Abstract: An optical amplifier system and method are disclosed for amplifying CWDM channels. The optical amplifier system includes a first optical amplifier that includes a fluoride-based optical fiber of a first length and a second optical amplifier that includes a fluoride-based optical fiber of a second length. The first length of fluoride-based optical fiber in the first optical amplifier is different than the second length of fluoride-based optical fiber in the second optical amplifier. When in operation, the first optical amplifier receives optical signals for CWDM channels and amplifies the CWDM channels. The second optical amplifier then receives the optical signals and amplifies the CWDM channels. Between the first optical amplifier and the second optical amplifier, the optical amplifier system generates a continuous gain bandwidth over the CWDM channels.

Abstract: A communication system and method are disclosed to provide a wider gain bandwidth. One embodiment of the invention is a communication system comprising a transmitter, a Phosphate-doped fiber span, a receiver, and a continuous wavelength light system. When in operation, the transmitter transmits optical signals over the Phosphate-doped fiber span for receipt by the receiver. Concurrently, the continuous wavelength light system pumps continuous wavelength light onto the Phosphate-doped fiber span. The pumping by the continuous wavelength light system generates a total gain bandwidth of at least 120 nm.

Abstract: A discrete optical amplifier system is disclosed comprising a Dispersion Compensating Fiber (DCF), a first order pump system, and a second order pump system. The first order pump system is set to a first power and is configured to backward pump onto the DCF. The second order pump system is set to a second power and is configured to forward pump onto the DCF. One or both of the first power and the second power are set based on a power ratio. The first and second pump systems generate a gain in an optical signal traveling on the DCF. The power ratio, the first power, and the second power are set to generate a low noise figure for the gain in the optical signal, and are set to distribute the gain along the DCF to reduce fiber non-linearities affecting the optical signal while traveling over the DCF.

Abstract: A communication system for distributed Raman amplification of optical signals is disclosed. The communication system comprises a first fiber span, a second fiber span, and an amplifier system. The amplifier system generates a light beam and splits the light beam into a first portion and a second portion. The amplifier system transfers the first portion of the light beam onto the first fiber span so that the first portion of the light beam backward propagates over the first fiber span. The amplifier system transfers the second portion of the light beam onto the second fiber span so that the second portion of the light beam forward propagates over the second fiber span.

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 amplifier system is disclosed comprising a discrete amplifier system and a distributed amplifier system. The discrete amplifier system receives optical signals and amplifies the optical signals having wavelengths in a target wavelength band. The target wavelength band has a bandwidth of at least 80 nm. The distributed amplifier system amplifies the optical signals having wavelengths in a longer wavelength band of the target wavelength band, a shorter wavelength band of the target wavelength band, or both.

Abstract: An optical communication link that has an optical transmission line constructed by combining a positive dispersion optical fiber having a positive dispersion value with a negative dispersion optical fiber having a negative dispersion value, in a wavelength region to be used: wherein a dispersion value of the positive dispersion optical fiber is 5 ps/nm/km or more and 15 ps/nm/km or less; and wherein DPS values of both the positive dispersion optical fiber and the negative dispersion optical fiber are 250 nm or more, the DPS values being obtained by dividing dispersion values of the respective fibers at a wavelength of 1550 nm by a dispersion gradient.

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: 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 communication link that has an optical transmission line constructed by combining a positive dispersion optical fiber having a positive dispersion value with a negative dispersion optical fiber having a negative dispersion value, in a wavelength region to be used:

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: 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: 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 relates to a dispersion shifted optical fiber having zero dispersion at a wavelength band of 1.5 &mgr;m, which suppresses an increase of transmission loss and an increase of polarization mode dispersion when carrying out fiber drawing. An optical fiber according the invention is provided with the first core (refractive index n1.), the second core (refractive index n2), the first clad (refractive index n3) and second clad (refractive index n4) in this order from the center to outside, wherein the abovementioned refractive indexes are in a relationship of n1>n4>n2>n3, Ge which is at a ratio of 0.4 to 1.0% for the value of relative refractive index difference with respect to the second clad is doped on the first core, which is at a ratio of 0.1 to 0.5% for the value of relative refractive index difference with respect to the second clad is doped on the second core as in the above, and the second clad is SiO2, which has a thickness from 1 &mgr;m or more to 40 &mgr;m or less.