Optical design of endoscopic shape-tracker using quantum dots embedded in fiber bundles

Jessica Eisenstein, Robb Gavalis, Peter Y. Wong, Caroline G.L. Cao

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Colonoscopy is the current gold standard for colon cancer screening and diagnosis. However, the near-blind navigation process employed during colonoscopy results in endoscopist disorientation and scope looping, leading to missed detection of tumors, incorrect localization, and pain for the patient. A fiber optic bend sensor, which would fit into the working channel of a colonoscope, is developed to aid navigation through the colon during colonoscopy. The bend sensor is comprised of a bundle of seven fibers doped with quantum dots (QDs). Each fiber within the bundle contains a unique region made up of three zones with differently-colored QDs, spaced 120° apart circumferentially on the fiber. During bending at the QD region, light lost from the fiber's core is coupled into one of the QD zones, inducing fluorescence of the corresponding color whose intensity is proportional to the degree of bending. A complementary metal oxide semiconductor camera is used to obtain an image of the fluorescing end faces of the fiber bundle. The location of the fiber within the bundle, the color of fluorescence, and the fluorescence intensity are used to determine the bundle's bending location, direction, and degree of curvature, respectively. Preliminary results obtained using a single fiber with three QD zones and a seven-fiber bundle containing one active fiber with two QDs (180° apart) demonstrate the feasibility of the concept. Further developments on fiber orientation during bundling and the design of a graphical user interface to communicate bending information are also discussed.

Original languageEnglish (US)
Title of host publicationNovel Optical Systems Design and Optimization XII
StatePublished - 2009
Externally publishedYes
EventNovel Optical Systems Design and Optimization XII - San Diego, CA, United States
Duration: Aug 3 2009Aug 4 2009

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


ConferenceNovel Optical Systems Design and Optimization XII
Country/TerritoryUnited States
CitySan Diego, CA


  • bend sensor
  • CMOS
  • endoscopy
  • fiber optics
  • fluorosensor
  • Quantum dots

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


Dive into the research topics of 'Optical design of endoscopic shape-tracker using quantum dots embedded in fiber bundles'. Together they form a unique fingerprint.

Cite this