High-gain Optical Parametric Amplifier Module by Using a PPLN Waveguide and Its Application to Quadrature Squeezing

Abstract

Optical parametric amplification is expected as a key technique for high-speed optical fiber communication and optical quantum computing. We developed a high-gain and broadband optical parametric amplifier (OPA) module by using a periodically poled lithium niobate (PPLN) waveguide, the single-mode core of which is directly bonded to a lithium tantalate substrate. The OPA is assembled as a pump-combiner-integrated module with four optical-fiber input/output ports. By improving the fabrication processes of the PPLN waveguide and the assembly techniques of OPA modules, we achieved over-30-dB phase sensitive amplification with a continuous-wave pump. By using the PPLN waveguide, we successfully obtained over-6-dB squeezed light, the spectral bandwidth of which was 2.5 THz. This high-gain broadband OPA module will help build an advanced information society.