Widely tunable long-period gratings fabricated in polymer-clad ion-exchanged glass waveguides

ALong-period-grating filters were fabricated in polymer-clad ion-exchanged BK7 glass waveguides. The transmission spectra of the filters exhibited strong polarization dependence. A contrast as high as 25 dB at the resonance wavelength was obtained. The temperature sensitivity of the filters was measured to be 9.0 nm deg C, which allows potential wavelength tuning over the entire S+C+L band of ~180 nm with a temperature control over a range of ~20C.