Monolithic $1\times4$ Reconfigurable Electro-Optic Tunable Interleaver in Lithium Niobate Thin Film

We propose and experimentally demonstrate a monolithically integrated 1× 4 reconfigurable electro-optic tunable interleaver in X-cut lithium niobate thin film by cascading three asymmetrical Mach-Zehnder interferometers into two stages. Over a wide wavelength range from 1530 nm to 1605 nm, our fabricated device exhibits polarization-insensitive center wavelengths and channel spacing of ~50 GHz, slightly different switching voltages of 4.5 V and 6.7 V, and extinction ratios of 8-15 dB and 7-13 dB for the transverse electric (TE) and the transverse magnetic (TM) polarized input light, respectively.