Cascaded bent waveguide type lithium niobate polarization rotator

Abstract

The invention discloses a cascaded bent waveguide type lithium niobate polarization rotator, which comprises a first-stage polarization rotator and a second-stage polarization rotator, the first-stage polarization rotator comprises a first bent waveguide, and the second-stage polarization rotator comprises a second bent waveguide. Each of the first bent waveguide and the second bent waveguide is composed of two Euler bent waveguides with gradually changed widths and an arc waveguide, and the first Euler bent waveguide with a gradually changed width, the arc waveguide and the second Euler bent waveguide with a gradually changed width are sequentially connected end to end. The second Euler bent waveguide with the gradually changed width in the first polarization rotator is connected with the first Euler bent waveguide with the gradually changed width in the second polarization rotator. The width of the Euler bent waveguide gradually changes linearly along with the bending angle. According to the cascaded bent waveguide type lithium niobate polarization rotator, lossless conversion of a light field mode of signal light from a straight waveguide mode to a bent waveguide mode can be realized by utilizing the Euler bent waveguides with the gradually changed width, so that the loss of the whole polarization rotator is reduced.

Description

technical field [0001] The invention belongs to the field of optical communication, in particular to a lithium niobate polarization rotator based on cascaded Euler bending and arc bending. Background technique [0002] With the rapid development of integrated lithium niobate platforms with high-performance electro-optic response, people's demand for integrated polarization control devices is increasing. The emergence of polarization beam splitter (Polarization Beam Splitter, PBS), polarizer (Polarizer) and polarization rotator (Polarization Rotator, PR) makes on-chip polarization adjustment simple. Both polarizing beam splitters and polarizers can achieve waveguide single-polarization operation, but cannot rotate the waveguide polarization. The emergence of polarization rotators solves the problem of polarization rotation very well. [0003] Traditional lithium niobate devices need to be prepared by titanium diffusion (Titanium-Diffusion, TiD) or proton exchange (Proton-Ex...

AI Technical Summary

Problems solved by technology

However, due to the anisotropic material properties of lithium niobate and the large inclination angle of the etched waveguide sidewall, the preparation of integrated polarization control devices is challenging.

The lithium niobate waveguide PR based on surface plasmon can efficiently realize polarization rotation, but the inherent ohmic loss of metal materials makes the insertion loss (Insertion Loss, IL) of this type of device relatively large

The lithium niobate waveguide PR based on the directional coupler (Directional Coupler, DC) effectively reduces the IL of the device, but the size of this type of device is large

This makes the traditional lithium niobate polarization rotator unable to achieve ideal device performance and difficult to meet the needs of practical applications

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