Characterization and comparison of optical source relative intensity noise and effects in optical coherence tomography

This thesis research investigates the effects of optical source noise in optical coherence tomography (OCT). While shot noise, thermal noise and relative intensity noise (RIN) (excess photon noise) constitute optical noise, RIN is the least understood and often the most significant factor limiting the sensitivity of an optical system. The existing and prevalent theory being used for estimating RIN for various light sources in OCT is questionable, and cannot be applied uniformly for different types of sources. The origin of noise in various sources varies significantly, owing to the different physical nature of photon generation. In this thesis, RIN of several OCT light sources are characterized and compared. Light sources include a super-luminescent diode (SLD), an erbium-doped fiber amplifier (EDFA), multiplexed SLDs, and a continuous wave (cw) laser. A method for the reduction of RIN by amplifying the SLD light output by using a gain-saturated semiconductor optical amplifier (SOA) is reported. Also, measurements using a time-domain OCT (TD-OCT) system are performed to verify the effects of optical source noise reduction on OCT data. Simulations comparing OCT and ISAM images assuming an identical optical source noise are also performed and explained.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Shin, Sunghwan

Contributors dc:contributor

• Boppart, Stephen A.

• optical coherence tomography
• relative intensity noise

Statement dc:rights

• Copyright 2010 Sunghwan Shin

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/18570

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/18570