Optimization of integrated polarization filters

Abstract

This study reports on the design of small footprint, integrated polarization filters based on engineered photonic lattices. Using a rods-in-air lattice as a basis for a TE filter and a holes-in-slab lattice for the analogous TM filter, we are able to maximize the degree of polarization of the output beams up to 98% with a transmission efficiency greater than 75%. The proposed designs allow not only for logical polarization filtering, but can also be tailored to output an arbitrary transverse beam profile. The lattice configurations are found using a recently proposed parallel tabu search algorithm for combinatorial optimization problems in integrated photonics.

Lorenz–Mie theory for 2D scattering and resonance calculations

“…It serves as a synthesis of all the theoretical concepts discussed in the previous two sections, including scattering of focused beams by coupled cylinders and eigenstates drawn from the SALT formulations. Two-dimensional photonic crystals (PhCs) based on arrangements of cylindrical scatterers are one of the prime candidates for modelling using 2D-GLMT [28,47,56,73,74]. Although PhCs are strictly speaking infinite periodic arrangements of scatterers, 2D-GLMT does not require a symmetric arrangement, nor is it meant to be applied to infinite structures.…”

“…Using optimization methods presented in [73,74], one is able to engineer a lattice configuration for simultaneous polarization filtering and beam shaping, that is obtaining a given beam shape after filtering. A configuration optimized for the conversion of an incident Gaussian beam to a identical -but polarized -Gaussian beam is shown in Fig.…”

“…This corresponds to a degree of polarization of more than 98 %. More details about the configurations, as well as the optimization of a TE polarizer, can be found in [74].…”

“…This implies that the TE component of the beam (E y ) is more strongly scattered, suggesting HIS based designs are suitable for filtering this polarization out and favouring the TM polarization. This bandgap analysis, based on the plane wave expansion method, is detailed in [74].…”

“…Two-dimensional PhCs based on arrangements of cylindrical scatterers are one of the prime candidates for modelling using 2D-GLMT [28,47,56,73,74]. Although PhCs are strictly speaking infinite periodic arrangements of scatterers, 2D-GLMT does not require a symmetric arrangement, nor is it meant to be applied to infinite structures.…”