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 provides devices and methods for dynamic dispersion compensation. According to one embodiment of the invention, a dispersion compensating device includes a negative dispersion fiber having an input configured to receive the optical signal, the negative dispersion fiber having a length and dispersion sufficient to remove any positive chirp from each wavelength channel of the optical signal, thereby outputting a negatively chirped optical signal; an amplifying device configured to amplify the negatively chirped optical signal; and a nonlinear positive dispersion fiber configured to receive the negatively chirped optical signal. The devices of the present invention provide broadband compensation for systems having a wide range of variable residual dispersions.

Abstract: An optically-pumped mode-locked fiber ring laser for optical clock recovery of multiple wavelength division multiplexed optical signals actively mode-locks a plurality of outputs of the laser as a plurality of recovered clocks for a plurality of the multiple wavelength division multiplexed optical signals.

Abstract: An optical waveguide fiber having a high threshold for stimulated Brillouin scattering is disclosed which is suitable as a nonlinear fiber. The optical fiber has a core with one or more core segments. The optical effective area at a wavelength of 1550 nm is less that 30 ?m2.

Abstract: The present invention comprises an optical fiber have a small effective area and a positive dispersion suitable for use in the reshaping and regeneration of optical signals. The optical fiber according to the present invention has an effective area between about 10 ?m2 and 16 ?2, and a total dispersion between about 4 ps/nm/km and 8 ps/nm/km. Also disclosed is a method of making the inventive fiber wherein a high core relative refractive index can be achieved.

Abstract: An optically active fiber (30) is disclosed for making a fiber laser (18) or an amplifier (16). This double-clad structured active fiber (30) has a core (34), doped with an optically excitable ion having a three-level transition. The core (34) has a core refractive index and a core cross-sectional area. An inner cladding (32) surrounds the core (34). The inner cladding (32) has an inner cladding refractive index less than the core refractive index, an inner cladding cross-sectional area between 2 and 25 times greater than that of the core cross-sectional area, and an aspect ratio greater than 1.5:1. An outer cladding (36) surrounds the inner cladding (32) and has an outer cladding refractive index less than the inner cladding refractive index.

Abstract: The present invention comprises an optical fiber have a small effective area and a positive dispersion suitable for use in the reshaping and regeneration of optical signals. The optical fiber according to the present invention has an effective area between about 10 &mgr;m2 and 16 &mgr;m2, and a total dispersion between about 4 ps/nm/km and 8 ps/nm/km. Also disclosed is a method of making the inventive fiber wherein a high core relative refractive index can be achieved.

Abstract: Apparatus for recovering clock pulses of wavelength division multiplexed optical signals passed therethrough. The apparatus comprises an optically-pumped laser cavity defining a cavity length and comprising a nonlinear medium pumped at a wavelength selected to give efficient parametric amplification within said medium. The cavity length corresponds to an integer multiple of bit periods of at least one of the multiplexed optical signals. The optical signals copropagate through the medium with the pump radiation. The apparatus further comprises an optical path for recirculating a proportion of the output from the laser cavity back through the laser cavity. In this way, idler waves are generated symmetrically about the pump wavelength by four wave mixing with the at least one of the multiplexed optical signals and recirculated through the laser cavity to be amplified by parametric amplification in order to recover wavelength division multiplexed clock pulses.

Abstract: The present invention provides devices and methods for dynamic dispersion compensation. According to one embodiment of the invention, a dispersion compensating device includes a negative dispersion fiber having an input configured to receive the optical signal, the negative dispersion fiber having a length and dispersion sufficient to remove any positive chirp from each wavelength channel of the optical signal, thereby outputting a negatively chirped optical signal; an amplifying device configured to amplify the negatively chirped optical signal; and a nonlinear positive dispersion fiber configured to receive the negatively chirped optical signal. The devices of the present invention provide broadband compensation for systems having a wide range of variable residual dispersions.

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 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: Apparatus for recovering clock pulses of wavelength division multiplexed optical signals passed therethrough. The apparatus comprises an optically-pumped laser cavity defining a cavity length and comprising a nonlinear medium pumped at a wavelength selected to give efficient parametric amplification within said medium. The cavity length corresponds to an integer multiple of bit periods of at least one of the multiplexed optical signals. The optical signals copropagate through the medium with the pump radiation. The apparatus further comprises an optical path for recirculating a proportion of the output from the laser cavity back through the laser cavity. In this way, idler waves are generated symmetrically about the pump wavelength by four wave mixing with the at least one of the multiplexed optical signals and recirculated through the laser cavity to be amplified by parametric amplification in order to recover wavelength division multiplexed clock pulses.

Abstract: An optical amplifier is provided comprising an optical fiber ring, and a pump light emitting device providing a primary pump wavelength. The pump light emitting device is optically coupled to the optical fiber ring and utilizes the primary pump wavelength to generate a secondary pump wavelength. Optical signal amplification and secondary pump wavelength lasing occur within the same section of the optical fiber ring.

Abstract: A semiconductor laser having an external cavity including a single-mode optical fiber. A Bragg grating is written onto the fiber which defines the end of the optical cavity, selects the lasing wavelength, and discriminates against the lasing of higher-order transverse modes in the multi-mode gain region. In one embodiment, the semiconductor laser includes an optically active vertical-cavity semiconductor stack similar to a vertical-cavity surface emitting laser. The stack is optically pumped either from the front or the back over a relatively large area such a multi-mode beam is output. Optics couple the multi-mode beam to the single-mode input of the fiber. A partially transmissive mirror of reflectivity between 25 and 40% may be placed on the output surface of the semiconductor stack to form a coupled-cavity laser. A plurality of laser diodes can be angularly positioned around the area of the semiconductor stack being pumped to increase the total pump power.

Abstract: An optical amplifier is provided comprising an optical fiber ring, and a pump light emitting device providing a primary pump wavelength. The pump light emitting device is optically coupled to the optical fiber ring and utilizes the primary pump wavelength to generate a secondary pump wavelength. Optical signal amplification and secondary pump wavelength lasing occur within the same section of the optical fiber ring.

Abstract: A method of making a phosphosilicate fiber comprises the steps of: (i) manufacturing a preform containing phosphorus doped silica; and (ii) drawing phosphosilicate fiber from said preform at a temperature in the range of 1700° C. to 1900° C.

Abstract: An optically active fiber (30) is disclosed for making a fiber laser (18) or an amplifier (16). This double-clad structured active fiber (30) has a core (34), doped with an optically excitable ion having a three-level transition. The core (34) has a core refractive index and a core cross-sectional area. An inner cladding (32) surrounds the core (34). The inner cladding (32) has an inner cladding refractive index less than the core refractive index, an inner cladding cross-sectional area between 2 and 25 times greater than that of the core cross-sectional area, and an aspect ratio greater than 1.5:1. An outer cladding (36) surrounds the inner cladding (32) and has an outer cladding refractive index less than the inner cladding refractive index.