JPH08166527A - Optical conversion device - Google Patents

Abstract

PURPOSE: To provide an optical conversion device which reduces a size and cost, has high reliability and is capable of executing single core bidirectional optical communication with high reliability. CONSTITUTION: This optical conversion device 30 is installed in a single core bidirectional communication line and is used to transmit a first light signal L and to receive a second light signal L2. The optical conversion device described above has a substrate 20, a laser beam emitting source 24 which is disposed at this substrate 20 and is used to transmit the first light signal L1, a light receiving section 22 which is disposed at the substrate 20 and is used to receive the second light signal L2 and an optical element 26 which is an optical element 26 to be disposed at the substrate 20, reflects the first light signal L1 delivered from the laser beam emitting source 24, allows the transmission of the second light signal L2 and leads the light signal to the light receiving section 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical conversion device provided in a one-core bidirectional communication line for transmitting an optical signal.

[0002]

2. Description of the Related Art When transmitting a signal by optical communication, a one-core bidirectional communication line system using one optical fiber as shown in FIG. 6 or a two-core system using two optical fibers is used. The two-way communication line method is used. In the one-core bidirectional communication line system of FIG. 6, one optical fiber F is used between one optical transmission device 1 and the other optical transmission device 2. On the other hand, in the two-core bidirectional communication line system of FIG. 7, two optical fibers F1 and F2 are used between one optical transmission device 1 and the other optical transmission device 2.

For example, in the one-core type bidirectional communication line system of FIG. 6, as shown in FIG.
The light emitting element 3, the light receiving element 4, the directional coupler 5, the lens, and the like are included, and the light emitting element 3, the light receiving element 4, the directional coupler 5, and the lens, which are these separate parts, are assembled into a housing. Are configured. Similarly, the other optical transmission device 2 also has a light emitting element 3, a light receiving element 4, a directional coupler 5 and a lens.

[0004]

In the conventional one-core system or two-core system bidirectional communication line system, the optical transmission equipment is
It must be composed of separate light emitting element 3, light receiving element 4, directional coupler 5, lens, etc., which is a major obstacle to downsizing and cost reduction. FIG. 9 shows another conventional optical module used for bidirectional communication. This conventional module is a module having a light emitting / receiving element, and includes a light emitting element 10, a light receiving element 11, a collimator 12, and P.
It has a BS (polarizing beam splitter) 13, an optical fiber collimator 14, an optical connector receptacle 15 and an optical connector ferrule 16. An optical fiber F is connected to the optical connector ferrule 16. Using such a so-called OE / EO converter (optical / electrical / optical converter), an optical line repeater or a demultiplexer (for transmitting one signal to several optical fiber lines), etc. It is not easy to realize, and the configuration is complicated and expensive. Further, a laser diode module for optical communication has a laser diode, a lens, and an optical fiber assembled into one module, and is called a pig tail or the like from its shape. The other end of the pigtail is connected to the output connector of the device.

Therefore, the present invention has been made in order to solve the above problems, and provides an optical conversion device capable of miniaturization, cost reduction, and highly reliable one-core bidirectional optical communication. It is an object.

[0006]

SUMMARY OF THE INVENTION In the present invention, the above object is provided with an optical conversion for transmitting a first optical signal and receiving a second optical signal provided in a one-fiber bidirectional communication line. A device, a substrate, a laser emission source provided on the substrate for transmitting the first optical signal, and a light receiving unit provided on the substrate for receiving the second optical signal. When,
An optical element provided on the substrate, wherein the first optical signal sent from the laser emission source is given to the communication line, and the second optical signal from the communication line is guided to the light receiving unit. And a light conversion device including an optical element. In the present invention, the optical element is preferably a prism having a semi-transmissive mirror or a polarization beam splitter. In the present invention, the position of the light receiving portion and the position of the optical axis of the laser light emission source are preferably separated from each other by a predetermined distance. In the present invention,
Preferably, a plurality of sets of the light receiving section and the laser emission source are provided. In the present invention, preferably further comprising an optical fiber and a lens element for guiding the first optical signal to the optical fiber and for guiding the second optical signal from the optical fiber to the optical element, A lens element is integrally provided.

[0007]

According to the above structure, in the present invention, the laser light emitting source, the light receiving portion, and the optical element are provided on the substrate.
The laser emission source emits a first optical signal. The light receiving section receives the second optical signal. The optical element gives the first optical signal sent from the laser emission source to the communication line, and guides the second optical signal from the communication line to the light receiving unit. In the present invention, preferably, when the position of the light receiving portion and the position of the optical axis of the laser light emission source are apart from each other by a predetermined distance, a communication line having a first optical signal emitted from the laser light emission source is provided. The second light signal from another communication line can be received by the light receiving unit. In the present invention, preferably, when a plurality of sets of the light receiving portion and the laser light emitting source are provided, a plurality of first optical signals emitted from the plurality of laser light emitting sources can be respectively applied to the plurality of communication lines. In addition, the plurality of second optical signals from the other plurality of communication lines can be respectively received by the plurality of light receiving units. In the present invention, preferably further an optical fiber, and guiding the first optical signal to the optical fiber,
Further, a lens element for guiding the second optical signal from the optical fiber to the optical element is provided, and the lens element is integrally provided. By integrating them, miniaturization can be achieved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The examples described below are
Since it is a preferred specific example of the present invention, various technically preferable limitations are attached, but the scope of the present invention is, unless otherwise stated to limit the present invention, in the following description.
It is not limited to these modes. FIG. 1 is a perspective view showing a preferred embodiment of the light conversion device of the present invention. The light conversion device 30 includes a substrate 20, a light receiving portion 22, a laser light emitting source 24, a prism 26, a semiconductor element 32, and preferably a light receiving portion 28 for monitoring laser light of the laser light emitting source. The optical conversion device 30 of FIG. 1 is an optical conversion device that is provided in a one-fiber bidirectional optical communication line to send out a first optical signal and receive a second optical signal. The substrate 20 of the light conversion device 30 has a length S1 of, for example, 3.3.
The width S2 is very small, for example 1.8 mm. The prism 26 and the semiconductor element 32 described above are provided on the upper surface 20 a of the substrate 20. Board 20
Is, for example, silicon Si or gallium arsenide (GaA
s) It is a semiconductor substrate, and the light receiving portion 22 is formed on the upper surface 20a of the substrate 20.

As shown in FIGS. 1 and 2, the prism 26 is also called a micro prism or a trapezoidal prism, and one side of the prism 26 is a semi-transparent mirror 3 having a slanted surface.
4 are formed. The semi-transmissive mirror 34 has a first optical signal (laser light) L sent from the laser emission source 24.
The second optical signal L2 which reflects the light 1 and is sent from the optical fiber F of FIG. 2 and guided through the coupling lens 36.
Is a semi-transmissive mirror for transmitting light. The inclination angle of the semi-transmissive mirror 34 is preferably 45 ° with respect to the plane of the substrate 20, for example.

The semiconductor element 32 includes the above-mentioned laser light emitting source 24 and the monitor light receiving portion 28. The laser emission source 24 preferably uses a laser diode,
The transmitting portion of the laser light emitting source 24 for transmitting the first optical signal L1 faces the semi-transmissive mirror 34 of the prism 26. A laser beam L3 for monitoring is emitted from the rear side of the laser emission source 24, and the laser beam L3 for monitoring is received by the light receiving section 28 for monitoring. By monitoring the laser light L3 in this way, the sending state of the first optical signal L1 of the laser light emission source 24 is monitored, and the drive of the laser light emission source 24 is controlled. The light receiving section 22 receives the second optical signal L2 guided through the optical fiber F and the coupling lens 36.
Is a light-receiving portion for receiving light, and for example, a photodiode is used.

The substrate 20 of the optical conversion device 30 constructed as shown in FIG. 1 is arranged in a package 40 as shown in FIG. The upper center part of this package 40 is
An opening 42 is formed, and the coupling lens 36 is integrally attached to the opening 42. Accordingly, the light conversion device 30, the package 40, and the lens 3
6, preferably the optical fiber F is integrally formed. The coupling lens 36 is preferably a convex lens, and is configured to guide the second optical signal L2 guided from the optical fiber F to the semi-transmissive mirror 34 of the prism 26.
On the other hand, the coupling lens 36 guides the first optical signal L1 sent from the laser emission source 24 to the incident end face 44 of the optical fiber F.

Next, the operation of the light conversion device shown in FIGS. 1 and 2 will be described. In the optical conversion devices of FIGS. 1 and 2, first, the first optical signal L1 from the laser emission source 24 is
As shown in FIG. 2, the light is emitted from the laser emission source 24, reflected vertically upward by the semi-transmissive mirror 34 of the prism 26, focused by the coupling lens 36, and guided to the incident end face 44 of the optical fiber F. The optical fiber F guides the first optical signal L1 to the coupling lens of another optical conversion device (not shown). The other light conversion device is the same as the light conversion device 30 shown in FIGS. 1 and 2. Thus, the first optical signal L1 from the laser emission source 24 is transmitted to the trapezoidal prism 26.
It is reflected by the tilted semi-transmissive mirror 34 and is injected into the optical fiber F through the coupling lens 36.

On the other hand, the second optical signal L2 sent from the laser emission source of another optical conversion device and passing through the optical fiber F is passed through the coupling lens 36 and the prism 26.
Is guided to the semi-transmissive mirror 34. The semi-transmissive mirror 34 refracts the second optical signal L2 by the semi-transmissive mirror 34 and makes it incident on the light receiving portion 22 below the prism 26.
At this time, part of the second optical signal L2 is reflected by the semi-transmissive mirror 34 and is incident on the laser emission source 24 side. However, the second optical signal L2 is transmitted to the laser emission source 24. Since it is the laser light of another laser emission source, it is incoherent with respect to the laser emission source 24 and does not interfere with the first optical signal L1 of this laser emission source 24 and does not interfere with the first optical signal L1. Does not affect the injection of.

Further, the light transmitted through the semi-transmissive mirror 34 of the prism 26 by the first optical signal L1 from the laser light emission source 24, the lower surface 26a of the prism 26 and the substrate (semiconductor substrate) 2
At the interface with the upper surface 20a of 0 (actually, the interface between the substrate 20 and the adhesive for fixing the prism 26), since the incident angle is large, the first optical signal L1 is totally reflected and received. Since the portion 22 does not become stray light, the S / N of the light receiving signal in the light receiving portion 22 is not deteriorated, or the light receiving signal in the light receiving portion 22 is maintained at a required S / N level. You can 1 and 2
In the embodiment of FIG.
By using the (polarization beam splitter), the amount of light transmitted by the first optical signal L1 from the laser emission source 24 can be made extremely small.

Another Embodiment Next, another embodiment of the optical conversion device of the present invention will be described. The optical conversion device 130 of the present invention shown in FIG. 3 is applied as an optical repeater (amplifier), unlike the embodiments shown in FIGS. This light conversion device 130 has almost the same structure as the light conversion device 30 shown in FIGS. 1 and 2, but the following points are different. In the embodiment shown in FIGS. 1 and 2, the emission optical axis of the first optical signal L1 from the laser emission source 24 is arranged at a position substantially in series with the pattern of the light receiving section 22. That is, the emission optical axis of the laser emission source 24 and the pattern of the light receiving section 22 are
It has an inline configuration. As a result, FIG. 1 and FIG.
In the embodiment, the end face of the laser emission source 24 and the light receiving portion 22 are
Since the center of the pattern has a mirror image relationship with the semi-transmissive mirror 34 of the prism 26, the first optical signal or the second light is transmitted through one lens through the coupling lens 36. Only one of the signals can be imaged.

On the other hand, in the embodiment of FIG. 3, as shown in FIG. 4, the surface PH1 of the laser emission source 124 including the optical axis for emitting the first optical signal L1 and the light receiving portion 122 of the prism 126. A space d is provided between the planes PH2 passing through the center of the formation pattern of. That is, in the embodiments of FIGS. 3 and 4, the end face 134 of the first optical fiber F3 is actually used.
The end faces of the second optical fiber F4 are arranged vertically separated from each other in the plane of FIG. Since the distance d is provided between the surfaces PH1 and PH2 as described above, the second optical signal L2 emitted from the end surface of the first optical fiber F3 as the communication line in FIG. 3 is indicated by a broken line. Through the coupling lens 136 and the semi-transmissive mirror 134, the substrate 1
20 and a laser emission source 12
The first optical signal L1 from No. 4 can be coupled to the end face 144 of the second optical fiber F4 as a communication line via the coupling lens 136 as shown by the solid line. The distance d can be designed with a degree of freedom depending on the distance between the first optical fiber F3 and the second optical fiber F4 and the magnification of the coupling lens 136.

FIG. 5 shows another embodiment of the light conversion device of the present invention. The light conversion device 230 of FIG.
4 is an application example of the light conversion device 130 of FIG. 4, and a characteristic is that the laser emission source 224 and the light receiving unit 222 are one set,
That is, a plurality of sets of the laser emission source 24 and the light receiving section 22 are set. For example, n sets of this set are set. As a result, a second optical signal (light receiving signal) from one optical fiber is transmitted from a plurality of required laser light emitting sources 24 as a first optical signal, and the second optical signal is received by a different optical fiber. It can be branched and transmitted. That is, the plurality of first optical signals emitted from the plurality of laser emission sources 224 can be supplied to the plurality of communication lines, respectively, and the plurality of second optical signals from another plurality of communication lines can be supplied. The plurality of light receiving portions 222 of the prism 226 can receive the light.

The present invention is not limited to the above embodiment. Instead of the prism as the optical element described above, a PB
It is also possible to use S (polarizing beam splitter), and even if PBS is used, the first optical signal can be given to the coupling lens side and the second optical signal can be guided to the light receiving unit as in the case of using the prism. it can. In the illustrated embodiment described above, it is also possible to form a driver circuit for a laser emission source such as a laser diode on a semiconductor substrate,
Alternatively, separate drive IC chips can be integrated in the same package. As described above, in the embodiment of the present invention, a small EO / OE converter can be realized, and since this optical converter is a hybrid optical integrated circuit, high reliability can be obtained. Not only the one-core bidirectional line but also the configuration of the relay amplifier and the duplexer can be easily realized. The module of the light conversion device integrated with the coupling lens, which is a lens element, is small in size, and can be easily bonded to an optical fiber. This optical fiber is preferably integrally configured with a coupling lens, a package and the like. Moreover, such an optical conversion device of the present invention is small and inexpensive.

[0019]

As described above, according to the present invention, it is possible to carry out one-core bidirectional optical communication with high reliability and downsizing.

[Brief description of drawings]

FIG. 1 is a diagram showing a preferred embodiment of a light conversion device of the present invention.

FIG. 2 is a diagram showing the overall structure of the optical conversion device of FIG.

FIG. 3 is a diagram showing another embodiment of the optical conversion device of the invention.

FIG. 4 is a plan view of the embodiment of FIG.

FIG. 5 is a diagram showing another embodiment of the optical conversion device of the invention.

FIG. 6 is a diagram showing a conventional single-core bidirectional communication line system.

FIG. 7 is a diagram showing a conventional two-core bidirectional communication line system.

FIG. 8 is a diagram showing a configuration of a conventional one-core bidirectional communication line.

FIG. 9 is a view showing an example of a light emitting and receiving integrated module.

[Explanation of symbols]

 20 substrate 22 light receiving part 24 laser emission source 26 prism (optical element) 30 light conversion device 34 semi-transmissive mirror

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H01S 3/18 H04B 10/24

Claims (6)

[Claims] 1. A one-way bidirectional communication line is provided with a first
Is an optical conversion device for sending out the optical signal and receiving the second optical signal, a substrate, a laser emission source provided on the substrate for sending out the first optical signal, and the substrate A light-receiving unit for receiving the second optical signal, and an optical element provided on the substrate, for providing the communication line with the first optical signal sent from the laser emission source. And an optical element for guiding the second optical signal from the communication line to the light receiving section. 2. The light conversion device according to claim 1, wherein the optical element is a prism having a semi-transmissive mirror or a polarization beam splitter. 3. The optical conversion device according to claim 1, wherein the position of the light receiving section and the position of the optical axis of the laser light emitted from the laser emission source are separated from each other by a predetermined distance. 4. The light conversion device according to claim 3, further comprising a plurality of sets of the light receiving section and the laser emission source. 5. An optical fiber and a lens element for guiding the first optical signal to the optical fiber and for guiding the second optical signal from the optical fiber to the optical element, wherein the lens element is integrated. The optical conversion device according to claim 1, wherein the optical conversion device is provided in. 6. The optical conversion device according to claim 5, wherein the optical fiber is provided integrally with the lens.