Apparatus and method for rangings and noise reduction of low coherence interferometry (LCI) and optical coherence tomography (OCT) signals

Abstract

Apparatus, method, logic arrangement and storage medium are provided for increasing the sensitivity in the detection of optical coherence tomography and low coherence interferometry (''LCI'') signals by detecting a parallel set of spectral bands, each band being a unique combination of optical frequencies. The LCI broad bandwidth source can be split into N spectral bands. The N spectral bands can be individually detected and processed to provide an increase in the signal-to-noise ratio by a factor of N. Each spectral band may be detected by a separate photo detector and amplified. For each spectral band, the signal can be band pass filtered around the signal band by analog electronics and digitized, or, alternatively, the signal may be digitized and band pass filtered in software. As a consequence, the shot noise contribution to the signal is likely reduced by a factor equal to the number of spectral bands, while the signal amplitude can remain the same. The reduction of the shot noise increases the dynamic range and sensitivity of the system.

Description

[0001] This application is a divisional application of the invention patent application with application number 03802734.8. [0002] The filing date of the original case: January 24, 2003. [0003] Title of original patent invention: Apparatus and method for ranging and noise reduction of low-coherence interferometry (LCI) and optical coherence tomography (OCT) signals using parallel detection of spectral bands. [0004] Original application number: 03802734.8, international application number: PCT / US03 / 02349 [0005] Cross-references to related applications [0006] This application claims Ser. No. 60 / 351,904, filed January 24, 2002, entitled "Ranging and Summarizing of Low Coherence Interferometry (LCI) and Optical Coherence Tomography (OCT) Signals Using Parallel Detection of Spectral Bands." Apparatus and Method for Scattering Noise Reduction," and Pending U.S. Provisional Patent Application No. 10 / 136,813, filed April 30, 2002, entitled "Using Dynamic Feedback to Control...

AI Technical Summary

Problems solved by technology

Because of the limited charge storage capacity, the reference arm power needs to be of the same order as the sample arm power, causing autocorrelation noise on the sample arm beam

Also, since no carrier is generated, the noise in this system will be 1 / f noise

Third, even with the short integration times of current state-of-the-art CCD technologies, phase instabilities in interferometers reduce fringe visibility for cross-correlation spectral density modulation

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