PROJECT SUMMARY Despite advances in OCT technology over the past two decades, retinal OCT systems are still limited by their speed. This has many consequences on how OCT is used. Perhaps most significantly, current speeds restrict the imaged field to a fraction of the total retinal area. This prevents diseases of the peripheral retina from being imaged in routine OCT scans. Two recent technologies in the field of OCT and photonics may offer a technological path toward much higher-speed retinal OCT. The first is a circular-ranging OCT method that employs optical-domain compression to avoid acquisition barriers to high-speed imaging. The second in Lithium- Niobate-on-insulator (LNOI) photonic integrated filters, which can be leveraged to create high-performance and low-cost CR-OCT laser sources. In this work, we propose studies to evaluate the feasibility of a CR-OCT/LNOI platform that is 100-fold faster than commercially available retinal OCT systems. In Aim 1, we will fabricate a wavelength-stepped optical filter based on LNOI circuits. In Aim 2, we will use this filter to build a high- performance mode-locked CR-OCT laser source. If successful, this work will define a technical strategy toward comprehensive retinal imaging by OCT.