Generation of pulsed squeezed light at telecommunication wavelength using a high efficiency PPLN optical waveguide

In the present work, we report the generation of pulsed squeezed light at 1550 nm by parametric amplification in a low-optical-loss high-efficiency PPLN-WG of length 51 mm developed by NIMS/Waseda. We observed -1.7 dB of squeezing and +6.5 dB of anti-squeezing when the pump pulse energy was only 3nJ (peak power was 0.5 W). The results indicate that the waveguide is capable of generating more than 6 dB squeezing by improving optical losses by shortening the WG length, anti-reflecting coating on WG surfaces, and temporal shaping of the local oscillator, and more that 10 dB squeezing may be possible by using the state of-the-art high efficiency photodiodes.