Continuous-wave optical parametric amplification in photonic integrated circuits

Optical parametric amplifiers (OPAs) utilize the nonlinearities of optical materials for gain generation, enabling signal amplification across a wide range of wavelengths, operating unidirectionally, and facilitating very large optical gain over a substantial bandwidth and noise-less, i.e. phase-sensitive optical amplification. Despite the marquee breakthroughs achieved with highly nonlinear optical fibers in the early 2000s, commercial adoption has been hampered by the requirements for very long fiber length, mitigation of parasitic nonlinearities, and high pump powers. Photonic integrated waveguides combine much stronger optical confinement with a stronger Kerr nonlinearity and the ability to precisely low engineer the optical dispersion over a wide wavelength range yet have suffered from high linear and nonlinear optical propagation losses and low power handling capacity, mandating pulsed operation. In this presentation, I will review recent work on the breakthrough of achieving strong, broadband, and time-continuous travelling wave parametric amplification in photonic integrated circuits based on silicon nitride and gallium phosphide.