Abstract: A nonlinear polarization amplifier stage includes a gain medium operable, to receive a multiple wavelength optical signal. The amplifier stage also includes a pump assembly operable to generate at least one pump wavelength for introduction to the gain medium. The amplifier stage further includes a coupler operable to introduce the at least one pump wavelength to the gain medium to facilitate amplification of at least a portion of the multiple wavelength optical signal through nonlinear polarization. In one particular embodiment, at least a wavelength or an intensity of the at least one pump wavelength is manipulated to affect the shape of a gain curve associated with the multiple wavelength optical signal in the amplifier stage.

Abstract: A fiber optic transmission system for a metropolitan area network includes a plurality of interface devices operable to be coupled to a fiber optic transmission link carrying an optical signal and having a length of 300 km or less. The link has a transmission loss associated with an unpumped state of the link, and the plurality of interface devices collectively introduce a loss of at least 6 decibels to the link. The system also includes a distributed Raman amplifier stage coupled to the link, the distributed Raman amplifier stage operable to pump at least a portion of the link to reduce the transmission loss of the at least a portion of the link compared to its unpumped state, the reduced link transmission loss facilitating allocation of at least a portion of a gain to at least partially offset the loss associated with the plurality of interface devices.

Abstract: A broadband fiber transmission system includes a transmission line with at least one zero dispersion wavelength &lgr;o and transmits an optical signal of &lgr;. The transmission line includes a distributed Raman amplifier that amplifies the optical signal through Raman gain. One or more pump sources are included and operated at wavelengths &lgr;p for generating a pump light to pump the Raman amplifier. &lgr; is close to &lgr;0 and &lgr;0 is less than 1540 nm or greater than 1560 nm.

Abstract: A broadband fiber transmission system includes a transmission line with at least one zero dispersion wavelength &lgr;o and transmits an optical signal of &lgr;. The transmission line includes a distributed Raman amplifier that amplifies the optical signal through Raman gain. One or more semiconductor lasers are included and operated at wavelengths &lgr;p for generating a pump light to pump the Raman amplifier. &lgr; is close to &lgr;o and &lgr;0 is less than 1540 nm or greater than 1560 nm.

Abstract: In one aspect of the invention, a method of managing one or more optical elements includes storing in a memory, provisioning information describing at least one setting of an optical element and monitored information describing at least one operational characteristic of the optical element. At least a portion of the monitored information is correlated with at least a portion of the provisioning information. The method further includes maintaining in the memory, a correlation history comprising the provisioning information stored over time and the monitored information correlated to that provisioning information.

Abstract: In one aspect of the invention, an apparatus operable to convert wavelengths of a plurality of optical signals includes a coupler operable to receive a pump signal and a plurality of input signals each input signal comprising at least one wavelength different than the wavelengths of others of the plurality of input optical signals. The apparatus further includes an optical medium operable to receive the pump signal and the plurality of input signals from the couplet, wherein the pump signal and each of the plurality of input signals are synchronized to overlap at least partially during at least a part of the time spent traversing the optical medium to facilitate generation of a plurality of converted wavelength signals each comprising a wavelength that is different than the wavelengths of at least some of the plurality of input signals. Various embodiments can result in low cross-talk and/or low polarization sensitivity.

Abstract: A Raman amplifier assembly includes a Raman amplifier configured to receive a signal from a signal source. The signal travels in an upstream direction in the Raman amplifier. A first pump source is coupled to the Raman amplifier. The first pump source produces a first pump beam that travels in a downstream direction and is counter-propagating relative to the signal. A second pump source is coupled to the Raman amplifier and produces a second pump beam that travels in the upstream direction. The second pump source has an average relative intensity noise of less than −80 dB/Hz.

Abstract: A broadband nonlinear polarization amplifier includes an input port for inputting an optical signal having a wavelength &lgr;. A distributed gain medium receives and amplifiers the optical signal through nonlinear polarization. The distributed gain medium has zero-dispersion at wavelength &lgr;0. A magnitude of dispersion at &lgr; is less than 50 ps/nm-km. One or more semiconductor lasers are operated at wavelengths &lgr;p for generating a pump light to pump the distributed gain medium. An output port outputs the amplified optical signal.

Abstract: A multi-stage Raman amplifier includes a first Raman amplifier stage having a first sloped gain profile operable to amplify a plurality of signal wavelengths, and a second Raman amplifier stage having a second sloped gain profile operable to amplify at least most of the plurality of signal wavelengths after those wavelengths have been amplified by the first stage. The second sloped gain profile is approximately complementary slope to the slope of the first sloped gain profile. The combined effect of the first and second Raman stages contributes to an approximately flat overall gain profile over the plurality of signal wavelengths.

Abstract: A Raman amplifier apparatus includes an optical transmission line with an input to receive an optical signal, an output that passes the optical signal, a first Raman gain fiber and a second Raman gain fiber. A first WDM is positioned between the second Raman gain fiber and the output. A first set of pump wavelengths is input to the first WDM. A second WDM is positioned between the first and second Raman gain fibers. A second set of pump wavelengths is input to the second WDM. At least a portion of the first set of pump wavelengths are different than the second set of pump wavelengths. The first and second set of pump wavelengths propagate in the same direction.

Abstract: An in-line broadband amplifier includes at least one input fiber and a WDM splitter coupled to the input fiber. The splitter splits an optical signal into at least a first wavelength and a second wavelength. A transition from a stop band to a pass band of the splitter occurs in 20 nm or less. A Raman amplifier and a rare-earth doped optical amplifier are coupled to the splitter. A WDM combiner is coupled to the Raman amplifier and the rare-earth doped optical amplifier. The WDM combiner combines an optical signal into at least a first wavelength and a second wavelength. A transition from a stop band to a pass band of the combiner occurs in 20 nm or less. An output fiber is coupled to the WDM combiner.

Abstract: A Raman amplifier assembly includes a Raman amplifier configured to receive a signal from a signal source. The signal travels in an upstream direction in the Raman amplifier. A first pump source is coupled to the Raman amplifier. The first pump source produces a first pump beam that travels in a downstream direction and is counter-propagating relative to the signal. A second pump source is coupled to the Raman amplifier and produces a second pump beam that travels in the upstream direction. The second pump source has an average relative intensity noise of less than −80 dB/Hz.

Abstract: An amplifier apparatus includes an optical transmission line with a Raman amplification region that provides a pump to signal power conversion efficiency of at least 20%. The Raman amplification region is configured to amplify a signal with multiple wavelengths over at least a 30 nm range of wavelengths. A pump source is coupled to the optical transmission line. An input optical signal is amplified in the Raman amplification region and an output signal is generated that has at least 100 mW more power than the input optical signal.

Abstract: An apparatus and method are described for exploiting almost the full almost 25 THz of bandwidth available in the low-loss window in optical fibers (from 1430 nm to 1620 nm) using a parallel combination of optical amplifiers. The low-loss window at about 1530 nm-1620 nm can be amplified using erbium-doped fiber amplifiers (EDFAs). However, due to the inherent absorption of the erbium at shorter wavelengths, EDFAs cannot be used below about 1525 nm without a significant degradation in performance. For the low-loss window at approximately 1430-1530 nm, amplifiers based on nonlinear polarization in optical fibers can be used effectively. A broadband nonlinear polarization amplifier (NLPA) is disclosed which combines cascaded Raman amplification with parametric amplification or four-wave mixing. In particular, one of the intermediate cascade Raman order wavelengths &lgr;r should lie in close proximity to the zero-dispersion wavelength &lgr;0 of the amplifying fiber.

Abstract: A multi-stage optical amplifier includes an optical fiber with at least a first Raman amplifier fiber and a second Raman amplifier fiber. The optical fiber is configured to be coupled to at least one signal source that produces at least a signal wavelength &lgr;s and at least two pump sources that collectively produce a pump beam of wavelength &lgr;p. Pump wavelength &lgr;p is less than signal wavelength &lgr;s. Signal input, signal output and a first pump input port are each coupled to the optical fiber. The first Raman amplifier fiber is positioned between the signal input port and the pump input port. The second Raman amplifier fiber is positioned between the pump input port and signal output port. A second pump input port is coupled to the optical fiber and positioned between the second Raman amplifier fiber and the signal output port. A first lossy member is positioned between the pump input port and the signal output port.

Abstract: An amplified broadband optical signal is produced in a transmission system. An optical signal is divided into a first beam and a second beam. The first beam has a wavelength less than a predetermined wavelength. The second beam has a wavelength greater than the predetermined wavelength. The first beam is directed to a transmission link in the transmission system. The transmission system includes a distributed Raman amplifier. The distributed Raman amplifier operates in the wavelength range less than 1480 nm. The second beam is directed to a second amplifier. The first and second beams are combined. An amplified broadband optical signal is produced.

Abstract: A Raman amplifier assembly includes a Raman amplifier configured to receive a signal from a signal source. The signal travels in an upstream direction in the Raman amplifier. A first pump source is coupled to the Raman amplifier. The first pump source produces a first pump beam that travels in a downstream direction and is counter-propagating relative to the signal. A second pump source is coupled to the Raman amplifier and produces a second pump beam that travels in the upstream direction. The second pump source has an average relative intensity noise of less than −80 dB/Hz.

Abstract: In one aspect of the invention, a control system for use in an optical amplifier includes a plurality of control legs, each operable to receive one of plurality of portions of an optical signal, wherein each of the plurality of portions comprises a different percentage of the optical signal. The system further includes a plurality of registers, each associated with one of the control legs and each operable to store a value proportional to the portion of the optical signal communicated in the associated control leg. The system also includes a controller operable to select one of the values stored in one of the plurality of registers and to scale that value by a scaling factor to generate a scaled value, wherein the scaling factor is determined at least in part by the percentage of the optical signal associated with that value. The controller is operable to generate, based at least in part on the scaled value, a control signal operable to affect the gain of the amplifier.

Abstract: One aspect of the invention includes an optical amplifier operable to amplify a plurality of optical wavelength signals at least in part through Raman amplification. The amplifier includes an input operable to receive a plurality of wavelength signals and an output operable to communicate an amplified version of at least some of the plurality of wavelength signals. The amplifier further includes a pump assembly operable to generate one or more pump signals and a gain medium operable to receive the plurality of wavelength signals and the one or more pump signals and to facilitate amplification of at least some of the plurality of wavelength signals. The amplifier has associated with it a noise figure having a shape varying as a function of wavelength. At least one of the one or more pump signals is operable to have its power varied to selectively control the shape of the noise figure.

Abstract: A method of broadband amplification divides an optical signal of wavelength of 1430 nm to 1620 nm at a preselected wavelength into a first beam and a second beam. The first beam is directed to at least one optical amplifier and produces an amplified first beam. The second beam is directed to at least one rare earth doped fiber amplifier to produce an amplified second beam. The first and second amplified beams are combined.