Compact integrated silica wavelength filters

The realization of compact low-loss wavelength filters using two-dimensional integrated optics (2DIO) in a silica-on-silica material system is reported. Two designs suitable for data-communications applications are reported: a 4 × 4 channel 6.4-nm channel wavelength spacing device and an 8 × 8 channel 3.2-nm channel wavelength spacing device. The devices are fabricated in one deep etch step, and after cleaving the four-channel device has a footprint of 4 × 3 mm and the eight-channel device 8 × 6.5 mm. The average crosstalk of the devices is >22 dB for adjacent channels and 26 dB for nonadjacent channels, and their fiber-to-fiber insertion losses are less than or equal 12 dB.