JP2005091460A - Bidirectional optical module, optical transmitter and receiver and optical transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical module which prevents one part of optical signals outputted by one's own light emitting element from propagating as a clad mode and being made incident to one's own light receiving element so as to suppress a deterioration in receiving characteristics. <P>SOLUTION: The bidirectional optical module is provided with a surface light emitting element 96, a transmission part comprising a wavelength division multiplexing (WDM) element 5 that reflects a transmitted optical signal outgoing from the surface light emitting element and a light receiving part 98 which is arranged on the back side of the transmission part viewing from optical fibers for transmission 92, 94. Input light is transmitted by the WDM element and is made incident to the light receiving part and output light from the surface light emitting element is reflected by the WDM element and is made to proceed to the optical fibers for transmission. Because the propagation of the output light from the light emission element up to the light receiving element of the light receiving part can be prevented, the single-fiber bidirectional optical module excellent in receiving characteristics can be obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an apparatus that performs bidirectional optical communication using a single optical fiber, and more particularly to a bidirectional optical module, an optical transmission / reception apparatus, and an optical transmission system that are used in such an apparatus.

FIG. 9 is a diagram illustrating an example of a conventional single-core bidirectional optical module disclosed in, for example, the following patent document. 9A is a perspective view of the single-core bidirectional optical module 800, and FIG. 9B is a cross-sectional view of the optical module 800 taken along the XY plane in FIG. 9A. As shown in FIG. 9, an optical module 800 receives an optical signal input from a light emitting element 86 that converts an input electrical signal into an optical signal, and an optical fiber 4A for transmitting / receiving an optical signal to be transmitted / received to / from the outside. A wavelength division multiplexing (WDM = Wavelength Division Multiplexing) that reflects the light signal emitted from the core 3 of the optical fiber 4A and the light signal emitted from the core 3 of the optical fiber 4A, enters the light receiving element 88, and transmits the output light of the light emitting element 86. ) Element 85 is provided. The light emitting element 86 is bonded to the chip carrier 87. The optical fiber 2A composed of the core 1 and the clad 2 and the optical fiber 4A composed of the core 3 and the clad 4 embed one optical fiber in a groove provided on one surface of the glass substrate 10, and are almost equal to this optical fiber. After fixing with the adhesive agent 11 which has a refractive index, the diagonal groove | channel 12 orthogonal to an optical fiber was made in the glass substrate 10 and it was made. A wavelength division multiplexing element 85 is inserted into the groove 12 and fixed. The light emitting element 86 is accurately aligned so that output light is input to the core 1. The light receiving element 88 is fixed to the glass substrate 10 by solder bumps 7 after the input light from the optical fiber 4A is accurately aligned with the position where the light is emitted from the wavelength division multiplexing element 85 and incident.
JP 2001-324655 A (summary, FIG. 9)

  The electrical signal applied to the light emitting element 86 is converted into an optical signal, input to the core 1 of the optical fiber 2A, passes through the wavelength division multiplexing element 85 that multiplexes or separates the optical signal, and enters the core 3. On the other hand, the optical signal input from the core 3 of the optical fiber 4A is reflected by the wavelength division multiplexing element 85, enters the light receiving element 88, is converted into an electric signal, and is output. As described above, the conventional optical module 800 can exchange optical signals for transmission and reception with a single transmission optical fiber.

  However, in the conventional optical module, as indicated by the dotted arrow in the cross-sectional view of FIG. 9B, the optical signal output from the light emitting element 86 is also input to the clad 2, and the clad mode is reflected by refraction. There is a problem of optical crosstalk that propagates and enters the light receiving element 88 as stray light and becomes interference light with respect to the received light.

With respect to this problem, a technique for improving light isolation in a bidirectional optical module having a light emitting element and a light receiving element has been disclosed (see Patent Document 1 below). In this document, while maintaining the arrangement relationship of the light emitting element, the light receiving element, and the WDM element shown in FIG. Various proposals have been made such as fixing with a fixing resin having a refractive index lower than that of the clad. However, it is difficult to say that it is always satisfactory, because it is necessary to add elements to realize the proposal, and the proposal cannot be expected to be sufficiently effective.
Therefore, it would be advantageous to have a bi-directional optical module with a novel structure that can reduce interference light without adding special elements.

  The bidirectional optical module according to claim 1, wherein a transmission optical signal to be transmitted and a reception optical signal to be received are exchanged with an external optical waveguide, and a predetermined electric signal is converted into the transmission optical signal. A surface-emitting light-emitting element; receiving means for receiving a received optical signal from the extraction optical waveguide and converting it into an electrical signal; and reflecting the transmitted optical signal output from the light-emitting element to reflect in the extraction optical waveguide And optical multiplexing / demultiplexing means for demultiplexing the received optical signal input from the lead-out optical waveguide and applying it to the receiving means. With this configuration, the light receiving element can be disposed behind the light emitting element, and since the clad mode does not propagate to the light receiving element, an optical module with less interference light and excellent reception characteristics can be obtained.

  The bidirectional optical module according to claim 2 is the bidirectional optical module according to claim 1, wherein the optical waveguide is embedded, and a notch perpendicular to the optical waveguide is inclined at least to a position where the core of the optical waveguide passes. A waveguide substrate in which one of the optical waveguides divided by the cut becomes the lead-out optical waveguide, and the optical multiplexing / demultiplexing means is inserted into the notch, in the vicinity of the optical multiplexing / demultiplexing means The light emitting element is directly bonded to the waveguide substrate. With this configuration, the light receiving element can be arranged behind the light emitting element, and the clad mode does not propagate to the light receiving element, so that an optical module with less interference light and excellent reception characteristics can be obtained. Since the can-type package is unnecessary, the price of the optical module can be reduced.

  A bidirectional optical module according to a third aspect is the bidirectional optical module according to the first aspect, wherein the receiving means is optically coupled to the extraction optical waveguide via the optical multiplexing / demultiplexing means. The second optical waveguide and a light receiving element arranged so as to be able to efficiently receive the output light from the second optical waveguide.

  The bidirectional optical module according to claim 4 is the bidirectional optical module according to claim 1, wherein one end of the receiving means is optically coupled to the extraction optical waveguide via the optical multiplexing / demultiplexing means. A second optical waveguide whose other end is inclined with respect to its optical axis, and a second optical waveguide that is disposed in parallel to the surface of the other end of the second optical waveguide and that is emitted from the second optical waveguide. A total reflection element that reflects a received optical signal and a light receiving element that is arranged so that the received optical signal reflected by the total reflection element can be received efficiently.

  The bidirectional optical module according to claim 5 is the bidirectional optical module according to claim 4, wherein the optical waveguide is embedded, and at least first and second cuts parallel to each other perpendicular to the optical waveguide are provided in the optical waveguide. A waveguide substrate provided obliquely to a position through which the core passes, wherein the optical waveguide at the end sectioned by the first cut is defined as the lead-out optical waveguide, and the optical waveguide between the first and second cuts Is the second optical waveguide, the total reflection element is inserted and bonded to the second cut, and the light receiving element is directly bonded to the waveguide substrate in the vicinity of the total reflection element. With this configuration, it is possible to obtain a small optical module with excellent reception characteristics and excellent mass productivity.

  The bidirectional optical module according to claim 6 is the bidirectional optical module according to claim 1, wherein the optical waveguide is embedded, and a notch perpendicular to the optical waveguide is inclined at least to a position where the core of the optical waveguide passes. A waveguide substrate in which one of the optical waveguides divided by the cut becomes the lead-out optical waveguide, and an electric circuit substrate on which the light emitting element is directly bonded. Wave means is inserted and bonded, and the light emitting element is bonded to the waveguide substrate in the vicinity of the optical multiplexing / demultiplexing means. With this configuration, since an electric circuit board is mounted in advance, it is possible to perform active alignment in which the optical axis of the light emitting element is adjusted while monitoring the output of the light emitting element. Can be realized.

  The bidirectional optical module according to claim 7 is the bidirectional optical module according to claim 4, wherein the optical waveguide is embedded and at least first and second cuts parallel to each other perpendicular to the optical waveguide are provided. A waveguide substrate provided obliquely to a position through which the core passes, a first electric circuit substrate in which the light emitting element is directly bonded, and a second electric circuit substrate in which the light receiving element is directly bonded. The optical multiplexing / demultiplexing means is inserted and bonded to the first cut, the total reflection element is inserted and bonded to the second notch, and the light emitting element is bonded to the waveguide substrate in the vicinity of the optical multiplexing / demultiplexing means The light receiving element is bonded to the waveguide substrate in the vicinity of the total reflection element. With this configuration, active alignment is possible, and a compact and low-cost optical module with excellent reception characteristics can be realized.

  The bidirectional optical module according to claim 8 is the bidirectional optical module according to claim 7, wherein the first and second electric circuit boards are the same electric circuit board. With this configuration, it is possible to further reduce the size of an optical module that is excellent in reception characteristics and excellent in mass productivity.

  A bidirectional optical module according to a ninth aspect is the bidirectional optical module according to any one of the first to eighth aspects, wherein the light emitting element is a laser diode. With this configuration, since a surface emitting laser diode is provided as a light emitting element, an excellent optical module capable of long-distance transmission can be obtained.

  A bidirectional optical module according to a tenth aspect is the bidirectional optical module according to any one of the first to ninth aspects, wherein the optical waveguide is an optical fiber.

  The bidirectional optical module according to claim 11 is the bidirectional optical module according to any one of claims 2 and 5 to 7, wherein the optical waveguide is integrated on the waveguide substrate. It is what.

  A bidirectional optical module according to a twelfth aspect is the bidirectional optical module according to any one of the first, third, fourth, eighth and ninth aspects, wherein the optical waveguide is integrated on a waveguide substrate. It is a waveguide.

  A bidirectional optical module according to a thirteenth aspect is the bidirectional optical module according to any one of the sixth to eighth aspects, wherein the light emitting element bonded directly to the electric circuit board is connected to the waveguide substrate. An adhesive having substantially the same refractive index as that of the optical waveguide is used for bonding. With this configuration, since the refractive indexes of the optical waveguide and the adhesive are matched, the loss of the light emitting element and the optical multiplexing / demultiplexing means is reduced, and good output intensity characteristics can be obtained.

  The bidirectional optical module according to claim 14 is the bidirectional optical module according to any one of claims 2 and 5 to 7, wherein the waveguide substrate is made of quartz glass. With this configuration, quartz glass is transparent to the wavelength band of signal light used for optical communications, so there is little refraction or irregular reflection between the optical waveguide and the substrate, and an optical module with excellent reception characteristics. Can be obtained.

  The bidirectional optical module according to claim 15 is the bidirectional optical module according to any one of claims 2 and 5 to 7, wherein the waveguide substrate is made of a silicon crystal. With this configuration, since the silicon crystal is transparent to the wavelength band of signal light used for optical communication, an optical module with less refraction and irregular reflection between the optical waveguide and the substrate and excellent reception characteristics is obtained. be able to.

  A bidirectional optical module according to a sixteenth aspect is the bidirectional optical module according to any one of the second and fifth to seventh aspects, wherein the waveguide substrate is made of a polymer. With this configuration, since the polymer is transparent to the wavelength band of signal light used for optical communication, there is little refraction or irregular reflection between the optical waveguide and the substrate, and an optical module with excellent reception characteristics can be obtained. Can do.

  The bidirectional optical module according to claim 17 is the bidirectional optical module according to any one of claims 1 to 16, wherein the optical multiplexing / demultiplexing means inputs the received optical signal from the extraction optical waveguide. Are wavelength division multiplexing elements that transmit the wavelength components of the transmitted optical signal and reflect the wavelength components of the transmission optical signal output from the light emitting element. With this configuration, the clad mode does not propagate to the light receiving element, so that an optical module with less interference light and excellent reception characteristics can be obtained.

  The bidirectional optical module according to claim 18 is the bidirectional optical module according to any one of claims 1 to 16, wherein the optical multiplexing / demultiplexing means inputs the received optical signal from the extraction optical waveguide. Is a half mirror element in which a part of the transmitted light signal is transmitted and a part of the transmission optical signal output from the light emitting element is reflected.

  According to a nineteenth aspect of the present invention, there is provided the bidirectional optical module according to any one of the first to eighteenth aspects, and a signal capable of driving the light emitting element included in the bidirectional optical module with an electrical signal to be transmitted. An optical circuit comprising: a drive circuit for converting the output signal; an amplifier circuit for amplifying the output signal of the light receiving element included in the bidirectional optical module; It is a transmission / reception device. With this configuration, it is possible to obtain an optical transmission / reception apparatus for a single-core bidirectional optical communication system with a wavelength division multiplexing system with less interference light and excellent reception characteristics.

  According to a twentieth aspect of the present invention, there is provided the optical transceiver according to the nineteenth aspect, means for supplying the electric signal to be transmitted to the drive circuit, and means for using the data signal output from the electric circuit. By providing the optical transmission system, single-core bidirectional optical communication is possible.

  A twenty-first aspect of the invention includes the two optical transmission / reception devices according to the nineteenth aspect, wherein the two optical transmission / reception devices are connected to each other by a transmission optical fiber, and the transmission optical signal and the reception optical signal are connected to each other. This is an optical transmission system using different wavelengths. With this configuration, it is possible to obtain a wavelength division multiplexing optical transmission system with less interference light and excellent reception characteristics.

  According to one embodiment of the present invention, the transmitter includes a surface light emitting element and a wavelength division multiplexing element that reflects a transmission optical signal emitted from the surface light emitting element, and is located behind the transmitter as viewed from the transmission optical fiber. By arranging the receiving unit, it is possible to prevent the output light from the surface light emitting element from propagating to the light receiving element of the receiving unit, so that it is possible to obtain a bidirectional optical module with less interference light and excellent receiving characteristics. it can.

Further, according to another embodiment of the present invention, an apparatus capable of performing single-core bidirectional communication with excellent reception characteristics can be obtained by using an optical module in which the influence of crosstalk is reduced. This includes an optical transceiver and an optical transceiver module.
According to still another embodiment of the present invention, an optical transmission system can be obtained by providing the optical transmission / reception apparatus of the present invention on both the transmission side and the reception side and connecting them with optical fibers.

Hereinafter, the present invention will be described in detail with reference to embodiments of the present invention and the accompanying drawings.
In addition, when showing the same element in several drawing, the same referential mark is attached | subjected.
<Principle of the invention>
FIG. 1 is a diagram conceptually showing a bidirectional optical module of the present invention in order to explain the principle of the present invention. In FIG. 1, a bidirectional optical module 900 according to the principle of the present invention includes a surface light-emitting element 96 such as a surface-emitting laser diode that converts an electrical signal to be transmitted into a transmission optical signal, and one optical waveguide cut obliquely. The optical waveguides 92 and 94 made in this way, the wavelength division multiplexing element 5 inserted between the cut surfaces of these optical waveguides 92 and 94, and the wavelength division multiplexing element 5 provided on the optical waveguide 94 and passing through the wavelength division multiplexing element 5 The light receiving unit 98 receives the received optical signal.

The optical waveguide 92 serves as a port for transmitting / receiving a transmission optical signal and a reception optical signal to / from the outside. Here, the optical waveguide 92 is temporarily referred to as a “drawing optical waveguide”. The wavelength division multiplexing element 5 has a characteristic of reflecting the optical signal output from the surface light emitting element 96 and transmitting the received optical signal incident from the optical waveguide 92. The light receiving unit 98 may be a light receiving element (not shown in FIG. 1) that directly receives the output light of the optical waveguide 94, or the end surface of the optical waveguide 94 is cut obliquely and positioned parallel to the cut surface. A combination of a total reflection element (not shown in FIG. 1) and a light receiving element (not shown in FIG. 1) for receiving the output light of the total reflection element may be used.
The present invention has the structure as described above, and the output light of the surface light emitting element 96 is reflected by the wavelength division multiplexing element 5 so that the output light of the surface light emitting element 96 does not reach the light receiving element as stray light. .
The optical waveguides 92 and 94 may be optical fibers embedded in grooves formed in a glass substrate (10 or 20 described later), or may be optical waveguides integrated on a glass substrate.

<First Embodiment>
FIG. 2 shows a bidirectional optical module 100 according to the first embodiment of the present invention. 2A is a perspective view, and FIG. 2B is a cross-sectional view taken along a plane XY in FIG. 2A. In FIG. 2, the optical module 100 according to the first embodiment of the present invention includes a chip carrier 9 to which a light receiving element 8 is bonded, a glass substrate 10 in which optical fibers 2A and 4A and a wavelength division multiplexing element 5 are embedded. The surface emitting laser diode 6 is flip-chip bonded to the glass substrate 10. A groove for embedding an optical fiber is cut in the glass substrate 10 in advance. After embedding one optical fiber in the groove and fixing with an adhesive 11, a groove 12 orthogonal to the optical fiber is formed obliquely. Thus, a groove 12 for inserting the optical fibers 2A, 4A and the wavelength division multiplexing element 5 is formed in the glass substrate 10. The wavelength division multiplexing element 5 is bonded to the groove 12. The wavelength division multiplexing element 5 reflects the transmission optical signal output from the surface emitting laser diode 6 and transmits the input reception optical signal. The surface emitting laser diode 6 is provided with solder bumps 7 and is flip-chip bonded to the glass substrate 10 using the solder bumps. At this time, the mounting position of the surface emitting laser diode 6 is accurately bonded to the position where the marker is attached. Instead of the glass substrate 10, a silicon crystal substrate or a polymer substrate that is transparent with respect to the wavelength of the optical signal used for optical communication may be used.

The operation of the optical module configured as described above will be described with reference to FIG.
First, an electric signal input to the surface emitting laser diode 6 is converted into an optical signal, reflected by the wavelength division multiplexing element 5, input to the core 3 of the optical fiber 4A, and output as an output optical signal of the optical module. The On the other hand, the optical signal input from the core 3 is transmitted by the wavelength division multiplexing element 5, enters the light receiving element 8, is converted into an electrical signal, and is output.

  As described above, according to the optical module 100 of the first embodiment of the present invention, by using the surface emitting laser diode, the light receiving element can be disposed behind the light emitting element, and the cladding mode is the light receiving element. A bidirectional optical module with less interference light and excellent reception characteristics can be obtained without propagating up to.

<Second Embodiment>
FIG. 3 shows a bidirectional optical module 100a according to the second embodiment of the present invention. 3A is a perspective view, and FIG. 3B is a cross-sectional view taken along a plane XY in FIG. 3A. In FIG. 3, the optical module 100 a according to the second embodiment of the present invention has the total reflection element 25 mounted obliquely behind the wavelength division multiplexing element 5 and the light receiving element 28 in the vicinity of the total reflection element 25. The optical module 100 is the same as the optical module 100 according to the first embodiment except that the glass substrate 20 is flip-chip bonded. A groove for embedding an optical fiber is cut in the glass substrate 20 in advance. After the optical fiber is embedded in the groove and fixed with the adhesive 11, the wavelength division multiplexing element 5 and the total reflection element 25 are inserted. By forming the oblique grooves 13 and 13 in the glass substrate 20, the optical fibers 2A, 16A and 4A are also produced. The wavelength division multiplexing element 5 and the total reflection element 25 are inserted into the grooves 12 and 13 and bonded.

  As is clear from the above description, the operation of the optical module 100a is the same as the operation of the optical module 100 except for the operation related to the received optical signal after passing through the wavelength division multiplexing element 5. Explaining only the difference, the received optical signal transmitted through the wavelength division multiplexing element 5 is reflected by the total reflection element 25, enters the light receiving element 28, is converted into an electric signal, and is output.

  Therefore, according to the optical module 100a of the second embodiment of the present invention, by using the surface emitting laser diode 6, the light receiving element 28 can be arranged behind the light emitting element 28, and the cladding mode is the light receiving element 28. Therefore, it is possible to obtain an optical module for a single-core bidirectional optical communication system with less interference light and excellent reception characteristics. Furthermore, since the light receiving element 28 is also integrated with the glass substrate 20, the optical module 100a can be reduced in size.

<Third Embodiment>
FIG. 4 shows a bidirectional optical module 100b according to the third embodiment of the present invention. 4A is a perspective view, FIG. 4B is a cross-sectional view cut along a plane XY in FIG. 4A, and FIG. 4C is a cross-sectional view along line aa ′. The optical module 100b of FIG. 4 includes a cable 21 and a connector 22 that use a surface-emitting laser diode 26 as a wire for electric wiring instead of flip-chip bonding the surface-emitting laser diode 6 shown in FIG. 3 is bonded to the electric circuit board 27, and the surface emitting laser diode 26 is bonded to the glass substrate 20 with the adhesive 30, and the light receiving element 28 shown in FIG. 3 except that the light receiving element 38 is bonded to the electric circuit board 39 with the cable 23 and the connector 24 and then the light receiving element 38 is bonded to the glass substrate 20 with the adhesive 30. It is.

Since the surface emitting laser diode 26 and the light receiving element 38 are inputted and outputted with optical signals from the back surface, the back surface may be partially removed by etching in order to increase the light emission efficiency and the light receiving efficiency. Further, instead of the glass substrate 20, a silicon crystal substrate or a polymer substrate transparent to the wavelength of the optical signal used for optical communication may be used. Connectors 22 and 24 are connected to the electric circuit boards 27 and 39 by cables 21 and 23, respectively. The cables 21 and 23 may be flexible boards having a high degree of mechanical freedom. When the surface emitting laser diode 26 and the light receiving element 38 are bonded to the glass substrate 20, the output optical signal or the output electric signal can be monitored via the connectors 22 and 24. Therefore, the core 3 of the optical fiber 4A is used. Positioning can be performed so that the output optical signal or the output electrical signal has an appropriate value while inputting / outputting the optical signal.
As is clear from the above configuration, the operation of the optical module 100b is the same as the operation of the optical module 100a of FIG.

  Thus, according to the optical module 100b of the third embodiment of the present invention, by using the surface emitting laser diode 26, the light receiving element 38 can be arranged behind the laser diode 26, and the cladding mode is the light receiving element. Therefore, it is possible to obtain an optical module with less interference light and excellent reception characteristics. Furthermore, since the light receiving element 38 can also be integrated with the glass substrate 20, the optical module 100b can be reduced in size. Furthermore, since the positioning of the laser diode 26 and the light receiving element 38, which are light emitting elements, can be performed while monitoring the output signal, high-accuracy positioning can be simplified, which helps to reduce the price.

<Fourth embodiment>
FIG. 5 shows a bidirectional optical module 100c according to the fourth embodiment of the present invention. 5A is a perspective view, and FIG. 5B is a cross-sectional view taken along a plane XY in FIG. 5A. The optical module 100c shown in FIG. 5 has an electric circuit board 27 with a cable 21 and a connector 22, an electric circuit board 39 with a cable 23 and a connector 24, and an electric circuit board 40 with one cable 41 and a connector 42. The optical module 100b is the same as the optical module 100b of FIG.
The operation of the optical module 100c is the same as that of the optical module 100b.

As described above, according to the optical module of the fourth embodiment of the present invention, the same effect as that of the third embodiment can be obtained, and the number of parts is further reduced, so that the assembly can be simplified and the cost can be reduced. be able to.
In the example of FIG. 5A, one cable 41 and connector 42 are used for the electric circuit board 40, but the connectors 22, 24 are used for the electric circuit board 40 as in the embodiment of FIG. May be individually connected by cables 21 and 23.

<Fifth embodiment>
In the optical modules 100 and 100a to 100c of FIGS. 2 to 5 described above, the example in which the optical fibers 2A and 4A are used as the optical waveguide has been shown. However, the grooves formed along the optical axis direction of the glass substrate 10 or 20 An optical waveguide may be formed. FIG. 6 shows an example of an optical module 110 in which the optical fibers 2A and 4A of the optical module 100 shown in FIG. Similarly, in the optical modules 100a to 100c of FIGS. 3 to 5, the same effect can be obtained even if the optical fiber is replaced with an optical waveguide integrated on the glass substrate 10 or 20.

<Sixth Embodiment>
FIG. 7 is a schematic block diagram showing the structure of an optical transceiver that performs single-core bidirectional optical communication using the above-described bidirectional optical module as a sixth embodiment of the present invention. In FIG. 7, the optical transceiver 60 includes a bidirectional optical module 900 (including 100a to 100c and 110 represented by 100) according to any of the above embodiments, and the light receiving element 8 of the bidirectional optical module 900. An amplifier circuit 64 that amplifies the received signal from the signal 28 or 38, a clock recovery circuit 66 that extracts a clock component from the received signal, a data recovery circuit 68 that recovers a data signal from the received signal and the clock signal, and an optical module A drive circuit 62 for driving the included light emitting element 6 or 26 is included. The optical transceiver 60 is optically coupled to the transmission optical fiber 74.

  The optical signal transmitted through the transmission optical fiber 74 is input to the bidirectional optical module 900 of the optical transceiver 60. The optical signal input to the bidirectional optical module 900 is transmitted through the wavelength division multiplexing element 5, input to the light receiving element 8, 28 or 38, converted into an electrical signal, and output to the amplifier circuit 64. The electric signal amplified by the amplifier circuit 64 is branched into two, one being input to the clock recovery circuit 66 and the other being input to the data recovery circuit 68. The clock recovery circuit 66 generates a clock signal from the input electric signal and supplies it to the data recovery circuit 68 and other circuit portions. In addition, the data reproduction circuit 68 reproduces the data signal by performing waveform shaping on the input electric signal using the clock signal input from the clock reproduction circuit 66. A signal to be transmitted in the optical transmitter / receiver 60 is input to the light emitting element 6 or 26 of the bidirectional optical module 900 through the drive circuit 62 and converted into an optical signal, and this optical signal is reflected by the wavelength division multiplexing element 5. And coupled to the transmission optical fiber 74.

  Thus, according to the apparatus of the sixth embodiment of the present invention, a good data signal and clock signal can be obtained without the transmission optical signal of the own station interfering with the reception optical signal. The device according to the present embodiment may be an independent device or an optical transceiver module as long as it performs single-core bidirectional optical communication.

<Seventh embodiment>
FIG. 8 is a schematic block diagram of an optical transmission system according to the seventh embodiment of the present invention. In the optical transmission system of FIG. 8, two devices 70 and 72 that perform optical transmission and reception are connected by an optical fiber 74 for transmission. Each of the two devices 70 and 72 includes the optical transmission / reception device (or module) 60 shown in FIG. 7 for performing single-core bidirectional optical communication. In each of the optical transmission / reception apparatuses 60 of the two apparatuses 70 and 72, the light receiving element and the wavelength division multiplexing element are selected so that the other can receive the wavelength of the optical signal output by one so that communication can be established. . Moreover, it is preferable that each optical transmission / reception apparatus 60 uses a different frequency for transmission / reception.

  For example, if the optical transmission / reception device 60 of the device 70 transmits light of 1.3 μm band and receives light of 1.5 μm band, the optical transmission / reception device 60 of the device 72 uses light in the reverse band for transmission / reception. . In this way, by connecting two optical transmitters / receivers having different wavelengths of the optical signal to be transmitted and the optical signal to be received through the optical fiber and facing each other, a bidirectional optical fiber that reduces the influence of crosstalk with a single optical fiber. Communication can be performed.

The wavelength division multiplexing element 5 in FIG. 7 used in the above-described embodiment reflects the wavelength component of the optical signal output from the light emitting element 6 or 26 and is input from the extraction optical waveguide (transmission optical fiber) 74. The wavelength component of the optical signal may be transmitted.
Further, the wavelength division multiplexing element 5 is a half mirror that reflects a part of the wavelength component of the optical signal output from the light emitting element 6 or 26 and transmits a part of the wavelength component of the optical signal input from the extraction optical waveguide 74. An element may be sufficient.
The above is merely an example of an embodiment for explaining the present invention. Therefore, it is easy for those skilled in the art to make various changes, modifications, or additions to the above-described embodiment.

  According to the present invention, a bidirectional optical module with less interference light and excellent reception characteristics can be obtained, and an apparatus and system using the same can be obtained. Therefore, the present invention can be used in the field of optical communication. .

The figure which showed the bidirectional | two-way optical module of this invention notionally The figure which shows the structure and operation | movement of a bidirectional | two-way optical module by the 1st Embodiment of this invention. The figure which shows the structure and operation | movement of a bidirectional | two-way optical module by the 2nd Embodiment of this invention. The figure which shows the structure and operation | movement of a bidirectional | two-way optical module by the 3rd Embodiment of this invention. The figure which shows the structure and operation | movement of a bidirectional | two-way optical module by the 4th Embodiment of this invention. The figure which shows the structure and operation | movement of a bidirectional | two-way optical module by the 5th Embodiment of this invention. 1 is a schematic block diagram showing the structure of a single-core bidirectional optical transceiver according to a sixth embodiment of the present invention using the bidirectional optical module shown in any of FIGS. 7 is a schematic block diagram showing an optical transmission system that performs optical communication using the single-core bidirectional optical transceiver 60 of FIG. 7 according to the seventh embodiment of the present invention. The figure which shows an example of the conventional single-core bidirectional optical module

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 3, 15 Optical fiber core 2, 4, 16 Optical fiber clad 2A, 4A, 16A Optical fiber 5, 85 Wavelength division multiplexing element 6, 26, 96 Surface emitting type laser diode as surface emitting element 7 Solder bump 8, 28, 38 Light-receiving element 9, 87 Chip carrier 10, 20 Glass substrate 11, 30 Adhesive 12 Wavelength division multiplexing element insertion groove (groove)
13 Total reflection element insertion groove 21, 23, 41 Wire for electric wiring (cable)
22, 24, 42 Connector 25 Total reflection element 27, 39, 40 Electric circuit board 50, 51, 92, 94 Optical waveguide 60 Optical transmitter / receiver 61, 74 Transmission optical fiber 62 Drive circuit 64 Amplifying circuit 68 Data recovery circuit 70 72 Light transmission / reception device 86 Light emitting element 98 Light receiving unit 100, 100a to 100c, 110, 900 Bidirectional optical module

Claims (21)

A lead optical waveguide for transmitting and receiving a transmission optical signal to be transmitted and a reception optical signal to be received;
A surface-emitting light-emitting element that converts a predetermined electrical signal into the transmission optical signal;
Receiving means for receiving a received optical signal from the extraction optical waveguide and converting it into an electrical signal;
The transmission optical signal output from the light emitting element is reflected and multiplexed with the light in the extraction optical waveguide, and the reception optical signal input from the extraction optical waveguide is transmitted and demultiplexed to Optical multiplexing / demultiplexing means to be given to the receiving means,
Bidirectional optical module provided. By embedding the optical waveguide and providing an incision perpendicular to the optical waveguide obliquely at least to a position where the core of the optical waveguide passes, one of the optical waveguides delimited by the incision becomes the extraction optical waveguide A waveguide substrate,
Inserting the optical multiplexing / demultiplexing means into the notch,
The bidirectional optical module according to claim 1, wherein the light emitting element is directly bonded to the waveguide substrate in the vicinity of the optical multiplexing / demultiplexing means. The receiving means is
A second optical waveguide disposed so as to be optically coupled to the extraction optical waveguide via the optical multiplexing / demultiplexing means;
The bidirectional optical module according to claim 1, further comprising: a light receiving element disposed so as to efficiently receive output light from the second optical waveguide. The receiving means is
A second optical waveguide having one end disposed so as to be optically coupled to the extraction optical waveguide via the optical multiplexing / demultiplexing means, and the other end inclined with respect to the optical axis;
A total reflection element that is arranged in parallel to the other end surface of the second optical waveguide and reflects the received optical signal emitted from the second optical waveguide;
The bidirectional optical module according to claim 1, further comprising a light receiving element arranged so that the received optical signal reflected by the total reflection element can be efficiently received. A waveguide substrate embedded with an optical waveguide and provided obliquely to a position where at least the core of the optical waveguide passes through first and second parallel cuts perpendicular to the optical waveguide;
The optical waveguide at the end delimited by the first cut is the extraction optical waveguide,
The optical waveguide between the first and second cuts is the second optical waveguide,
Inserting and adhering the total reflection element to the second cut,
The bidirectional optical module according to claim 4, wherein the light receiving element is directly bonded to the waveguide substrate in the vicinity of the total reflection element. An optical waveguide is embedded, and a notch perpendicular to the optical waveguide is obliquely provided at least to a position where the core of the optical waveguide passes, so that one of the optical waveguides delimited by the notch becomes the extraction optical waveguide A waveguide substrate;
An electric circuit board directly bonded to the light emitting element,
Insert and bond the optical multiplexing / demultiplexing means to the notch,
The bidirectional optical module according to claim 1, wherein the light emitting element is bonded to the waveguide substrate in the vicinity of the optical multiplexing / demultiplexing means. A waveguide substrate in which an optical waveguide is embedded, and first and second cuts parallel to each other orthogonal to the optical waveguide are provided obliquely to a position where at least the core of the optical waveguide passes;
A first electric circuit board on which the light emitting element is directly bonded;
A second electric circuit board directly bonded to the light receiving element;
The optical multiplexing / demultiplexing means is inserted and bonded to the first cut,
The total reflection element is inserted and bonded to the second cut,
Adhering the light emitting element to the waveguide substrate in the vicinity of the optical multiplexing / demultiplexing means,
The bidirectional optical module according to claim 4, wherein the light receiving element is bonded to the waveguide substrate in the vicinity of the total reflection element.   The bidirectional optical module according to claim 7, wherein the first and second electric circuit boards are the same electric circuit board.   The bidirectional light module according to claim 1, wherein the light emitting element is a laser diode.   The bidirectional optical module according to claim 1, wherein the optical waveguide is an optical fiber.   The bidirectional optical module according to any one of claims 2 and 5 to 7, wherein the optical waveguide is an optical waveguide integrated on the waveguide substrate.   The bidirectional optical module according to any one of claims 1, 3, 4, 8, and 9, wherein the optical waveguide is an optical waveguide integrated on a waveguide substrate.   9. Both according to claim 6, wherein an adhesive having substantially the same refractive index as that of the optical waveguide is used for adhering the light emitting element directly bonded to the electric circuit substrate to the waveguide substrate. Mukko module.   8. The bidirectional optical module according to claim 2, wherein the waveguide substrate is made of quartz glass.   The bidirectional optical module according to claim 2, wherein the waveguide substrate is made of silicon crystal.   The bidirectional optical module according to any one of claims 2 and 5 to 7, wherein the waveguide substrate is made of a polymer.   The optical multiplexing / demultiplexing means is a wavelength division multiplexing element that transmits the wavelength component of the received optical signal input from the extraction optical waveguide and reflects the wavelength component of the transmitted optical signal output from the light emitting element. 17. The bidirectional optical module according to any one of 1 to 16.   The optical multiplexing / demultiplexing means is a half mirror element that transmits a part of the received optical signal input from the extraction optical waveguide and reflects a part of the transmitted optical signal output from the light emitting element. The bidirectional optical module according to any one of 16. The bidirectional optical module according to any one of claims 1 to 18,
A drive circuit for converting an electrical signal to be transmitted into a signal capable of driving the light emitting element included in the bidirectional optical module;
An amplifier circuit for amplifying an output signal of the light receiving element included in the bidirectional optical module;
An electric circuit for reproducing a data signal and a clock signal from the output signal of the amplifier circuit;
Optical transmitter / receiver provided. An optical transceiver according to claim 19,
Means for providing the drive circuit with the electrical signal to be transmitted;
An optical transmission system capable of performing single-core bidirectional optical communication by including means for using the data signal output from the electric circuit. 20. An optical transmission system comprising the two optical transceivers according to claim 19, wherein the two optical transceivers are connected to each other by a transmission optical fiber, and different wavelengths are used for the transmission optical signal and the reception optical signal.