312 results about "Raman amplifiers" patented technology

The present invention provides a Raman amplifier and the like comprising a structure for keeping the flatness of power spectrum of Raman-amplified signal light. The Raman amplifier comprises an optical fiber for Raman-amplifying a plurality of signal channels of signal light having respective center optical frequencies different from each other; a pumping light supply section for supplying N (N being an integer of 2 or more) pumping channels of pumping light having respective center optical frequencies different from each other to the optical fiber; and a feedback section for detecting a part of the signal light Raman-amplified within the optical fiber when the pumping light is supplied thereto, and controlling the pumping light supply section such that the Raman-amplified signal light has a substantially flat power spectrum with respect to an optical frequency direction according to the result of detection. In particular, the feedback section divides the detected Raman-amplified signal light into N optical frequency ranges defined so as to include respective Raman amplification peaks as optical frequencies lower than respective center optical frequencies of the pumping channels of pumping light by an optical frequency shift of about 15 THz, and controls the pumping light supply section such that the Raman-amplified signal light has a power fluctuation of 2 dB or less in each of thus divided N optical frequency ranges.

A method of determining the gain characteristic of a Raman amplifier includes the steps of launching a pump light signal into a fiber; preliminary adjusting the power of the pump light signal to a value that lies in a range where the amplified spontaneous emission noise originating from the pump light signal is substantially proportional to the on/off gain provided by the power of the pump light signal; monitoring the power of the amplified spontaneous emission noise signal; varying the power of the pump light signal; measuring a variation in the power of the amplified spontaneous emission noise signal corresponding to the pump power variation; and determining the gain characteristic of the amplifier from the relative variation in pump power and the measured variation in noise power.

A Raman amplifier having a microstructured fiber and at least one pump laser, optically connected to one end of the microstructured fiber. The pump laser is adapted for emitting a pump radiation at a wavelength λ_p, and the microstructured fiber has a silica-based core surrounded by a plurality of capillary voids extending in the axial direction of the fiber. The core of microstructured fiber has at least one dopant added to silica, the dopant being suitable for enhancing Raman effect.

Raman amplifier systems and methods with an integrated Optical Time Domain Reflectometer (OTDR) for integrated testing functionality include an amplifier system, an OTDR and telemetry subsystem, and a method of operation. The OTDR and telemetry subsystem is configured to operate in an OTDR mode when coupled to a line in port and to operate in a telemetry mode when coupled to a line out port. The OTDR and telemetry subsystem enables on-demand fiber testing while also operating as a telemetry channel that is both a redundant optical service channel (OSC) and provides a mechanism to monitor Raman gain over time. The OTDR and telemetry subsystem minimizes cost and space by sharing major optical and electrical components between the integrated OTDR and other functions on the Raman amplifier.

An optical communication system that includes an optical network is disclosed having a plurality of nodes and a plurality of optical fiber links which includes optical fiber links that interconnect the nodes. Signals passing through the network are similarly pre-compensated and/or similarly post-compensated. The network preferably includes dispersion-managed optical fiber spans, and preferably further includes distributed amplification, preferably erbium amplifiers and/or Raman amplifiers. Preferably, the network is transparent.

A method and apparatus for enabling multiple optical line termination (OLT) devices to share a feeder fiber are disclosed. For example, the optical network comprises a plurality of optical line termination (OLT) devices, where each OLT device having a transceiver for sending and receiving optical signals. The optical network further comprises a wave division multiplexer (WDM) combiner, coupled to the plurality of OLT devices, for combining optical signals received from the plurality of OLT devices. The optical network further comprises an optical extender box comprising at least one hybrid SOA-Raman amplifier, wherein the optical extender box is coupled to the WDM combiner via a first standard single mode fiber section. Finally, the optical network further comprises at least one optical splitter coupled to the optical extender box via a second standard single mode fiber section.

Raman amplification of a WDM signal with excellent gain flatness across a very large bandwidth is achieved. Co-propagating and counter-propagating Raman pumping are combined in the same fiber. Multiple pumping wavelengths are employed. Wavelengths employed for co-propagating pumping and wavelengths employed for counter-propagating pumping alternate in order of wavelength. In one embodiment, N co-propagating pump wavelengths and N+1 counter-propagating pump wavelengths are used. Alternatively, one may use N+1 co-propagating pump wavelengths and N counter-propagating pump wavelengths.

An optical transmission system capable of monitoring the operating status of Raman-amplifier repeaters even when an optical transmission line is partly disrupted by a fiber failure. An end station sends a monitoring command signal to request a particular repeater to report its operating status, together with a response carrier wave for use in that reporting. With their different wavelengths, an upstream wavelength selector in the repeater selectively passes the monitoring command signal while reflecting back the response carrier wave. Responsive to the command, a monitoring controller creates a response message containing operating status information. An excitation unit performs Raman amplification with a pump beam modulated by a modulation controller, so that the response message be superimposed on the response carrier wave propagating on the upstream link. The resulting monitoring response signal is routed from the upstream wavelength selector to a downstream optical coupler and sent back to the requesting end station.

Devices for generating a laser beam are disclosed. The devices include a silicon micro ring having at least one silicon optical waveguide disposed at a distance from the micro ring. The radius and the cross-sectional dimension of the microring, the cross-sectional dimension of the waveguide, and the distance between the micro ring and the waveguide are determined such that one or more pairs of whispering gallery mode resonant frequencies of the micro ring are separated by an optical phonon frequency of silicon. Methods of manufacturing a lasing device including a silicon micro ring coupled with a silicon waveguide are also disclosed.

An optical fiber propagates and amplifies a second signal light that is a wavelength-multiplexed signal of a first signal light of a plurality of wavelengths and a reference light that is out of a wavelength range of amplification. An excitation light source outputs an excitation light for amplifying the second signal light. A beam splitter splits a portion of the second signal light into the first signal light and the reference light. A signal light level detecting unit detects a level of the first signal light. A reference light level detecting unit detects a level of the reference light. A signal level setting unit calculates a target value for constantly maintaining a Raman gain, and controls the output level of the excitation light in such a way that the first signal level matches with the target value.

A laser system for semiconductor inspection includes a fiber-based fundamental light source for generating fundamental light that is then converted/mixed by a frequency conversion module to generate UV-DUV laser light. The fundamental light source includes a nonlinear chirp element (e.g., a Bragg grating or an electro-optic modulator) that adds a nonlinear chirp to the seed light laser system prior to amplification by the fiber amplifier(s) (e.g., doped fiber or Raman amplifiers). The nonlinear chirp includes an x² or higher nonlinearity and is configured to compensate for the Self Phase Modulation (SPM) characteristics of the fiber-based amplifiers such that fundamental light is generated that has a spectral E95 bandwidth within five times that of the seed light. When multiple series-connected amplifiers are used, either a single nonlinear chirp element is provided before the amplifier string, or chirp elements are included before each amplifier.

A semiconductor laser module has a Fabry-Perot type semiconductor laser device, an optical fiber, and first and second lenses. The tip of the optical fiber, on which the laser beam falls, is askew polished. The optical fiber is fixed in such a manner that the axis of the optical fiber makes an angle with respect to an optical axis of the laser beam. Coatings that avoid reflection are formed on the tip of the optical fiber, and on the first and second lenses.

The invention discloses an extra-long station spacing emergency communication method. In the method, optical amplification devices are arranged at two line interruption ends; and a new optical transmission channel is established in the middle of a line by using an optical cable, and comprises a forward error correction (FEC) coding device, a power amplifier EDFA-BA, a Raman amplifier FRA, a preliminary amplifier EDFA-PA and dispersion compensation equipment DCM which are configured in turn, wherein the power amplifier EDFA-BA is connected with the Raman amplifier FRA by using a G.652 optical cable. The extra-long station spacing emergency communication method can reduce the use of relay equipment, solve the problems of optical fiber line interruption, relay station damage or maintenance, optical fiber ageing and the like of an electric power system; and by configuring different optical amplification schemes, a new transmission channel can be quickly established by using redundant or backup optical fibers, thereby fulfilling the aim of emergency communication.

A method and apparatus for providing passive optical networks with extended reach and/or splitting ratio are disclosed. For example, the optical network comprises a first optical line termination (OLT) device having a transceiver for sending and receiving optical signals. The optical network further comprises an optical extender box comprising at least one hybrid SOA-Raman amplifier, wherein the optical extender box is coupled to the first optical line termination device via a first standard single mode fiber section. Finally, the optical network further comprises an optical splitter coupled to the optical extender box via a second standard single mode fiber section.