Delay line interferometer
Encyclopedia
A delay line interferometer (DLI) can be a Mach-Zehnder interferometer
or Michelson interferometer
based on two-beam interference, in which one beam is time-delayed to the other by a desired interval.
Delay line interferometers are also known as optical DPSK demodulator
s. They convert a phase-keyed signal into an amplitude-keyed signal. In this application, an incoming differential phase-shift keying (DPSK) optical signal is first split into two equal-intensity beams in two arms of a Mach Zehnder or Michelson interferometer, in which one beam is delayed by an optical path difference corresponding to 1-bit time delay. After recombination, the two beams interfere with each other constructively or destructively. The resultant interference intensity is the intensity-keyed signal.
Mach-Zehnder interferometer
The Mach–Zehnder interferometer is a device used to determine the relative phase shift between two collimated beams from a coherent light source. The interferometer has been used, amongst other things, to measure small phase shifts in one of the two beams caused by a small sample or the change in...
or Michelson interferometer
Michelson interferometer
The Michelson interferometer is the most common configuration for optical interferometry and was invented by Albert Abraham Michelson. An interference pattern is produced by splitting a beam of light into two paths, bouncing the beams back and recombining them...
based on two-beam interference, in which one beam is time-delayed to the other by a desired interval.
Delay line interferometers are also known as optical DPSK demodulator
Optical DPSK demodulator
An Optical DPSK demodulator is a device that provides a method for converting an optical differential phase-shift keying signal to an intensity-keyed signal at the receiving end in fiber-optic communication networks...
s. They convert a phase-keyed signal into an amplitude-keyed signal. In this application, an incoming differential phase-shift keying (DPSK) optical signal is first split into two equal-intensity beams in two arms of a Mach Zehnder or Michelson interferometer, in which one beam is delayed by an optical path difference corresponding to 1-bit time delay. After recombination, the two beams interfere with each other constructively or destructively. The resultant interference intensity is the intensity-keyed signal.