An ultracompact, bandwidth-tunable filter has been demonstrated using a silicon-on-
insulator (SOI) wafer. The device is based on cascaded grating-assisted contra-directional
couplers (GACDCs). It also involves the use of a subwavelength grating (SWG) structure. By
heating one of the heaters on GACDCs, a bandwidth tunability of∼ 6 nm is achieved. Owing
to the benefit of having a large coupling coefficient between SWG and strip waveguides, the
length of the coupling region is only 100 µm. Moreover, the combination of the curved SWG …

… Existing solutions for tunable filters on SOI include structures based on microring resonators
(MRRs) [5], Mach Zehnder interferometers (MZIs) [6] and cascaded grating-assisted
contra-directional couplers (GACDCs) [7] and so on. For MRRs and MZIs structures, the devices
have limited bandwidth (less than 10 nm) and … In this paper, we propose a compact bandwidth
tunable filter with cascaded GACDCs using subwavelength grating (SWG). And apodization is
employed to suppress sidelobes and realize a high suppression ratio. Using thermally controlled …