JPH08316911A - Optical signal regenerator - Google Patents

Abstract

(57) [Abstract] [Purpose] To realize an optical signal regenerator that is less susceptible to timing jitter and other fluctuations. A sinusoidal optical clock signal is generated by phase-locking with an optical signal data train. The generated sinusoidal optical clock signal is converted into a pulsed optical clock signal. The pulsed optical clock signal and the optical signal data train are input to the optical regenerator to obtain the regenerated optical signal data train. The same fluctuation as the phase fluctuation that the optical clock signal receives is given to the optical signal data train by passing through another optical path of the same length. The phase fluctuation of the optical clock signal is canceled by the phase fluctuation of the optical signal data string. [Effect] It is possible to reproduce an optical signal data string with little distortion.

Description

Detailed Description of the Invention

[0001]

The present invention is used in optical communication. The present invention is suitable for use in an optical repeater. The present invention is suitable for use in an optical switch. The present invention relates to a technique for relaying and reproducing an optical signal data string.

[0002]

2. Description of the Related Art A conventional optical signal regenerator will be described with reference to FIG. FIG. 8 is a block diagram of a conventional device. The optical signal regenerator comprises an optical clock signal generator 70 and an optical signal regenerator with a non-linear loop mirror 80. The optical clock signal generator 70 is disclosed in Japanese Patent Application No. 6-295099 by the applicant of the present application (not yet published at the time of application of the present application).
Has been proposed by.

In the optical clock signal generator 70, a laser diode 1 oscillating at a frequency f1 and a laser diode 2 oscillating at a frequency f2 are combined with the output light of the laser diodes 1 and 2, and the frequency difference (f
1-f2), an optical coupler 3 for outputting an optical signal, an optical coupler 4 for inputting a differential frequency output from the optical coupler 3 and an optical signal data string, and a signal appearing in the output light of the optical coupler 4. The optical signal correlator 6 for identifying the coincidence of phases, the photodetector 7 for detecting the output of the optical signal correlator 6, and the control circuit 8 to which the output of the photodetector 7 is input are provided. The oscillation frequency of the laser diode 1 is controlled by the control circuit 8 according to the detection output of the device 6 so that the phase difference between the optical signal data string and the frequency of the difference between the output of the optical coupler 3 is minimized. Is taken out as an optical clock signal.

The operation of the optical clock signal generator 70 will be briefly described. The laser diodes 1 and 2 perform single mode continuous oscillation at the optical frequencies f1 and f2, respectively, and the difference between the optical frequencies f1 and f2 is set to be substantially equal to the optical clock signal frequency. In the configuration of FIG. 8, at least one of the laser diodes 1 and 2 is
It is necessary that the oscillation frequency be variable by a control signal from the outside and that the difference (f1-f2) between the oscillation frequencies can be adjusted. In the description below, it is assumed that the oscillation frequency of the laser diode 1 is variable and the oscillation frequency of the laser diode 2 is fixed. The light output from the laser diodes 1 and 2 is combined by the optical coupler 3,
The amplitude of the composite wave changes sinusoidally with 1 / | f1-f2 | as the cycle. Laser diode 1
The combined waves of 2 and 2 are combined with the optical signal data string by the optical coupler 4, and then input to the optical signal correlator 6.
However, the optical signal data sequence is intensity-modulated by a return-to-zero (RZ) code. The optical signal correlator 6 outputs the largest optical signal or the smallest optical signal when the phases of the combined wave of the laser diodes 1 and 2 and the optical signal data string match, and has a function of detecting the phase difference between them. Is. The structure is, for example, “S. Kawanishi
and M. Saruwatari, "New-type phase-locked loop using
traveling-wave laser diode optical amplifier for
very high speed optical transmission ", Electron.Let
t., vol.24, pp.1452-1453, 1988 ", so detailed description will be omitted.

The output signal of the optical signal correlator 6 is converted into an electric signal by the photodetector 7. The control circuit 8 controls the oscillation frequency of the laser diode 1 so as to maximize the output while monitoring the output of the optical signal correlator 6 converted into an electric signal. The combined wave having the period of 1 / | f1-f2 | of the laser diodes 1 and 2 synthesized by the optical coupler 3 by the above operation obtains an optical clock signal synchronized with the bit period of the optical signal data string. The optical signal data train can be obtained by passing the optical signal outputted from the output port of the optical coupler 4 through the optical filter 9 which transmits only the light having the wavelength of the optical signal data train.

The optical clock signal output from the optical clock signal generation unit 70 and the optical signal data string passing through the optical clock signal generation unit 70 are input to the non-linear loop mirror 80. Optical signal switching by the non-linear loop mirror 80 is described in, for example, "NJ Doran and D. Wood," Non-linear-optica.
l loop mirror ", Optics Letters, vol.13, No.1, pp.56-5
Since it is described in detail in "8,1988", detailed explanation is omitted.

The optical signal data train that has passed through the optical clock signal generator 70 is amplified by the optical amplifier 10 and then coupled to the loop fiber 15 by the wavelength division multiplex coupler 13 having a wavelength dependence and passes through the loop fiber 15. It is then output by the wavelength division multiplex coupler 14 having wavelength dependence.

On the other hand, the optical clock signal generated by the optical clock signal generator 70 is coupled to the loop by the optical coupler 12 after passing through the optical isolator 11. Here, it is assumed that the optical signal from the optical coupler 12 is split at 50:50.

First, the case where the signal of the optical signal data string is "0" will be described. The optical signal propagates in the clockwise direction (cp) or the counterclockwise direction (ccp) in the loop fiber 15 separated into two by the optical coupler 12. These two optical signals have the same optical path (loop fiber 15)
Since they propagate in opposite directions, the phase difference after propagation becomes zero. Therefore, at the output of the optical coupler 12, the optical clock signal is output to the input port.

On the other hand, when the optical signal data string is "1", the refractive index of the optical fiber changes depending on the optical signal data string. At this time, since the clockwise light propagates in the same direction as the optical signal data string, it is greatly affected by the change in the refractive index.
On the other hand, the counterclockwise light is less affected by the change in the refractive index associated with the optical signal data string. Therefore, a phase difference occurs between the clockwise light and the counterclockwise light when the loop fiber 15 is rotated once. If the phase difference between the clockwise light and the counterclockwise light is set to π, the optical clock signal is output from another port that is not the clock input side of the optical coupler 12. That is, the output port of the optical clock signal can be controlled by "1" or "0" of the optical signal data string, so that the optical data signal string is reproduced.

[0011]

In the conventional optical signal regenerator, a composite wave component of two laser diode lights is used as an optical clock signal. In this case, the optical clock signal is a sinusoidal signal, and the phase difference is set to be π when the peak time of the optical clock signal coincides with “1” of the optical signal data string.

However, since the optical clock signal is sinusoidal, the optical signal is output from the signal reproduction output port of the nonlinear loop mirror even when the phase relationship between the optical signal data string and the optical clock signal is slightly deviated due to timing jitter or the like. Therefore, it is difficult to configure an optical signal regenerator that is less affected by timing jitter.

The present invention has been made against such a background, and an object of the present invention is to provide an optical signal reproducing apparatus which is not easily affected by fluctuations such as timing jitter. It is an object of the present invention to provide an optical signal reproduction device that can reproduce an optical signal data string with little distortion. It is an object of the present invention to provide an optical signal regenerator that can be downsized and simplified.

[0014]

SUMMARY OF THE INVENTION The present invention provides an optical clock signal generating means for outputting an optical clock signal phase-synchronized with an optical signal data string, and an optical signal for switching the optical clock signal according to the optical signal data string. The optical signal reproducing device is provided with an optical reproducing device for reproducing

Here, the feature of the present invention resides in that a waveform shaping means for sharply shaping the waveform of the output optical clock signal of the optical clock signal generating means is provided.

As a result, it is possible to realize an optical signal regenerator which is unlikely to be affected by fluctuations such as timing jitter.

The waveform shaping means generates a new frequency component by a non-linear effect and a PLC (Planar Lightwave Ci) that compresses the pulse by a dispersion effect.
(rcuit) pulse compression means is preferable. As a result, the optical clock signal can be compressed into pulses without using a pulse compression fiber that requires a long optical path.

A delay corresponding to the effective delay time of the waveform shaping means is given to the path of the optical signal data stream after branching the phase information supplied to the optical clock signal generation means to the optical reproduction means. It is desirable to provide a delay means. Alternatively, the delay means preferably includes means for passing the optical signal data string in the reverse direction through the optical path included in the waveform shaping means. As a result, it is possible to cancel the fluctuations of the optical clock signal and the optical signal data sequence generated in the optical path included in the waveform shaping means.

It is desirable to provide an adjusting means for finely adjusting the relative phases of the optical clock signal and the optical signal data string input to the optical reproducing means. Thereby, the relative phase shift between the optical clock signal and the optical signal data string can be easily corrected.

[0020]

A sinusoidal optical clock signal is generated by phase synchronization with the optical signal data train. The generated sinusoidal optical clock signal is converted into a pulsed optical clock signal. The pulsed optical clock signal and the optical signal data train are input to the optical regenerator to obtain the regenerated optical signal data train.

Since the optical clock signal is pulsed,
It is possible to prevent the reproduced optical signal from being affected by fluctuations such as timing jitter.

In order to convert the sinusoidal optical clock signal into a pulsed optical clock signal, a pulse compression fiber may be used, or a new frequency component is generated from the sinusoidal optical clock signal by a non-linear effect. May be used and PLC pulse compression may be used which compresses the pulse by the dispersion effect. In this case, since a long optical path is not used, it is not necessary to compensate for the phase difference between the optical signal data train and the optical clock signal, which is useful for simplification and miniaturization of the device.

When the optical clock signal is converted into a pulse signal, the optical clock signal undergoes phase fluctuation when passing through a pulse compression fiber having a long optical path length. Therefore, it is preferable to give the optical signal data train the same fluctuation as the phase fluctuation received by the optical clock signal by passing through another optical path having the same length. After that, the pulsed optical clock signal and the optical signal data string are input to the optical regenerator to obtain the regenerated optical signal data string. At this time, the phase fluctuation of the optical clock signal is canceled by the phase fluctuation of the optical signal data string. To be done.

Alternatively, the optical signal data train may be subjected to the same fluctuation as the phase fluctuation received by the optical clock signal by passing the optical path through which the optical clock signal has passed in the opposite direction.

[0025]

【Example】

(First Embodiment) The configuration of the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of the first embodiment of the present invention.

According to the present invention, an optical clock signal generator 70 as an optical clock generating means for outputting an optical clock signal which is phase-synchronized with an optical signal data train, and an optical clock signal which is switched in accordance with the optical signal data train is used. Nonlinear loop mirror 80 as an optical reproducing means for reproducing a signal
It is an optical signal reproducing device provided with.

Here, the feature of the present invention resides in that a pulse signal converting section 90 is provided as a waveform shaping means for sharply shaping the waveform of the output optical clock signal of the optical clock signal generator 70.

In FIG. 1, 1 is a first laser diode, 2 is a second laser diode, 3 and 4 are optical couplers, 6 is an optical signal correlator, 7 is a photodetector, 8 is a control circuit, and 9 is Optical filters, 30 and 10 are optical amplifiers, 31
Is a fiber for pulse compression, 11 is an optical isolator, 12
Is an optical coupler with a separation ratio of 50:50, 13 and 14 are wavelength division multiplexing (WDM) couplers, and 15 is a loop fiber.

The optical clock signal generator 70 for generating a sinusoidal optical clock signal is the same as the conventional example. Also,
The signal reproducing section by the non-linear loop mirror 80 is also the same as the conventional example. Here, if the sinusoidal optical clock signal generated by the optical clock signal generation unit 70 is converted into a pulse signal and then input to the non-linear loop mirror 80, a signal reproduction device that is not easily affected by timing jitter can be configured. You can Therefore, in the present invention, the sinusoidal optical clock signal is converted into a pulse signal.

The sinusoidal optical clock signal generated by the optical clock signal generator 70 is amplified by the optical amplifier 30. The optical clock signal amplified by the optical amplifier 30 is input to the pulse compression fiber 31. Inside the fiber 31 for pulse compression, a plurality of frequency components are generated due to a non-linear effect during propagation of the optical fiber. Since the phase relationships of the plurality of frequency components are automatically synchronized, the sinusoidal optical clock signal is converted into a pulse signal as the optical fiber propagates.

As described above, as a method of converting into a pulse signal while propagating through an optical fiber, a method of using a dispersion-decreasing fiber whose dispersion value decreases in the longitudinal direction of the optical fiber (PV Mamyshev, et al., "Generation of fund
amental soliton trains for high-bit-rate optical fi
ber communication lines ", IEEE J. Lightwave Technolo
gy, vol.27, NO.10, PP.2347-2355, 1991), using dispersion-shifted fiber (EASwanson et al., "23GHz a
nd 123GHz Soliton Pulse Generation Using CW Lasers
and Standard Single mode Fiber ", IEEE Photonice Te
chnology Letters, vol.6, No.7, 1994), a method of combining dispersion-shifted fiber and dispersion-decreasing fiber (SVC
hernikov, et al., "70Gbit / s fiber based source of fu
ndamental solitons at 1550nm ", Electron.Letters, vo
(See l.28, No.13, 1992), using a dispersion-shifted fiber and an ordinary single-mode fiber, and arranging them so that their dispersion values are comb-shaped (SVChernikov, et al., "Integra.
ted all optical fiber source of multigigahertz sol
iton pulse train ", Electron.Letters, Vol.29, No.20,19
See 93).

In the method using the dispersion-decreasing fiber and the method using the dispersion-shifting fiber, a plurality of new frequency components are generated by the nonlinear effect (self-phase modulation effect) during the propagation of the optical fiber, and at the same time, the phases of the frequency components are generated. Since the relationship is synchronized, the compression of the pulse is taking place.

In the method of combining the dispersion-shifted fiber and the dispersion-decreasing fiber and the method of using the dispersion-shifted fiber and the normal single-mode fiber and arranging them so that their dispersion values are in a comb shape, there is a portion for generating a new frequency component. A separate optical fiber is used for the compression part of the pulse. Whichever method is used, it is necessary to adjust the optical fiber length and dispersion value according to the bit rate of the generated optical clock signal.

On the other hand, the optical signal data string is output from the optical coupler 4 through the optical filter 9. Further, by adding an optical amplifier to the input section of these optical fibers, it is possible to effectively generate a plurality of new frequency components.

The pulsed optical clock signal is input to the loop fiber 15 which is the main body of the nonlinear loop mirror 80 after passing through the optical isolator 11. The optical data signal train is amplified by the optical amplifier 10, then input to the loop fiber 15 from the wavelength division multiplexing coupler 13 and output from the wavelength division multiplexing coupler 14. This optical signal data string becomes a control signal for the non-linear loop mirror 80. As described in the conventional example, the operation of the non-linear loop mirror 80 is such that the optical clock signal is switched depending on the state of "1" or "0" of the optical signal data string to reproduce the optical signal data string.

FIG. 2 shows a comparison of reproduced signal waveforms when the optical clock signal is a pulse signal and when it is sinusoidal. Figure 2
FIG. 6 is a diagram for explaining a comparison between the reproduced waveforms of the conventional example and the present invention. 2A to 2C are conventional examples.
The present invention includes (d) to (f). In the above, it was explained that the reproduction is performed by switching the non-linear mirror 80 by "1" and "0" of the signal of the optical data signal sequence, but in reality, the optical clock signal and the optical fiber of the optical signal data sequence By using the difference in propagation speed (Walk-off effect), the area where the phase is shifted by π is made rectangular, and switching is performed depending on whether there is an optical signal data string in that area, or the pulse width of the optical clock signal is Switching is performed by making the pulse width smaller than the pulse width of the signal data string. The time region in which this switching is performed is called the switching time window. FIG. 2 shows an example of switching using the Walk-off effect. Here, the optical signal data string shows the state of overtaking the optical clock signal during the propagation of the optical fiber, and the broken line represents the timing fluctuation due to the jitter. 2 (a)-
As shown in (c), when the optical clock signal is a sine wave, it is affected by the change in the switching window due to the jitter, and the waveform of the reproduced optical signal is found to change due to the jitter. . On the other hand, as shown in FIGS. 2 (d) to 2 (f), it is found that the pulse does not depend on the jitter. If the optical clock signal is pulsed,
The wider the switching window is, the stronger the jitter becomes, but it is necessary to prevent the adjacent optical clock signal from being affected. As described above, by pulsing the optical clock signal, it is possible to configure an optical signal reproducing device that is resistant to jitter.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a block diagram of the second embodiment of the present invention. Here, 43 is a semiconductor optical amplifier, 4
4 is a PLC type pulse compression circuit. The second embodiment of the present invention is different from the first embodiment of the present invention in that it converts a sinusoidal optical clock signal into a pulse signal. Therefore, in the second embodiment of the present invention, only the portion converted into the pulse signal will be described. The optical clock signal generated by the optical clock signal generator 70 is a composite wave of two frequency signals. This optical clock signal is input to the semiconductor optical amplifier 43. The semiconductor optical amplifier 43 generates a new frequency component having an interval of two frequency differences due to the nonlinear effect (four-wave mixing). The output of the semiconductor amplifier 43 is input to the PLC type pulse compression circuit 44. The PLC type pulse compression circuit 44 is described by K. Takiguchi et al., "Dispersi.
on compensation using a planar lightwave circuit o
ptical equalizer ", IEEE Photonics Technology Letter
PLC disclosed in s, Vol. 6, No. 4, pp. 561-564, 1994.
A type dispersion equalizer can be used. This dispersion equalizer consists of asymmetric Mach-Zehnder interferometers connected in multiple stages. An arbitrary dispersion value can be given by adjusting the optical path length difference between the two optical paths of the asymmetric Mach-Zehnder interferometer and the number of connection stages. To date, this PLC dispersion compensator has achieved a dispersion value up to about 600 ps / nm with a band of 20 GHz. When the frequency band is widened, the controllable dispersion value becomes small. However, the semiconductor amplifier 43
Since the phase difference between the new frequency component generated at 1 and the frequency component of the input signal is small, the output signal of the semiconductor amplifier 43 can be designed to be compressed by the PLC type pulse compression circuit 44.

In the first embodiment of the present invention, it has been explained that there is a method of arranging the dispersion shift fiber and the dispersion value of the ordinary optical fiber so as to form a comb shape. In this method, a new frequency component is generated by the self-phase modulation effect in the dispersion-shifted fiber portion, and a new frequency component is generated by the self-phase modulation effect in the normal dispersion fiber. , Pulse compression and chirping correction. In the second embodiment of the present invention, a new frequency component is generated by four-wave mixing inside the semiconductor optical amplifier 43. The pulse compression can be realized by an optical fiber whose dispersion is controlled as in the first embodiment of the present invention, but here, the PLC type pulse compression circuit 44 performs the pulse compression. In the second embodiment of the present invention, the semiconductor optical amplifier 43
Since the PLC type pulse compression circuit 44 is used, it can be converted into a pulse signal without using a long optical fiber (having a length of several km) as shown in the first embodiment of the present invention. The optical signal can be regenerated without being affected by the phase fluctuation during the propagation of the long optical fiber.

(Third Embodiment) A third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram of the apparatus of the third embodiment of the present invention. Here, 39 is an optical fiber.
The third embodiment of the present invention is different from the first embodiment of the present invention in that the optical signal data string passing through the optical filter 9 passes through the optical fiber 39. In order to convert the optical clock signal into a pulse signal, it passes through the pulse compression fiber 31, but since the length of this optical fiber reaches several km, there is a possibility that phase fluctuations may occur during propagation due to disturbance or the like. Therefore, the optical fiber 39 having a length that gives the same amount of phase fluctuation as the phase fluctuation in the pulse compression fiber 31.
Have been inserted. As a result, the pulse compression fiber 3
Phase fluctuations at 1 are canceled out in the non-linear loop mirror 80. Therefore, the influence of phase fluctuations due to disturbances and the like is eliminated.

(Fourth Embodiment) A fourth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram of the device of the fourth embodiment of the present invention. Here, 41 and 42 are optical circulators. In the optical circulators 41 and 42, the light input to the port is output to the port, the light input to the port is output to the port, the light input to the port is output to the port, and the light input to the port is output to the port. And The optical clock signal generator 70 for generating a sinusoidal optical clock signal is the same as that of the first embodiment of the present invention, and therefore its explanation is omitted.

The optical clock signal generated by the optical clock signal generator 70 is amplified by the optical amplifier 30 and then input to the port 41 _{1 of the} circulator 41. The optical clock signal is output from the port 41 ₂ of the optical circulator 41 and input to the pulse compression fiber 31. The pulse compression fiber 31 performs conversion into a pulse signal.
The optical clock signal converted into the pulse signal is input to the port 42 ₁ of the optical circulator 42, output from the port 42 ₂ and input to the optical regenerator by the nonlinear loop mirror 80. On the other hand, the optical data signal sequence is input to the port 42 ₄ of the optical circulator 42 after passing through the optical filter 9. The optical signal data string passes through the pulse compression fiber 31 and is input to the port 41 ₂ of the optical circulator 41.
It is output from the port 41 ₃ . The optical signal data string is then amplified by the optical amplifier 10 and becomes a control signal for the nonlinear loop mirror 80. In the operation of the non-linear loop mirror 80, as described in the conventional example, the optical clock signal is switched depending on the presence / absence of the optical signal data string to reproduce the optical signal data string.

According to the fourth embodiment of the present invention, since the optical clock signal and the optical signal data train propagate in the same optical fiber in opposite directions, they undergo similar phase fluctuations. As a result, the phase fluctuation in the pulse compression fiber 31 is canceled in the nonlinear loop mirror 80. Therefore, the influence of phase fluctuations due to disturbances and the like is eliminated.

(Fifth Embodiment) A fourth embodiment of the present invention will be described with reference to FIG. FIG. 6 is a block diagram of the device of the fifth embodiment of the present invention. Here, 40 is an optical path fine adjustment unit. In the fifth embodiment of the present invention, only parts different from the third embodiment of the present invention will be described. As the bit rate of the optical signal data string increases, it is possible to remove the influence of the phase fluctuation in the pulse compression fiber 31 only by the optical fiber 39 as shown in the third embodiment of the present invention, but the optical clock. It becomes difficult to match the positional relationship between the signal and the pulse of the optical signal data train. Therefore, an optical path fine adjustment unit 40 that can finely adjust the optical path length is arranged in the subsequent stage of the optical fiber 39, and is configured to be compatible with an ultrahigh-speed optical data signal.

The detailed structure of the optical path fine adjustment unit 40 is shown in FIG. FIG. 7 is a diagram showing various configuration examples of the optical path fine adjustment unit 40. In configuration method 1 of FIG. 7A, two mirrors and a corner cube are used. The input light is reflected by the mirror and guided to the corner cube. In the corner cube, it is reflected twice and guided to the mirror. At this time, by moving the corner cube in the direction of the arrow, the distance between the two mirrors and the corner cube can be changed to change the optical path length.

In the construction method 2 of FIG. 7B, the optical path is made by opposing the tip of the optical fiber with a lens for collimating the emitted light, facing each other, and slightly changing the distance between the collimating lenses. To fine tune.

In the construction method of FIG. 7C, the piezoelectric element (PZ
An optical fiber is wound around T). The piezoelectric element (PZT) expands or contracts when a voltage is applied. Therefore, the optical fiber also expands and contracts as the PZT expands and contracts. Therefore, the optical path can be finely adjusted by controlling the voltage applied to the PZT. In PZT,
Control of μm / V order is possible, and high-speed signals can be handled. The control range can be expanded by increasing the number of windings of the fiber.

Now, specific requirements for the optical path fine adjustment unit 40 will be described. For example, when controlling the positional relationship of the pulses of the 10 Gb / s data signal, the requirement as the optical path fine adjustment unit 40 is that the optical path for 1 bit length can be finely lengthened. One bit length is 100 ps. Also,
The propagation time in the optical fiber is about 5 ns per 1 m. Therefore, the optical path fine adjustment unit 40 only needs to be able to finely adjust the optical path within the range of 20 mm. In the case of 100 Gb / s data, the optical path may be finely adjusted within the range of 2 mm.

Further, if the fine adjustment accuracy is 1% of the fine adjustment range, the control accuracy is 200 μm, 100 in the case of 10 Gb / s.
In the case of Gb / s, the control accuracy is 20 μm. Therefore, in the case of 10 Gb / s data, as shown in FIG.
It can be controlled by the method (b). On the other hand, in the case of higher speed (100 Gb / s), the method of FIG. 7 (c) is promising.

[0049]

As described above, according to the present invention,
It is possible to realize an optical signal regenerator that is not easily affected by timing jitter and other fluctuations. Therefore, it is possible to reproduce the optical signal data string with less distortion. Further, the device configuration can be downsized and simplified by using the nonlinear effect (four-wave mixing) and the PLC type pulse compression means.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of an apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a comparison between reproduced waveforms of a conventional example and the present invention.

FIG. 3 is a block diagram of a device according to a second embodiment of the present invention.

FIG. 4 is a block configuration diagram of a third embodiment device of the present invention.

FIG. 5 is a block configuration diagram of an apparatus according to a fourth embodiment of the present invention.

FIG. 6 is a block configuration diagram of a fifth embodiment device of the present invention.

FIG. 7 is a diagram showing various configuration examples of an optical path fine adjustment unit.

FIG. 8 is a block diagram of a conventional device.

[Explanation of symbols]

1 1st laser diode 2 2nd laser diode 3, 4, 12, 41, 42 Optical coupler 6 Optical signal correlator 7 Photodetector 8 Control circuit 9 Optical filter 10, 30 Optical amplifier 11 Optical isolator 13, 14 Wavelength Split multiplex coupler 15 Loop fiber 31 Pulse compression fiber 39 Optical fiber 40 Optical path fine adjustment unit 41 _{1 to} 41 ₃ , 42 _{1 to} 42 ₄ ports 43 Semiconductor optical amplifier 44 PLC type pulse compression circuit 70 Optical clock signal generation unit 80 Non-linear loop Mirror 90 pulse signal converter

Claims (5)

[Claims] 1. An optical clock signal generating means for outputting an optical clock signal phase-synchronized with an optical signal data stream, and an optical regenerating means for switching the optical clock signal according to the optical signal data stream to regenerate the optical signal. An optical signal regenerator comprising: an optical signal regenerator for sharply shaping the waveform of the output optical clock signal of the optical clock signal generator. 2. The waveform shaping means is a frequency generating means for generating a new frequency component by a non-linear effect, and a PLC (Planar Lightwave) for compressing a pulse by a dispersion effect.
(Circuit) pulse compression means. 3. A delay corresponding to an effective delay time of the waveform shaping means in a path of the optical signal data string after branching the phase information supplied to the optical clock signal generation means to the optical reproduction means. A delay means for providing
Alternatively, the optical signal regenerator described in 2. 4. The optical signal regenerator according to claim 3, wherein said delay means includes means for passing the optical signal data sequence in the reverse direction to the optical path included in said waveform shaping means. 5. The optical signal regenerator according to claim 1, further comprising adjusting means for minutely adjusting the relative phases of the optical clock signal and the optical signal data string input to the optical regenerating means.