Buried anti resonant reflecting optical waveguide based on porous silicon material for an integrated Mach Zehnder structure

Abstract

A buried anti resonant reflecting optical waveguide for an integrated Mach Zehnder structure based on porous silicon material is achieved using a classical photolithography process. Three distinct porous silicon layers are then elaborated in a single step, by varying the porosity (thus the refractive index) and the thickness while respecting the anti-resonance conditions. Simulations and experimental results clearly show the antiresonant character of the buried waveguides. Significant variation of the reflectance and light propagation with different behavior depending on the polarization and the Mach Zehnder dimensions is obtained. Finally, we confirm the feasibility of this structure for sensing applications.

Racetrack micro-resonators based on ridge waveguides made of porous silica

“…Other optical structures have been developed with both lateral and vertical confinement using photolithography processes [20,21] or a direct laser writing method [22]; for example, buried waveguides have been used to fabricate integrated Mach-Zehnder interferometers for sensing applications [23,24]. Recently, the first single side coupled micro-ring resonator based on PS [25] has been fabricated using standard electron beam lithography and reactive ion etching.…”

Porous silicon integrated Mach-Zehnder interferometer waveguide for biological and chemical sensing

“…However waveguides that confine light in two dimensions require some transverse confinement structure in addition to a planar dielectric stack. Techniques to incorporate transverse confinement include lithographic patterning and dry etching of multi layers [23], masking of the crystalline silicon substrate prior to electrochemical etching [24][25][26], direct laser oxidation of the surrounding regions, as we use here [27,28].…”