that it can be electrically connected to the communication terminal device 121 by a pluggable plug, attachment / detachment and replacement can be facilitated. In addition, the convex portion 123 that directly fits into the optical connector housing 117 with the communication terminal device.
Is provided, the stress generated when attaching or detaching the optical connector 113 is not applied to the lead terminal, and it is possible to avoid disconnection due to poor contact of the lead portion and metal fatigue.

Therefore, the above-described operation can solve the conventional problems with respect to the form of the optical transmission module and the mounting method thereof, and provide a manufacturing method suitable for mass production. Therefore,
A low-cost and highly reliable optical transmission component can be easily realized.

[0063]

As described above, according to the present invention, it is possible to provide a low-cost and highly reliable optical transmission module suitable for mass production.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an optical coupling system constituting an optical transmission module according to an embodiment of the present invention.

FIG. 2 is a partial detailed view of the optical coupling system shown in FIG.

FIGS. 3A and 3B are cross-sectional views of a waveguide substrate.

FIG. 4 is a perspective view of a waveguide substrate.

FIGS. 5A and 5B are views showing a cross section of the waveguide substrate. FIGS.

FIG. 6 is a perspective view showing another configuration example of the waveguide substrate.

FIG. 7 is a diagram (part 1) illustrating mounting of the optical coupling system on a support;

FIG. 8 is a diagram (part 2) illustrating the mounting of the optical coupling system on the support.

FIG. 9 is a diagram (part 3) illustrating the mounting of the optical coupling system on the support.

FIGS. 10A and 10B are diagrams showing a molding process.

FIG. 11 is a perspective view of an optical transmission module.

FIGS. 12A and 12B are diagrams showing connections between an optical transmission module and an optical fiber connector.

FIGS. 13A and 13B are diagrams showing attachment of an optical transmission module to a communication terminal device.

FIG. 14 is a perspective view showing an optical coupling system constituting an optical transmission module according to another embodiment of the present invention.

FIG. 15 is an exploded perspective view showing an optical coupling system constituting an optical transmission module according to still another embodiment of the present invention.

[Description of Signs] 2,2 'photoelectric conversion element 3,3' ferrule 4,4 'substrate 5 waveguide substrate 21 optical filter

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04B 10/135 10/13 10/12 (72) Inventor Hironao Hakogi 4 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Chome 1-1 Fujitsu Limited F term (reference) 2H037 AA01 BA02 BA11 BA24 DA03 DA04 DA06 5F073 AB21 AB28 BA02 EA03 EA15 5F088 AA01 BA10 BB01 EA09 EA11 HA05 JA13 JA14 LA01 5K002 AA07 BA05 BA07 BA31 DA01 FA01

Claims (7)

[Claims] 1. An optical fiber having a fiber end, a ferrule into which the optical fiber is inserted and fixed so that the fiber end is exposed, and a ferrule such that the fiber end and a photoelectric conversion element are arranged close to each other. And a substrate on which the photoelectric conversion element is mounted; and a waveguide substrate having an optical waveguide structure and fixed to the substrate so that the fiber end and the photoelectric conversion element are optically coupled to the optical waveguide structure. Optical transmission module provided with. 2. The optical transmission module according to claim 1, further comprising: a second optical fiber; and a second substrate on which the second optical fiber is mounted, wherein the second substrate is An optical transmission module fixed to the waveguide substrate so that the second optical fiber is optically coupled to the optical waveguide structure. 3. The optical transmission module according to claim 2, wherein the photoelectric conversion element includes a light receiving element and a light emitting element, and the optical waveguide structure includes the optical fiber, the light receiving element, the light emitting element, and the light emitting element. Two optical fibers respectively having first to fourth ports optically coupled to each other, wherein the first port and the second and third ports are coupled by a first wavelength and Port 1 and the fourth
An optical transmission module further comprising an optical filter provided in association with the optical waveguide structure such that the port is coupled to the second wavelength different from the first wavelength. 4. The optical transmission module according to claim 3, wherein the optical waveguide structure is in a radiation mode between the second and third ports and the optical filter with respect to the second wavelength. Optical transmission module configured as follows. 5. The optical transmission module according to claim 1, further comprising: a second photoelectric conversion element; and a second substrate on which the second photoelectric conversion element is mounted. An optical transmission module, wherein the substrate is fixed to the waveguide substrate such that the second photoelectric conversion element is optically coupled to the optical waveguide structure. 6. The optical transmission module according to claim 5, wherein the photoelectric conversion element and the second photoelectric conversion element are a light emitting element and a light receiving element, respectively, and the optical waveguide structure is the optical fiber. First to third optically coupled light emitting elements and the light receiving elements, respectively.
Wherein the first port and the second port are coupled by a first wavelength and the first port and the third port are different from the first wavelength. An optical transmission module further comprising an optical filter provided in connection with the optical waveguide structure so as to be coupled by the wavelength of the optical transmission module. 7. The optical transmission module according to claim 1, wherein the ferrule includes a first cylindrical portion and a second portion obtained by cutting the cylindrical portion to a position near the optical fiber. The substrate includes: a first V-shaped groove on which the first portion is seated; and a second V-shaped groove having a slope coplanar with one slope of the first V-shaped groove. An optical transmission module, wherein the second portion is in contact with a slope of the second V-shaped groove.