JPH03238405A - Module integrated with optical transmitter/receiver - Google Patents

Abstract

PURPOSE:To decrease the number of optical parts and to adjust optical coupling parts as well as to decrease fixing points by constituting the above module in such a manner that a piece of optical fiber plays the role of a transmission line, an optical coupling lens and an optical reflector. CONSTITUTION:A groove 20 is formed in the direction perpendicular to one end of plural waveguides 2, 3, 4 and the optical fiber 21 is fixed by an optical adhesive 22 to the prescribed position of this groove 20 and the front end of the optical fiber 21 is formed to the angle to totally reflect the light propagating in the waveguide 3 in a prescribed direction. The optical fiber 21 and the waveguide 3 are optically coupled; in addition, a light emitting element 8 and a light receiving element 10 and the waveguides 2, 4 exclusive of the waveguide 3 are optically coupled by the body part of the optical fiber 21. Namely, the module is so constituted that a piece of the optical fiber 21 plays the role of the transmission line, the optical coupling lens and the optical reflector. The optical parts are decreased in this way and since the assembly of the optical coupling part is executed simply by inserting and fixing the optical 21 into the groove 20, the easy adjustment of the assembly and the optical coupling is feasible.

Description

[Detailed description of the invention] Table of contents Overview Industrial field of application Conventional technology Problems to be solved by the invention Means for solving the problems Implementation Example Outline of the effects of the invention Overview Wideband I S D N (Integrated 5e)
A small number of optical transceiver integrated modules are applied to optical interfaces of subscriber terminals installed in each home in advanced optical communication systems such as rv+ce O+gital~etwork). Optical transmitter/receiver integration allows for miniaturization by performing optical coupling with fewer parts, reduces adjustment man-hours, lowers costs, and improves overall reliability. A waveguide type combining module, in which a plurality of waveguides are formed on a waveguide substrate so that one end thereof is parallel to each other, and light is multiplexed or demultiplexed by the plurality of waveguides. In an integrated optical transceiver module that includes a wave transmitter, an optical transmitter circuit having a light emitting element, and an optical receiver circuit having a light receiving element, a waveguide substrate is disposed at right angles to one end of the plurality of waveguides. A groove is provided on the top, and an optical fiber whose bottom end is shaped at an angle that totally reflects the light propagating through one of the plurality of waveguides in a predetermined direction is fixed in a predetermined position of the groove with an optical adhesive. The optical fiber is optically coupled to the waveguide which is in contact with the distal end portion of the optical fiber via the optical adhesive, and the body portion of the optical fiber via the optical adhesive allows the light emission to occur. The element and the light receiving element are configured to be optically coupled to a waveguide other than the waveguide that is in contact with the tip of the optical fiber via the optical adhesive.

Industrial Field of Application The present invention is applicable to broadband ISDN (Integrate
The present invention relates to an integrated optical transceiver module that is applied to the optical interface section of subscriber terminals installed in each home in advanced optical communication systems such as d5serviceD+g+tal\eHv○rk).

This type of optical transceiver integrated module is used for boat fishing:
It consists of a waveguide that separates/combines light of several different wavelengths, an optical transmitter circuit, and an optical receiver circuit.

In addition, since this optical transmitter/receiver integrated module is installed outdoors, it must operate stably in harsh environments.
It is necessary to lower prices by increasing mass productivity.

BACKGROUND OF THE INVENTION FIG. 8 is a plan view showing the structure of a conventional optical transceiver integrated module.

In this figure, 1 is lithium niobate (LiNbO3
), etc., is a waveguide substrate. An optical waveguide 2 is formed at a predetermined position on the surface of the waveguide substrate 1 by a method such as thermally diffusing titanium (T1), and first optical waveguides 2 are formed on both sides of the four optical waveguides 2 using the same material and the same method. A branched optical waveguide 3 and a second branched optical waveguide 4 are formed.

Furthermore, an optical fiber 6 inserted and fixed into a link 5 made of ruby or the like is adhered to one end of the optical waveguide 2 with an ultraviolet curing optical adhesive 7 (5). Furthermore, at the other end of the optical waveguide 2, a light emitting element 8 such as a semiconductor laser is installed via a ball lens 9. The laser beam output from the light emitting element 8 is as shown in the figure. As shown by arrow Y1, it is coupled to optical waveguide 2 via ball lens 9.

In addition, a light receiving element 10 such as a photodiode is installed at the end of the first branched optical waveguide 3 via a ball lens 11, and the light that is S-branched from the optical waveguide 2 and propagates through the first branched optical waveguide 3 is However, as shown by the arrow Y2 in the figure, the ball lens 1
1 and enters the light receiving element 10. Furthermore, an optical fiber 12 is installed at the end of the second branch optical waveguide 4 via a reflection plate 13 that is set at a predetermined angle and reflects light. Optical waveguide 4
As shown by arrow Y3 in the figure, the light propagating through the reflecting plate 1
3 and enters the optical fiber 12.

In addition, the waveguide substrate 1, the light emitting element 8, and the light receiving element 1 described above are also included.
0, ball lens 9.11, reflector plate 13 and other parts,
An electronic circuit (not shown) is placed in a metal box 15 indicated by a dashed line.
The optical transmitter/receiver integrated module is configured. Therefore, this optical transmitter/receiver integrated module can demultiplex/combine light of a plurality of wavelengths, and can also be applied as an interface section of a transmission path to transmit and receive light.

Problems to be Solved by the Invention By the way, there are five problems with the above-mentioned optical transceiver integrated module.
), ball lenses 9, 11 and a reflection plate 13 are used for optical coupling between each optical waveguide 2, 3° 4 of a waveguide substrate 1, a light emitting element 8, a light receiving element 10, and an optical fiber 12.
These need to be adjusted and fixed individually. Having such a large number of parts makes it difficult to miniaturize the entire module; it also requires a lot of adjustment man-hours, leading to high costs. There was a problem. Furthermore, the large number of parts and the large amount of adjustment man-hours lead to a high overall failure probability and a large number of maladjusted parts.

In other words, this is a problem that reduces the reliability of the entire module.
Ru.

Is this the main investigation? This was done in view of two points,
An optical transceiver that can be made smaller by optically coupling with a small number of parts, reduce adjustment man-hours, lower costs, and improve overall reliability. (The purpose is to provide ΔIhimonyur.

Means for Solving the Problems The present research is based on a method in which a plurality of waveguides are mutually connected at one end on a waveguide substrate.
,), and which multiplexes or demultiplexes light using the plurality of waveguides, an optical transmitting circuit having a light emitting element, and an optical transmitting circuit having a light receiving element In the optical transceiver integrated module comprising a receiving circuit, a groove is formed on the waveguide substrate in a direction perpendicular to one end of the plurality of waveguides, and an optical adhesive is attached at a predetermined position of the formed groove. The optical fiber is fixed with an agent, and the tip of the fixed optical fiber is shaped at an angle that totally reflects the light propagating through the waveguide in a predetermined direction.

and optically coupling the optical fiber to the waveguide that is in contact with the tip of the optical fiber via the optical adhesive,
The light-emitting element and the light-receiving element are optically coupled to a waveguide other than the waveguide contacting the tip of the optical fiber via the optical adhesive by the body of the optical fiber via the optical adhesive. Configure.

Further, the tip of the optical fiber may be formed at an angle such that the light propagating through the waveguide is not totally reflected but is branched.

Furthermore, a dielectric multilayer film may be provided at the tip of the optical fiber so that the light propagating through the waveguide is not totally reflected but is branched.

According to another aspect of the present invention, an inclined surface of the waveguide substrate, which is perpendicular to one end of the plurality of waveguides, directs the light propagating through the waveguides. A V-shaped groove is formed at an angle that causes total reflection below the waveguide substrate,
The rod lens is fixed in a predetermined position in the V-shaped groove formed using an optical adhesive.

Then, any one of the waveguides and the light receiving element are optically coupled via the V-shaped groove, and any of the plurality of waveguides and the light emitting element are coupled via the optical adhesive and the rod lens. and an optical fiber having a spherical tip.

Function: According to the above-mentioned horizontal diaphragm, the light propagating through the waveguide is totally reflected at the tip of the optical fiber, propagates through this optical fiber, and is transmitted to the transmission line. Since the body of the lens performs the same function as a rod lens, the light passing through the other waveguides passes through the optical adhesive, is focused by the optical fiber, and is incident on the light receiving element. The output light is collected by an optical fiber, transmitted through an optical adhesive, and propagated to other waveguides.

Therefore, one optical fiber plays the role of a transmission line, an optical coupling lens, and an optical reflector, thereby reducing the number of optical components and making the overall size smaller. Insert and fix: Since the optical coupling part has already been assembled, it is easy to assemble it and adjust the light balance.

In addition, the tip of the optical fiber may be formed at an angle such that the light propagating through the waveguide is not totally reflected and is branched at a predetermined branching ratio, or the tip of the optical fiber may be coated with a dielectric+1 multilayer film. If the light propagating through the waveguide is not totally reflected but is branched at a predetermined branching ratio, the branched light can be propagated through the optical fiber and other waveguides, respectively. That is, the tip part plays the role of a splitter, and the number of optical components is not increased.

Furthermore, on the waveguide substrate, light propagating in a direction perpendicular to the plurality of waveguides and whose sloped surface propagates along the iJ path,
When a V-shaped groove is formed at an angle that causes total reflection in the vertical downward direction with respect to the upper surface of the waveguide substrate, and a rod lens is fixed at a predetermined position of the formed V-shaped groove with an optical adhesive,
The light propagating through the waveguide is totally reflected downward on the slope of the shaped groove and enters the light receiving element, and the light passing through other waveguides passes through the optical adhesive and is focused by the rod lens. The light is incident on an optical fiber having a spherical tip, and the light output from the light emitting element is collected by a rod lens, transmitted through an optical adhesive, and propagated to another waveguide.

Therefore, by using the shaped groove and the rod lens, it is possible to couple the reflection 7Ar (reflection angle) between the two, thereby reducing the number of optical parts and downsizing the whole.Furthermore, the optical coupling section It is easy to assemble and adjust the warpage.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing the structure of an integrated optical transmitter/receiver module according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line 1--2 shown in FIG. In these figures, parts corresponding to those of the conventional example shown in FIG. 8 are given the same reference numerals.

In FIGS. 1 and 2, 5), reference numeral 1 denotes a waveguide substrate made of silicon (Si) or the like. A guide waveguide 2 is formed at a predetermined position on the surface of the waveguide substrate 1 by a method such as thermally diffusing titanium (TI), and one end is formed on both sides of the optical waveguide 2 using the same material and the same method. A first branched optical waveguide 3 and a second branched optical waveguide 4 are formed so as to be parallel to each other.

Further, a predetermined shape a20, such as a square shape or the semi-cylindrical shape shown in the figure, is formed at a predetermined position on the upper part of the waveguide substrate l in a direction perpendicular to each optical waveguide 2, 3.4. An optical fiber 21 is fitted into this groove 20 so as to cross the end of each optical waveguide 2° 3.4, and is fixed with an optical adhesive 22. IflL, the same part of the second optical fiber plays the role of rod lens = q function,
In addition, when fixing the optical fiber 21, as shown by arrow Y6 in FIG.
5). Also, is the optical adhesive 22 similar to the optical waveguide? ;It has the refractive index of light, and in addition to the effect of fixing the optical fiber 21,
Each leading wave ¥82.3.4 has the effect of propagating light in the same way as f.

Furthermore, the distal end of the optical fiber 21, that is, the portion located at the end of the first branched optical waveguide 3 is connected to the first branched optical waveguide 3 or a.
The angle at which all of the propagating light radiates, for example: It is formed at an angle of 145 degrees; Then, it is totally reflected at the tip of the optical fiber 21 and propagated in the direction of arrow Y4a.

Further, a light emitting element 8 such as a semiconductor laser and a light receiving element 10 such as a photodiode are placed and fixed at predetermined positions on the waveguide substrate 1, and the light output from the light emitting element 8 is directed to the arrow Y5 in the figure. As shown in FIG.
As shown by arrow Y6, the light is focused by the optical fiber 21 via the optical adhesive 22 and is incident on the light receiving element 10.

At the left end of the waveguide board l, there is an optical fiber halo inserted and fixed into the link 5 pulled from ruby etc.
An optical adhesive 7 is used to bond the end face of the waveguide substrate 1 to a portion where the end of the optical waveguide 2 is exposed.

In addition to the above-mentioned parts, there are electronic circuits (not shown), etc.
- It is housed in a metal box 15 shown by a dotted chain line, and an optical transceiver integrated module is constructed 5).

According to the configuration, the optical waveguide 2 and the light emitting element 8
Further, optical coupling between the second branch optical waveguide 4 and the light receiving element 10 is performed by an optical fiber 21 serving as a transmission path, and furthermore, the light propagated from the first branch optical waveguide 3 is connected to the optical fiber 2 It is reflected at the tip of the optical fiber 21, and is transported to the optical fiber 21.

Therefore, as in the conventional example shown in FIG. 8, ball lenses 9, 10 . 5) Using the reflective plate 13
Since optical coupling can be performed using only the large fiber 21, the number of optical parts can be reduced, and the number of adjustment and fixing points for the optical switching section can be reduced by A.

Next, referring to FIG. 3, an integrated optical transceiver module according to a second embodiment of the present invention will be explained in detail. In this figure, the parts corresponding to the parts of the first embodiment shown in FIG.

The difference between this second embodiment and the first embodiment is that the angle of the tip of the fiber 21 is totally reflected, and furthermore, the angle of the tip of the fiber 21 is completely reflected. , and the 1st branch master's guide 5
A third branch optical waveguide 30 is formed at a predetermined position on the zero extension line, and an optical fiber 6' inserted and fixed into a ring 5' is bonded to the end thereof with an optical adhesive 7'.

That is, according to such a configuration, the light propagating through the first branched optical waveguide 3 is branched at the tip of the optical fiber 21 in the directions of arrows Y4 and eY7.

The light branched in the direction of arrow Y4 propagates through the optical fiber 21, and the light branched in the direction of arrow Y7 propagates through the third branch optical waveguide 30 and is transmitted to the optical fiber 6'.

Therefore, the lights of different wavelengths branched at the tip of the optical fiber 21 can be transmitted to different transmission paths.

Next, a third example will be described. The configuration of this third embodiment is almost the same as that of the second embodiment shown in FIG. It is formed at an angle that totally reflects the light propagated from the tip, and a dielectric multilayer film is formed at its tip (j).

That is, according to such a configuration, similarly to the second embodiment, the light propagating from the first branch optical waveguide 3 is branched in the directions of arrows Y4 and Y7 at the tip of the optical fiber 21. , the light branched in the direction of arrow Y4 propagates through the optical fiber 21, and the light branched in the direction of arrow Y7 propagates through the third branch optical waveguide 30 and is transmitted to the optical fiber halo'.

Therefore, the lights of different wavelengths branched at the tip of the optical fiber 21 can be transmitted to different transmission paths.

Next, a fourth embodiment of the present invention; a two-way optical transceiver integrated module will be described in 5) with reference to FIGS. 4 to 7. Figure 4:'i A plan view showing the structure of an optical transmitter/receiver-imaging module according to the fourth embodiment of the present invention, Figure 5 is a sectional view taken along the line ■-V shown in Figure 4, The figure is a cross-sectional view taken along the line ■--■ shown in FIG. 4, and FIG. 7 is a cross-sectional view taken along the line ■--■ shown in FIG. 4. In these figures, the same reference numerals are given to the parts corresponding to those of the first embodiment shown in FIG.

In FIG. 4, 1 is a waveguide substrate, 2 is an optical waveguide, 3 is a first branch optical waveguide, and 4 is a second branch optical waveguide 4.

At predetermined positions on the upper part of the waveguide substrate 1, each optical waveguide 2.3.
A ■-shaped groove 40 is formed in a direction perpendicular to 4.

As shown in FIG.
0a totally reflects the light propagating through the first branch leading waveguide 3, and this totally reflected light is incident almost perpendicularly to the horizontal plane of the waveguide substrate l, as shown by the arrow EOY8, and The angle θ is such that the light enters the light receiving element 10 such as a photodiode placed at a predetermined position on the lower surface of the substrate l. It is molded into.

That is, in the case of the waveguide substrate 1 according to this embodiment, since silicon material is applied, the refractive index of the silicon material is −3.
, 5, the critical total reflection angle θ, is θ, = co s−' (1/3.5) = 73°.

Therefore, the angle θ0 of the slope 40a of the ■-shaped groove 40 is set to 73°.
By doing the following, the light propagating through the first branched optical waveguide 3 is totally reflected.

Further, in order to completely reflect the light and make it perpendicular to the horizontal plane of the waveguide substrate 1, the angle θ is determined. It is sufficient to form the shape at 45°. Note that the formation of the {circle around (2)}-shaped groove 40 can be performed by a dinging saw or etching.

Further, a rod lens 41 is fitted into the square groove 40 so as to cross each end of the optical waveguide 2 and the first branched optical waveguide 4, and is fixed with an optical adhesive 22'. Further, a light emitting element 8 such as a semiconductor laser and an output optical fiber 42 (see FIG. 6) having a tapered spherical tip are placed and fixed at a predetermined position on the waveguide base Vil. te', I).

However, when fixing the rod lens 41, the center of the rod lens 41 should be aligned with the optical axis of each optical waveguide 2, 4 (as shown in FIGS. (see BU YIO).

Further, the optical adhesive 22 for fixing the rod lens 41 is V
Since it is bonded to the shape groove 40, the condition for total reflection of the light propagating through the optical waveguide 2 is broken in such a component part due to the shape a40. That is, as shown by the arrow Y9 in FIG. 6, the light propagating through the optical waveguide 2 undergoes 11ffil, is focused by the rod lens 41, and is coupled to the optical fiber 42.

Also, at the left end of the waveguide substrate 1, a ruby or the like;
An optical fiber halo inserted and fixed in the ring 5 is placed on the end surface of the waveguide substrate 1 at a portion where the end of the optical waveguide 2 is exposed.
They are bonded together with an optical adhesive 7, and furthermore, in addition to these parts, electronic circuits (not shown) are housed in a metal box 15 indicated by a dashed line, thereby forming an integrated optical transceiver module. ing.

According to this configuration, the leading waveguide 2 and the optical fiber 4
2, the second branch optical waveguide 4 and the light emitting element 8 are optically coupled by the rod lens 41, and the first branch optical waveguide 3 (2: the light carried is
The light is totally reflected by the light receiving element 101 and integrated.

Therefore, as in the conventional example shown in FIG. 8, optical coupling ball lenses 9, 10 . And since optical coupling can be performed with the rod lens 41 and the V-shaped structure 40 without using the reflector 13,
The number of optical components can be reduced, and the number of adjustment warpage fixing locations of the optical coupling section can be reduced.

Further, in this fourth embodiment, the rod lens 41 is used as the optical coupling component, but an optical fiber may be used instead. Furthermore, if the tip of the optical fiber is formed at an angle 5) to prevent total reflection, as in the example shown in Figure 3, what will happen? Does each light have a different wavelength? : It is possible to transmit to the transmission line of the route, and the number of parts for optical coupling increases: Manashi).

As described in detail, the present invention: = Twisted: 2. Since optical coupling can be performed with a small number of optical components, the following effects are achieved.

The entire C moneur can be made smaller.

○ Adjustment man-hours can be reduced and assembly can be easily performed. Moreover, mass productivity can be improved thereby.

(2) Furthermore, the effects of (2) and (2) can reduce costs.

Since the number of G parts is small and the number of adjustment points is small, overall reliability can be improved.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the structure of an integrated optical transceiver module according to the first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line 1--2 shown in FIG. A plan view showing the structure of an integrated optical transceiver module according to a second embodiment of the present invention, FIG.
5 is a plan view showing the structure of the integrated optical transmitter/receiver module according to the embodiment, FIG. 5 is a sectional view taken along the line ■-V shown in FIG. 4, and FIG. FIG. 7 is a cross-sectional view taken along the line ■--■ shown in FIG. 4, and FIG. 8 is a plan view showing the structure of a conventional optical transceiver integrated module. DESCRIPTION OF SYMBOLS 1. Waveguide substrate, 2.3, 4... Waveguide, 8... Dog generating element, ', 0... Light receiving element, 20... Groove, 21... Optical fiber 22... Optical adhesive , 40...V-shaped groove, 4i...C:/torlens.

Claims (1)

[Claims] 1. A plurality of waveguides (2, 3, 4) on a waveguide substrate (1)
A waveguide type multiplexer/demultiplexer that is formed parallel to each other at one end and multiplexes or demultiplexes light using the plurality of waveguides (2, 3, 4), and a light emitting element (8). In an integrated optical transmitter/receiver module consisting of an optical transmitter circuit and an optical receiver circuit having a light receiving element (10), a waveguide substrate is disposed at right angles to one end of the plurality of waveguides (2, 3, 4). (1) A groove (20) is provided on the top, and the tip thereof becomes one (3) of the plurality of waveguides (2, 3, 4).
An optical fiber (21) shaped at an angle that totally reflects the light propagating in a predetermined direction is fixed to a predetermined position of the groove (20) with an optical adhesive (22), and the optical fiber (21) and the waveguide (3) which is in contact with this tip via the optical adhesive (22), and the optical fiber (2) via the optical adhesive (22).
1), the light emitting element (8), the light receiving element (10), and the tip of the optical fiber (21) are connected to the waveguide other than the waveguide (3) via the optical adhesive (22). An integrated optical transceiver module characterized by optically coupling wave paths (2, 4). 2. Connect the tip of the optical fiber (21) to the waveguide (
2. The optical transmitter/receiver integrated module according to claim 1, wherein the optical transmitter/receiver integrated module is formed at an angle such that the propagating light is not totally reflected but is branched. 3. A dielectric multilayer film is provided at the tip of the optical fiber (21) so that the light propagating through the waveguide (3) is not totally reflected;
2. The integrated optical transceiver module according to claim 1, wherein the optical transceiver integrated module is branched. 4. Multiple waveguides (2, 3, 4) on the waveguide substrate (1)
A waveguide type multiplexer/demultiplexer that is formed parallel to each other at one end and multiplexes or demultiplexes light using the plurality of waveguides (2, 3, 4), and a light emitting element (8). In an integrated optical transceiver module consisting of an optical transmitting circuit and an optical receiving circuit having a light receiving element (10), the inclined surface directs the light propagating through the waveguide (3) to the waveguide substrate (1). V formed at an angle that causes total reflection downwards
A shaped groove (40) is provided on the waveguide substrate (1) so as to be perpendicular to one end of the plurality of waveguides (2, 3, 4), and the light receiving element (10) is placed on the waveguide substrate (1). A rod lens (41) is fixed to a predetermined position of the V-shaped groove (40) with an optical adhesive (22).
Optically coupling the arbitrary waveguide (3) and the light receiving element (10) via the shaped groove (40), and via the optical adhesive (22) and the rod lens (41),
Any of the plurality of waveguides (2, 4) and the light emitting element (8)
) and an optical fiber (42) having a spherical tip are optically coupled to each other.