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:
“Keep on adding, keep on walking, keep on progressing: do not delay on the road, do not go back, do not deviate.”
—St. Augustine (354–430)
“What comes over a man, is it soul or mind
That to no limits and bounds he can stay confined?
You would say his ambition was to extend the reach
Clear to the Arctic of every living kind.
Why is his nature forever so hard to teach
That though there is no fixed line between wrong and right,
There are roughly zones whose laws must be obeyed?”
—Robert Frost (1874–1963)