Reconfigurable electro-optic frequency shifter

TL;DR

This paper presents a reconfigurable on-chip electro-optic frequency shifter in lithium niobate nanophotonics, capable of high-frequency shifts, tunable beam splitting, and scalable cascaded frequency operations for advanced photonic information processing.

Contribution

The work introduces a novel, precisely controlled electro-optic frequency shifter with reconfigurable capabilities, achieving high efficiency and low loss in integrated lithium niobate photonics.

Findings

Frequency shifts up to 28 GHz with ~99% efficiency

Reconfigurable tunable frequency-domain beam splitter

Scalable to cascaded shifts beyond 100 GHz

Abstract

Here we demonstrate an on-chip electro-optic frequency shifter that is precisely controlled using only a single-tone microwave signal. This is accomplished by engineering the density of states of, and coupling between, optical modes in ultra-low loss electro-optic waveguides and resonators realized in lithium niobate nanophotonics. Our device provides frequency shifts as high as 28 GHz with measured shift efficiencies of ~99% and insertion loss of <0.5 dB. Importantly, the device can be reconfigured as a tunable frequency-domain beam splitter, in which the splitting ratio and splitting frequency are controlled by microwave power and frequency, respectively. Using the device, we also demonstrate (non-blocking) frequency routing through an efficient exchange of information between two distinct frequency channels, i.e. swap operation. Finally, we show that our scheme can be scaled to achieve cascaded frequency shifts beyond 100 GHz. Our device could become an essential building-block for future high-speed and large-scale classical information processors as well as emerging frequency-domain photonic quantum computers.