2017/03/31 by Diego Pérez-Galacho, Diego Pérez‐Galacho, Carlos Alonso‐Ramos +11
Engineering · Physics and Astronomy · #Band-pass filter #Bandwidth (computing) #Extinction ratio #Fabrication #Materials science #Optical Network Technologies #Optical filter #Optics #Optoelectronics #Photonic Crystals and Applications #Photonic and Optical Devices #Photonic integrated circuit #Photonics #Physics #Realization (probability) #Silicon #Silicon on insulator #Stopband #Telecommunications #Wavelength #physics.optics #quant-ph
paper · pdf · doi:10.1364/ol.42.001468
published as Optics Letters, 2017, 42 (8), pp.1468-1471
openalex publication_date 2017/03/31 · arxiv created 2017/05/29 · arxiv updated 2017/05/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
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 corrugation widths of a few nanometers or double-etch geometries, hampering device fabrication. Here we report, for the first time, to the best of our knowledge, 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, 220 nm thick, Si Bragg filter featuring a corrugation width of 150 nm, a rejection bandwidth of 1.1 nm, and an extinction ratio exceeding 40 dB. This represents a 10-fold width increase, compared to conventional single-periodicity, single-etch counterparts with similar bandwidths.