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 demodulators. 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.
Famous quotes containing the words delay and/or line:
“Face troubles from their birth, for tis too late to cure
When long delay has given the evil strength.
Haste then; postpone not to the coming hour: tomorrow
Hell be less ready whos not ready now.”
—Ovid (Publius Ovidius Naso)
“A line will take us hours maybe;
Yet if it does not seem a moments thought,
Our stitching and unstitching has been naught.”
—William Butler Yeats (18651939)