Improved waveguide structures derived from new rapid optimization techniques

Abstract

We present structures obtained with numerical optimization techniques capable of efficiently channeling light at a fraction of the length of a conventional taper. These results could open the way to novel designs in ultra-short light injection devices. We also consider the rather different problem of how to optimise the transmission through a photonic crystal bend. We show how, using a deterministic global optimisation algorithm, novel optimal geometries can be obtained leading to considerable performance improvements.

Topology optimization and fabrication of photonic crystal structures

“…The resulting designs are inherently free from geometrical restrictions such as the number of holes, hole shapes etc., thereby allowing the large potentials of PhC components to be exploited to hitherto unseen levels. Previously reported optimization tools for such components have all been restricted to deal with circular holes [9][10][11]. To demonstrate the method, we have designed and fabricated an optimized PhC Z-bend consisting of two successive 120° waveguide bends [12].…”

Inverse design of phononic crystals by topology optimization

“…More traditional studies of photonic crystal structures using a few design variables and optimization based on either numerical sensitivity analysis, genetic algorithms, simulated annealing or a combination of these are seen in Refs. [9,10].…”

All-dielectric unidirectional dual-grating output coupler

“…Vertically tapered couplers normally consist of an adiabatic variation of the modal index of a waveguide by means of a gradual geometric variation, similar to a prism coupler, but normally results in a large beam divergence. Transversely tapered couplers can be either adiabatic transverse variations [2] or a numerically optimized series of end facet couplings that utilize multilayer resonance effects [3,4]. In either case, the use of a final end facet coupling retains the same potential for end-facet damage in high power configurations.…”