Multi-channel swept source optical coherence tomography concept based on photonic integrated circuits

TL;DR

This paper introduces a novel multi-channel swept source OCT system using photonic integrated circuits with low-loss polarization routing, enabling faster in-vivo retinal imaging and potential for monolithic integration.

Contribution

It proposes a new low-loss polarization-dependent path routing approach for PIC-based OCT, demonstrated with a silicon nitride PIC system, enabling multi-channel parallel measurement.

Findings

Potential tenfold increase in acquisition speed for multi-channel OCT

Successful in-vivo retinal imaging with the prototype system

CMOS-compatible fabrication for future integration

Abstract

In this paper, we present a novel concept for a multi-channel swept source optical coherence tomography (OCT) system based on photonic integrated circuits (PICs). At the core of this concept is a low-loss polarization dependent path routing approach allowing for lower excess loss compared to previously shown PIC-based OCT systems, facilitating a parallelization of measurement units. As a proof of concept for the low-loss path routing, a silicon nitride PIC-based single-channel swept source OCT system operating at 840 nm was implemented and used to acquire in-vivo tomograms of a human retina. The fabrication of the PIC was done via CMOS-compatible plasma-enhanced chemical vapor deposition to allow future monolithic co-integration with photodiodes and read-out electronics. A performance analysis using the results of the implemented photonic building blocks shows a potential tenfold increase of the acquisition speed for a multi-channel system compared to an ideal lossless single-channel system with the same signal-to-noise ratio.