Exploring the impacts of long-period corrugation and phase gratings on a cascade of phase-shifted lithium niobate waveguides with the combined theoretical and experimental approaches

摘要

Highly reliable and low-cost long-period corrugation and phase gratings based on a cascade of phase-shifted lithiumniobate waveguides are theoretically analyzed, experimentally realized and characterized in a logical sequence. Therealization of these phase-shifted waveguide gratings (LPWG) is subsequently achieved via a two-step proton exchangemethod. The measurement results have demonstrated that the maximum dip contrast is up to 19.73 dB and the narrowestfull-width-at-half-maximum (FWHM) is close to 2.34 nm. Furthermore, for the cascaded pi-phase-shifted long-periodwaveguide gratings (LPWG), the two resonance wavelengths are symmetrically shifted away from the center wavelengthin response to an increase in the number of LPWG sections incorporated.