The invention provides a compact, combined stretcher-compressor assembly which utilizes a single grating element. The single grating element is preferably a holographic transmission grating element. The grating element has first and second surfaces which are opposed major surfaces with a thickness between the surfaces. The grating pattern is patterned in or on the grating element. The grating element is arranged in the assembly to receive a beam for stretching laser pulses in a stretcher beam path, and in the same arrangement, to receive a beam for compressing laser beam pulses in a compressor beam path. The stretcher and compressor beam paths pass through the single grating element. Respective reflecting means are arranged to provide a desired number of passes through the grating element by the stretcher beam path, and through the grating element by the compressor beam path.
A dispersion compensator having relatively uniform transmission characteristics over the bandwidth of a communication channel. The compensator is designed to process an optical signal corresponding to the communication channel by decomposing that signal into spectral components, routing different components along different optical paths that impart relative delays between the components, and recombining the delayed components spatially and directionally to generate a processed optical signal with reduced chromatic dispersion. In one embodiment, the compensator includes a diffraction grating optically coupled to a mirror array, in which different mirrors receive light corresponding to different communication channels. For each channel, a desired group delay value is produced by selecting the curvature of the corresponding mirror. A compensator employing independently addressable, variable-curvature mirrors enables generation of variable, channel-specific group delays. A representative compensator of the invention can be designed to generate variable group delays between about +400 and -400 ps/nm while maintaining transmission band uniformity of better than about .+-.0.4 dB over a channel bandwidth of about 60 GHz.
A pulse compressor. In one embodiment, the pulse compressor comprises an optical medium adapted for receiving a beam of light in an incident optical path and dispersing it into its constituent spectral colors to form a dispersed beam of light in an output optical path, where the optical medium is configured such that when an incident beam of light is received by the optical medium, it passes through the optical medium four times, in a back and forth manner, and leaves the optical medium in the form of a corresponding output beam of light.
A fiber laser cavity that includes a laser gain medium for receiving an optical input projection from a laser pump. The fiber laser cavity further includes a positive dispersion fiber segment and a negative dispersion fiber segment for generating a net negative dispersion for balancing a self-phase modulation (SPM) and a dispersion induced pulse broadening/compression in the fiber laser cavity for generating an output laser with a transform-limited pulse shape wherein the laser gain medium further amplifying and compacting a laser pulse. The gain medium further includes a Ytterbium doped fiber for amplifying and compacting a laser pulse. The fiber laser cavity further includes a polarization sensitive isolator and a polarization controller for further shaping the output laser.
A fiber laser cavity that includes a laser gain medium for receiving an optical input projection from a laser pump. The fiber laser cavity further includes a positive dispersion fiber segment and a negative dispersion fiber segment for generating a net negative dispersion for balancing a self-phase modulation (SPM) and a dispersion induced pulse broadening/compression in the fiber laser cavity for generating an output laser with a transform-limited pulse shape wherein the wherein said laser gain medium further comprising a double cladding Ytterbium-doped Photonics crystal fiber (DC YDPCF) for amplifying and compacting a laser pulse. The fiber laser cavity further includes a polarization sensitive isolator and a polarization controller for further shaping the output laser.
