Optical democulator
AssigneeResearch Development Corporation of Japan
InventorKoji Mizuno
Life of this patent
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Abstract
An optical demodulator includes a nonlinear element which responds to both light and a microwave-submillimeter wave (far infrared radiation). An optical signal modulated by a modulating wave in which a subcarrier consisting of the microwave-submillimeter wave is modulated by a signal wave, and a local oscillated signal consisting of a microwave-submillimeter wave the same in frequency as the subcarrier are added to the nonlinear element, to fetch the signal wave by a heterodyne system.
Claims5
An optical demodulator for demodulating a modulated optical signal wave to obtain a signal wave, said optical demodulator comprising:
- a semiconductor diode responsive to light and microwave-submillimeter waves;
- a waveguide circuit for applying a local oscillated signal to said semiconductor diode;
- and
- means for fetching a signal wave produced by said semiconductor diode by a heterodyne system,
- wherein said semiconductor diode produces the signal wave in response to simultaneous
- irradiation of said semiconductor diode with a modulated optical signal wave having a microwave-submillimeter subcarrier wave modulated by the signal wave, and
- application, via said waveguide circuit, of a local oscillated signal having the same frequency as the subcarrier wave to said semiconductor diode.
An optical demodulator for demodulation of an optical signal by a heterodyne system, comprising:
- a waveguide circuit;
- a semiconductor diode responsive to light waves and microwave-submillimeter waves for obtaining a signal wave from a modulated optical signal, said semiconductor diode loaded on said waveguide circuit, and generating optical conductive current when irradiated with an optical signal;
- and
- means for fetching the optical conductive current produced by said semiconductor diode by a heterodyne system.
A method of demodulating a modulated optical signal having a subcarrier microwave-submillimeter wave modulated by a signal wave to obtain the signal wave, comprising the steps of:
- irradiating the modulated optical signal on a semiconductor diode, and simultaneously
- applying a local oscillated wave having the same frequency as the subcarrier wave to said semiconductor diode.
Dependencies are inferred from the claim text.