Electron Beam Direct-Write Tunable Polymeric Waveguide Grating Filter

We report a tunable electron beam direct-write polymeric waveguide Bragg grating filter based on a negative tone epoxy. The waveguide filter, with a 5-mm-long first-order grating, exhibits a transmission peak of -27 dB and a 3-dB bandwidth of ∼0.8 nm, and there is an excellent agreement between experimental data and simulation results. The temperature response of the filter is also characterized. The rate of change of refractive index dn/dT is ∼ -1.8 × 10^-4/°C at 1550-nm wavelength for both transverse electric and transverse magnetic polarizations, and the rate of change of peak wavelength dλ/dT is ∼ -0.14 nm/°C. The tuning performance is comparable to other grating devices fabricated using multiple processing steps.