An Octave-Spanning Optical Parametric Amplifier Based on a Low-Dispersion Silicon-Rich Nitride Waveguide

Optical amplification is one of the main applications of nonlinear optics, and broadband optical parametric amplifiers are useful not only for multiple data channels in a communication system but for ultrashort optical pulses in ultrafast optics as well. We propose an octave-spanning parametric amplifier in a dual-pump scheme, enabled by advanced dispersion flattening and strong Kerr nonlinearity in a silicon-rich nitride waveguide. A comprehensive nonlinear model is used to study cascaded (non)degenerate parametric processes, by taking wavelength-dependent nonlinearity and all-order dispersion into account. The obtained gain spectrum has a 3-dB bandwidth of one octave from 126 to 244 THz (i.e., 1151 nm), and the gain reaches 11 dB. We show that the proposed amplifier is in principle tolerant to variations of physical parameters, such as pump power, propagation loss, and dispersion. We also examine the amplification of an ultrafast 13-fs soliton pulse with a sech(2) waveform. The gain can reach 8 dB, with the pulse shape well maintained.