Abstract: The invention provides a cascade Raman laser including a pumping laser light source that generates pumping light, a cascade Raman resonator having an input-side optical reflector that receives the pumping light and selectively reflects light of each wavelength corresponding to a n-th Stokes ray (n is an integer more than 1) of Raman scattering to the pumping light, a Raman optical fiber that is connected to the input-side optical reflector and generates Raman scattering light at least by the pumping light and an output-side optical reflector that is connected to the Raman optical fiber and selectively reflects light of each wavelength corresponding to the n-th Stokes ray and a blocking device interposed between the pumping laser light source and the cascade Raman resonator and blocks the first Stokes ray generated within the cascade Raman resonator from entering the pumping laser light source side.

Abstract: The invention provides a cascade Raman laser including a pumping laser light source that generates pumping light, a cascade Raman resonator having an input-side optical reflector that receives the pumping light and selectively reflects light of each wavelength corresponding to a n-th Stokes ray (n is an integer more than 1) of Raman scattering to the pumping light, a Raman optical fiber that is connected to the input-side optical reflector and generates Raman scattering light at least by the pumping light and an output-side optical reflector that is connected to the Raman optical fiber and selectively reflects light of each wavelength corresponding to the n-th Stokes ray and a blocking device interposed between the pumping laser light source and the cascade Raman resonator and blocks the first Stokes ray generated within the cascade Raman resonator from entering the pumping laser light source side.

Abstract: An optical fiber holding apparatus in accordance with the present invention is characterized in that the same comprises a surface in order to hold an optical fiber which is to be a state of which is rolled up so as not to overlap with each other, wherein at least the surface is formed of a thermo conductive molding body which has a thermal conductivity to be higher than or equal to 0.5 W/mK, and which has an Asker C hardness to be between twenty and fifty. Or, the same comprises a peripheral surface in order to roll up and hold an optical fiber, wherein at least the peripheral surface is formed of a thermo conductive molding body which has the thermal conductivity to be higher than or equal to 0.5 W/mK, and which has the Asker C hardness to be between twenty and fifty. Moreover, it is desirable for the thermo conductive molding body to have a compressive strength of which a peak value is between ten and thirty N/cm2 and a stabilized value is between three and ten N/cm2.

Abstract: An optical transmission fiber is formed to include a relatively low-index, relatively thin outer cladding layer disposed underneath the protective polymer outer coating. Stray light propagating along an inner cladding layer(s) within the fiber will be refracted into the thin outer cladding (by proper selection of refractive index values). The thin dimension of the outer cladding layer allows for the stray light to “leak” into the outer coating in a controlled, gradual manner so as to minimize heating of the coating associated with the presence of stray light. The inventive fiber may also be bent to assist in the movement of stray light into the coating.

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: An optical transmission fiber is formed to include a relatively low-index, relatively thin outer cladding layer disposed underneath the protective polymer outer coating. Stray light propagating along an inner cladding layer(s) within the fiber will be refracted into the thin outer cladding (by proper selection of refractive index values). The thin dimension of the outer cladding layer allows for the stray light to “leak” into the outer coating in a controlled, gradual manner so as to minimize heating of the coating associated with the presence of stray light. The inventive fiber may also be bent to assist in the movement of stray light into the coating.

Abstract: A Raman amplifier according to the present invention comprises a plurality of pumping means using semiconductor lasers of Fabry-Perot, DFB, or DBR type or MOPAs, and pumping lights outputted from the pumping means have different central wavelengths, and interval between the adjacent central wavelength is greater than 6 nm and smaller than 35 nm. An optical repeater according to the present invention comprises the above-mentioned Raman amplifier and adapted to compensate loss in an optical fiber transmission line by the Raman amplifier. In a Raman amplification method according to the present invention, the shorter the central wavelength of the pumping light the higher light power of said pumping light.

Abstract: A Raman amplifier according to the present invention comprises a plurality of pumping means using semiconductor lasers of Fabry-Perot, DFB, or DBR type or MOPAs, and pumping lights outputted from the pumping means have different central wavelengths, and interval between the adjacent central wavelength is greater than 6 nm and smaller than 35 nm. An optical repeater according to the present invention comprises the above-mentioned Raman amplifier and adapted to compensate loss in an optical fiber transmission line by the Raman amplifier. In a Raman amplification method according to the present invention, the shorter the central wavelength of the pumping light the higher light power of said pumping light.

Abstract: A Raman amplifier according to the present invention comprises a plurality of pumping means using semiconductor lasers of Fabry-Perot, DFB, or DBR type or MOPAs, and pumping lights outputted from the pumping means have different central wavelengths, and interval between the adjacent central wavelength is greater than 6 nm and smaller than 35 nm. An optical repeater according to the present invention comprises the above-mentioned Raman amplifier and adapted to compensate loss in an optical fiber transmission line by the Raman amplifier. In a Raman amplification method according to the present invention, the shorter the central wavelength of the pumping light the higher light power of said pumping light.

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: An optical transmission fiber is formed to include a relatively low-index, relatively thin outer cladding layer disposed underneath the protective polymer outer coating. Stray light propagating along an inner cladding layer(s) within the fiber will be refracted into the thin outer cladding (by proper selection of refractive index values). The thin dimension of the outer cladding layer allows for the stray light to “leak” into the outer coating in a controlled, gradual manner so as to minimize heating of the coating associated with the presence of stray light. The inventive fiber may also be bent to assist in the movement of stray light into the coating.

Abstract: An optical transmission fiber is formed to include a relatively low-index, relatively thin outer cladding layer disposed underneath the protective polymer outer coating. Stray light propagating along an inner cladding layer(s) within the fiber will be refracted into the thin outer cladding (by proper selection of refractive index values). The thin dimension of the outer cladding layer allows for the stray light to “leak” into the outer coating in a controlled, gradual manner so as to minimize heating of the coating associated with the presence of stray light. The inventive fiber may also be bent to assist in the movement of stray light into the coating.

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: 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: An optical transmission fiber is formed to include a relatively low-index, relatively thin outer cladding layer disposed underneath the protective polymer outer coating. Stray light propagating along an inner cladding layer(s) within the fiber will be refracted into the thin outer cladding (by proper selection of refractive index values). The thin dimension of the outer cladding layer allows for the stray light to “leak” into the outer coating in a controlled, gradual manner so as to minimize heating of the coating associated with the presence of stray light. The inventive fiber may also be bent to assist in the movement of stray light into the coating.

Abstract: An optical transmission fiber is formed to include a relatively low-index, relatively thin outer cladding layer disposed underneath the protective polymer outer coating. Stray light propagating along an inner cladding layer(s) within the fiber will be refracted into the thin outer cladding (by proper selection of refractive index values). The thin dimension of the outer cladding layer allows for the stray light to “leak” into the outer coating in a controlled, gradual manner so as to minimize heating of the coating associated with the presence of stray light. The inventive fiber may also be bent to assist in the movement of stray light into the coating.

Abstract: An optical signal amplifier includes a light source, a depolarizer, and a gain medium that transfers energy from a pump beam output from the depolarizer to the optical signal. The depolarizer may include one or more birefringent optical fibers which support two polarization modes, a fast mode and a slow mode. The light propagates in the fast mode at a higher velocity than the light propagates in the slow mode so as to impart phase delay as the light propagates in the birefringent optical fibers, thereby at least partially depolarizing the beam. A method for using the amplifier with different types of transmission fibers enables the matching of depolarizers with relatively high percentage of degree of polarization, depending on fiber type, while staying below polarization dependent gain requirements.

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: A Raman amplifier according to the present invention comprises a plurality of pumping means using semiconductor lasers of Fabry-Perot, DFB, or DBR type or MOPAs, and pumping lights outputted from the pumping means have different central wavelengths, and interval between the adjacent central wavelength is greater than 6 nm and smaller than 35 nm. An optical repeater according to the present invention comprises the above-mentioned Raman amplifier and adapted to compensate loss in an optical fiber transmission line by the Raman amplifier. In a Raman amplification method according to the present invention, the shorter the central wavelength of the pumping light the higher light power of said pumping light.

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.