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

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 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.

In vivo human retinal swept source optical coherence tomography and angiography at 830 nm with a CMOS compatible photonic integrated circuit

“…In a SS-OCT system the acquisition time needed for a B-scan is mainly given by the speed of the swept source and the amount of sampling points (A-scans per B-scan). A multi-channel configuration as proposed in 16 , where multiple sample arms are acquired with multiple detection arms, would increase effective imaging speed, while keeping the same system sensitivity compared to a standard single channel configuration. Such a multi-channel configuration can be used in several ways, depending on the requirements: faster, wider FOV or finer lateral resolution/sampling.…”

“…The measured spectra through the PIC further demonstrate the broadband capability of the waveguides and the on-chip building blocks, which are designed to support 100 nm bandwidth. The broadband capability of the PIC and its building blocks is discussed in detail in Nevlacsil et al 16 . A low number of averaging further demonstrates a realistic clinical imaging scenario.…”

“…Nevlacsil et al recently proposed a concept for an on-chip multi-channel SS-OCT system, in which multiple sample beams are used to increase the effective acquisition speed while maintaining the system sensitivity of a standard single beam system 16 . Unlike in fiber or free-space optics, PICs have the inherent advantage that multiple functions can be integrated on a single chip without the need for additional components or additional efforts for alignment or maintenance.…”

Enhanced medical diagnosis for dOCTors: a perspective of optical coherence tomography

“…In addition to its small form factor, multiple functional photonic building blocks can be printed on a single chip, which opens up new and/or easier realizable possibilities for OCT system designs, such as multichannel sample arm configuration/parallelized imaging as proposed recently. 363 Several sample arm paths could scan the sample in parallel, which would increase the effective A-scan rate without sacrificing imaging performance.…”

Microparticle-based Biochemical Sensing Using Optical Coherence Tomography and Deep Learning

“…A-scans) can be acquired at rates exceeding 100kHz, allowing for volumetric imaging of roughly 3mm x 3mm x 3mm volumes per second with 10µm resolution in all dimensions. Recent work to miniaturize these systems 33,34 offers the potential of a portable, low-cost device for continuous in vivo monitoring, making SS-OCT an ideal candidate to acquire a non-invasive readout of microparticle biosensors.…”