JP3082032B2 - Optical signal multiplex transmission equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical signal multiplexing transmission apparatus suitable for forming and transmitting multiplexed optical signals in ultra-high-speed multiplexed optical communication.

[0002]

2. Description of the Related Art A multiplex communication system is used for transmitting and receiving a large amount of information. For example, in the pulse modulation method, a pulse signal is transmitted at a fixed time interval, and therefore, as shown in FIG. 9, the pulse signals p ₁ to pn from the lines 1 to _n are transmitted through one transmission line. be able to. As shown in FIG. 10, the repetition period of the first synchronization signal is divided into n + 1 equal parts on the basis of the synchronization signal, and input signals of n lines are placed at the equal points, and the signals are passed through a mixing / amplifying circuit. Sent. A delay circuit is used to arrange the n input signals at equal intervals. On the receiving side, the operation opposite to that on the transmitting side is performed to separate the multiplexed signal into the original individual lines.

[0003] As the amount of information is further increased, an ultra-high-speed multiplex optical communication system has attracted attention as an ultra-high-speed communication system. In a communication system using an optical signal, as shown in FIG. 11, an electric signal 81 is transmitted from a laser diode LD or a light-emitting diode LED to an optical signal 84 via a driving unit 82 on the transmitting side. And the optical signal 84 is transmitted by the optical fiber cable 85.
On the receiving side, the transmitted optical signal 86 is converted to an avalanche photodiode APD or a photodiode PD.
The signal is converted into an electric signal by a photoelectric conversion unit 87, which is amplified by the amplifying unit 88 to obtain a desired electric signal 89.

[0004] The above-mentioned optical communication system has the features that the transmission loss of the optical fiber cable is small, the relay interval can be widened, broadband high-speed communication can be realized, and electromagnetic interference is not obstructed. Attention has been paid to the capacity communication system, and its practical use is being promoted.

[0005] In order to realize such ultra-high-speed multiplexed optical communication, an ultra-high-speed transmitting / receiving device is required. A light emitting diode LED or a semiconductor laser diode LD is used as a conventional light emitting device.
It generates light with high coherence in which the phase and frequency of the light are the same as D. For this reason, the LD has a spectral width of the output light of about 10 angstroms and a small radiation angle, and can be used for a single mode optical fiber cable with low loss. The frequency is set to several tens of GHz.
Reported the generation of an ultrashort pulse laser beam of 100 femtoseconds, and the operation in the THz band has come into view. When an LD capable of high-speed operation is used for the electro-optical conversion section, high-speed operation is naturally required for the operation of the semiconductor element which is an electronic switch of the drive circuit.

However, the operating limit of a normal semiconductor device is one.
Since it is about 00 GHz, it cannot be used in ultra-high-speed multiplexed optical communication at 100 Gbit / sec or more.
Further, when the drive circuit section is constituted by a digital logic circuit, it becomes considerably complicated, and the higher the multiplicity, the more difficult it is to integrate.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a circuit device for transmitting a time-series optical signal with a simple circuit configuration in ultra-high-speed multiplex optical communication.

Another object of the present invention is to provide a circuit device for transmitting a time-series optical signal having a delay circuit using a high-speed semiconductor light emitting element in ultra-high-speed multiplex optical communication.

Another object of the present invention is to provide an integrated circuit for transmitting a time-series optical signal in ultra-high-speed multiplex optical communication.

[0010]

According to the present invention, there is provided a semiconductor light emitting device which is optically branched and coupled to an optical fiber cable, or a semiconductor light emitting device connected to the semiconductor light emitting device. respectively, are determined by said capacitive the delay times of the plurality of sections using <br/> capacity including an input capacitance including the junction capacitance at least as part comprises as at least part of the input capacitance and the inductance of the element A delay circuit having a time constant is provided, and a synchronization signal is applied to an input terminal of the delay circuit to sequentially propagate the time constant and the number of the sections and a cycle of a product of the time constant to each section. Applying a transmission signal to the semiconductor light emitting element in each section, and transmitting the transmission signal corresponding to each section as the synchronization signal propagates through the section with the time constant. There is converted into an optical signal by the semiconductor light emitting element of each of the sections, are to be multiplexed in the order said each section by the optical fiber cable.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a semiconductor light emitting device, there are a light emitting diode LED and a semiconductor laser diode LD.
LD is suitable for high-speed operation, and operation at GHz or higher is possible. Several tens of GH for MQW structure and DFBLD
It is possible to operate in z, and further, in the MLLD, it is possible to generate an ultrashort pulse of femtosecond.

In the present invention, a delay circuit is formed by using a plurality of semiconductor light-emitting elements and connecting their input terminals to each other through a low-resistance, for example, thin conductive line via an inductance component of the line. A capacitance C using at least a part of a capacitance component of an input impedance in the semiconductor light emitting element; and an inductance L of the conductive line.
Thus, a circuit device having a structure in which the time constant (LC) ^1/2 determined by the following equation is adjusted to the shift of the multiplexed optical signal whose component is the input signal of each line is formed.

Further, an input signal is applied to each section having the semiconductor light emitting element, and at this time, light emission from the semiconductor light emitting element is biased to zero or a relatively low state. When a synchronization signal is propagated to a delay circuit composed of a single semiconductor light emitting device or an integrated circuit, the synchronization signal is set to a signal voltage sufficient for the semiconductor light emitting device to emit light. For example, the semiconductor light emitting device is driven by the synchronization signal to emit light sequentially, and an optical signal sequentially enters an optical fiber cable optically coupled to the semiconductor light emitting device.

Since the cycle of the input signal in each section is adjusted to be longer than the propagation cycle of the synchronization signal, the signal pulse in each section is shaped into a time constant according to the cycle of the synchronization signal. The signals transmitted from each section to the optical fiber cable are time-seriesed when the optical fiber cable converges, and transmitted as a multiplexed optical signal by the optical fiber cable.

[0015]

FIG. 1 shows a ten-channel multiplexed optical signal transmitting apparatus 10 according to a first embodiment of the present invention, wherein the multiplexed optical signal transmitting apparatus 10 includes a plurality of series-connected inductances 11 and adjacent inductances. As a delay circuit composed of an input capacitor 13 of a semiconductor laser diode 12 with each anode connected between 11, a constant k-type circuit of 10 sections is provided.

An electric synchronization signal 14 is applied to the input terminal of the constant k-type circuit via an impedance Zi, a termination matching resistor Zi is connected to the output terminal, and a bias current is connected to the anode of the laser diode 12. Is connected via a protection resistor R. The impedance Zi is set equal to the termination matching resistance Zi. Further, the laser diode 1
2 correspond to each channel 1 to 10 for each anode,
An input signal 15 composed of a time-series pulse signal is applied. Further, each cathode of the laser diode 12 is grounded, and a branch portion 17 of an optical fiber cable 16 is optically coupled to an end face of each laser diode 12,
A multiplexed optical signal output 18 is obtained from the optical fiber cable 16.

The anodes of the laser diode 12 are connected by a metal conductor having a width of 0.1 mm and a length of 1 mm so that the value Li of the inductance 11 becomes 1 nH, and the input capacitance is 10 pF. In this case, Li of the inductance 11 at both ends is given by Li / 2.
At this time, the time constant of the constant k-type circuit is 0.1n (nano)
Second, and the terminating matching resistor Zi is 10 ohms.

FIG. 2 is a perspective view of the laser diode 12. The active layer 21 is made of non-doped InGaAsP having a band gap wavelength of 1.3 μm, and p and n are formed.
It is sandwiched between the type InP cladding layers 22 and 23. The carrier concentration of the cladding layer is 5 × 10 ¹⁷ / cc.
And the thickness is 1.5 microns. The anode and cathode p ⁺ and n ⁺ InP contact layers 24 and 25
The carrier concentration is 1 × 10 ¹⁹ / cc and 2 × 1 respectively.
0 ¹⁸ / cc with thicknesses of 0.3 microns and 5 microns, respectively.
Micron. An anode electrode 26 and a cathode electrode 27 provided on the contact layers 24 and 25, respectively.
Are formed by Au / AuZn and Au / AuGeNi, respectively. The connection between the anodes of the laser diode 12 and the value Li of the inductance 11
Is provided on an insulating film 29 provided for surface protection, and is connected to the anode electrode 26 through a contact hole 31. The laser diode 12 has a width of 10 microns and a length of 300 microns.

The laser diode 12 has a laser oscillation threshold current of 40 mA, and the bias voltage at this time is about 1.6 V. As described above, the input signal 15 is applied to the laser diode 12 by the bias voltage Va.
Current bias that does not cause laser oscillation when superimposed, ie, a bias of 10 mA. Since the voltage of the synchronizing signal 14 is provided at about 0.5 V, the voltage of the synchronizing signal 14 is further superimposed on the laser diode 12, and a current of 100 mA flows, thereby causing a predetermined laser oscillation.

The input signal 15 having a pulse width of 1 ns is applied to the laser diode 12 in each section of the ten sections of the constant k-type circuit constituting the delay circuit.
In this state, when the synchronization signal 14 is propagated to the delay circuit, the synchronization signal 14 and the input signal 1 are transmitted in each section.
5 causes the laser diode 12 to oscillate,
An optical signal is transmitted to a branch portion 17 of the optical fiber cable 16 coupled to the laser diode 12, and a multiplexed optical signal that is time-sequentially arranged in each section at a branch point of the optical fiber cable is synthesized. The data is transmitted via the optical fiber cable 16.

FIG. 3 shows the distribution of the optical signal output with respect to the electrical signals of 10 channels. That is, since the constant k-type circuit in the ten sections is configured to have a time constant of 0.1 ns, the pulse width applied to the input terminal is 0.05.
As the synchronization signal 14 of n seconds propagates in each section with the time constant, the input signal 15 of each channel having a pulse width of 1 ns applied to each section becomes one cycle of the synchronization signal 14, that is, The laser diode 12 outputs an optical signal having a pulse width of 0.05 ns during 1 ns given by the product of the time constant of 0.1 ns and the number of sections of tens.
At this time, as is apparent from FIG.
Are cut into 1/10 by the synchronizing signal 14 and correspond to each channel 1 to 10, and a time-division signal output is obtained. The synchronization between the transmitting side and the receiving side may be the same as in the conventional time division communication system.

As is apparent from FIG. 3, since the input signal 15 has a longer period in proportion to the multiplicity (10 in this example), a low-speed input signal processing circuit can be used. Therefore, the degree of freedom in designing the input signal processing circuit is increased.

FIG. 4 shows a ten-channel multiplexed optical signal transmitting apparatus 40 according to a second embodiment of the present invention, and the same components as those in the first embodiment are denoted by the same reference numerals. In this embodiment, a semiconductor laser diode 41 for sharing input and output signals is provided separately from the laser diode 12 constituting the delay circuit.

As is known, laser diodes can be excited not only electrically but also by light. The laser light to be pumped must have a higher energy than the band gap energy of the laser diode being pumped. Therefore, in this embodiment, a laser diode 12 having an AlGaAs / GaAs double heterojunction having a band gap wavelength of 0.8 μm is used as the laser diode 12 of the delay circuit.
A laser diode 41 having an InGaAsP / InP double heterojunction is used similarly to the embodiment.

A current bias of 10 mA is applied to the laser diode 12 constituting the delay circuit by a power supply of a voltage Va, and the laser diode 12 oscillates by a synchronization signal 14. Further, a power supply of a voltage Va 'is connected to the anode of the laser diode 41 via a protection resistor R', and a current bias of 10 mA is applied thereto, and the laser oscillation is performed by the laser light from the laser diode 12 of the delay circuit. It is set as follows.

An input signal 15 composed of a time-series pulse signal
Is applied to each anode of the laser diode 12,
The time constants of the input signal 15 and the synchronization signal 14 are the same as in the first embodiment. When the synchronization signal 14 is propagated to a constant k-type circuit in ten sections of the delay circuit, the laser light of the laser diode 12
Through the laser diode 41. Therefore, the laser diode 41 is excited by the incident laser light, and the electrical / optical conversion of the input signal 15 in each section is performed as in the first embodiment. An optical signal is transmitted to a branch portion 17 of the optical fiber cable 16 coupled to the laser diode 41, and a multiplexed optical signal that is time-sequentially arranged in each section at a branch point of the optical fiber cable is synthesized. Optical fiber cable 16
Sent via

The first and second embodiments are based on the premise that the period of the input signal is relatively long and the impedance of the lines constituting the circuit is very small and can be ignored. However, when the impedance of the line is not negligible, for example, when a parallel conductor is used at a high frequency, instead of the lumped constant circuit as described above, the impedance in the line direction, the distribution constant in which the admittance between the lines exists in a distributed manner. Must be treated as a circuit.

FIGS. 5 to 7 show an integrated circuit of an optical signal transmitting apparatus according to a third embodiment of the present invention. Here, the integrated circuit is treated as a distributed constant circuit in consideration of the impedance of the line. The device will be described.

In this embodiment, a semiconductor laser diode is driven by using a high-speed MIS type electrostatic induction transistor (SIT) in the delay circuit.
FIG. 5 shows a GaAs basic element 50 constituting the integrated circuit.
The basic element 50 is a normally-off type MIS gate SIT having an AlGaAs heterojunction.

The MIS gate SIT is a semi-insulating substrate 5
1, a Se-doped n ⁺ region 52 having a carrier density of 5 × 10 ¹⁸ / cc and having a thickness of several hundred angstroms and serving as a drain, and a carrier density of 5 × 10 ¹⁸ / cc and a thickness of 5 × 10 ¹⁸ / cc. Has a Se-doped n ⁺ region 53 serving as a source of several hundred angstroms, and a Zn-doped p ⁺ as a barrier region between the drain and the source.
The barrier region 54 is provided with a non-doped n ⁻ region 5 having a carrier density of 1 × 10 ¹⁷ / cc or less.
It is sandwiched between 5,56. The thickness of the non-doped n ⁻ region 55 on the drain side is about 15 Å, and the thickness of the non-doped n ⁻ region 56 on the source side is about 10 Å. In order to form the MIS gate, an AlGaAs layer 57 having an Al composition of 0.5 is provided so as to cover the regions 54, 55, 56, and a gate electrode 58 having a length of 1 _g is formed on the AlGaAs layer 57.
Are formed.

As the drain and source electrodes 59 and 61, a structure for forming a good low-resistance metal semiconductor contact with an n-type GaAs crystal is applied. For example, AuGe / Ni
/ Au is used. Further, Al is used for the gate electrode 58. Although the extensions of the barrier region 54 and the non-doped regions 55 and 56 are directly terminated immediately below the source electrode 61, the insulating film may not be interposed particularly by the depletion layer of SIT. The semi-insulating substrate 51
Is provided with a Ti / Au electrode 62 as a ground.

The conductive traces 63 6 for connecting the a plan view of an integrated circuit of the basic element 50, the width _{w g} is 10 microns, the length _{l g} is the gate electrode 58 of 0.1 microns,
To adjust the impedance including the inductance,
The width is 5 microns and the length is 160 microns. Each drain electrode 59 is connected by a conductive line 64.

InGaAsP / I having the same structure as the laser diode 12 in the first embodiment.
An nP double heterojunction laser diode 65 is mounted on the substrate 51 via a cathode electrode (not shown). The laser diode 65 has a width of 3 μm and a length of 150 μm, and a metal line 67 is provided to connect the source electrode 61 of the SIT to the anode electrode 66 of the laser diode 65. An input signal supply electrode 68 is connected to each anode electrode 66, and a laser light output from the laser diode 65 is incident on an optical fiber cable 69.

In the integrated circuit, the laser diode 65 is separately mounted on the integrated circuit board 51,
Although a so-called hybrid integrated circuit is formed, a hybrid integrated circuit in which a MIS gate SIT is mounted on a laser diode substrate or a monolithic integrated circuit in which a MIS gate SIT and a laser diode are integrated on the same substrate may be used. .

FIG. 7 shows an equivalent circuit of the integrated circuit. The gate input capacitance Ci is given by a distributed MIS gate capacitance, and the inter-gate line impedance Zg has a distributed capacitance of the line in addition to the distributed inductance Li. ing. Here, Z _D and Z _S are the respective MIS gates SIT5
0, the conductive line 64 connecting the drains and the source electrode to the line 6 between the anode electrodes of the laser diode 65.
7, and Zo is the line impedance of the cathode electrode of the laser diode 65.

In the above embodiment, the equivalent gate input capacitance is 210 fF (femtofarad) and the inductance is 20 pH. The time constant of the distributed constant circuit is 2 psec, and the terminal matching impedance Zi of the gate electrode is 10 ohms. The synchronization pulse signal 71 applied to the gate has a period of 20 psec at 0.5 V, and a _VDD of 1.5 V is applied to the drain. An input signal 72 having a period of 40 psec or more is applied to the anode electrode 66 through the input signal supply electrode 68 of the laser diode 65 in each section from the signal input circuit.

In the optical signal transmitting device, the time constant 2p
Second, when a synchronization signal 71 having a voltage of 0.5 V is applied to the delay circuit of the SIT 50, the SIT 50 in each section is sequentially switched with the propagation of the synchronization signal 71, and the laser diode 65 in each section is switched. V _DD
Is applied to the laser diode 65 together with the input signal 72 applied to the laser diode 65.
Oscillates, and an optical signal is output from the optical fiber cable 74 through the branch portion 73 of the optical fiber cable optically coupled to the laser diode 65.

In this case, the distributed impedance Z of each of the input lines and the cathode line of the laser diode 65.
_The output signal may be delayed due to _S and Zo, but since the delay is uniformly generated in the laser diode 65, the delay on the output side of the optical signal is not related to the signal transmission. The optical fiber cables 73 from each section are bundled together by an optical fiber cable 74, where optical signals are combined in a time series in the order of the sections, multiplexed and transmitted.

In the above embodiment, the GaAs MIS type SIT has been described as a semiconductor device.
Other than In, Ga, Al, As, P or Sb
Group 3-5 compound semiconductors or mixed crystals using them;
A semiconductor element such as a Group 6 compound semiconductor or another high-speed bipolar transistor or field-effect transistor of Si may be used.

In the first to third embodiments, 10
Although described in the section, it is sufficient to configure a constant k-type circuit in the n section to cope with the n-multiplexed optical signal, and it is understood that the circuit is a very simple circuit.

In the first to third embodiments, a constant k-type circuit as shown in FIG. 8A is used as a delay circuit. However, as shown in FIG. A circuit may be used, in which case it is advantageous for use at higher frequencies.

Further, in the above-described embodiment, an apparatus using a laser diode has been described. However, similar effects can be obtained by using an integrated circuit including a laser diode instead of the laser diode.

In the present invention, InGaAsP
/ InP double heterojunction laser diode and AlG
Although an aAs / GaAs double heterojunction laser diode is used, the same applies to the case of using another group III-V compound semiconductor composed of elements such as In, Ga, Al, As, and P, or a mixed crystal therebetween. Clearly, it works.
Further, in the frequency region which is inferior in the speed or coherence as compared with the laser diode but not so high as compared with the laser diode, the light emission composed of the compound semiconductor and the mixed crystal thereof may be used. Diodes can also be used.

[0044]

According to the present invention, there is provided a semiconductor light emitting device which is optically branched and coupled to an optical fiber cable, or a semiconductor device connected to the semiconductor light emitting device. comprising a delay circuit having a time constant the delay time of the plurality of sections by using a capacitance including an input capacitance including the junction capacitance at least as part respectively, it is determined by said capacitor and said inductance, an input terminal of the delay circuit A synchronous signal is applied to each section and the time constant is propagated in sequence with a period of a product of the number of sections, and a transmission signal is applied to the semiconductor light emitting element in each section, and the synchronization signal is As the time constant propagates through each section, the transmission signal corresponding to each section is converted into an optical signal by the semiconductor light emitting element in each section, and the optical fiber It is to be multiplexed in the order the respective sections by bus cable. Therefore, a new circuit device for transmitting a multiplexed optical signal with a simple circuit configuration is obtained, and an indispensable and useful device for ultra-high-speed multiplexed optical communication is achieved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a multiplexed optical signal transmission device according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a laser diode according to the present invention.

FIG. 3 is a diagram showing a state of distribution of an optical signal output to electric signals of 10 channels in the present invention.

FIG. 4 is a diagram illustrating a ten-channel multiplexed optical signal transmitting apparatus according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a cross section of a basic element in an integrated circuit of a multiplexed optical signal transmitting apparatus according to a third embodiment of the present invention.

FIG. 6 is a plan view schematically showing an integrated circuit according to a third embodiment of the present invention.

FIG. 7 is a diagram showing an equivalent circuit of an integrated circuit according to a third embodiment of the present invention.

FIG. 8 is a diagram showing a constant k-type circuit and an inductive m-type circuit applied in the present invention.

FIG. 9 is a diagram showing a multiplex pulse signal in a conventional multiplex communication system.

FIG. 10 is a diagram showing a conventional multiplex signal transmission circuit.

FIG. 11 is a diagram showing an optical cable transmission system in conventional ultra-high-speed multiplex optical communication.

[Explanation of symbols]

10: multiplexed optical signal transmission device, 11: inductance, 1
2 laser diode, 13 input capacitance, 14 electrical synchronization signal, 15 input signal, 16 optical fiber cable, 17 optical fiber cable branch, 21 active layer, 22, 23 cladding layer, 24 , 25 contact layer, 26 anode electrode, 27 cathode electrode, 28
Conductive line, 29: insulating film, 31: contact hole, 4
1: laser diode, 42: optical fiber cable, 5
0: normally-off type MIS gate SIT, 51: semi-insulating substrate, 52, 53 ... n ⁺ region, 54 ... p ⁺ region, 5
5, 56 ... non-doped n ^- region, 57 ... AlGaAs
Layer 58 gate electrode 59 drain electrode 61 source electrode 62 Ti / Au electrode 63 and 64 conductive line 65 laser diode 66 anode electrode 6
7: metal line, 68: input signal supply electrode, 71: synchronous pulse signal, 72: input signal, 73: branch portion of optical fiber cable, 74: optical fiber cable

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-259638 (JP, A) JP-A-2-235034 (JP, A) JP-A-5-40778 (JP, A) JP-A-2- 113650 (JP, A) JP-A-3-200364 (JP, A) JP-A-60-256124 (JP, A) JP-A-63-111032 (JP, U) JP-T-61-501363 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) H04B 10/00-10/28 H04J 14/00-14/08 H03M 9/00 G02B 6/00 H01S 3/00

Claims (7)

(57) [Claims] And 1. A least a portion of the input capacitance including a junction capacitance of the semiconductor light-emitting elements, each optically coupled to the inductance and the optical fiber cable having a conductive path
And comprising a delay circuit having a time constant the delay time of the plurality of sections are determined respectively by said capacitor and said inductor with a capacitor comprising in said by applying a synchronizing signal to the input terminal of the delay circuit In each section, the time constant and the number of the sections are sequentially propagated with a cycle of a product of the number of the time constants, and a transmission signal is applied to the semiconductor light emitting element in each section, and the synchronization signal is the time constant. As the signal propagates in each section, the transmission signal corresponding to each section is converted into an optical signal by the semiconductor light emitting element in each section, and the transmission signal is multiplexed in the order of each section by the optical fiber cable. Multiplexing transmission device for optical signals. 2. The optical signal multiplexing transmission apparatus according to claim 1, wherein the synchronization signal is superimposed on the biased semiconductor light emitting device, and the light emitting intensity of the semiconductor light emitting device is modulated. Are respectively determined delay times of the plurality interval by said capacitor and said inductor with a capacitor comprising at least as a part of the input capacitance including a junction capacitance of the inductance and the semiconductor device having the wherein the conductive traces A delay circuit having a time constant, and a semiconductor light emitting element driven by the semiconductor element in each section and optically coupled to an optical fiber cable, and applying a synchronization signal to an input terminal of the delay circuit. In each section, the time constant and the number of the sections are sequentially propagated with a cycle of a product of the number of the time constants, and a transmission signal is applied to the semiconductor light emitting element in each section, and the synchronization signal is the time constant. As the signal propagates through the sections, the transmission signal corresponding to each section is converted into an optical signal by the semiconductor light emitting element in each section, and the optical fiber A multiplex transmission apparatus for optical signals, which is multiplexed in the order of each section by an EVA cable. 4. An apparatus for multiplexing and transmitting an optical signal according to claim 1, wherein said semiconductor light emitting device comprises a laser diode. 5. The delay circuit according to claim 1, wherein the delay circuit is a constant k circuit or an induction m circuit.
The optical signal multiplex transmission apparatus according to claim 1 or 3, wherein the apparatus comprises a pattern circuit. 6. The optical signal multiplex transmission apparatus according to claim 3, wherein said semiconductor element comprises a laser diode, and said semiconductor light emitting element is driven by an optical output from said laser diode. 7. The optical signal multiplex transmission apparatus according to claim 3, wherein said semiconductor element comprises an electrostatic induction transistor, and said semiconductor light emitting element is driven by an output from said electrostatic induction transistor. .