Silicon Photonic Wire Filter Based on Core-to-Cladding Mode Coupling

We demonstrate a silicon photonic wire filter, which uses sidewall long-period gratings for core- to-cladding mode coupling. The period and depth of fabricated grating are 1.8 mum and 20 nm, respectively. The total length of long-period grating is 455 mum. The measured maximum attenuation at the center wavelength is about 9.5 dB. The bandwidth of the transmission dip is 0.9 nm.