Creation and measurement of broadband squeezed vacuum from a ring optical parametric oscillator

We report a 65 MHz-bandwidth triangular-shaped optical parametric oscillator (OPO) for squeezed vacuum generation at 860 nm. The triangle structure of our OPO enables the round-trip length to reach 45mm as a ring cavity, which provides a counter circulating optical path available for introducing a probe beam or generating another squeezed vacuum. Hence our OPO is suitable for the applications in high-speed quantum information processing where two or more squeezed vacua form a complicated interferometer, like continuous-variable quantum teleportation. With a homemade, broadband and low-loss homodyne detector, a direct measurement shows 8 : 4 dB of squeezing at 3MHz and also 2 : 4 dB of squeezing at 100 MHz. (C) 2016 Optical Society of America