Patent ID: 7808715

Claim:
An interferometric method comprising the steps of: splitting, at a splitting location, an input light beam into a first beam and a second beam; recombining, at a recombination location, said first beam and said second beam to produce at least one output beam, wherein said first beam will travel a first optical path length (OPL) from said splitting location to said recombination location, wherein said second beam will travel a second OPL from said splitting location to said recombination location, wherein when said input light beam carries phase modulated data with a fixed time interval between two adjacent data symbols, then the difference in optical path lengths between said first OPL and said second OPL is about equal to said time interval multiplied by the speed of light; and detecting each said output beam with a photodetector; wherein said at least one output beam is coupled into said photodetector without at least one fiber optic between said recombination location and said photodetector; and wherein at least one lens is operatively positioned between said recombination location and said photodetector.