A channel drop filter in hetero-woodpile-structure

Off-plane directional coupler in woodpile structure

“…It is expected to serve as a good platform for ultra-compact novel optical devices. In the past few years, woodpile structure has been investigated theoretically and experimentally [17][18][19][20][21][22][23][24]. Recently, in-plane optical devices in woodpile structure have been reported [18,20,21].…”