JPS6195634A - Optical repeater element - Google Patents

Abstract

PURPOSE:To eliminate the need for a power supply cable by supplying power while using a photoelectric converting element formed on a semiconductor substrate in an optical repeater element where a photodetector, a signal processing section and a light emitting element on the same semiconductor substrate. CONSTITUTION:Signal light transmitted from a transmitter 1 and a YAG laser light transmitted from a YAG laser light source 2 are combined by a translucent mirror 3 and fed to the optical repeater element 7 via an optical fiber 4. The repeater element 7 consists of a branching section 9 formed on the same semiconductor substrate, a signal light photodetection section 10, a YAG laser light photodetection section 11, a signal processing section 12, a light emitting element 13 and a power control circuit 14. The photodetector 11 converts the YAG laser light into an electric energy and gives it to the power supply control circuit 14. The power supply control circuit 14 applies the supplied energy to the photodetector 10 and the signal processing circuit 12 as power via wires 151-153, 154 and 155.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a power feeding system for an optical relay element that can be used in an optical communication device.

[Prior art]

In recent years, in the field of optical communications, the loss of optical fibers has been reduced, and the performance of semiconductor lasers as transmitters and light receiving elements as receivers has improved, and expectations for optical communications have further increased.
In addition, the range of applications for optical communications is increasingly expanding.

The basic components of the optical communication equipment used for this optical communication are:
For example, optical transmitters such as semiconductor lasers and light emitting diodes, optical transmission lines such as optical fiber cables, optical receivers such as APD (avalanche photodiode) and FD (photodiode), amplification of weakened signals, and distortion a signal processing circuit that has functions such as waveform shaping to return the waveform to its original state;
These include the optical receiver, signal processing circuit, optical repeater including the optical transmitter, and the like. However, recently, there has been an increasing demand for smaller and lighter optical communication equipment, lighter optical transmission lines, and improved electrical noise resistance. Research and development on optical relay elements in which light emitting parts and the like are integrated on one substrate are being actively carried out.

Energy for driving such an optical relay element is generally supplied from an electric cable separate from the optical cable, or from outside the optical relay element (by an electric cable twisted together with the optical fibers within the optical cable). I was doing a lot of things. Since such electrical cables are usually made of copper wire, optical cables including electrical cables have significantly impaired the light weight, which is one of the characteristics of optical fibers.

In addition, electric cables are easily affected by electromagnetic induction, and if a shield is provided over the entire cable to avoid electromagnetic induction, it would not be necessary to further increase the weight of the optical cable, so it is difficult to use such optical cables. The drawback was that it was difficult to expand the range of applications of optical communication devices.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical relay element that eliminates the above-mentioned drawbacks and expands the range of application of optical communication devices.

[Structure of the invention]

According to the present invention, a light receiving element that receives an optical signal and converts it into an electrical signal, a signal processing circuit that fully amplifies the electrical signal and shapes the waveform, and a light emitting element that is driven by the processed electrical signal are made of the same semiconductor. An optical relay element included on a substrate receives optical energy from outside the semiconductor substrate and converts it into electrical energy to receive the light receiving element and the signal processing circuit.

A photoelectric conversion element that supplies power to the light emitting element is provided on the semiconductor substrate.'t-I! f! An optical relay element having an f characteristic is obtained.

[Explanation of Examples]

Next, embodiments of the present invention will be described with reference to the drawings.

1 to 4 are diagrams for explaining one embodiment of the optical relay element according to the present invention, FIG. 1 is a plan view of the optical relay element according to the embodiment of the present invention, and FIG. 3 is an equivalent circuit diagram of the embodiment shown in FIGS. 1 and 2, and FIG. 4 is a schematic block diagram of an optical communication device using the optical relay element of the embodiment according to the present invention.

In FIG. 4, reference numeral 1 denotes a signal light transmitter having a semiconductor laser with a transmission wavelength of 1.3 μm. 2 is the oscillation wavelength 1
．． It is a YAG laser light source of 0.06 μm and has an output of 100 W. 3 is a semi-transparent mirror that combines the signal light and the YAG laser light. 4 is a single mode optical fiber with a core diameter of 10 μm and has a total summary IKm. 501゜502, 503 are signal light and Y
When the YAG laser beam was input to the optical fiber 4 using the optical system 502, 503t", the incidence efficiency was about 85%. Therefore, the incidence efficiency of the YAG laser beam was about 85%. The input power to the optical fiber 4 is about 85 W. Also, the transmission loss of the optical fiber 4 was about 1.5 dB/, at a wavelength of 1.06 μm.
The output power of the YAG laser beam from the optical fiber 4 is approximately 60W. 6 is an optical system, 7 is an optical relay element according to an embodiment of the present invention, and the substrate is made of n-InP.

The optical relay element 7 includes waveguides 801, 802, 803, 80.
4. Demultiplexer 9 that separates signal light and YAG laser light, signal light receiving element 10 using a phototransistor, Y
AG laser light receiving element 11, electrical signal processing circuit 12
, a light emitting element 13 and a power supply control circuit 14.

The signal light and YAG laser light that entered the optical fiber 4 are
After propagating through the optical fiber 4 and exiting, the light enters the waveguide 801 by the optical system 6 and is guided to the demultiplexer 9 .

The demultiplexer 9 separates the signal light and YAG laser light again.
The signal light propagates through the waveguide 802 and reaches the signal light receiving element 10.
The YAG laser beam propagates through the waveguide 803 and enters the YAG laser beam light receiving element 11 . The YAG laser light receiving element 11 converts the optical energy of the incident YAG laser light into electrical energy, and sends the electrical energy to the power supply control circuit 14 via wiring 154 and 155 provided on the substrate of the optical relay element 7. introduce. The power supply control circuit 14 supplies the bias voltage of the light receiving element 10 for the signal light via the distribution circuit [151°155],
Power for driving the light emitting element 13 is supplied to wirings 152 and 15, respectively.
5 and wirings 153, 155t-. on the other hand,
The signal light receiving element 10 converts the incident signal light into an electrical signal and outputs it to the signal processing circuit 12 via the wiring 156. After the signal processing circuit 12 fully amplifies the signal and shapes the waveform,
It is output to the light emitting element 13 via the wiring 157. Thereby, the signal light is regenerated and transmitted to the next stage through the waveguide 804.

Next, the configuration of the optical relay element 7 will be explained in detail using FIGS. 1 and 2, and the function of the optical relay element 7 will be explained in detail using FIG. 3.

In FIG. 1, only the relay circuit network formed on the substrate 7a is shown.

In FIGS. 1 and 2, the constituent components of the waveguide 801 are T
iO□, and the constituent components of the insulating film 701 are TiO□-8i0
It is 2. The refractive index of the waveguide 801 is 2.50 at the wavelength of YAG laser light of 1.06 μm, and 2.48 at the wavelength of the signal light of 1.3 μm. In addition, in the insulating film 701, the content of Tie is controlled, and the refractive index at a wavelength of 1.06 μm and the wavelength of 1.3 μm are controlled.
Both refractive indexes at m are approximately 1.55. The demultiplexer 9 has TiO□-810 as its constituent component, and controls the content of TiO2 so that the refractive index of the demultiplexer 9 is 1 at a wavelength of 1.06 μm.
．． 762, the wavelength is 1.3 μm and it is 1.755. Further, the cross section of the waveguide 801 was approximately square, and each side was approximately 10 μm, so that the incidence efficiency when the YAG laser light was incident on the waveguide 801 was approximately 85%. Since the power of the light emitted from the optical fiber 4 is 60W, the power incident on the waveguide 801 is approximately 50W.

The incident angle at which the YAG laser light and signal light propagated through the waveguide 801 enter the demultiplexer 9 is set to be 45'. Therefore, considering the relationship between the refractive index of the waveguide 801 and the demultiplexer 9, the YAG laser beam with a wavelength of 1.06 μm is totally reflected in the demultiplexer 9, and the signal light with a wavelength of 1.3 μm is transmitted without being totally reflected. .

The YAG laser beam totally reflected by the demultiplexing section 9 passes through the waveguide 803.
The light propagates, is totally reflected by a reflection element 91 having the same component as the one-wavelength splitter 9, and is reflected back, and then enters the light receiving element 11. The light receiving element 11 is a pn junction type solar cell, where lla is S (sulfur)-doped n-GiAs, and llb is Zn (zinc) 1-doped fpp-GiAs. n-Ga
An antireflection film is provided on the surface of As.

Since the lengths of waveguides 801 and 803 are short, waveguide 801
The YAG laser beam incident on the waveguide is hardly attenuated during propagation through the waveguides 801 and 803.

Therefore, the power of the YAG laser beam incident on the light receiving element 11 is approximately 50W. Further, since the conversion efficiency of the light receiving element 11 was about 10%, the maximum electrical output of the light receiving element was about 5W. The output of the light receiving element 11 is transmitted to the source control circuit 14 through wires 154 and 155 (not shown in FIG. 2, but shown in FIG. 1) provided on the substrate 7a. This power supply control circuit 14 allows the AI wiring 151
, 152, 153° 155 (shown in FIG. 1) t - Light receiving element 10 for signal light, signal processing circuit 122 light emitting element 1
Suitable power is supplied to each of the three.

The good signal light transmitted through the demultiplexer 9 propagates through a waveguide 802 having the same components as the waveguides 801 and 803 and enters the light receiving element 10 . The light receiving element 10 is a photodiode whose main component is InP, and 10a is an n-type photodiode doped with Sn (tin).
10b is an fcp type doped with Cd (cadmium). Further, an antireflection film 10C is provided on the surface of the n-type portion 10a. The signal light is 1 due to the light receiving element 10! All wiring 156°155° (shown in Figure 1)
The signal is transmitted to the signal processing circuit 12 as an electrical signal. The signal processing circuit 12 amplifies and waveform-shapes the No. 18 light,
It is output as an electrical signal to the light emitting element 13 via the A1 wiring 157°155. The light emitting element 13 is made of n-InGaAs
In a semiconductor laser including a P layer, 13a is p-InP, 1
3b is n-InGaAsP which becomes an active layer. The light emitting element 13 converts the signal light into an optical signal, and after the converted optical signal propagates through a waveguide 804 having the same components as the waveguides 801, 802, and 803, it is sent to the next stage.

Next, the wiring pattern of the optical relay element 2 will be explained using FIGS. 1 and 3.

The wiring 154 is connected to the YAG laser beam by the light receiving element 11.
The wiring that transmits the electric power obtained by converting AG laser light into electrical energy to the power supply control circuit 14 connects the n-GiAs lla of the light receiving element 11 of the YAG laser light and the non-GND side of the power supply control circuit 14. It's tied. Wiring 15
5 is the wiring on the GND side, and the light receiving element 11 of the YAG laser beam
Of these, it is connected to p-GaAs11b. Wiring 15
1 is a wiring for supplying power for driving the signal light receiving element 10 from the power supply control circuit 14 to the signal light receiving element 10 through the resistor tf;
is connected to The wiring 153 is a wiring that supplies all the power for driving the light emitting element 13, and is connected to the GND of the power supply control circuit 14.
The other side is the p-I of the light emitting element 13 through the resistor 3.
Connected to nP13a. The GND side of the light emitting element 13 is connected to the substrate 7a. The wiring 156 is a wiring for transmitting an electrical signal obtained by fully photoelectrically converting an optical signal by the signal light receiving element 10 to the signal processing circuit 12. In this embodiment, the signal light receiving element 10 is used as the main component as described above. Ingredients are In
Since the P photodiode is used, the signal light receiving element 1
The electrical signal that is the output of 0 is output as a change in current. This current change is transmitted to the signal processing circuit 12 as a voltage change occurring across the resistor R2.

The input impedance of the signal processing circuit 120 is very large compared to sb, and most of the current flowing through the light receiving element 10t flows through R1. In the signal processing circuit 12, the signal is amplified and waveform shaped as described above, and then outputted as a current change through the wiring 157f.

The resistor R3 is made very large compared to the output impedance of the signal processing circuit 12. (a) Most of the output current of the signal processing circuit 12 flows through the light emitting element 131, and changes in the output current are directly transmitted to the light emitting element 13. transmitted to. As a result, the light is converted back into an optical signal and emitted from the light emitting element.

As described above, the optical relay element of this embodiment has the basic optical relay function of amplifying and waveform-shaping an incident optical signal and then outputting it again as an optical signal.

In this embodiment, there is no need to use, for example, a copper wire cable to supply driving power to the light receiving element for optical relay, the light emitting element of the signal processing circuit 2, etc., so the weight of the optical fiber cable can be significantly reduced. υ, and the effects of electromagnetic induction can also be avoided.

In this embodiment, the material of the substrate of the optical relay element is InP, but the material of the substrate is not particularly limited. Also Y
The material of the light receiving element for AG laser light is not limited to GaAs either. Moreover, the core f of the optical waveguide is installed on the optical relay element board.
T i O2, clad t T i O2-8i02 and L, optical demultiplexerffit T i 02- S i O
Although the material of the optical waveguide and the material of the optical separation section are not particularly limited to the above-mentioned materials, the YAG laser beam is totally reflected at the optical separation section, and the signal light is reflected at the separation section. It should be made of a material that allows the light to pass through. Further, the light receiving element 1 and the light emitting element can also be made of other materials.

Furthermore, in this embodiment, a YAG laser beam was used as an optical energy source, but an optical 7-eyeper cable was used.

CO2 laser light may be used as long as the materials of the waveguide 2-branching section on the optical relay element board, the light receiving element (the light receiving element for YAG laser light in this embodiment), etc. are changed to appropriate materials. Also, the power supply on the optical relay element board! In this embodiment, Afi is used as the wiring material for transmitting the air signal, but other materials may be used. Further, although the optical repeater element of this embodiment is used in an optical communication device using a single mode optical fiber cable, it can also be used in an optical communication device using a multimode optical fiber cable. Furthermore, the number of optical fibers that make up the optical fiber cable is not particularly limited. In addition, the number of layers of the YAG laser light receiving element, the semiconductor laser light receiving element, and the light emitting element was three layers each including the substrate. The number of layers may be different from that.

〔Effect of the invention〕

Finally, the advantage of the present invention is that the optical repeater can be made smaller. It is possible to reduce the weight of the optical transmission line, and to eliminate the adverse effects of electromagnetic induction from the optical transmission line. Therefore, it can be expected that the application area of optical communication devices will expand.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of the optical relay element according to the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 3 is a circuit diagram of the optical relay element shown in FIG. 1. 4 are schematic block diagrams of an optical communication device using an optical relay element according to the present invention. 1...Signal light transmitter, 2...YAG
Laser light source, 3...Semi-transparent mirror, 4...Single mode optical fiber s 501゜502.503...
...Optical system, 6...Optical system, 7...
Optical relay element, 701... Insulating film, 7a...
...Substrate, 801゜802.803,804...Curved waveguide, 9...Demultiplexer, 91...Reflection element, 10...Signal light receiving element , 10a...
...N-type part of the signal light receiving element, 10b...
p-type part of light receiving element for signal light, 10C... anti-reflection film, 11... light receiving element for YAG laser light, 1
1a... n-type part of the light receiving element for YAG laser light,
11b... p-type part of light receiving element for YAG laser light, 11C... antireflection film, 12... signal processing circuit, 13... light emitting element, 13m...
...p-type part of light-emitting element, 13b...n-type part of light-emitting element, 14...power control circuit, 151,1
52゜153.154, 155, 156.157...
...Wiring, R,, R2, R3...Resistance.

Claims (1)

[Claims] An optical relay that includes, on the same semiconductor substrate, a light receiving element that receives an optical signal and converts it into an electrical signal, a signal processing circuit that amplifies and shapes the electrical signal, and a light emitting element that is driven by the processed electrical signal. The element includes a photoelectric conversion element on the semiconductor substrate that receives optical energy from outside the semiconductor substrate and converts it into electrical energy, and the power generated by the photoelectric conversion element is used to convert the light receiving element, the signal processing circuit, and the light emitting element into electrical energy. Optical relay element that operates the element.