Quadratic soliton mode-locked degenerate optical parametric oscillator

Abstract

By identifying the similarities between the coupled-wave equations and the parametrically driven nonlinear Schrödinger equation, we unveil the existence condition of the quadratic soliton mode-locked degenerate optical parametric oscillator in the previously unexplored parameter space of near-zero group velocity mismatch. We study the nature of the quadratic solitons and divide their dynamics into two distinctive branches depending on the system parameters. We find the nonlinear interaction between the resonant pump and signal results in phenomena that resemble the dispersive two-photon absorption and the dispersive Kerr effect. Origin of the quadratic soliton perturbation is identified and strategy to mitigate its detrimental effect is developed. Terahertz comb bandwidth and femtosecond pulse duration are attainable in an example periodically poled lithium niobate waveguide resonator in the short-wave infrared and an example orientation-patterned gallium arsenide free-space cavity in the long-wave infrared. The quadratic soliton mode-locking principle can be extended to other material platforms, making it a competitive ultrashort pulse and broadband comb source architecture at the mid-infrared.

Integrated photonics on thin-film lithium niobate

“…The combination of the GVD at both frequencies reveals different nonlinear dynamics as modelled in ref. [293]. It is also known that periodically poled LN (PPLN) can be used to generate an effective Kerr nonlinearity, the sign of which can be manipulated by choosing a positive/negative phase mismatch condition [294].…”

Quadratic Solitons in Singly Resonant Degenerate Optical Parametric Oscillators

“…The upper zone is characterized by the two resonant effective TPA peaks and associated nonlinear phase anomalies symmetrically located at . In comparison to DR-DOPO, the expression is similar except that the pump detuning is now replaced by the phase mismatch parameter [34]. As phase mismatch parameter can be set at a much higher value than the pump detuning, SR-DOPO is advantageous in the ultrabroad bandwidth of its effective third-order nonlinearity and thus it can support solitons with larger bandwidth without perturbation and tolerate larger walk-off between pump and signal.…”

“…As the temporal walk-off D1 increases, the resonance closer to the center frequency (Ω=0) asymptotically approaches Ω = ξ / D1 while the other resonance continues to move away from the center frequency. In comparison to DR-DOPO, the expression is similar except that the pump detuning is now replaced by the phase mismatch parameter [34].…”

Controllable soliton transition and interaction in nonlocal nonlinear media

“…Various lines of researches have been developed, such as spatiotemporal light bullets found in multicore and multimode fibers [7]; vector solitons were investigated in nonlinear fractional Schrödinger equation [8]. The dynamics of loop soliton [9] and the nature of quadratic soliton have also been discussed [10].…”