JP2010050758A - Multiple wavelength light-generating apparatus and multiple wavelength light transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multiple wavelength light-generating apparatus in which frequency control of a light entering into an optical fiber is easily performed and capable of stably suppressing SBS, and to provide a multiple wavelength light transmission system. <P>SOLUTION: In the multiple wavelength light transmission system having the multiple wavelength-generating apparatus 10A for generating a multiple wavelength light, and an optical fiber 12 for connecting the multiple wavelength light-generating apparatus 10A to a receiver 11 for receiving the multiple wavelength light generated by the multiple wavelength light-generating apparatus 10A, the multiple wavelength light-generating apparatus 10A has a CW light source 13 for oscillating a light having a single frequency, a modulator 14 for modulating light oscillated from the CW light source 13, and a signal generator 15 for generating an electric signal having a frequency of double amount of Brillouin frequency shift of the optical fiber 12 and for applying the electric signal to the modulator 14. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a multi-wavelength light generator and a multi-wavelength light transmission system in an optical transmission system.

  In recent years, large capacity and long distance have been advanced in optical fiber communication. The transmission capacity is rapidly increasing with the development of wavelength division multiplexing (WDM) technology. At the research level, the light multiplexed into one optical fiber reaches several thousand waves. However, the number of necessary light sources is enormous. Therefore, studies on multi-wavelength light generators that generate light of a plurality of wavelengths from a single light source are underway.

  On the other hand, the optical fiber has a characteristic of low loss, and long-distance optical fiber communication using this is realized. Further, with the advent of optical amplifiers such as erbium-doped fiber amplifiers (EDFAs), longer distances have been realized. In long-distance communication systems such as submarine communications, a plurality of optical amplifiers are arranged in the transmission line to compensate for optical loss due to transmission. From the viewpoint of reducing the cost of the transmission system, the relay interval for optical amplification by EDFA is as follows: It needs to be expanded as much as possible. By increasing the power of the signal light incident on the optical fiber, the distance can be further increased, but by stimulated Brillouin scattering (SBS), which is one of the nonlinear phenomena occurring in the optical fiber. The incident light intensity is limited.

From the above, when further increasing the capacity and extending the distance, it is necessary to suppress the SBS because the incident light intensity is limited by the SBS even in the WDM transmission using the multi-wavelength light generator described above. There is. SBS is a scattering phenomenon caused by the interaction between incident light and acoustic phonons. When light is incident on an optical fiber, it has a frequency lower by a frequency called Brillouin shift frequency f _{B in the} direction of propagation opposite to the incident light. Generates Stokes light.

This is because when light having a frequency of f _S is incident on the optical fiber, a gain centered on (f _S −f _B ) as shown in FIG. 10 is generated. Further, a loss occurs in the frequency (f _S + f _B ), and the spectral characteristic of the loss is a characteristic of the positive / negative inversion of the gain characteristic.

When the incident light intensity becomes larger than a value called the SBS threshold, strong Stokes light is generated, and a saturation phenomenon called depletion occurs in the incident light. This is a phenomenon in which the intensity of transmitted light observed at the output end of the optical fiber saturates at a certain value as the incident light intensity on the optical fiber increases, and the generated frequency (f _S −f _B ) Stokes light causes a loss in the frequency f _S and gives a loss to the incident light. Further, since transmission quality deteriorates due to the occurrence of SBS, the incident light intensity must be set to a value equal to or less than the SBS threshold.

  Therefore, by utilizing the fact that the Brillouin shift frequency changes depending on the amount of fluorine and germanium dioxide added to the optical fiber, the temperature of the optical fiber, and the tension applied to the optical fiber, fluorine added in the longitudinal direction of the optical fiber. A technique for expanding the Brillouin gain spectrum and suppressing SBS by changing the amount of germanium dioxide or changing the temperature of the optical fiber and the tension applied to the optical fiber has been proposed.

  However, in these technologies, it is necessary to newly install a special SBS suppression optical fiber or a tensioned optical fiber cable and change the optical fiber transmission line, and transmission using an already installed optical fiber. Not adaptable to the system and not economical.

  Therefore, by preparing a light source that emits light having a frequency that is twice as small as the Brillouin frequency shift amount of the optical fiber for the light for which SBS is to be suppressed, the light is combined with the light for which SBS is to be suppressed and is incident on the optical fiber. A technique for suppressing the generation of Stokes light has been proposed.

The configuration and principle of SBS suppression will be described with reference to FIGS. When light having an intensity equal to or greater than the SBS threshold (with a frequency of f _S ) is incident on the optical fiber, Stokes light having a frequency of (f _S −f _B ) is generated by the SBS, as shown in FIG. Therefore, depletion occurs in incident light, and the intensity of transmitted light is limited.

Here, when the light with the frequency f _S is the SBS suppression target light, the SBS suppression target light and the SBS suppression light with the frequency (f _S −2 × f _B ) are combined and incident on the optical fiber. 11B, the loss generated at the frequency (f _S −f _B ) due to the SBS of the SBS suppression light and the gain of the SBS suppression target light due to the SBS cancel each other, and the Stokes light of the SBS suppression target light Generation | occurrence | production can be suppressed and generation | occurrence | production of SBS can be suppressed.

  When the light intensity of the SBS suppression target light is increased, the generated gain increases. To cancel this, the SBS of the SBS suppression target light can be suppressed by increasing the light intensity of the SBS suppression light. As a result, the SBS threshold value of the SBS suppression target light increases.

  However, the light intensity of the SBS suppression target light is further increased, and the light intensity of the SBS suppression light is further increased in order to cancel the gain generated thereby. Depletion occurs, and the gain generated by the SBS of the SBS suppression target light cannot be canceled by the loss generated by the SBS of the SBS suppression light. Due to the depletion of the SBS suppression light, there is an upper limit to the SBS suppression effect on the SBS suppression target light. The upper limit of this SBS suppression effect can be expanded by increasing the wavelength multiplexing number n.

Hereinafter, the principle will be described with reference to a case where n is 3 (FIG. 11C). By setting the frequency interval of the three lights to 2 × f _B , the gain and loss due to the SBS of the adjacent signal light overlap, so that the generation of Stokes light can be suppressed and the generation of SBS can be suppressed. If light of three frequencies is called x, y, and z from the left, the gain generated by the SBS of z cancels the loss generated by the SBS of y, and the gain generated by the SBS of y is reduced by the SBS of x. The losses that occur will cancel out.

  That is, z is SBS suppression target light. y is SBS suppression target light, and also plays the role of SBS suppression light. x is SBS suppression light. As described in the example in the case where n is 2, when the light intensity of z is increased, it is necessary to increase the light intensity of y in order to cancel the gain generated by the SBS. However, when the light intensity of y exceeds a certain value, depletion due to SBS occurs in y, and the gain generated by SBS of z cannot be canceled out. However, when n is 3, x can cancel the gain due to SBS of y, so that SBS of y can be suppressed. That is, by increasing the light intensity of x and y, the SBS suppression effect on z is increased compared to the case where n is 2.

  Thus, the SBS suppression effect of the SBS suppression target light can be increased by increasing the number of SBS suppression light having a smaller frequency than the SBS suppression target light.

An example of a configuration for suppressing SBS will be described with reference to FIG. To a light source 33 for emitting a SBS suppression-pressure target light frequency f _S, 2 times lower by the frequency of the Brillouin frequency shift amount f _B of the optical fiber 32 than the frequency f _S of the SBS suppression target light (f _S -2 × f _B) A light source 34 that emits SBS-suppressed light is installed, and the optical fiber 32 that is connected to the receiver 31 that receives multi-wavelength light is combined and incident via an optical coupler 35. Even when the wavelength multiplexing number n is 3 or more, SBS can be suppressed by preparing n light sources and setting the frequency interval of each light source to twice the Brillouin frequency shift amount of the optical fiber.

T. Ohara et al., "Over-1000-Channel Ultradense WDM Transmission With Supercontinuum Multicarrier Source", JOURNAL OF LIGHTWAVE TECHNOLOGY, Vol. 24, No. 6, JUNE 2006, pp.2311-2317 K. Shiraki et al., "Performance of Strain-Free Stimulated Brillouin Scattering Suppression Fiber", JOURNAL OF LIGHTWAVE TECHNOLOGY, Vol. 14, No. 4, APRIL 1996, pp.549-554 J. Hansryd et al., "Increase of the SBS Threshold in a Short Highly Nonlinear Fiber by Applying a Temperature Distribution", JOURNAL OF LIGHTWAVE TECHNOLOGY, Vol. 19, No. 11, NOVEMBER 2001, pp.1691-1697 P. WeBels et al., "Novel suppression scheme for Brillouin scattering", OPTICS EXPRESS, Vol. 12, No. 19, 20 SEPTEMBER 2004, pp.4443-4448 Y. Aoki et al., "Input Power Limits of Single-Mode Optical Fibers due to Stimulated Brillouin Scattering in Optical Communication Systems", JOURNAL OF LIGHTWAVE TECHNOLOGY, Vol. 6, No. 5, MAY 1988, pp.710-719 K. Mori, "Stabilisation of optical frequency of modelocked laser diode with Fabry-Perot filter for supercontinuum-based optical ITU grid", Electronics Letters, Vo1. 41, 2005, pp.328-329

  However, in the above technique for preparing a plurality of light sources, it is necessary to control the oscillation frequency for each light source in order to control the frequency of light incident on the optical fiber, and the frequency interval between the light sources is set to a desired interval. It is not easy to control, there is a possibility that SBS cannot be stably suppressed, and it is not effective from the viewpoint of economy.

  The present invention has been made in view of the above problems, and provides a multi-wavelength light generator and a multi-wavelength light transmission system that can easily control the frequency of light incident on an optical fiber and can stably suppress SBS. For the purpose.

The multi-wavelength light generator according to the first invention for solving the above-mentioned problems is
In a multi-wavelength light generator that generates multi-wavelength light,
A CW light source that oscillates light of a single frequency;
A modulator for modulating light oscillated from the CW light source;
And a signal generator for generating an electric signal having a frequency twice as large as a Brillouin frequency shift amount of an optical fiber to be transmitted by the multi-wavelength light generator and applying the electric signal to the modulator.

The multi-wavelength light generator according to the second invention for solving the above-mentioned problems is
In the multi-wavelength light generator according to the first invention,
The modulator is a Mach-Zehnder type intensity modulator that modulates the intensity of light oscillated from the CW light source, and a phase modulator that modulates the phase of light modulated by the Mach-Zehnder type intensity modulator,
The signal generator is a sine wave generator that generates a sine wave electric signal having a frequency twice the Brillouin frequency shift amount of the optical fiber and applies the sine wave electric signal to the Mach-Zehnder intensity modulator and the phase modulator. It is characterized by that.

A multi-wavelength light generator according to a third invention for solving the above-mentioned problems is as follows.
In a multi-wavelength light generator that generates multi-wavelength light,
A mode-locked laser that oscillates light having a plurality of line spectra;
A signal generator for generating an electric signal having a frequency twice the Brillouin frequency shift amount of an optical fiber to be transmitted by the multi-wavelength light generator and applying the electric signal to the modulator in the mode-locked laser; It is characterized by.

A multi-wavelength optical transmission system according to a fourth invention for solving the above-mentioned problems is as follows.
A multi-wavelength light generator for generating multi-wavelength light;
In a multi-wavelength optical transmission system having an optical fiber connecting the multi-wavelength light generator and a receiver that receives the multi-wavelength light generated by the multi-wavelength light generator,
The multi-wavelength light generator is
A CW light source that oscillates light of a single frequency;
A modulator for modulating light oscillated from the CW light source;
And a signal generator for generating an electric signal having a frequency twice the Brillouin frequency shift amount of the optical fiber and applying the electric signal to the modulator.

A multi-wavelength optical transmission system according to a fifth invention for solving the above-mentioned problems is as follows.
In the multi-wavelength optical transmission system according to the fourth invention,
The modulator is a Mach-Zehnder type intensity modulator that modulates the intensity of light oscillated from the CW light source, and a phase modulator that modulates the phase of light modulated by the Mach-Zehnder type intensity modulator,
The signal generator is a sine wave generator that generates a sine wave electric signal having a frequency twice the Brillouin frequency shift amount of the optical fiber and applies the sine wave electric signal to the Mach-Zehnder intensity modulator and the phase modulator. It is characterized by that.

A multi-wavelength optical transmission system according to a sixth invention for solving the above-described problems is as follows.
A multi-wavelength light generator for generating multi-wavelength light;
In a multi-wavelength optical transmission system having an optical fiber connecting the multi-wavelength light generator and a receiver that receives the multi-wavelength light generated by the multi-wavelength light generator,
The multi-wavelength light generator is
A mode-locked laser that oscillates light having a plurality of line spectra;
And a signal generator for generating an electric signal having a frequency twice the Brillouin frequency shift amount of the optical fiber and applying the electric signal to the modulator in the mode-locked laser.

  According to the present invention, since the frequency interval between the generated multi-wavelength lights is controlled only by the repetition frequency of the electric signal, the control becomes easy and SBS generated in the optical fiber can be stably suppressed.

  Further, according to the present invention, SBS generated in the optical fiber can be stably suppressed, so that the intensity of transmitted light from the optical fiber output end can be increased, and the transmission distance can be increased. The quality of the incident signal can be improved. That is, it is possible to realize a large capacity, long distance, and high quality of optical fiber communication.

  Further, according to the present invention, since SBS can be suppressed without changing the existing optical fiber transmission line, it is economical.

  Hereinafter, embodiments of a multi-wavelength light generating apparatus and a multi-wavelength optical transmission system according to the present invention will be described with reference to FIGS.

[Embodiment 1]
FIG. 1 shows the configuration of a multiwavelength light generator and a multiwavelength light transmission system according to this embodiment.
The multi-wavelength optical transmission system according to this embodiment includes a multi-wavelength light generator 10A according to this embodiment, which will be described later, and a receiver that receives multi-wavelength light from the multi-wavelength light generator 10A and the multi-wavelength light generator 10A. 11 for transmission.

The multi-wavelength light producing apparatus 10A according to the present embodiment generates multi-wavelength light, and includes a CW light source 13 that oscillates single-frequency CW (Continuous Wave) light, and light oscillated from the CW light source 13. A modulator 14 for modulation and a signal generator 15 for generating an electric signal to be applied to the modulator 14 are provided. The signal generator 15 has a repetition frequency that is twice the Brillouin frequency shift amount f _B of the optical fiber 12. The electric signal which has is generated.

In this embodiment, the modulator 14 modulates the CW light source 13 that oscillates CW light having a single frequency f _S. The light output from the modulator 14 becomes light having a line spectrum with a frequency interval corresponding to the repetition frequency of the electrical signal applied to the modulator 14. That is, by setting the frequency of the signal generator 15 that generates the electric signal applied to the modulator 14 to twice the Brillouin frequency shift amount f _B of the optical fiber 12, the frequency interval [2 × f _B ] multi-wavelength light can be generated.

In this embodiment, even if the frequency of the CW light source 13 changes, the frequency interval of the generated multi-wavelength light is constant as long as the repetition frequency of the electrical signal in the signal generator 15 does not change. In other words, in the prior art, the optical frequency control is required by the light source itself that oscillates the light incident on the optical fiber, but this is not necessary. As described above, in this embodiment, it is only necessary to control the repetition frequency of the electric signal with high accuracy and stability, so that the frequency interval can be accurately and stably compared with the optical frequency control with the light source itself. [2 × f _B ] multi-wavelength light can be generated.

Here, an experimental result in the case where a Mach-Zehnder LN intensity modulator is used as the modulator and the number of wavelength multiplexing n is 3 is shown. In the experiment, a dispersion compensation fiber (DCF) 10 km having a Brillouin frequency shift amount f _B of 9.467 GHz was used. Further, the CW light is intensity-modulated by a Mach-Zehnder LN intensity modulator using a sine wave electric signal having a frequency of [2 × f _B ] generated by a sine wave generator, and as shown in FIG. Multi-wavelength light having one frequency was generated and used as incident light. The three generated multi-wavelength lights are referred to as Pump1, Pump2, and Pump3 from the left in FIG.

  FIG. 3 shows the intensities of transmitted light and reflected light with respect to the incident light intensity when CW light having a single frequency is incident on the DCF used in the experiment. It can be seen that in the region where the incident light intensity is 8 dBm or more, the transmitted light intensity is saturated and the transmitted light intensity does not increase to about −1.6 dBm or more.

  On the other hand, FIG. 4 shows the intensities of transmitted light and reflected light with respect to the incident light intensity when the three multi-wavelength lights shown in FIG. 2 are simultaneously incident on the DCF used in the experiment. Compared with the result of FIG. 3, it can be seen that, in Pump 1, the transmitted light intensity increases to 2.6 dBm, and thus SBS is suppressed. In the case of Pump2, since the transmitted light intensity increased to 1.4 dBm, the SBS suppression effect was confirmed for Pump2. With regard to Pump3, the result is the same as that of FIG. 3, and there is no SBS suppression effect.

The deviation from twice the Brillouin frequency shift amount f _B of the DCF used in the experiment is Δf, and the frequency interval of the three multi-wavelength lights shown in FIG. 2 is changed in the range of Δf = −100 MHz to +100 MHz. FIG. 5 shows the intensity of backscattered light (Stokes light) of each incident light. In FIG. 5, as can be seen from the graphs of Pump1 and Pump2, it can be seen that the suppression effect of Stokes light is maximized by setting the frequency interval to [2 × f _B ] (that is, Δf = 0).

FIG. 6 shows an experimental system of transmission characteristics using the multi-wavelength light generator according to this embodiment.
In this experimental system, multi-wavelength light having three frequencies shown in FIG. 2 is generated by a Mach-Zehnder type LN intensity modulator 17 connected to a sine wave generator 16 that generates a sine wave electric signal. Then, the generated multi-wavelength light is intensity-modulated by a Mach-Zehnder LN intensity modulator 19 connected to a pulse pattern generator 18 that generates a signal pulse, and three 2.5 Gbps NRZ signals are generated. I let you. This was amplified to 20 dBm by the optical amplifier 20 and made incident on the optical fiber 12 (dispersion compensation fiber (DCF) 10 km) having a Brillouin frequency shift amount f _B of 9.467 GHz.

Of the output light from the optical fiber 12 (DCF), the light with the shortest wavelength was extracted by the optical filter 21, and the bit error rate (BER) was measured. The measurement results are shown in FIG. In FIG. 7, in the case of “with suppression”, the frequency interval between the three generated lights is set to [2 × f _B ], and in the case of “without suppression”, it is set to [2 × f _B −100 MHz]. “Back to back” is the BER when DCF is removed from the experimental system. As a result of this experiment, an error floor was observed when SBS was not suppressed, but by setting the frequency interval Δf to [2 × f _B ], a result similar to the “Back to back” characteristic was obtained. Thus, it can be seen that the SBS suppression effect can be stably obtained by using this embodiment.

[Embodiment 2]
FIG. 8 shows configurations of the multi-wavelength light generator and the multi-wavelength optical transmission system according to the present embodiment.
The multi-wavelength light transmission system according to this embodiment includes a multi-wavelength light generator 10B according to this embodiment, which will be described later, and a receiver that receives multi-wavelength light from the multi-wavelength light generator 10B and the multi-wavelength light generator 10B. 11 for transmission. That is, the configuration of the multi-wavelength light generator 10B is different from the multi-wavelength light generator 10A according to the first embodiment. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

The multi-wavelength light producing apparatus 10B according to the present embodiment also generates multi-wavelength light. As shown in FIG. 8, a Mach-Zehnder type intensity modulation that modulates the intensity of light oscillated from the CW light source 13 and the CW light source 13 is provided. 17, a phase modulator 22 that modulates the phase of the light modulated by the Mach-Zehnder type intensity modulator 17, and a sine wave generator that generates a sine wave electric signal to be applied to the Mach-Zehnder type intensity modulator 17 and the phase modulator 22. The sine wave generator 16 generates a sine wave electric signal having a repetition frequency twice as large as the Brillouin frequency shift amount f _B of the optical fiber 12.

  That is, the multi-wavelength light producing apparatus 10B according to the present example is the same as the multi-wavelength light generating apparatus 10A according to the first embodiment, except that the modulator 14 is a Mach-Zehnder type intensity modulator 17 and the phase modulator 22, and the signal generator 15 is a sine. The wave generator 16 is used.

  Therefore, the multi-wavelength light generation apparatus and the multi-wavelength light transmission system according to the present embodiment can obtain the same effects as the multi-wavelength light generation apparatus and the multi-wavelength light transmission system according to the first embodiment.

  In addition, in the multi-wavelength light producing apparatus 10B according to the present embodiment, by taking the above-described configuration, only the amplitude of the electric signal of the sine wave generator 16 applied to the Mach-Zehnder type intensity modulator 17 and the phase modulator 22 is increased. Therefore, since the number of generated line spectra can be increased and the intensity deviation of the generated line spectrum can be reduced, it can be applied to a multi-wavelength light source of a transmission system having a large number of wavelength multiplexing. (Non-patent document 5).

[Embodiment 3]
FIG. 9 shows configurations of the multi-wavelength light generator and the multi-wavelength optical transmission system according to this embodiment.
The multi-wavelength optical transmission system according to this embodiment includes a multi-wavelength light generator 10C according to this embodiment, which will be described later, and a receiver that receives multi-wavelength light from the multi-wavelength light generator 10C and the multi-wavelength light generator 10C. 11 for transmission. That is, the configuration of the multi-wavelength light generator 10C is different from the multi-wavelength light generator 10A according to the first embodiment and the multi-wavelength light generator 10B according to the second embodiment. Therefore, the same components as those in the first and second embodiments are denoted by the same reference numerals, and redundant description is omitted.

The multi-wavelength light producing apparatus 10C according to the present embodiment also generates multi-wavelength light. As shown in FIG. 9, a mode-locked laser 24 that oscillates light having a plurality of line spectra, and a mode-locked laser 24 And a signal generator 23 for generating an electric signal to be applied to the modulator, and the signal generator 23 generates an electric signal having a repetition frequency twice as large as the Brillouin frequency shift amount f _B of the optical fiber 12. It is.

The spectrum of the optical pulse oscillated from the mode-locked laser 24 is composed of a line spectrum arranged at intervals matching the repetition frequency of the pulse of the applied electric signal. Therefore, the frequency of the electric signal applied from the signal generator 23 to the modulator installed in the cavity of the mode-locked laser 24 is set to be twice the Brillouin frequency shift amount f _B of the optical fiber 12, so that each line The spectral interval is twice the Brillouin frequency shift amount f _B of the optical fiber 12, and multi-wavelength light capable of suppressing SBS can be generated.

  With the above configuration, the multi-wavelength light generation apparatus and the multi-wavelength light transmission system according to this embodiment can obtain the same effects as the multi-wavelength light generation apparatus and the multi-wavelength light transmission system according to Embodiments 1 and 2.

  In addition, before the generated multi-wavelength light is incident on the optical fiber 12, it is incident on the multi-wavelength light generating optical fiber to cause a nonlinear effect, thereby increasing the number of generated line spectra (Non-Patent Document). 6).

[Other Embodiments]
As a technique for suppressing SBS, in addition to the technique used in the present invention, there is a technique of adding phase modulation to an incident signal to widen the spectrum width of the incident signal. However, the present invention can be combined with this technique. Thus, a further SBS suppression effect can be realized.

  The present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiment examples may be appropriately combined.

  The present invention can suppress the occurrence of stimulated Brillouin scattering (SBS), increase the intensity of an optical signal that can be incident on an optical fiber, and realize long-distance transmission in a transmission system. be able to.

It is a schematic block diagram which shows an example of embodiment of the multiwavelength light generator and multiwavelength optical transmission system which concern on this invention. It is a graph which shows the incident light spectrum used in experiment. It is a graph which shows the change of the transmitted light with respect to incident light intensity | strength, and the reflected light intensity | strength in case CW light of a single frequency injects into DCF. 3 is a graph showing changes in transmitted light and reflected light intensity with respect to incident light intensity when the multi-wavelength light shown in FIG. 2 is incident on the DCF. 3 is a graph showing the change in the intensity of Stokes light of each incident light when the frequency interval Δf is changed in the range of [2 × f _B ] to ± 100 MHz when the multiwavelength light shown in FIG. 2 is incident on the DCF. . It is a schematic block diagram which shows the experiment system of the transmission characteristic using the multiwavelength light generator which concerns on this embodiment. It is a graph which shows the measurement result of the bit error rate in the experimental system of the transmission characteristic shown in FIG. It is a schematic block diagram which shows another example of embodiment of the multiwavelength light generator which concerns on this invention, and a multiwavelength optical transmission system. It is a schematic block diagram which shows another example of embodiment of the multiwavelength light generator which concerns on this invention, and a multiwavelength optical transmission system. It is a graph which shows the spectrum of the Brillouin gain and loss which generate | occur | produce by stimulated Brillouin scattering. It is a figure explaining the principle of the suppression technique of a stimulated Brillouin scattering. It is a schematic block diagram which shows the conventional optical transmission system.

Explanation of symbols

10A, 10B, 10C Multi-wavelength light generator 11 Receiver 12 Optical fiber 13 CW light source 14 Modulator 15 Signal generator 16 Sine wave generator 17 Mach-Zehnder type intensity modulator 18 Pulse pattern generator 19 Mach-Zehnder type intensity modulator 20 Light Amplifier 21 Optical filter 22 Phase modulator 23 Signal generator 24 Mode-locked laser

Claims (6)

In a multi-wavelength light generator that generates multi-wavelength light,
A CW light source that oscillates light of a single frequency;
A modulator for modulating light oscillated from the CW light source;
And a signal generator for generating an electric signal having a frequency twice as large as a Brillouin frequency shift amount of an optical fiber to be transmitted by the multi-wavelength light generator and applying the electric signal to the modulator. Wavelength light generator. The multi-wavelength light generator according to claim 1,
The modulator is a Mach-Zehnder type intensity modulator that modulates the intensity of light oscillated from the CW light source, and a phase modulator that modulates the phase of light modulated by the Mach-Zehnder type intensity modulator,
The signal generator is a sine wave generator that generates a sine wave electric signal having a frequency twice the Brillouin frequency shift amount of the optical fiber and applies the sine wave electric signal to the Mach-Zehnder intensity modulator and the phase modulator. The multi-wavelength light generator characterized by the above-mentioned. In a multi-wavelength light generator that generates multi-wavelength light,
A mode-locked laser that oscillates light having a plurality of line spectra;
A signal generator for generating an electric signal having a frequency twice the Brillouin frequency shift amount of an optical fiber to be transmitted by the multi-wavelength light generator and applying the electric signal to the modulator in the mode-locked laser; A multi-wavelength light generator characterized by the above. A multi-wavelength light generator for generating multi-wavelength light;
In a multi-wavelength optical transmission system having an optical fiber connecting the multi-wavelength light generator and a receiver that receives the multi-wavelength light generated by the multi-wavelength light generator,
The multi-wavelength light generator is
A CW light source that oscillates light of a single frequency;
A modulator for modulating light oscillated from the CW light source;
A multi-wavelength optical transmission system comprising: a signal generator that generates an electric signal having a frequency twice as large as a Brillouin frequency shift amount of the optical fiber and applies the signal to the modulator. The multi-wavelength optical transmission system according to claim 4,
The modulator is a Mach-Zehnder type intensity modulator that modulates the intensity of light oscillated from the CW light source, and a phase modulator that modulates the phase of light modulated by the Mach-Zehnder type intensity modulator,
The signal generator is a sine wave generator that generates a sine wave electric signal having a frequency twice the Brillouin frequency shift amount of the optical fiber and applies the sine wave electric signal to the Mach-Zehnder intensity modulator and the phase modulator. A multi-wavelength optical transmission system. A multi-wavelength light generator for generating multi-wavelength light;
In a multi-wavelength optical transmission system having an optical fiber connecting the multi-wavelength light generator and a receiver that receives the multi-wavelength light generated by the multi-wavelength light generator,
The multi-wavelength light generator is
A mode-locked laser that oscillates light having a plurality of line spectra;
A multi-wavelength optical transmission system comprising: a signal generator that generates an electric signal having a frequency twice as large as a Brillouin frequency shift amount of the optical fiber and applies the signal to a modulator in the mode-locked laser.

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