| 摘要 |
<p>Methods and apparatus for performing optical coherence-domain reflectometry (OCDR) and optical coherence tomography (OCT) include techniques for increasing the number of depths of a sample that can be scanned simultaneously; these techniques relax or eliminate pathlength scanning requirements of the delay line. Depth encoding and differentiating/separating of depth-related data is accomplished using several frequency-encoding approaches, such as multiple-pathlength delay line that imposes a different frequency shift one each different pathlength or delay by employing a rotating reflective cylinder, stretching a fiber optic member, tilting a mirror to impose a linear phase ramp on the spectrum of the light wave, operating an accousto-optic beam deflector. Use of Mach-Zehnder interferometers and cascades of Mach-Zehnder interferometers with respective path lengths between its two arms to obtain frequency encoding for OCDR and OCT.</p> |
