Ultracompact integrated polarizers using bent asymmetric coupled waveguides

Abstract

A new type of integrated polarizer based on bent coupled optical waveguides is proposed. The simplicity of the device geometry permits its realization using only basic standard fabrication steps. A deep etched waveguide silicon nitride TE-pass implementation has been studied using a full vector 3D mode solver and beam propagation techniques. The characteristics of the underlying physical mechanism bring in flexibility to the design of broadband devices robust against fabrication tolerances. The possibility of incorporating almost designtransparent polarizers in photonic integrated circuits is also discussed.

Radiation in bent asymmetric coupled waveguides

“…The addition of a physical mechanism to control the refractive index in the exterior arc can be used to implement variable attenuators and/or integrated modulators. Also, the high differential attenuation for TE and TM polarizations can be used in integrated polarization handling devices [33].…”

Asymmetric Concentric Microring Resonator Label-Free Biosensors

“…The reference cover medium is water and our analyses include the effect of the absorption in the sensor surrounding medium. We use the waveguide geometry of [7][8][9][10][11], typical of the silicon nitride platform. The height h (see Figure 2) of the silicon nitride waveguides takes as fixed value of 300 nm and the width of the inner microring waveguide will always be 1 µm.…”

“…These guiding geometries have been proven particularly useful for the reduction of the footprint of silicon nitride devices. Furthermore, the acute differential losses for TE and TM polarizations in these structures have been exploited in the fabrication of ultracompact integrated polarizers [10,11].…”

“…Biosensors based on concentric microresonators in the symmetric case were analyzed in [13][14][15]. Whereas the coupled-resonator model is necessary for describing the operation of nonconcentric rings [16,17], the modal method used in [8][9][10][11] provides a more direct approach in concentric arrangements. This technique provides a very large degree of accuracy, necessary in the design of devices to be incorporated in fabricated photonic chips [9,11], at a low computational cost.…”

“…In these cases, the exterior waveguide acts as an efficient shielding against the effects of radiation. It is noteworthy that the best-case solutions rest in broad regions in the optimization parameter plane where performance variations are smooth, resulting in designs that are resilient against fabrication tolerances [9][10][11].…”