A broadband and compact TE-pass/TM-stop polarizer is presented based on hybrid plasmonic grating (HPG) on an x-cut Lithium-Niobate-on-isolator (LNOI) platform. By comprehensively analyzing the effects of metal width on mode effective index, mode similarity, and mode conversion, we demonstrate the structure with a narrow metal layer. The simulation results indicate that the polarizer with a compact length of 9 m achieves an extinction ratio over 20 dB within the wavelength range from 1470 nm to 1700 nm. The insertion loss is below 2.3 dB in C-band. Furthermore, the polarizer exhibits large fabrication tolerance to current fabrication technology.

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We proposed a design of a fundamental TM mode waveguide optical isolator using lithium niobate on insulator (LNOI) and deposited magneto-optical film. The optical isolator adopts an asymmetric Mach-Zehnder interferometer (MZI) structure composed of two 1×2 MMIs, non-reciprocal and reciprocal waveguides. We used three methods to calculate the non-reciprocal phase shift (NRPS) of the lithium niobate (LN)/ Ce: YIG composite waveguide and got similar results. The device shows about 51.98 nm 30 dB isolation bandwidth and 1.20 dB simulated insertion loss at the wavelength of 1550 nm. The fabrication tolerances and a suitable process are also discussed to meet the state-of-art technology and material properties.