Polarization-sensitive optical coherence tomography (PS-OCT) allows imaging of tissue birefringence. In practice, however, PS-OCT images are often confounded by high noise and confusing artifacts. A full understanding of the intrinsic and instrumentation-derived signal and noise properties of PS-OCT has not been developed. In this presentation, we describe a Monte Carlo (MC) simulator of PS-OCT local birefringence imaging that recapitulates the noise and signal properties observed in empirical images and, as such, can be used to understand and improve PS-OCT methods. The MC simulator builds upon a previously described MC methodology that supports arbitrary three-dimensional geometries. To this, we have added support for MC simulation of transverse speckle correlation. This is important because many of the noise sources in PS-OCT are driven by interactions with the speckle field. We have developed a method to support polarization-dependent measurements of birefringent tissues. Both additive (due to finite SNR) and polarization-mode dispersion noise can be incorporated. To demonstrate the utility of the simulator, we use it to reveal a previously unappreciated noise that results from the design of conventional local birefringence extraction algorithms, and we describe an improved method that lowers noise in both simulated and empirical datasets. We anticipate that this simulator will enable new explorations into the fidelity of PS-OCT measurements and accelerate the optimization of PS-OCT methods and algorithms.
Dynamic response of lightweight structures is affected by the mass of a transducer. The additional mass of the transducer
is defined as a mass loading for the system, which is comparable to the weight of the structures, such as composites and
thin cantilever beam/bar. In this paper, we measure the bending and torsion mode frequencies with and without mass
loading to the lightweight structures by using lightweight optical fiber sensor (OFS) and conventional accelerometer.
The frequency difference is verified by the finite element method using ANSYS software. The OFS, benefited to its
lightweight, has shown the advantage of measuring vibration frequency accurately without affecting the dynamic
response of the structure.
An optical fiber vibration/acoustic sensor based on polarization diversity scheme has been developed to study the
vibration of the highway pavement slabs with vehicles passing. This process induced the birefringence change in a 50m
sensing fiber embedded along the FRP bars. The damping of the impact in time domain and a 2Hz vibration frequency
Using a fast polarization mode dispersion (PMD) with 15-second interval and long measurement duration (>24h), we
found the correlation between polarization effects, tides and sun radiation on submarine fibers. We also found that
using state of polarization measurement we can measure the vibration frequency of the optical fibers.
A polarization dependent loss (PDL) vector equation of motion in Stokes space was derived in a system interacting with polarization mode dispersion (PMD). A new PDL measurement method based on the PDL vector equation was proposed and validated by numerical simulation and experiment.