Abstract: An all-fiber optical pulse compression arrangement comprises a concatenated arrangement of a section of input fiber (e.g., a single mode fiber), a graded-index (GRIN) fiber lens and a section of pulse-compressing fiber (e.g., LMA fiber). The GRIN fiber lens is used to provide mode matching between the input fiber (supporting the propagation of chirped optical pulses) and the pulse-compressing fiber, with efficient pulse compression occurring along the length of the LMA fiber. The dispersion and length of the LMA fiber section are selected to provide the desired degree of pulse compression; for example, capable of reconstituting a femtosecond pulse as is used in supercontinuum generation systems.

Abstract: A fiber laser having at least one pair of reflectors coupled to an optical fiber, the at least one pair of reflectors defining an optical cavity between the at least one pair of reflectors and being configured to reflect light within the optical cavity. At least one light pump is coupled to the optical fiber and configured to provide pump light into the optical cavity, and at least one medium is positioned within the optical cavity and configured to generate signal light from the pump light in the optical cavity. Further, at least one grating positioned within the optical cavity and configured to couple the signal light out of the optical cavity.

Abstract: The output modal content of optical fibers that contain more than one spatial mode may be analyzed and quantified by measuring interference between co-propagating modes in the optical fiber. By spatially resolving the interference, an image of the spatial beat pattern between two modes may be constructed, thereby providing information about the modes supported by the optical fiber. Measurements of the phase front exiting the optical fiber under test are advantageously performed in the far field.

Abstract: The output modal content of optical fibers that contain more than one spatial mode may be analyzed and quantified by measuring interference between co-propagating modes in the optical fiber. By spatially resolving the interference, an image of the spatial beat pattern between two modes may be constructed, thereby providing information about the modes supported by the optical fiber.

Abstract: An optical continuum source is formed that is used to generate both a continuum and one or more light peaks outside the bandwidth of the continuum. In particular, one or more fiber Bragg gratings exhibiting a resonant wavelength less than the short wavelength edge (or greater than the long wavelength edge) of a predetermined continuum are inscribed into a section of highly nonlinear fiber (HNLF) and used to generate the additional light peaks. Gratings may also be formed for areas along the fiber where the continuum spectral power density is essentially “zero”. It has been discovered that the use of a Bragg grating generates phase matching with the propagating optical signal, thus resulting in the creation of the additional peaks.

Abstract: An all-fiber supercontinuum source is formed as a hybrid combination of a first section of continuum-generating fiber (such as, for example, highly-nonlinear fiber (HNLF)) spliced to a second section of continuum-extending fiber (such as, for example, photonic crystal fiber (PCF)). The second section of fiber is selected to exhibit an anomalous dispersion value in the region of the short wavelength edge of the continuum generated by the first section of fiber. A femtosecond pulse laser source may be used to supply input pulses to the section of HNLF, and the section of PCF is spliced to the termination of the section of HNLF. A section of single mode fiber (SMF) is preferably inserted between the output of the laser source and the HNLF to compress the femtosecond pulses prior to entering the HNLF.

Abstract: An optical continuum source is formed that is used to generate both a continuum and one or more light peaks outside the bandwidth of the continuum. In particular, one or more fiber Bragg gratings exhibiting a resonant wavelength less than the short wavelength edge (or greater than the long wavelength edge) of a predetermined continuum are inscribed into a section of highly nonlinear fiber (HNLF) and used to generate the additional light peaks. Gratings may also be formed for areas along the fiber where the continuum spectral power density is essentially “zero”. It has been discovered that the use of a Bragg grating generates phase matching with the propagating optical signal, thus resulting in the creation of the additional peaks.

Abstract: In accordance with the present invention, a bulk optic material (for example, silica) is processed to form a spatially microstructured element, such as a photonic bandgap (PBG) structure. An ultra-short laser pulse source is used as an input signal that is applied to the bulk optic PBG structure to generate an enhanced continuum output. The PBG structure may comprise any type of one-, two- or three-dimensional grating structure, where the selected structure will dictate the type(s) of enhancement(s) that are present in the generated continuum—generally in the form of a broadened continuum and/or the inclusion of one or peaks in the continuum. The use of a relatively small-dimensioned bulk material allows for the continuum to be generated without the need for any type of optical confinement (waveguide). In one embodiment, the bulk PBG structure may be is subjected to one or more additional processes (such as UV exposure, electromagnetic field application, etc.

Abstract: A passively mode-locked, figure-eight laser is formed of all normal dispersion fiber, eliminating the need for using anomalous dispersion fiber. The fiber is selected to be polarization maintaining, with the remaining components of the laser (couplers, isolator, gain fiber) also formed as polarization maintaining elements. In one embodiment, a section of Yb-doped fiber is used as the gain element. An external modulation component (amplitude or phase) is preferably used to initiate the passive mode locking.

Abstract: Enhancement of the supercontinuum generation performance of a highly-nonlinear optical fiber (HNLF) is accomplished by performing at least one post-processing treatment on the HNLF. Particularly, UV exposure of the HNLF will modify its dispersion and effective area characteristics so as to increase its supercontinuum bandwidth, without resorting to techniques such as tapering or introducing unwanted reflections into the HNLF. The UV exposure can be uniform, slowly varying or aperiodic along the length of the HNLF, where the radiation will modify the nonlinear properties of the HNLF. Various other methods of altering these properties may be used. The output from the HNLF can be monitored and used to control the post-processing operation in order to achieve a set of desired features in the enhanced supercontinuum spectrum.

Abstract: Enhancement of the supercontinuum generation performance of a highly-nonlinear optical fiber (HNLF) is accomplished by incorporating at least one Bragg grating structure in the HNLF. The Bragg grating results in reflecting a core-guided signal into signal which also remains core-guided. The supercontinuum radiation generated by such an arrangement will exhibit a substantial peak in its energy at the grating resonance of the Bragg grating and a region of increased radiation in a narrow wavelength band on the long wavelength side of the peak. A number of such Bragg gratings may be formed so as to “tailor” the enhancements provided in the supercontinuum radiation. Various, well-known Bragg grating modifications (tuning, chirped, blazed, etc.) may also be used in the inventive structure to enhance the generated supercontinuum.

Abstract: A swept wavelength source for broad bandwidth Raman pump applications includes a source of ultrashort (e.g., picosecond) optical pulses. The pulse train output from the source is then applied as an input to a linear dispersive element (such as a section of negative dispersion-shifting fiber) which functions to “stretch” the ultrashort pulses, causing the pulses to become separated in time, with a continuous shift in the wavelength through the length of the pulse.

Abstract: A swept wavelength source for broad bandwidth Raman pump applications includes a source of ultrashort (e.g., picosecond) optical pulses. The pulse train output from the source is then applied as an input to a linear dispersive element (such as a section of negative dispersion-shifting fiber) which functions to “stretch” the ultrashort pulses, causing the pulses to become separated in time, with a continuous shift in the wavelength through the length of the pulse.

Abstract: An optical fiber suitable for generation of a supercontinuum spectrum when light pulses of femtosecond (10−15 sec.) duration are launched at a certain wavelength into the fiber. The fiber includes a number of sections of highly non-linear fiber (HNLF) wherein each section exhibits a different dispersion at the wavelength of the launched light pulses. The fiber sections are joined, for example, by fusion splicing the sections in series with one another so that the dispersions of the sections decrease from an input end to an output end of the fiber. In the disclosed embodiment, a low noise, coherent supercontinuum spanning more than one octave is generated at the output end of the fiber when pulses of light of 188 fs duration are launched into the fiber at a repetition rate of 33 MHz and with an energy of three nanojoules per pulse.

Abstract: An optical fiber suitable for generation of a supercontinuum spectrum when light pulses of femtosecond (10−15 sec.) duration are launched at a certain wavelength into the fiber. The fiber includes a number of sections of highly non-linear fiber (HNLF) wherein each section exhibits a different dispersion at the wavelength of the launched light pulses. The fiber sections are joined, for example, by fusion splicing the sections in series with one another so that the dispersions of the sections decrease from an input end to an output end of the fiber. In the disclosed embodiment, a low noise, coherent supercontinuum spanning more than one octave is generated at the output end of the fiber when pulses of light of 188 fs duration are launched into the fiber at a repetition rate of 33 MHz and with an energy of three nanojoules per pulse.

Abstract: A Raman amplified dispersion compensation module has a first dispersion compensating fiber (DCF) with an input end and an output end. The first DCF has a known Raman gain coefficient (gr(&lgr;)), Raman effective fiber area (AReff), and dispersion characteristic. An input end of a second DCF is arranged to receive light signals from the output end of the first DCF. The second DCF has a known gain coefficient and effective area, and a dispersion characteristic selected to cooperate with that of the first DCF to produce a desired total module dispersion. The lengths of the DCFs are selected in a manner that optimizes the overall module gain.