Low-power, agile electro-optic frequency comb spectrometer for integrated sensors

TL;DR

This paper introduces an integrated, low-power electro-optic frequency comb spectrometer on a chip that can interrogate temperature and acceleration sensors with high sensitivity, suitable for quantum and optical computing applications.

Contribution

It demonstrates a novel on-chip spectrometer using an integrated lithium niobate modulator with ultralow drive voltages and broad frequency agility, enabling advanced sensing capabilities.

Findings

Achieved ultralow RF drive voltages, seven orders of magnitude lower than previous methods.

Successfully interrogated on-chip temperature and off-chip acceleration sensors with high sensitivity.

Compatible with existing photonic integrated circuit technologies.

Abstract

Sensing platforms based upon photonic integrated circuits have shown considerable promise; however, they require corresponding advancements in integrated optical readout technologies. Here, we present an on-chip spectrometer that leverages an integrated thin-film lithium niobate modulator to produce a frequency-agile electro-optic frequency comb for interrogating chip-scale temperature and acceleration sensors. The chirped comb process allows for ultralow radiofrequency drive voltages, which are as much as seven orders of magnitude less than the lowest found in the literature and are generated using a chip-scale, microcontroller-driven direct digital synthesizer. The on-chip comb spectrometer is able to simultaneously interrogate both an on-chip temperature sensor and an off-chip, microfabricated optomechanical accelerometer with cutting-edge sensitivities of $\approx 5\ {\mu} \mathrm{K} \cdot \mathrm{Hz}^{-1/2}$ and $\approx 130\ \mu \mathrm{m} \cdot \mathrm{s}^{-2} \cdot \mathrm{Hz}^{-1/2}$, respectively. This platform is compatible with a broad range of existing photonic integrated circuit technologies, where its combination of frequency agility and ultralow radiofrequency power requirements are expected to have applications in fields such as quantum science and optical computing.