Design of a Photonic Integrated Device with an on-Chip k-Clock and Tunable Reference Arm for Swept-Source Optical Coherence Tomography

The paper presents a photonic integrated circuit (PIC) design that offers a high degree of integration of building blocks required to implement a swept-source optical coherence tomography (SS-OCT) system. The device includes an interferometer, sample arm, k-clock, and a tunable reference path integrated on a single chip implemented based on the silicon nitride fabrication platform. The PIC elements are optimized to perform low losses and minimal dispersion around a central operation wavelength of 1310 nm, which is critical for applications such as OCT. The device was simulated using Ansys Lumerical software. Simulation results show that the proposed PIC provides precise control of the scanning depth with a resolution of 0.725 nm/mV. Also, the frequency of the OCT signal does not exceed 17 GHz for scanning distances below 5 mm.