Demonstration of an Integrated LiNbO $_3$ Synchronized Double Phase Modulator and Its Application to Dual-Pump Fiber Optical Parametric Amplifiers and Wavelength Converters

We report the fabrication of an integrated LiNbO₃ Y-junction synchronized double phase modulator fully packaged for RF-application up to 40 GHz. This optical modulator allows for delivering simultaneously counter-phase high-speed modulation and coupling for two input channels. It was designed for application to fiber-optical parametric amplifier and wavelength converters for suppressing idler spectral broadening and signal gain distortion caused by phase modulation itself. With this component, Idler spectral broadening suppression is experimentally demonstrated over all the parametric gain band of a two-pump parametric amplifier operating in the 1.55-mum region. In addition, we present a useful technique for straightforward and full coupling of the pumps and the signal.