Michelson-interferometer-based delay-line interferometers

A method comprising the steps of:

• providing an input light beam modulated at a data rate comprising a time interval;
• splitting, at a splitting location in an interferometer, said 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;
• and
• detecting each said output beam with a photodetector;
• wherein said first beam travels a first optical path length (OPL) from said splitting location to said recombination location, said second beam travels a second OPL from said splitting location to said recombination location, and, 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.