Abstract: An optical source is presented comprising a laser and an optical filter in optical communication with the laser. The laser comprises an optical gain section; and an optical phase control section. The filter is configured to receive light output from the laser and filter the said received light. The source is configured to input the filtered light back into the laser.

Abstract: An optical source is presented comprising a laser and an optical filter in optical communication with the laser. The laser comprises an optical gain section; and an optical phase control section. The filter is configured to receive light output from the laser and filter the said received light. The source is configured to input the filtered light back into the laser.

Abstract: A hybrid integrated tuneable optical laser device, suitable for tuning to different wavelengths via a piezo micromotor (6) controlled optical filter (4) in an external cavity. Once the laser is fixed at a selected wavelength, no power is required to be applied to the wavelength tuning element to maintain the wavelength stability.

Abstract: An optoelectronic device has at least a first facet (S), a first waveguide (2) and a second waveguide (3). The waveguides are substantially coincident at the first facet (6), such that light travelling along the first waveguide (2) is reflected into the second waveguide (3) by the first facet (6). The first facet (6) is formed by precision cleaving. Preferably an etch feature is incorporated in the same mask level as that to define the waveguide core.

Abstract: An optoelectronic device has at least a first facet (S), a first waveguide (2) and a second waveguide (3). The waveguides are substantially coincident at the first facet (6), such that light travelling along the first waveguide (2) is reflected into the second waveguide (3) by the first facet (6). The first facet (6) is formed by precision cleaving. Preferably an etch feature is incorporated in the same mask level as that to define the waveguide core.

Abstract: The present invention relates to an apparatus for determining the sum of first and second optical binary words. The apparatus uses a first optical logic gate and a second optical logic gate to generate respective first and second combination words which represent a logical combination of the binary words applied to the respective logic gates. The first and second combination words are then offset by one bit slot with respect to each other by an offsetting device to generate first and second offset combination words. These offset combination words are repeatedly fed back to the first and second logic gates. The binary sum of the original two words is given by the first combination word when each bit slot of the second combination words has the same logical state.

Abstract: The present invention relates to a method and apparatus for generating an optical bit slot window in which N bit slots having the same logical state are generated. A switching device is used which is coupled to an optical pulse source which generates optical pulses in successive bit slots, each optical pulse representing a logical state. Switching signals are then applied to a switching input of the switching device so as to selectively switch a connection between the input and an output. Consequently the logical state of the output is controlled to generate the required N bit slot window.

Abstract: A parity determining circuit is used to determine the parity of a binary word. The binary word is represented by a sequence of optical bit slots. Each bit slot defines a respective one of two complementary logical states. The circuit includes: an input pulse stream generator that generates copies of the binary word; a combining device that receives two binary words, offsets one word with respect to the other, and then combines them to form a combination word; and a circuit that applies a copy of the original binary word together with the combination word to the combining device a number of times in succession. This results in a combination word that has a number of bits in the same logical state and that indicates the parity of the binary word.

Abstract: A regenerative optical memory comprising a number of concatenated non-linear switching elements coupled by an optical storage element has a transfer function arranged so that only optical data having a pulse amplitude above a predetermined threshold is stored and the amplitude of optical data stored is substantially equalised to at least one predetermined level after a number of circulations within the optical memory. In a preferred embodiment, the optical memory is provided with an optical switching element within the optical loop for selectively switching at least a portion of the data pattern out of the optical loop in response to the application of an optical signal to an input of the optical switching element to alter the contents of the memory.