Band-rejection filter with widely tunable center wavelength and contrast using metal long-period grating on polymer waveguide

We demonstrate a widely tunable band-rejection filter using a metal long-period grating deposited directly on the cladding of a polymer waveguide. The contrast of the rejection band can be tuned by 28 dB with ∼45-mW electric power applied to the metal grating and the center wavelength can be tuned over the C+L-band with a temperature control of ∼40°C. The device can find applications as a tunable notch filter, a polarization-dependent loss compensator, or a variable attenuator.