Abstract: An optical fiber for performing pulse stretching, and fiber laser systems and methods using the pulse-stretching fiber are disclosed. The pulse-stretching (PS) fiber has low fourth-order dispersion (dispersion curvature) and a third order dispersion (dispersion slope) with a small negative, nearly zero or small positive value. Two different types of fiber laser systems that use the PS fiber in a manner that achieves optimum performance are described. The PS fiber enables an all-fiber (up to the final pulse compressor) ultra-short pulsed laser systems reaching pulse energies exceeding 100 ?J, average powers exceeding 100 W, and output pulse widths of less than 100 fs.

Abstract: An all-fiber chirped pulse amplification (CPA) system and method is provided that utilizes a hollow core photonic bandgap fiber as a pulse compressor and a dispersion compensating optical fiber as a pulse stretcher that are matched with respect to both the amount and slope of dispersion to avoid peak power-limiting pulse distortion. The CPA system includes a rare earth ion-doped optical fiber amplifier having an input and an output that amplifies optical pulses having a center wavelength of ?c, a pulse compressing length L1 of hollow core photonic bandgap fiber having a dispersion value D1 and a dispersion slope S1 that varies over a wavelength ? of the pulses that is optically connected to the output of the fiber amplifier and having a k-parameter defined by a ratio of D1 over the slope of the function D1(?) that is larger than about 50, and a pulse stretching length L2 of dispersion compensating optical fiber connected to the input of the fiber amplifier having a dispersion value D2 and dispersion slope S2.

Abstract: A ring-cavity, passively mode locked fiber laser capable of producing short-pulse-width optical pulses at a relatively low repetition rate. The fiber laser uses a one-way ring-cavity geometry with a chirped fiber Bragg grating (CFBG) at its reflecting member. The CFBG is part of a dispersion compensator that includes an optical circulator that defines a one-way optical path through the ring cavity. A doped optical fiber section is arranged in the optical path and serves as the gain medium. A pump light source provides the pump light to excite the dopants and cause the gain medium to lase. A saturable absorber is operable to effectuate passive mode-locking of the multiple modes supported by the ring cavity. The ring cavity geometry allows to achieve mode locking with single pulse operation in a longer cavity length than conventional linear cavities. Furthermore, the longer cavity length reduces the constraints on the chirp rate of the CFBG.

Abstract: A system for passively scrambling and unscrambling a, pulse optical signal transmitted through a multi-mode optical fiber is provided. The system includes a scrambling unit connected between a signal receiving end of said transmission fiber and an optical signal source that includes an optical fiber which creates a differential delay between two groups of optical modes of the signal that is at least one bit period long such that said optical signal is passively scrambled, and an unscrambling unit connected to a signal transmitting end of said transmission fiber having an optical fiber that counteracts said differential delay between said two groups of optical modes of the signal such that said optical signal is passively unscrambled.

Abstract: An optical-fiber-based light source that generates light via third-harmonic (TH) generation is disclosed. The light source includes a pump light source that provides pump light having a fundamental mode of wavelength ?P. The light source also includes an optical fiber optically coupled to the pump light source. The optical fiber's core refractive index profile has (i) a central region with a refractive index value ?1, (ii) a first annular region immediately surrounding the central region and having a refractive index value ?2, and (iii) a second annular region immediately surrounding the first annular region and having a refractive index value ?3. The optical fiber satisfies the conditions ?2<?1 and ?2<?3, and max{?1,?3}??2>1.2%. The pump light produces TH-generated light having a higher-order mode of wavelength ?TH=(1/3)?P and that is outputted at the optical fiber output end.

Abstract: A high energy, ultra short pulse ring fiber laser is provided that includes a passively mode locked, all optical fiber laser formed from a closed loop of optical fiber doped with erbium or other rare earth metal, a pump light source optically coupled to the loop of optical fiber, and a linear dispersion compensator that includes a pair of chirped Bragg gratings with substantially equal but opposite sign dispersion. The difference in dispersion between the pair of chirped Bragg gratings is adjusted so that it is substantially equal and opposite to the dispersion generated in the loop of optical fiber. The linear dispersion compensator includes a tuner which can individually stretch or compress the pair of chirped fiber Bragg gratings such that one of the gratings can be adjusted to cancel out the dispersion of the ring laser cavity, while the other grating is adjusted to eliminate third order dispersion of the cavity.

Abstract: A supercontinuum light emitting device comprises an effectively CW light source producing light of wavelength ?1 within a specified bandwidth and a nonlinear fiber optically coupled to the light source. The nonlinear fiber has a plurality of fiber segments with different zero dispersion wavelengths ?oi, where each successive fiber segment has zero dispersion wavelength ?oi which is larger than the zero dispersion wavelength of the preceding fiber and the zero dispersion wavelength of the first fiber segment is within ±20 nm of ?1.

Abstract: A supercontinuum light emitting device comprises an effectively CW light source producing light of wavelength ?1 within a specified bandwidth and a nonlinear fiber optically coupled to the light source. The nonlinear fiber has a plurality of fiber segments with different zero dispersion wavelengths ?oi, where each successive fiber segment has zero dispersion wavelength ?oi which is larger than the zero dispersion wavelength of the preceding fiber and the zero dispersion wavelength of the first fiber segment is within ±20 nm of ?1.

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: 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. The laser cavity has a cavity length corresponding to an integer multiple of bit periods of at least one of the multiplexed optical signals for receiving a pre-amplified version of the plurality of wavelength division multiplexed optical signals to provide gain modulation through a phase-insensitive parametric amplification and recirculating a proportion of the output from the laser cavity back through the laser cavity for spatially mode-locking the output of the laser cavity as a recovered clock.

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: 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.