Optical isolator based on the electro-optic effect in periodically poled lithium niobate with the addition of a half domain

Abstract

We propose an optical isolator based on the electro-optic (EO) effect of periodically poled lithium niobate (PPLN). When the EO effect occurs in PPLN under a TE field, each domain serves as a half-wave plate under the quasi-phase-matching condition, and PPLN shows optical activity similar to quartz. The introduction of an additional half-domain to the normal PPLN changes the incident azimuth angle of the reflected light. As a result, the reflected light does not return to the original polarization state. Thus, the optical rotation accumulates and optical isolation occurs. The isolator can be employed for all linearly polarized light and has the advantage of being used in a weak-light system with low driving voltage and high isolation contrast.

Broadband optical isolator based on helical metamaterials

“…They have been widely used in optical fiber communication networks, laser systems [2], optical sensing [3], optical information processing systems, and precision optical measurement systems [4] for preventing the adverse effects of back reflections. Moreover, an isolator generally improves the overall system design as it suppresses spurious interferences, interactions between different devices, and undesired light routing.…”