Tunable polymer waveguide notch filter using a thermooptic long-period grating

The feasibility of a polymer waveguide notch filter using a thermooptic long-period grating is demonstrated experimentally. It consists of a channel waveguide, a cladding surrounding the channel, and buffer layers sandwiching the cladding. Periodic heaters, placed on the filter surface, induce thermooptically a long-period grating. The attenuation of the filter is controlled by adjusting the power applied to the periodic heaters. The filter is made of thermocurable polymers by using conventional processes. For transverse-electric mode, its attenuation increases from 0 to 27 dB as the power applied to the periodic heaters increases from 0 to 851 mW. For the maximum attenuation spectrum, the 3-dB bandwidth of the attenuation band is 16 nut.