Enhanced Pulse Compression within Sign-Alternating Dispersion Waveguides

Abstract: Repeatedly alternating the sign of dispersion along a waveguide substantially increases the bandwidth to input peak power efficiency of supercontinuum generation (SCG). Here, we explore, theoretically and numerically, how to optimize sign-alternating dispersion waveguides for nonlinear pulse compression, so that the compression ratio is maximized. By exploring a previously unknown SCG phase effect, we find emergent phase effects unique to these structures where the spectral phase converges to a parabolic profile independent of uncompensated higher-order dispersion. The combination of an easy to compress phase spectrum, with low input power requirements, then makes sign-alternating dispersion a scheme for high-quality nonlinear pulse compression that removes the need for high powered lasers. Also, we show a new scheme for the design of practical waveguide segments that can compress SCG pulses to near transform-limited durations, which is integral for the design of these alternated waveguides and in general, for nonlinear pulse compression experiments. We conclude by showing how compression can be maximized for alternating dispersion waveguides within the integrated photonics platform, showing compression to two optical cycles.