Optical data latch
| DWPI Title: Optical data latch i.e. photonic integrated circuit, has optical waveguides connecting optical logic gates in cross-coupled arrangement, where output waveguide couples optical information out of latch |
| Abstract: An optical data latch is formed on a substrate from a pair of optical logic gates in a cross-coupled arrangement in which optical waveguides are used to couple an output of each gate to an photodetector input of the other gate. This provides an optical bi-stability which can be used to store a bit of optical information in the latch. Each optical logic gate, which can be an optical NOT gate (i.e. an optical inverter) or an optical NOR gate, includes a waveguide photodetector electrically connected in series with a waveguide electroabsorption modulator. The optical data latch can be formed on a III-V compound semiconductor substrate (e.g. an InP or GaAs substrate) from III-V compound semiconductor layers. A number of optical data latches can be cascaded to form a clocked optical data shift register. |
| Use: Optical data latch i.e. photonic integrated circuit. |
| Advantage: The waveguide electro absorption modulator is connected electrically in parallel with a resistor, thus providing increased operating speed. The latch requires only direct current (DC) electrical power sources for operation, for biasing the waveguide photodetector and waveguide electro absorption modulator, for operating semiconductor lasers to generate light to store the bit of optical information within the latch, and for operating optional semiconductor optical amplifiers which can be used to provide optical signal gain and regeneration in the latch. |
| Novelty: The latch (10) has a pair of optical logic gates (14) e.g. optical NOR gate, comprising a waveguide electro absorption modulator (22) that is electrically connected in series with a waveguide photodetector (20) having photodetector inputs (18), where light (26) is transmitted through the modulator forming an output (16) for the gates. Optical waveguides (30) connect the gates in a cross-coupled arrangement, where the output of each gate is optically connected to an input of the other gate to couple the light and an output waveguide couples the optical information out of the latch. |
| Filed: 9/11/2009 |
| Application Number: US2009558025A |
| Tech ID: SD 11197.0 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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