Time-domain measurement of twin beams produced by fiber amplifiers with an ultra-fast pulse train as a pump

A pulsed pumped four-wave mixing process via chi(3) non -linearity in an optical fiber can generate optical pulses with continuous variable quantum correlation. However, pairwise correlation of the generated pulses in this system has not been demonstrated. Here we report a time-domain measure-ment of an intensity difference squeezed state generated in a fiber. With a fast response differential detection system, we show the generated twin-beam pulses are pairwisely corre-lated, and-3.8-dB (-8.1 dB after detection losses correction) intensity difference squeezing degree is measured in the time domain. Our result is beneficial for generating multi-mode entangled state by time-division multiplexing in fiber sys-tem. (c) 2023 Optica Publishing Group