Abstract: An apparatus for measuring optical performance of a plurality of channels within an input optical multi-channel signal employs at least one optical interleaver to deinterleave the input signal into a plurality of channel subsets, each channel subset having a greater channel spacing than the input multi-channel signal, and a switch for sequentially submitting the deinterleaved subsets to an optical performance monitor (OPM). The design allows for relaxed specification of the OPM, e.g. its resolution and number of pixels.

Abstract: An optical fiber transmission system includes an optical transmitter for generating light; a dispersive optical fiber link optically coupled to the optical transmitter, for transmitting the light generated by the optical transmitter; and a chirped optical fiber grating, optically coupled to the optical transmitter and to the dispersive optical fiber link, for providing at least a partial dispersion compensation to the light generated by the optical transmitter, before the light is transmitted in the dispersive optical fiber link; the chirped optical fiber grating including a polarization-maintaining optical fiber having a chirped refractive index variation

Abstract: An optical transmission apparatus for transmission of optical signals at an optical wavelength of about 1550 nanometers. The optical transmission apparatus includes a single mode optical fiber link formed of optical fiber having substantially zero dispersion at an optical wavelength of about 1300 nanometers and a dispersion of about 17 picoseconds per nanometer-kilometer at an optical wavelength of about 1500 nanometers. Further, at least one dispersion compensating chirped optical fiber grating is coupled to the optical fiber link, the aggregate dispersion of the at least one dispersion compensating chirped optical fiber grating substantially compensating for the dispersion of the optical fiber link. Further, the at least one dispersion compensating chirped optical fiber grating is coupled at respective positions substantially symmetrically disposed about the longitudinal center of the optical fiber link.

Abstract: An optical device comprises an optical fibre device having wavelength-dependent optical characteristics mounted on a bimorph element operable to bend in response to an electrical control signal, so that the wavelength-dependent optical characteristics of the optical fibre device vary in response to bending of the bimorph element.

Abstract: The present invention provides for an optical waveguide device comprising a gratings, primarily in the form of fiber Bragg gratings, which are sampled, interleaved and chirped to achieve different functions. By interleaving sampled fiber Bragg gratings, each with a grating period which differs from the others by an amount corresponding to a multiple of a channel spacing, a predetermined and useful optical spectrum can be produced for the optical waveguide device. By making the sample periods for the fiber Bragg gratings different from each other, the resulting reflection spectrum has missing reflection peaks. A bandpass filter can be effectively created. Furthermore, by discretely varying the grating periods of sampled fiber Bragg gratings at intervals along the optical fiber containing the gratings, a more uniform optical spectrum is produced for the optical waveguide device.

Abstract: A method of forming optical waveguide gratings, such as in-fiber gratings, is described. The gratings are formed optically, with a phase mask being scanned by a writing laser beam to generate the grating pattern. The waveguide and phase mask are moved with respect to one another during the writing process, to vary the grating properties along the length of the grating. Relative movement in a single direction provides a chance of grating pitch, and so can be used to fabricate chirped or multi-wavelength gratings. Bi-directional dither alters the strength of the grating, and so can be used to fabricate apodised gratings.

Abstract: Passive, self-adjusting and tracking optical wavelength filters are described. The filters are absorptive and can be of either transmissive or reflective type. The filters comprise an unpumped doped optical waveguide configured so that signals of different wavelength are spatially decoupled to some extent. The self-adjustment of the filter centre wavelength is achieved by the combined effects of the power-dependent saturable absorption, provided by an appropriate dopant, and partial longitudinal hole burning provided by the spatial decoupling of the different wavelengths. External cavity lasers using this type of filter in the external cavity are also described. This external cavity configuration can provide stable single frequency operation of, for example, a semiconductor laser. By using a saturable absorber for the external cavity (e.g. an erbium doped fibre), longitudinal mode-hopping can be suppressed, ensuring single frequency operation.

Abstract: Polarization self-modulation of a laser produces high-frequency optical modulation without the use of high-speed electronics. This is accomplished by inserting into a laser cavity a polarization converter, which rotates the polarization of the laser light periodically as the light passes through the converter as it circulates in the cavity. The frequency of the modulation is determined by the cavity length. In one configuration, a quarter-wave retardation plate is used as the intracavity polarization converter in a Fabry-Perot laser. In a second embodiment, the converter is an electro-optic crystal which acts as an electronically-controllable half-wave retardation plate.