Ultra-Compact Band-Pass and Band-Stop Tunable Filters Based on Loop-Cascaded Nanobeam Structure

Abstract
We propose an ultra-compact band-pass and bandstop filter with bandwidth tunability based on the loop-cascaded nanobeam structure in simulation, with a small coupling region of 41 × 1 μm2. It features low insertion loss, large bandwidth tunable range and high sidelobe suppression ratio. By two-stage cascading, the bandwidth of the band-pass filter can be adjusted in the range of 6 nm-24 nm. We also experimentally demonstrate the loop-cascaded nanobeam band-pass and band-stop filter with a coupling region of only 17.5 × 1 μm2.
Funding Information
  • National Key Research and Development Program of China (2019YFB2203104)
  • Natural Science Foundation of China (61805137, 61835008)
  • Natural Science Foundation of Shanghai (19ZR1475400)
  • Open Project Program of Wuhan National Laboratory for Optoelectronics (2018WNLOKF012)