Improving Low-Dispersion Bandwidth of the Silicon Photonic Crystal Waveguides for Ultrafast Integrated Photonics

Abstract

We design a novel slow-light silicon photonic crystal waveguide which can operate over an extremely wide flat band for ultrafast integrated nonlinear photonics. By conveniently adjusting the radii and positions of the second air-holes rows, a flat slow-light low-dispersion band of 50 nm is achieved numerically. Such a slow-light photonic crystal waveguide with large flat low-dispersion wideband will pave the way for governing the femtosecond pulses in integrated nonlinear photonic platforms based on CMOS technology.

An Introduction to Nonlinear Integrated Photonics: Structures and Devices

“…Photonic crystals provide an excellent building block for photonic integrated circuits and for enhancing a variety of nonlinear optical processes as well [ 77 , 78 , 79 , 80 , 81 ]. A strong advantage of PhC cavities with ultra-small-mode volume V m is that quality factors can be relaxed while still achieving excellent Q/V m values; despite the fact that the quality factor is inversely proportional to the linewidth of the cavity, both high-bandwidth and low-threshold all-optical processes can be realized in a single system.…”

“…Figure 3 shows the design of a dispersion-engineered slow-light photonic crystal waveguide (PhCW); the blue circles represent the air-holes in a standard single-line defect (W1) PhCW with a lattice constant a, while the red circles represent the engineered air-holes, with radius decreasing from R to R2 and horizontally shifted from the dashed circles by ΔX [ 81 ].…”

“…By adjusting the radius R2 and lattice positions ΔX of the second air-holes rows, a very wide flat band larger than 50 nm could be obtained. Reproduced from [ 81 ] under Creative Commons License 3.0.…”