All fiber based miniature endoscopes with synchronized illumination and image acquisition
Fu-Jen Kao1*, Chih-Cheng Hsieh2,3, Zhan-Yu Chen1, Shao-Yu Lee1
1Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
2Division of Thoracic Surgery, Taipei Veterans General Hospital, Taipei, Taiwan
3Department of Surgery, National Yang-Ming University, Taipei, Taiwan
* Presenter:Fu-Jen Kao,
Endoscopy is one of the most powerful tools for diagnosing gastrointestinal system and minimally invasive surgery. Notably, conventional endoscopic light sources consist of incoherent LED and halogen light, which are coupled through optical fiber bundle of sizable diameter. However with the ever-decreasing size of the CMOS imaging sensors, there is always a demand for the reduction of the size of the light guide so that the footprint of the illumination components would not restrict an endoscope in exploiting the advantages of such ultra-compact CMOS sensors.
In this work, we report the successful implementation of all fiber based synchronized illumination and image acquisition to reduce the overall diameter of the endoscope to 0.49 mm. A coherent narrow-band (RGB) light source that provides much higher luminosity than traditional incoherent white light sources is used for illumination, taking advantages of the laser light’s high coherence for efficient light coupling. Notably, the narrow spectral band nature of the laser light sources also enables spectrally resolved imaging, which can be exploited to distinguish certain biological tissues or components. A high frame-rate monochrome CMOS camera is used in combination with synchronized and spectrally resolved illumination scheme for colour image or video acquisition and reconstruction. The ultraslim endoscope reported here will provide unprecedented opportunities in medical applications, especially for physical check-ups in suburb and countryside areas

1. Zhan-Yu Chen, Ankur Gogoi, Shao-Yu Lee, Yuan Tsai-Lin, Po-Wei Yi, Ming-Kuan Lu, Chih-Cheng Hsieh, Jin Chang Ren, Stephen Marshall and Fu-Jen Kao. Coherent Narrow-Band Light Source for Miniature Endoscopes. IEEE Journal of Selected Topics in Quantum Electronics.

Keywords: Endoscopy, Laser, CMOS, illumination