Abstract: A stabilized radiation source includes a distributed feedback laser, a back lens for coupling a portion of the output radiation into first and second optical paths, optical detectors for detecting radiation transmitted through the first and second paths, and for generating first and second signals indicative of radiation power, and a control circuit for controlling the laser in response to the signals for stabilizing. The first and second radiation paths are operable to provide substantially unfiltered and wavelength dependent filtered radiation transmission therethrough respectively to the detectors. Unfiltered radiation transmitted through the first path which is converted into the first signal is especially suitable for implementing laser output radiation power stabilization which is output radiation wavelength independent.

Abstract: The invention pertains to a communication system (300) including one or more communication channels (10), each channel comprising a transmitter unit (20) and a receiver unit (40). Each transmitter unit (20) is connected through an optical fiber link (30) to its associated receiver unit (40). In operation, each receiver unit (20) receives payload data from its associated sending client and adds overhead data to the payload data to generate corresponding aggregate data (600). The aggregate data of each transmitter unit (20) is conveyed through the fiber link (30) to its associated receiver unit (40) which receives the aggregate data, decodes it to separate the payload data from the overhead data and then outputs the payload data to its associated receiving client. The receiver unit (40) interprets the overhead data and uses it for controlling and managing the payload data in the system (300).

Abstract: A tuneable optical filter includes a moveable filter plate and an associated optical region for filtering an input radiation beam to provide corresponding filtered output radiation. The optical region has spatially varying filtration properties. Piezoelectric actuating elements are provided for moving the filter plate and its associated optical region relative to the beam for selecting a portion of the optical region for use in filtering the beam and thereby tuning the filter. The actuating elements are operable when driven by electrical signals to repetitively engage or be in repetitively slidable contact and thereby impart a lateral force to a surface of the filter plate for moving the optical region relative to the beam in at least one dimension. The filter is especially suitable for use in optical communication systems where there arises a need for occasional system reconfiguration involving retuning optical filters of the system.

Abstract: The invention concerns a tuneable optical filter (10) comprising: a moveable filter plate (20) and an associated optical region (30) for filtering an input radiation beam (40a) to provide corresponding filtered output radiation (40b), the optical region (30) has spatially varying filtration properties. Piezoelectric actuating elements (70a to 70d) are provided for moving the filter plate (20) and its associated optical region (30) relative to the beam (40a) for selecting a portion of the optical region (30) for use in filtering the beam (40a) and thereby tuning the filter (10), the actuating elements (70a to 70d) are operable when driven by electrical signals to repetitively engage or be in repetitively slidable contact and thereby impart a lateral force to a surface of the filter plate (20) for moving the optical region (30) relative to the beam (40) in at least one dimension.

Abstract: The invention pertains to a communication system (300) including one or more communication channels (10), each channel comprising a transmitter unit (20) and a receiver unit (40). Each transmitter unit (20) is connected through an optical fiber link (30) to its associated receiver unit (40). In operation, each receiver unit (20) receives payload data from its associated sending client and adds overhead data to the payload data to generate corresponding aggregate data (600). The aggregate data of each transmitter unit (20) is conveyed through the fiber link (30) to its associated receiver unit (40) which receives the aggregate data, decodes it to separate the payload data from the overhead data and then outputs the payload data to its associated receiving client. The receiver unit (40) interprets the overhead data and uses it for controlling and managing the payload data in the system (300).