Analysis of Design and Fabrication Parameters for Lensed Optical Fibers as Pertinent Probes for Sensing and Imaging

Park, Soongho; Rim, Seog-Hoon; Kim, Ju Wan; Park, Jinho; Sohn, Ik-Bu; Lee, Byeong Ha

doi:10.3390/s18124150

Cited by 9 publications

(9 citation statements)

References 21 publications

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“…This method uses a complex matrix formalism. It gives very reliable results and has been verified with experimental results of high precision for optical interferometric sensors [7,15]. However, the method is predominantly based on numerical computations for the general design of FBLSs for various applications.…”

Section: Introductionmentioning

confidence: 69%

“…Usually, the CLF of length l 1 is first spliced to the SMF and in the next step cleaved by a high-precision cleaver set-up to the appropriate length. Next, the ball lens is formed by the fusion splicer [15]. For a system with defined imaging characteristics it is necessary to know the expected back image distance, which is directly related to the CLF length l 1 and the ball lens radius R after shaping by the fusion splicer.…”

Section: Geometrical Optics Considerationmentioning

confidence: 99%

“…A much more appropriate computation is based on Gaussian beams (GBs) exiting the SMF, propagating through the coreless section and being refracted and reflected, respectively, at the spherical lens surface [7,15]. This method uses a complex matrix formalism.…”

Section: Introductionmentioning

confidence: 99%

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Design considerations and experimental investigations on fiber ball lens systems for optical metrology

et al. 2023

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Optical fibers play an important role in general, and in particular in the field of sensors. As part of a sensor system quite often fibers are coupled by a ball lens. For efficient usage, the fiber ball lens systems (FBLS) have to be optimized. The present work presents analytic expressions for design parameters of such systems. FBLS comprise sections of a single-mode optical fiber, a coreless fiber (CLF) and a ball lens. Their geometric dimensions have to be optimized for their use in different application in optical metrology. The derived expressions facilitate the optimum parameter choice which usually is done by expensive numerical simulations. For comparison and validation of the results by experiments, FBLS with different ball lens radii and CLF sections have been prepared by a fusion splicer technique. Their characteristics were investigated in the optical spectral ranges at 630nm and 1550nm. Experimental methods comprising far-field, near-field, reflection /transmission measurements with optical fibers validate the theoretical considerations. To our knowledge this is the first time that simple analytic approaches have been applied to the fabrication of FBLS. This facilitates and quickens their general design for different applications in optical metrology significantly.

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Section: Introductionmentioning

confidence: 69%

Section: Geometrical Optics Considerationmentioning

confidence: 99%

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Design considerations and experimental investigations on fiber ball lens systems for optical metrology

et al. 2023

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“…By setting and calibrating the offset between the needle tip and fiber's end surface (reference plane), the exact distance between the needle tip and the desired layer can be interpreted. To further enhance the SNR inside the cornea and protect the reference surface, a high-index epoxy ball lens is attached to the end of the single-mode fiber [35,36]. The ball lens was fabricated by applying a UV curable epoxy (NOA 170, n = 1.7, Norland, Cranbury, NJ, USA) to the fiber end, which naturally forms a semi-spherical shaped lens, owing to surface tension.…”

Section: Oct Distal Sensor Integrated Needlementioning

confidence: 99%

Demonstration of Optical Coherence Tomography Guided Big Bubble Technique for Deep Anterior Lamellar Keratoplasty (DALK)

Guo

Sarfaraz

Gensheimer

et al. 2020

Sensors

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Deep anterior lamellar keratoplasty (DALK) is a highly challenging procedure for cornea transplant that involves removing the corneal layers above Descemet’s membrane (DM). This is achieved by a “big bubble” technique where a needle is inserted into the stroma of the cornea down to DM and the injection of either air or liquid. DALK has important advantages over penetrating keratoplasty (PK) including lower rejection rate, less endothelial cell loss, and increased graft survival. In this paper, we successfully designed and evaluated the optical coherence tomography (OCT) distal sensor integrated needle for a precise big bubble technique. We successfully used this sensor for micro-control of a robotic DALK device termed AUTO-DALK for autonomous big bubble needle insertion. The OCT distal sensor was integrated inside a 25-gauge needle, which was used for pneumo-dissection. The AUTO-DALK device is built on a manual trephine platform which includes a vacuum ring to fix the device on the eye and add a needle driver at an angle of 60 degrees from vertical. During the test on five porcine eyes with a target depth of 90%, the measured insertion depth as a percentage of cornea thickness for the AUTO-DALK device was 90.05 % ± 2.33 % without any perforation compared to 79.16 % ± 5.68 % for unassisted free-hand insertion and 86.20 % ± 5.31 % for assisted free-hand insertion. The result showed a higher precision and consistency of the needle placement with AUTO-DALK, which could lead to better visual outcomes and fewer complications.

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“…Optical probes [1,2] are widely used in optical coherence tomography (OCT) and other sensing and imaging systems for investigating the internal structures of biological tissues and the intraluminal imaging of various organs. However, conventional probes are bulky and unwieldy, and thus, researchers have considered replacing them with lensed optical fibers [3][4][5]. In particular, a set of two lensed optical fibers can replace existing bulky optical lens systems for constructing compact microelectromechanical systems (MEMS) that can afford significantly improved imaging performances [6].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Lensed Optical Fibers for Biosensing Probes Using CO2 and Femtosecond Lasers

et al. 2021

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We propose a new method for precisely fabricating a lensed fiber with a desired focal length by first cleaving a coreless silica fiber using an ultrafast femtosecond laser without thermal effects and subsequently shaping the radius of curvature at the optical-fiber end using a CO2 laser. The precisely cleaved segment of the coreless silica fiber obtained with the femtosecond laser is attached to a long single-mode fiber. The beam-exposure time and laser power of the CO2 laser are adjusted to melt the coreless-fiber end to yield a uniform, consistent, and precise radius of curvature, thereby realizing a lensed optical fiber. The precision of the radius of curvature in this case is greater than those obtained with the conventional arc discharge method with thermal treatment requiring fairly complex processes and yielding relatively low fabrication accuracy. In our study, we observe a difference between the measured and calculated focal lengths of the fabricated lens, possibly because the exact value of the mode field diameter is uncertain. On the other hand, the beam size measured using the knife-edge method matches closely with the theoretical size. Our findings confirm the feasibility of fabricating lensed optical fibers for fiber-based biosensing using CO2 and femtosecond lasers.

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Analysis of Design and Fabrication Parameters for Lensed Optical Fibers as Pertinent Probes for Sensing and Imaging

Cited by 9 publications

References 21 publications

Design considerations and experimental investigations on fiber ball lens systems for optical metrology

Design considerations and experimental investigations on fiber ball lens systems for optical metrology

Demonstration of Optical Coherence Tomography Guided Big Bubble Technique for Deep Anterior Lamellar Keratoplasty (DALK)

Fabrication of Lensed Optical Fibers for Biosensing Probes Using CO2 and Femtosecond Lasers

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