Autocorrelation noise free Optical Coherence Tomography using the novel concept of resonant OCT (ROCT)

Abstract

Background: Optical Coherence Tomography OCT is a noninvasive imaging technique that takes pictures of cross sections of human body tissues with a great resolution compared to other techniques. Fourier Domain OCT method provides significant improvement of imaging speed and detection sensitivity but suffers from autocorrelation noise arising as interference signals from reflections of sample layers that tends to obscure some of sample structure details.Methods: We present in this paper a new implementation of Common Path Optical Coherence Tomography, based on a resonant structure. The structure employs a semiconductor optical amplifier SOA and uses two mirrors, one coated fiber end and the other is the sample under test. Amplified multiple reflections between the laser cavity high reflection mirror and the sample layers along with SOA gain behavior results in the reduction of autocorrelation noise. Results: Autocorrelation noise is greatly reduced by a factor of 5 dB compared to an ordinary FDOCT system. Conclusion:This new structure, with the absence of autocorrelation noise that covers some of the details of the sample under test in OCT setups, is capable practically of attaining images with higher resolution.

Complete Removal of Arbitrarily Strong and Arbitrarily Located Auto Correlation Artifacts in Spectral Domain Optical Coherence Tomography: Demonstration of an Efficient and Cost Effective Technique

“…The traditional method of ignoring autocorrelation by increasing the reference arm reflectivity [7] would not suffice in such cases. A variety of autocorrelation removal techniques have been suggested over the years, like averaging spectra over multiple points [8], using resonant acquisition [9], using an off-axis reference beam [10], dispersion encoding [11], various phase shifting methods [12,13,14] and various balanced detection methods 2 [15,16]. Additionally, several computational autocorrelation removal techniques [17,18,19] have also been proposed.…”