8-channel tunable drop device with thermal tuning for 100 GHz channel spacing

An 8-channel tunable drop module based on efficient thermal tuning of fiber Bragg gratings is reported. The drop module is designed for 100 GHz (0.8 nm) channel spacing in the 1550 nm telecom window. Wavelength shifts of 0.4 nm corresponding to half a channel spacing, and broadening of the transmission spectrum to >0.25 nm at the 25 dB level were achieved through thermal gradients. Isolation at the adjacent channel center was >25 dB. Over the adjacent channel passband isolation was >22 dB.