Time-domain measurement of ultra-fast intensity difference squeezed pulse pairs generated in fiber

Pulsed pumped four-wave mixing process via $\chi^{(3)}$ non-linearity in optical fiber can generate optical pulses with continuous variable quantum correlation. However, pair-wise correlation of the generated pulses in this system has not been studied. Here we report a time-domain measurement of an intensity difference squeezed state generated in fiber. With a fast response differential detection system, we show the generated twin-beam pulses are pair-wisely correlated, and -3.8 dB (-8.1 dB after detection losses correction) intensity difference squeezing degree is measured in time-domain. Our result is benefit for generating multi-mode entangled state by time-division multiplexing in fiber system.