Fiber lenses for ultra-small probes used in optical coherent tomography

Abstract

We present a design, construction and characterization of different variations of GRIN and ball fiber lenses, which were recently proposed for ultra-small biomedical imaging probes. Those fiber lens modules are made of a single mode fiber and a GRIN or ball fiber lens with or without a fiber spacer between them. The lens diameters are smaller than 0.3 mm. We discuss design methods, fabrication techniques, and measuring performance of the fiber lenses. The experimental results are compared to their modeling results. The fabrication of a high quality beam director for both lens types is presented as well. These fiber integrated beam directors could be added on the tips of the fiber lenses for side-view probes. A needle probe made by these fiber lenses is demonstrated as a sample of the ultra-small probe for biomedical imaging application. In vivo human finger images acquired by a swept source optical coherence tomography using the fiber lenses with different beam profiles were shown, which indicates the important impact of fibe

Numerical simulation of a gradient-index fibre probe and its properties of light propagation

“…These parameters are the same as those in Refs. [7] and [8], and thus our simulation results can be compared with the experimental ones in Refs. [7] and [8].…”

“…However, none of them presents the design theory of the probes. Since 2007, Mao et al [7,8] have studied the fabrication and the performance testing methods of the GRIN fibre probes. However, they have not obtained the profiles of the beam propagating within the probes.…”

Research on a Novel Fabry–Perot Interferometer Model Based on the Ultra-Small Gradient-Index Fiber Probe

“…The GRIN fiber probe is an all-fiber optical probe consisting of a single-mode fiber, a coreless fiber, and a GRIN fiber [14,15]. Due to its ultra-small size and superior focusing performance, it can be integrated with the signal arm of the fiber interferometer through a fusion process, which has been favored by scholars in recent years [16,17,18,19]. In this paper, we study the ultra-small GRIN fiber probe samples with high coupling efficiency for the F–P fiber interferometer and their organic combination with the F–P fiber interferometer.…”

In‐line optical fiber metallic mirror reflector for monolithic common path optical coherence tomography probes

“…Side‐viewing GRIN fiber and ball lens common path probes also require a separate reflector to direct the beam to the side of the probe which further complicates the optical design. Ball lens non common path probe design eliminates the need for a separate reflector by polishing the ball lens at an angle such that the sample signal reflects from the polished surface because of total internal reflection. The same cannot be achieved for GRIN fiber and ball lens‐based common path probes because the angle of the polished surface does not satisfy total internal reflection condition for the reference signal reflected from the glass–air interface.…”