The signal in optical coherence tomography is often modulated either in phase or by use of the Doppler modulation generated by a depth-scanning mechanism. The effect of each type of modulation on the signal’s amplitude is evaluated. The advantages of each type of modulation in terms of immunity to phase noise and penetration depth are discussed in relation to two envelope detection schemes, i.e., lock-in detection and rms-to-dc conversion. Phase noise due to drifts and demodulation instabilities causes distortion of the signal envelope and can be responsible in part for the speckle appearance of the image.
© 2004 Optical Society of America
(030.4280) Coherence and statistical optics : Noise in imaging systems
(060.2350) Fiber optics and optical communications : Fiber optics imaging
(060.5060) Fiber optics and optical communications : Phase modulation
(170.4500) Medical optics and biotechnology : Optical coherence tomography
Pascale Parrein and Joachim Meier, "Phase Noise and Phase Modulation in Optical Coherence Tomography," Appl. Opt. 43, 3010-3017 (2004)