Visible-telecom broadband optical isolator based on dynamic modulation in thin-film lithium niobate

TL;DR

This paper presents an ultra-broadband integrated optical isolator in thin-film lithium niobate that uses dynamic modulation to achieve high isolation over a wide wavelength range, including visible and telecom bands.

Contribution

The work introduces a novel dynamic standing-wave modulation technique in thin-film lithium niobate for broadband optical isolation, surpassing limitations of previous resonant or phase-matching methods.

Findings

Achieved ~100 nm bandwidth at 1550 nm and visible wavelengths.

Isolation ratio of 15 dB with insertion loss below 0.5 dB.

Operates simultaneously at visible and telecom wavelengths.

Abstract

Optical isolators are an essential component of photonic systems. Current integrated optical isolators have limited bandwidths due to stringent phase-matching conditions, resonant structures, or material absorption. Here, we demonstrate an ultra-broadband integrated optical isolator in thin-film lithium niobate photonics. We use dynamic standing-wave modulation in a tandem configuration to break Lorentz reciprocity and achieve isolation. We measure an isolation ratio of 15 dB and insertion loss below 0.5 dB for a design wavelength of 1550 nm. In addition, we experimentally show that this isolator can simultaneously operate at visible and telecom wavelengths with comparable performance. Isolation bandwidths ~100 nm can be achieved simultaneously at both visible and telecom wavelengths. Our device's large bandwidth, high flexibility, and real-time tunability can enable novel non-reciprocal functionality on integrated photonic platforms.