Multiple Simultaneous Optical Frequency Measurement
Patent application, filed 9 Jan 2001
DEPARTMENT OF THE NAVY WASHINGTON DC
Pagination or Media Count:
A signal processing apparatus for providing concurrent electrical frequency measurements of multiple, time-coincident signal inputs. In one embodiment of the present invention, an input signal is received that contains a plurality of individual signals independent of each other in frequency, phase, and electrical amplitude. A power splitter splits the input signal into two separate input signals. A delay line introduces a time delay to one of the two separate input signals. Two Bragg cells within a channelized optical phase measurement COPM device modulates two optical carrier signals with the delayed and non-delayed input signals, respectively, separating the modulated delayed and non-delayed input signals into multiple time- concurrent frequency channel signals. Upon exiting the Bragg cells, the two optical beams interfere spatially to develop an interference pattern along the phase and frequency channel number axes of a photodetector array. The resulting spatial intensity pattern phase variation is decoded to provide coarse frequency, phase, and amplitude measurements. A frequency encoder receives the photodetector outputs, corrects phase and amplitude data offsets, and converts phase to fine frequency. Finally, the frequency formatter concatenates coarse to fine frequency for readout.
- Electrooptical and Optoelectronic Devices