Abstract: An optical communication system includes a gain medium that is capable of receiving at least one optical signal that includes one or more optical signal wavelengths. The system also includes one or more pump sources that are capable of generating at least one pump signal for introduction to the gain medium. The pump signal includes one or more fractional Raman order pump wavelengths having a Raman gain peak that is a non-integer multiple of one stokes shift from each of the one or more optical signal wavelengths. In one particular embodiment, the pump signal interacts with the optical signal as the pump signal traverses at least a portion of the gain medium.

Abstract: Devices and methods for providing stimulated Raman lasing are provided. In some embodiments, devices include a photonic crystal that includes a layer of silicon having a lattice of holes and a linear defect that forms a waveguide configured to receive pump light and output Stokes light through Raman scattering, wherein the thickness of the layer of silicon, the spacing of the lattice of holes, and the size of the holes are dimensioned to provide Raman lasing. In some embodiments, methods include forming a layer of silicon, and etching the layer of silicon to form a lattice of holes with a linear defect that forms a waveguide configured to receive pump light and output Stokes light through Raman scattering, wherein the thickness of the layer of silicon, the spacing of the lattice of holes, and the size of the holes are dimensioned to provide Raman lasing.

Abstract: The present invention relates to a method and system of generating backward stimulated Rayleigh-Bragg scattering by focusing activating radiation through a multi-photon absorbing dye solution, thereby producing coherent output radiation with no measured frequency shift and measured pump threshold values independent of the spectral line width of the input activating radiation.

Abstract: An ultrasonic non-destructive evaluation (NDE) system operable to inspect target materials is provided. This ultrasonic NDE system includes an articulated robot, an ultrasound inspection head, a processing module, and a control module. The ultrasound inspection head couples to or mounts on the articulated robot. The ultrasound inspection head is operable to deliver a generation laser beam, a detection laser beam, and collect phase modulated light scattered by the target materials. The processing module processes the phase modulated light and produces information about the internal structure of the target materials. The control module directs the articulated robot to position the ultrasound inspection head according to a pre-determined scan plan.

Abstract: An optical device includes an input optical source that provides and optical signal to the optical device. A surface phonon polariton (SPP) nanostructure receives the optical signal that interacts with the SPP nanostructure to excite a Raman process and produce a Raman light signal. The Raman light signal comprises a broad spectral range from near infrared to far infrared.

Abstract: The invention provides a laser system (100) wherein the output may be selected from two or more different wavelengths of output laser light. The system (100) comprises a laser capable of having at least two different wavelengths of laser light resonating in the cavity (105) simultaneously. One of the frequencies is generated by a Raman crystal (135) which shifts the frequency of light generated by the lasing medium (125). A tunable non-linear medium (140), such as LBO, is provided in the cavity for selectively frequency converting at least one of the at least two different wavelengths of laser light. The conversion may be SHG, SFG or DFG for example. A tuner (145) is provided to tune the non-linear medium to select the particular wavelength to convert. Temperature tuning or angle tuning of the non-linear medium can be used. A Q switch (130) may also be provided in the cavity.

Abstract: A pulsed cascaded Raman laser (10) includes a pulsed light source (102) for generating a pulsed light (104) having an optical spectrum centered at a source wavelength. A non-linear Raman conversion fiber (106) is coupled to the pulsed light source (102). The pulsed light (104) traverses the nonlinear Raman conversion fiber (106) and the source power at the source wavelength is converted to a power output of an output signal (108) having an output wavelength longer than the source wavelength by a cascaded Stimulated Raman Scattering process, such that most of the source power is converted to the power of the last Stokes order in a single pass through the non-linear Raman conversion fiber (106).

Abstract: The present invention is directed to new laser-related uses for single-crystal diamonds produced by chemical vapor deposition. One such use is as a heat sink for a laser; another such use is as a frequency converter. The invention is also directed to a ?(3) nonlinear crystalline material for Raman laser converters comprising single crystal diamond.

Abstract: A laser system is provided which selectively excites Raman active vibrations in molecules. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and remote sensing.

Abstract: A semiconductor-based optical amplifier/attenuator is disclosed. An apparatus according to aspects of the present invention includes an optical waveguide disposed in semiconductor material. A first optical beam having a first wavelength is to be directed through the optical waveguide. The optical waveguide is optically coupled to receive a pump optical beam having a pump wavelength. The pump optical beam also has a power level sufficient to amplify the first optical beam via stimulated Raman scattering (SRS) in the optical waveguide. A diode structure is disposed in the optical waveguide. The diode structure coupled is to be selectively biased to selectively control free carrier lifetimes of the free carriers in the optical waveguide. This enables to selective amplification or attenuation of the first optical beam output from the optical waveguide.

Abstract: Optical fibers (e.g., fiber amplifiers and fiber lasers), and systems containing optical fibers (e.g., fiber amplifier systems and fiber laser systems) are disclosed.

Abstract: A semiconductor based Raman laser and/or amplifier with reduced two-photon absorption generated carrier lifetimes. An apparatus according to embodiments of the present invention includes optical waveguide disposed in semiconductor material and a diode structure disposed in the optical waveguide. The optical waveguide is to be coupled to a pump laser to receive a first optical beam having a first wavelength and a first power level to result in emission of a second optical beam of a second wavelength in the semiconductor waveguide. The diode structure is to be biased to sweep out free carriers from the optical waveguide generated in response to two photon absorption in the optical waveguide.

Abstract: A light source includes a wavelength shifter that is capable of shifting a shorter optical signal wavelength to a longer optical signal wavelength based at least in part on a Raman effect in a waveguide. The wavelength shifter includes a pump laser that operable to produce the shorter optical signal wavelength. The wavelength shifter also includes an intermediate stage that is coupled to the pump laser and capable of producing an intermediate optical signal wavelength. The intermediate optical signal wavelength is longer than the shorter optical signal wavelength. The wavelength shifter further includes a final stage capable of generating the longer optical signal wavelength. The final stage includes at least in part a ZBLAN waveguide and wherein the longer optical signal wavelength is greater than 1.7 microns and is greater than the intermediate pump signal wavelength.

Abstract: A method of operating a stretched-pulse Raman fiber laser includes producing laser radiation gain in a laser cavity using predominantly Raman amplification. Such a stretched-pulse Raman fiber laser has a laser cavity that includes a Negative Group Velocity Dispersion Fiber connected in series with a Positive Group Velocity Dispersion Fiber, a polarization controller and an isolator. In some examples, the Negative Group Velocity Dispersion Fiber is a Dispersion Compensating Fiber. In other examples, the Negative Group Velocity Dispersion Fiber is replaced by a Raman Specialty Fiber.

Abstract: Provided are a Raman amplifier and a Raman pumping method. A light source unit outputs a pumping light having a wavelength that periodically changes. A light intensity control unit varies a light intensity of the pumping light using the pumping light to improve the gain flatness of a Raman gain. A control unit directs the light intensity control unit to control the light intensity of the pumping light in synchronization with changes in the wavelength of the pumping light.

Abstract: A glass fiber (22) has a core (24) provided with Raman laser effect particles (28) embedded in a glass matrix (30), with glass cladding (26) around the core. The refractive index of the glass matrix (30) is matched to that of the Raman laser effect particles (28) so as to avoid scattering. It is not necessary to have a single crystal of Raman laser material to create a laser effect in the glass fiber. A length of fiber in the order of meters or tens of meters can produce optical laser light. It is possible to have a single fiber (22) emit laser light at different frequencies due to Stokes and Anti-Stokes emissions. A simple laser device can therefore produce several colors of laser beams.

Abstract: It is disclosed a pump energy source (20) for providing pump energy (E_p) to an optical transmission system (100) transmitting an optical signal along an optical fiber, in particular an optical transmission system (100) in which a beam of said pump energy (E_p) is introduced to said optical fiber so that said beam of said pump energy (E_p) copropagates with said optical signal.

Abstract: Disclosed is a Raman laser device (10) having a first cavity in which lasing occurs at a first frequency, and at least one second cavity in which lasing occurs at a second frequency. Thereby respective first and second waves inside the respective cavities are generated having a first power and a second power, respectively. Further, beams propagating outside the cavities are generated by coupling out a part of the first power and a part of the second power utilizing respective output mirrors. The part of the second power that is coupled out is attenuated without attenuating the complementary part of the second power remaining in the second cavity. The Raman laser device is characterized in that the part of the second power that is coupled out is attenuated utilizing at least one Fiber Bragg Grating (46, 62).

Abstract: Peak power of a coherent light beam generated by a laser and injected into an optical fiber is chosen so that the spectrum of the light beam emanating from the fiber, for illuminating particles, includes Raman lines.

Abstract: A fibre laser comprises a fibre light guide (3) having an active medium, a laser as pumping source (1) and a first pair of Bragg gratings (6, 8) forming a first resonator (4). The first pair of Bragg gratings (6, 8) resonates the pump laser (1) and there is provided a second pair of Bragg gratings (7, 9) resonating at the output wavelength of the fibre laser.

Abstract: A method for generating ultra-short pulse amplified Raman laser light. Short pulse laser light is amplified, and a portion thereof is introduced into a Raman oscillator to produce compressed laser light. The compressed light is introduced to a first Raman amplifier. The remainder of the short pulse laser light is introduced to a polarizer, and the reflected light is introduced into the first Raman amplifier to pump it. The light transmitted through the first Raman amplifier that has not contributed to pumping is introduced to a beam splitter to produce a second reflected light that is passed to a second Raman amplifier to pump that amplifier. The compressed light is amplified in the first Raman amplifier and introduced to the second Raman amplifier to further amplify it. This further amplified radiation is passed through delay lines to the beam splitter, which passes only first Stokes radiation to generate ultra-short pulse amplified Raman laser light.

Abstract: A medical laser apparatus comprises: a solid laser oscillating source which emits a beam of a wavelength ?1 in an infrared region of approx. 1040 nm to approx. 1080 nm; a first fiber-based Raman shifter including a first Raman fiber which generates, when receives the ?1-beam from the laser oscillating source, a first-order Stokes beam of a wavelength ?2 different from the wavelength ?1 by stimulated Raman scattering, the first Raman fiber being formed with a pair of fiber Bragg gratings which forms a resonator for the ?2-beam; a first nonlinear crystal which wavelength-converts the ?2-beam outputted from the first Raman wavelength shifter to a second harmonic beam of a wavelength ?2? in an orange region of approx. 580 nm to approx. 600 nm; and a light guiding optical system which guides the ?2?-beam to a treatment part.

Abstract: The present invention is a Raman laser and methods related thereto. In the preferred embodiments, the Raman laser comprises a laser pump signal in a fiber waveguide which is optically coupled to a micro-resonator through a fiber taper. The micro-resonator is constructed from a material that has a high Q when it is formed into a micro-resonator and is phase matched to the waveguide. The lasing frequency can be determined based upon the pump input or the micro-resonator material. In the preferred embodiments, the micro-resonator is constructed from a fused silica material. The present invention provides a compact laser with improved emissions and coupling efficiencies and the ability to use stimulated Raman scattering effects to create lasers having frequencies that are otherwise difficult to obtain. Alternative configurations include multiple micro-resonators on a single fiber waveguide and/or utilizing multiple waveguides attached to one or more micro-resonators.

Abstract: A cascaded Raman laser (10) has a pump radiation source (12) emitting at a pump wavelength ?p, an input section (14) and an output section (16) made of an optical medium. Each section (14, 16) comprises wavelength selectors (141, 142, . . . , 145 and 161, 162, . . . , 165) for wavelengths ?1, ?2, . . . , ?n?k, where n?3, ?p<?1<?2< . . . <?n?1<?n and ?n?k+1, ?n?k+2, . . . , ?n being k?1 emitting wavelengths of the laser (10). The laser further comprises an intracavity section (18) that is made of a non-linear optical medium, has a zero-dispersion wavelength ?0 and is disposed between the input (14) and the output (16) section. The wavelengths ?1, ?2, . . . , ?n?k of the wavelength selectors (141, 142, . . . , 145 and 161, 162, . . . , 165) and the zero-dispersion wavelength ?0 of the intracavity section (18) are chosen such that energy is transferred between different wavelengths by multi-wave mixing.

Abstract: Fiber laser systems. One system comprises a pump energy source, a first fiber and a WDM for transferring pump energy from the first fiber to a second fiber that comprises a grating for reflecting energy at a predetermined wavelength. The first fiber is devoid of a grating substantially reflecting energy of the predetermined wavelength. In another embodiment, a system includes a pump energy source and a fiber comprising a loop-shaped portion, a first non loop-shaped portion comprising a grating for reflecting pump energy, and a second non loop-shaped portion comprising a grating for reflecting a Stoke shifted wavelength.

Abstract: 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.

Abstract: The present invention is directed to a system and method which provide a Raman pump which is spectrally tailored in response to feedback from control structure associated with the Raman pump source. In certain embodiments of the present inventions, an incoherently beam combined laser (IBC) is utilized to provide a spectrally tailored Raman pump. In these embodiments, emitters in an emitter array are either individually addressable or block addressable to facilitate adjustment of emitter output power. By adjustment of the output power, the Raman pump may be spectrally tailored. The spectral tailoring can occur by employing suitable control algorithms to algorithms to dynamically maintain reasonably flat Raman gain.

Abstract: The present invention relates to a stable solid-state Raman laser, the solid-state Raman laser including a resonator cavity defined by at least two reflectors, a laser material located in the resonator cavity and capable of generating a cavity laser beam which propagates within the resonator cavity, a solid Raman medium located in the resonator cavity for shifting the frequency of the cavity laser beam to produce a Raman laser beam which propagates within the resonator cavity; and an output coupler for coupling and outputting the Raman laser beam from the resonator cavity, wherein at least one parameter selected from the group consisting of the position of the laser material relative to the position of the Raman medium in the cavity, the length of the cavity and the curvature of at least one of the reflectors, is selected such that changes in the focal lengths of both the laser material and the Raman medium as a result of thermal effects in the laser material and the Raman medium during operation of the laser

Abstract: A wavelength tunable laser comprising a laser diode and a closed external cavity formed by one or more optical resonators either horizontally or vertically coupled to adjacent waveguides. The optical resonator primarily functions as a wavelength selector and may be in the form of disk, ring or other closed cavity geometries. The emission from one end of the laser diode is coupled into the first waveguide using optical lens or butt-joint method and transferred to the second waveguide through evanescent coupling between the waveguides and optical resonator. A mirror system or high reflection coating at the end of the second waveguide reflects the light backwards into the system resulting in a closed optical cavity. Lasing can be achieved when the optical gain overcomes the optical loss in this closed cavity for a certain resonance wavelength which is tunable by changing the resonance condition of the optical resonator through reversed biased voltage or current injection.

Abstract: The present invention is a Raman laser and methods related thereto. In the preferred embodiments, the Raman laser comprises a laser pump signal in a fiber waveguide which is optically coupled to a micro-resonator through a fiber taper. The micro-resonator is constructed from a material that has a high Q when it is formed into a micro-resonator and is phase matched to the waveguide. The lasing frequency can be determined based upon the pump input or the micro-resonator material. In the preferred embodiments, the micro-resonator is constructed from a fused silica material. The present invention provides a compact laser with improved emissions and coupling efficiencies and the ability to use stimulated Raman scattering effects to create lasers having frequencies that are otherwise difficult to obtain. Alternative configurations include multiple micro-resonators on a single fiber waveguide and/or utilizing multiple waveguides attached to one or more micro-resonators.

Abstract: A semiconductor-based optical amplifier using optically-pumped stimulated scattering includes an optical signal source (pump) and a wavelength selective coupler. The coupler is connected to receive an input optical signal and the pump signal and output the combined signals in a waveguide having a semiconductor core. The intensity of the pump signal is selected so that stimulated scattering occurs when the pump signal is propagated in the semiconductor core. Further, the wavelength of the pump signal is selected so that the stimulated scattering causes emission of a signal shifted in wavelength to be substantially equal to the wavelength of the optical input signal. Consequently, the input signal is amplified as it propagates with the pump signal. The amplifier can be disposed between reflectors to form a laser.

Abstract: A modular, compact and widely tunable laser system for the efficient generation of high peak and high average power ultrashort pulses. Modularity is ensured by the implementation of interchangeable amplifier components. System compactness is ensured by employing efficient fiber amplifiers, directly or indirectly pumped by diode lasers. Peak power handling capability of the fiber amplifiers is expanded by using optimized pulse shapes, as well as dispersively broadened pulses. After amplification, the dispersively stretched pulses can be re-compressed to nearly their bandwidth limit by the implementation of another set of dispersive delay lines. To ensure a wide tunability of the whole system, Raman-shifting of the compact sources of the ultrashort pulses in conjunction with frequency-conversion in nonlinear optical crystals can be implemented, or an Anti-Stokes fiber in conjunction with fiber amplifiers and Raman-shifters are used.

Abstract: A continuous wave laser device (40) comprises a convoluted path or fiber (43) of Raman laser material that has been micromachined on to a substrate, the laser material fiber being covered by protective cladding (30). A 1 cm diameter substrate can have tens of meters of fiber fabricated on it and with a suitable choice for the laser material, e.g. Diamond, can output tens of hundreds of Watts of laser power. One possible use envisaged is as multicolor laser diodes, for example for projection television systems.

Abstract: A compressive strain GRIN-SCH-MQW active layer and a tensile strain GRIN-SCH-MQW active layer are laminated, and there are provided a diffraction grating formed in the vicinity of the compressive strain GRIN-SCH-MQW active layer and a diffraction grating formed in the vicinity of the tensile strain GRIN-SCH-MQW active layer, between the radiation end face and the reflection end face of the laser beam. A laser beam obtained by polarization-multiplexing a laser beam in the TE mode generated in the compressive strain GRIN-SCH-MQW active layer and a laser beam in the TE mode generated in the tensile strain GRIN-SCH-MQW active layer, and having a plurality of oscillation longitudinal modes of not larger than a predetermined output value is output by the wavelength selection characteristic of the diffraction gratings.

Abstract: In embodiments, the present invention is directed to systems and methods for operating an incoherently beam combined (IBC) laser. The IBC laser may comprise an integrated set of emitters or a set of discrete emitters. Each emitter is associated with a high-pass, low-pass, or bandpass optical filter. The emitters and filters are disposed in an ordered arrangement thereby defining a common optical path. Near the end of the common optical path, a focusing lens may be utilized to focus the output beams from each of the emitters into a fiber. A partially reflective component may be embedded in the fiber to provide feedback to each of the emitters. By selecting the optical characteristics of the filters, light originating from a specific emitter is fed back to the same emitter and to no other emitter. Accordingly, multiple external laser cavities are created on the same optical path.

Abstract: The present invention is directed to a system and method for providing a spectrally tailored Raman pump. The system and method employ an incoherently beam combined laser configuration to combine output beams from a plurality of emitters. Embodiments of the present invention provide emitter devices with electrodes adapted to allow addressability of various emitters. In some embodiments, each emitter is individually addressable thereby allowing the output power of each emitter to be controlled by a drive current. In another embodiment, blocks of emitters are coupled to a single current source. Each emitter of a block is operated at a common power level. In certain embodiments, blocks of emitters are driven at current levels significantly greater than the threshold current for the emitters to increase operating efficiency. Moreover, certain embodiments vary emitter spacing to increase linear power density and/or to allocate additional power to the blue end of the Raman pump.

Abstract: The present invention relates to a cascaded multi-wavelength Raman fiber laser adapted for emitting radiation of at least one wavelength &lgr;s1, with a length of optical fiber (13) having input (15) and output (16) sections, means (11) for introducing pump radiation of wavelength &lgr;p into said length of optical fiber (13), at least one pair of spaced-apart reflector means (151,161; . . .

Abstract: A method for adjusting the relative output power of individual output wavelengths of a multi-output-wavelength Raman laser (10) is disclosed. The method is characterized by the steps of suppressing the relative output power of a potentially most powerful output wavelength (98) in a first step (108), adjusting the relative output power of the shortest output wavelength (94) in a second step (110), adjusting the relative output power of further output wavelengths (96, 100, 102, 104) in a third step (112), and adjusting the relative output power of the potentially most powerful output wavelength (98) in a fourth step (114). Further, a device (68) that performs such a method is disclosed, i.e. a device for adjusting the relative output power of individual output wavelengths (94, 96, 98, 100, 102, 104) of such a laser (10).

Abstract: A semiconductor laser device including a light reflecting facet positioned on a first side of the semiconductor device, a light emitting facet positioned on a second side of the semiconductor device thereby forming a resonator between the light reflecting facet and the light emitting facet, and an active layer configured to radiate light in the presence of an injection current, the active layer positioned within the resonator. A wavelength selection structure is positioned within the resonator and configured to select a spectrum of the light including multiple longitudinal modes, the spectrum being output from the light emitting facet. Also, an electrode positioned along the resonator and configured to provide the injection current, and a tuning current that adjusts a center wavelength of the spectrum selected by the wavelength selection structure.

Abstract: A device (D) for amplifying optical signals is connected to an optical fiber (3) conveying an optical data signal and delivers into said optical fiber first and second optical pump signals at different wavelengths for amplifying the data signal by stimulated Raman scattering. Each pump signal comprises two pump signal components whose polarizations are mutually orthogonal. Moreover, the amplification device D comprises a control module 14 for delivering alternately a first combined pump signal and a second combined pump signal, the first combined pump signal comprising a component of the first pump signal and a component of the second pump signal that have mutually orthogonal polarizations and the second combined pump signal comprising the other component of the first pump signal and the other component of the second pump signal.

Abstract: A glass fiber (22) has a core (24) provided with Raman laser effect particles (28) embedded in a glass matrix (30), with glass cladding (26) around the core. The refractive index of the glass matrix (30) is matched to that of the Raman laser effect particles (28) so as to avoid scattering. It is not necessary to have a single crystal of Raman laser material to create a laser effect in the glass fiber. A length of fiber in the order of meters or tens of meters can produce optical laser light. It is possible to have a single fiber (22) emit laser light at different frequencies due to Stokes and Anti-Stokes emissions. A simple laser device can therefore produce several colors of laser beams.

Abstract: A medical laser apparatus comprises: a solid laser oscillating source which emits a beam of a wavelength &lgr;1 in an infrared region of approx, 1040 nm to approx. 1080 nm; a first fiber-based Raman shifter including a first Raman fiber which generates, when receives the &lgr;1-beam from the laser oscillating source, a first-order Stokes beam of a wavelength &lgr;2 different from the wavelength &lgr;1 by stimulated Raman scattering, the first Raman fiber being formed with a pair of fiber Bragg gratings which forms a resonator for the &lgr;2-beam; a first nonlinear crystal which wavelength-converts the &lgr;2-beam outputted from the first Raman wavelength shifter to a second harmonic beam of a wavelength &lgr;2′ in an orange region of approx. 580 nm to approx. 600 nm; and a light guiding optical system which guides the &lgr;2′-beam to a treatment part.

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: Disclosed is a Raman laser device (10) having a first cavity in which lasing occurs at a first frequency, and at least one second cavity in which lasing occurs at a second frequency. Thereby respective first and second waves inside the respective cavities are generated having a first power and a second power, respectively. Further, beams propagating outside the cavities are generated by coupling out a part of the first power and a part of the second power utilizing respective output mirrors. The part of the second power that is coupled out is attenuated without attenuating the complementary part of the second power remaining in the second cavity. The Raman laser device is characterized in that the part of the second power that is coupled out is attenuated utilizing at least one Fiber Bragg Grating (46, 62).

Abstract: It is disclosed a pump energy source (20) for providing pump energy (E_p) to an optical transmission system (100) transmitting an optical signal along an optical fiber, in particular an optical transmission system (100) in which a beam of said pump energy (E_p) is introduced to said optical fiber so that said beam of said pump energy (E_p) copropagates with said optical signal.

Abstract: Optical fibers (e.g., fiber amplifiers and fiber lasers), and systems containing optical fibers (e.g., fiber amplifier systems and fiber laser systems) are disclosed.

Abstract: A multiple spectral line Raman laser having adjustable relative power output between different spectral lines is provided. The laser includes a lasing cavity, first and second reflectors optically coupled to a back end of the cavity that reflects substantially all light having wavelengths of &lgr;1 and &lgr;2, respectively, and a tunable reflector assembly optically coupled to a front end of the cavity that reflects a selected proportion of said light having wavelengths of &lgr;1 and &lgr;2 in response to a single source of strain to control relative power output of light at these wavelengths. The lasing cavity may be a linear length of gain fiber, and the tunable reflector may include a single fiber Bragg grating (FBG) having a trapezoidal reflection profile, or a pair of fiber Bragg gratings mounted on either side of a flexible substrate such that when the substrate is bent, one FBG stretches while the other is compressed.

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: A cascaded Raman laser (10) has a pump radiation source (12) emitting at a pump wavelength &lgr;p, an input section (14) and an output section (16) made of an optical medium. Each section (14, 16) comprises wavelength selectors (141, 142, . . . , 145 and 161, 162, . . . , 165) for wavelengths &lgr;1, &lgr;2, . . . , &lgr;n−k, where n≧3, &lgr;p<&lgr;1<&lgr;2< . . . <&lgr;n−1<&lgr;n and &lgr;n−k+1, &lgr;n−k+2, . . . , &lgr;n being k≧1 emitting wavelengths of the laser (10). The laser further comprises an intracavity section (18) that is made of a non-linear optical medium, has a zero-dispersion wavelength &lgr;0 and is disposed between the input (14) and the output (16) section. The wavelengths &lgr;1, &lgr;2, . . . , &lgr;n−k of the wavelength selectors (141, 142, . . . , 145 and 161, 162, . . .

Abstract: A method for generating ultra-short pulse amplified Raman laser light. Short pulse laser light is amplified, and a portion thereof is introduced into a Raman oscillator to produce compressed laser light. The compressed light is introduced to a first Raman amplifier. The remainder of the short pulse laser light is introduced to a polarizer, and the reflected light is introduced into the first Raman amplifier to pump it. The light transmitted through the first Raman amplifier that has not contributed to pumping is introduced to a beam splitter to produce a second reflected light that is passed to a second Raman amplifier to pump that amplifier. The compressed light is amplified in the first Raman amplifier and introduced to the second Raman amplifier to further amplify it. This further amplified radiation is passed through delay lines to the beam splitter, which passes only first Stokes radiation to generate ultra-short pulse amplified Raman laser light.