Patent ID: 6798557
Filing Date: 2004-09-28
Classification: H04B,H04L

Abstract:
An optical encoder comprising:an optical signal splitter having an input and at least two outputs, the optical splitter being configured to split a continuous wave optical signal supplied to the input of the splitter into mutually coherent at least first and second continuous wave optical signals at said at least first and second outputs, respectively, of the splitter; an optical signal combiner having at least first and second inputs and an output being configured to combine at least first and second mutually coherent optical signals supplied to said at least first and second optical combiner inputs to yield a combined phase modulated optical signal at the combiner output, in said optical combiner, said at least first and second mutually coherent optical signals being overlapping and interfering with each other; an optical phase shifter having a predetermined fixed phase shift coupled in one optical path between said at least second output of the optical splitter and said at least second input to the optical combiner; and a first optical phase modulator coupled in another optical path between a first output of the optical splitter and said at least first input of the optical combiner, the first optical phase modulator being configured to be responsive to bits of a prescribed driving digital signal so that the phase of the supplied optical signal is modulated in binary fashion and has at least two phase states, wherein a binary phase coded optical signal results at the optical combiner output.