title: Analog CMOS design for optical coherence tomography signal detection and processing.
abstract: A CMOS circuit was designed and fabricated for optical coherence tomography (OCT) signal detection and processing. The circuit includes a photoreceiver, differential gain stage and lock-in amplifier based demodulator. The photoreceiver consists of a CMOS photodetector and low noise differential transimpedance amplifier which converts the optical interference signal into a voltage. The differential gain stage further amplifies the signal. The in-phase and quadrature channels of the lock-in amplifier each include an analog mixer and switched-capacitor low-pass filter with an external mixer reference signal. The interferogram envelope and phase can be extracted with this configuration, enabling Doppler OCT measurements. A sensitivity of -80 dB is achieved with faithful reproduction of the interferometric signal envelope. A sample image of finger tip is presented.
authors.affiliation: High Performance Analog Division, Texas Instruments, Tucson, AZ 85706, USA. vpecxuwei@gmail.com
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.forename: David L
authors.initials: DL
authors.lastname: Mathine
authors.forename: Jennifer K
authors.initials: JK
authors.lastname: Barton
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation*; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation*; D015203:Reproducibility of Results; D012666:Semiconductors; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D041623:Tomography, Optical Coherence / Q000295:instrumentation* / Q000379:methods