All fiber optics circular-state swept source polarization-sensitive optical coherence tomography

Abstract

Abstract. A swept source (SS)-based circular-state (CS) polarization-sensitive optical coherence tomography (PS-OCT) constructed entirely with polarization-maintaining fiber optics components is proposed with the experimental verification. By means of the proposed calibration scheme, bulk quarter-wave plates can be replaced by fiber optics polarization controllers to, therefore, realize an all-fiber optics CS SSPS-OCT. We also present a numerical dispersion compensation method, which can not only enhance the axial resolution, but also improve the signal-to-noise ratio of the images. We demonstrate that this compact and portable CS SSPS-OCT system with an accuracy comparable to bulk optics systems requires less stringent lens alignment and can possibly serve as a technology to realize PS-OCT instrument for clinical applications (e.g., endoscopy). The largest deviations in the phase retardation (PR) and fast-axis (FA) angle due to sample probe in the linear scanning and a rotation angle smaller than 65 deg were of the same order as those in stationary probe setups. The influence of fiber bending on the measured PR and FA is also investigated. The largest deviations of the PR were 3.5 deg and the measured FA change by ∼12 to 21 deg. Finally, in vivo imaging of the human fingertip and nail was successfully demonstrated with a linear scanning probe.

Single input state polarization sensitive swept source optical coherence tomography based on an all single mode fiber interferometer

“…Moreover, this demonstrates the correct adjustment of polarization states throughout the SM fiber system and that the application of the respective equations to calculate retardation and axis orientation is justified. The observed results show low deviations from expected values which are in the same range as reported previously with bulk optics and PM fiber based systems [18,35]. Furthermore, repeated measurements over extended time periods demonstrate that our system is rather stable over time with respect to the set polarization states.…”

“…Based on our alignment procedure and according to theoretical considerations published elsewhere [18,35] retardation and axis orientation measurements should be independent of each other (also see Eq. (2) and (3)).…”

“…A hybrid PM/SM fiber based system, using a predefined sampling beam polarization state, has been reported [35]. Furthermore, an SM fiber based system providing additional polarization sensitive image contrast is available from Thorlabs Inc. (PSOCT-1300 Module, thorlabs.com).…”

Polarization Sensitive Optical Coherence Tomography: A Review of Technology and Applications

“…Most implementations were done using free-space optics [14,[40][41][42][43][44], however fiber optic prototypes have also been reported based on polarization maintaining (PM) fiber optics [45][46][47][48][49][50][51][52] and regular single mode fibers [53][54][55].…”

Passive endoscopic polarization sensitive optical coherence tomography with completely fiber based optical components

“…These PSOCT implementations are complex because they require proper synchronization and are expensive due to the high cost of the active polarization modulating component. Other PSOCT implementations have interferometers made entirely out of PM fiber so that the polarization state of the light is defined at the sample surface 22 . This requires accurate reference and sample arm matching since the PM fiber introduces large offsets in polarization states due to its birefringence, or post-acquisition computational compensation.…”