Abstract: A pumping light source unit for Raman amplification includes at least one pumping light source that outputs a first pumping light covering a current amplification band; at least one additional pumping light source that outputs a second pumping light covering an amplification band to be extended; and a setting control unit that controls a setting for a gain of an entire amplification band by resetting outputs of the first pumping light and the second pumping light. The pumping light source unit has a function of extending the amplification band in a stepwise manner.

Abstract: A method, pump and Raman amplifier control an amount of stimulated Brillouin scattering (SBS) produced by the Raman amplifier pump so as to regulate a power penalty experienced by a receiver due to the SBS. A multi-mode semiconductor laser produces a multi-mode pump light having a dominate mode at a predetermined wavelength. At least a portion of the multi-mode pump light is coupled to a Raman gain medium in a forward pumping direction. A reflection sensor monitors reflected light that is at least partially reflected from said Raman gain medium. The reflection sensor has a passband characteristic that passes optical power of a dominate SBS peak of said reflected light, but suppresses other SBS peaks that are offset in wavelength from said dominate SBS peak. The optical power of the dominate SBS peak is compared to an optical power of the multi-mode pump light, and it is determined whether a result of the comparing step is above a predetermined threshold.

Abstract: A tunable multimode wavelength division multiplex Raman pump and amplifier, and a system, method, and computer program product for controlling a tunable Raman pump and amplifier. The tunability of the pump source is accomplished by controlling the optical output and central wavelengths of tunable semiconductor laser devices. The system includes a microprocessor-based controller that monitors an amplifier's performance and adjusts the drive current and/or wavelength of the tunable pumps of an amplifier to achieve a target performance.

Abstract: The present invention provides the following designing method: in a laser diode module or a depolarized laser diode module which has one laser diode and one polarization maintaining fiber connected to the output side thereof, the length of the polarization maintaining fiber is a value obtained by calculation of equation 37 with use of a longitudinal mode spacing ??output light from the Fabry Perot (FP) laser diode, an oscillating center wavelength ?0 of the laser light, a beat length LBeat 1 of the polarization maintaining fiber and an optical wavelength ?Beat used in the measurement of the LBeat 1.

Abstract: An optical fiber for Raman amplification amplifies a signal light with a pumping light. A chromatic dispersion at a wavelength of 1,550 nm is in a range between ?70 ps/nm/km and ?30 ps/nm/km. Raman gain efficiency with a pumping light of 1,450 nm is equal to or more than 5 (W×km)?1. Nonlinear coefficient at the wavelength of 1,550 nm is equal to or less than 5.0×10?9 W?1. Zero-dispersion wavelength is neither at a wavelength of the signal light nor at a wavelength of the pumping light. Cut-off wavelength is equal to or less than the wavelength of the pumping light.

Abstract: The present invention provides the following designing method: in a laser diode module or a depolarized laser diode module which has one laser diode and one polarization maintaining fiber connected to the output side thereof, the length of the polarization maintaining fiber is a value obtained by calculation of equation 37 with use of a longitudinal mode spacing ??output light from the Fabry Perot (FP) laser diode, an oscillating center wavelength ?0 of the laser light, a beat length LBeat 1 of the polarization maintaining fiber and an optical wavelength ?Beat used in the measurement of the LBeat 1.

Abstract: In a Raman amplifier using three or more pumping wavelengths, when the pumping wavelengths are divided into a short wavelength side group and a long wavelength side group at the boundary of the pumping wavelength having the longest interval between the adjacent wavelengths, the short wavelength side group includes two or more pumping wavelengths having intervals therebetween which are substantially equidistant, and the long wavelength side group is constituted by two or less pumping wavelengths.

Abstract: The present invention provides a pulse train generator comprising: a dual-frequency signal light source for generating a dual-frequency signal; a soliton shaper for soliton-shaping output light from the dual-frequency signal light source; and an adiabatic soliton compressor for performing adiabatic soliton compression on output light from the soliton shaper, and also provides a waveform shaper used in this pulse train generator, including a plurality of highly nonlinear optical transmission lines and a plurality of low-nonlinearity optical transmission lines which has a nonlinearity coefficient lower than that of the plurality of highly nonlinear optical transmission lines and which has a second-order dispersion value of which an absolute value is different from that of the plurality of highly nonlinear optical transmission lines.

Abstract: Disclosed are: a pump light source device for Raman amplification for outputting a pump light for causing signal lightwaves introduced into an optical fiber to undergo Raman amplification therein, the device including two light sources, a polarization beam combiner or a polarization-maintaining optical beam coupler to which two lightwaves are input and which is adapted to combine and output these lightwaves, and a depolarizer adapted to depolarize and output the input lightwaves, wherein the lightwaves output from the two light sources are input to the polarization beam combiner or the polarization-maintaining optical beam coupler to output a combined composite lightwave, the composite lightwave being input to the depolarizer to output a lightwave with lower degree of polarization; and a Raman amplification system using the same.

Abstract: When varying the Raman gain or the gain tilt of an optical amplifier, there is no need to individually adjust the output level of every pump light source or perform overall adjustment, making it possible to obtain a targeted gain with little adjustment.

Abstract: A pumping light source unit for Raman amplification includes at least one pumping light source that outputs a first pumping light covering a current amplification band; at least one additional pumping light source that outputs a second pumping light covering an amplification band to be extended; and a setting control unit that controls a setting for a gain of an entire amplification band by resetting outputs of the first pumping light and the second pumping light. The pumping light source unit has a function of extending the amplification band in a stepwise manner.

Abstract: In a Raman optical amplification system in which WDM optical signals comprising two or more signal bands are transmitted in a transmission line, and in which a plurality of pumping lightwaves are introduced into said transmission line so that WDM optical signals in the shortest signal band are Raman-amplified by said plurality of pumping lightwaves, the interval between the longest pumping wavelength and the next-longest pumping wavelength differs by 0.2 to 1.4 THz in frequency. This makes it possible to flatten the level of the WDM signals by means of canceling the Raman gain ripple on the longer wavelength region of the distributed amplification.

Abstract: In a Raman amplifier using three or more pumping wavelengths, when the pumping wavelengths are divided into a short wavelength side group and a long wavelength side group at the boundary of the pumping wavelength having the longest interval between the adjacent wavelengths, the short wavelength side group includes two or more pumping wavelengths having intervals therebetween which are substantially equidistant, and the long wavelength side group is constituted by two or less pumping wavelengths.

Abstract: A Raman amplifier, system and method using a plurality of pumps configured to pump light into an optical fiber so as to Raman-amplify an optical signal propagating through the optical fiber. The Raman amplifier also includes an optical coupler configured to optically interconnect the pumping device with the optical fiber, and a control unit configured to control the pumping device so as to achieve a target amplification performance. Further, the control unit monitors the Raman-amplified WDM signal and determines if the monitored Raman-amplified WDM signal is within an allowable tolerance of the target amplification performance. If the Raman-amplified signal is not within the allowable tolerance, the control unit actively controls the pumps to bring the monitored Raman-amplified signal within the allowable tolerance of the target amplification profile.

Abstract: A method, pump and Raman amplifier control an amount of stimulated Brillouin scattering (SBS) produced by the Raman amplifier pump so as to regulate a power penalty experienced by a receiver due to the SBS. A multi-mode semiconductor laser produces a multi-mode pump light having a dominate mode at a predetermined wavelength. At least a portion of the multi-mode pump light is coupled to a Raman gain medium in a forward pumping direction. A reflection sensor monitors reflected light that is at least partially reflected from said Raman gain medium. The reflection sensor has a passband characteristic that passes optical power of a dominate SBS peak of said reflected light, but suppresses other SBS peaks that are offset in wavelength from said dominate SBS peak. The optical power of the dominate SBS peak is compared to an optical power of the multi-mode pump light, and it is determined whether a result of the comparing step is above a predetermined threshold.

Abstract: In a Raman amplifier using three or more pumping wavelengths, when the pumping wavelengths are divided into a short wavelength side group and a long wavelength side group at the boundary of the pumping wavelength having the longest interval between the adjacent wavelengths, the short wavelength side group includes two or more pumping wavelengths having intervals therebetween which are substantially equidistant, and the long wavelength side group is constituted by two or less pumping wavelengths.

Abstract: First pump light for Raman-amplifying optical signal is inputted to the output end of the optical signal, and second pump light used for Raman-amplifying the first pump light and having a wavelength shorter than that of the first pump light is inputted to the input end of the optical signal. The second pump light is also inputted to the output end of the optical signal. The first pump light is also inputted to the input end of the optical signal. The Raman amplification band of the second pump light is made not to be overlapped with that of the optical signal. The wavelength of the second pump light is shorter than that of the first pump light by the Raman shift of the amplifier fiber. The light source of either the first or second pump light or both the light sources of them are multiplex optical sources. The first pump light is emitted from a semiconductor laser. Third pump light for Raman-amplifying the second pump light is directed to an optical transmission line.

Abstract: First pump light for Raman-amplifying optical signal is inputted to the output end of the optical signal, and second pump light used for Raman-amplifying the first pump light and having a wavelength shorter than that of the first pump light is inputted to the input end of the optical signal. The second pump light is also inputted to the output end of the optical signal. The first pump light is also inputted to the input end of the optical signal. The Raman amplification band of the second pump light is made not to be overlapped with that of the optical signal. The wavelength of the second pump light is shorter than that of the first pump light by the Raman shift of the amplifier fiber. The light source of either the first or second pump light or both the light sources of them are multiplex optical sources. The first pump light is emitted from a semiconductor laser. Third pump light for Raman-amplifying the second pump light is directed to an optical transmission line.

Abstract: In a Raman amplification method for pumping signal light with two or more pumping lights that have different wavelengths, the wavelengths and powers of the two or more pumping lights are combined, a part or all of the combined pumping lights are used for bidirectional pumping, and distribution of power of pumping light to the wavelengths is changed while the total power in the bidirectional pumping is not changed or is hardly changed. A part of the combined pumping lights are used for the forward pumping whereas all the pumping lights used in the combinations are used for the backward pumping. Among the combined pumping lights, the pumping lights on the short wavelength side are used for the forward pumping whereas all the pumping lights used in the combinations are used for the backward pumping. In any combination, the power of the backward pumping light is larger than that of the forward pumping light.

Abstract: In a Raman amplifier using three or more pumping wavelengths, when the pumping wavelengths are divided into a short wavelength side group and a long wavelength side group at the boundary of the pumping wavelength having the longest interval between the adjacent wavelengths, the short wavelength side group includes two or more pumping wavelengths having intervals therebetween which are substantially equidistant, and the long wavelength side group is constituted by two or less pumping wavelengths.