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arXiv · 1705.10237

Optical pump-rejection filter based on silicon sub-wavelength engineered photonic structures

Diego Pérez-Galacho·Carlos Alonso-Ramos·Florent Mazeas·Xavier Le Roux·Dorian Oser·Weiwei Zhang·Delphine Marris-Morini·Laurent Labonté·Sébastien Tanzilli·Éric Cassan·Laurent Vivien
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Abstract

The high index contrast of the silicon-on-insulator (SOI) platform allows the realization of ultra-compact photonic circuits. However, this high contrast hinders the implementation of narrow-band Bragg filters. These typically require corrugations widths of a few nanometers or double-etch geometries, hampering device fabrication. Here we report, for the first time, on the realization of SOI Bragg filters based on sub-wavelength index engineering in a differential corrugation width configuration. The proposed double periodicity structure allows narrow-band rejection with a single etch step and relaxed width constraints. Based on this concept, we experimentally demonstrate a single-etch, $\mathbf{220\,nm}$ thick, Si Bragg filter featuring a corrugation width of $\mathbf{150\,nm}$, a rejection bandwidth of $\mathbf{1.1\,nm}$ and an extinction ratio exceeding $\mathbf{40\,dB}$. This represents a ten-fold width increase compared to conventional single-periodicity, single-etch counterparts with similar bandwidths.

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Diego Pérez-Galacho, Carlos Alonso-Ramos, Florent Mazeas, Xavier Le Roux, Dorian Oser, Weiwei Zhang, Delphine Marris-Morini, Laurent Labonté, Sébastien Tanzilli, Éric Cassan, Laurent Vivien. 2017-05-29. Optical pump-rejection filter based on silicon sub-wavelength engineered photonic structures. https://doi.org/10.1364/ol.42.001468

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