scholarly journals An Analytical Model for Describing the Power Coupling Ratio between Multimode Fibers with Transverse Displacement and Angular Misalignment in an Optical Fiber Bend Sensor

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4968
Author(s):  
Wern Kam ◽  
Yong Sheng Ong ◽  
Sinead O’Keeffe ◽  
Waleed S. Mohammed ◽  
Elfed Lewis
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Theoretical Calculations ◽  
Optical Fiber Sensor ◽  
Coupling Efficiency ◽  
Transverse Displacement ◽  
Coupling Ratio ◽  
Angular Misalignment ◽  
Multimode Fibers ◽  
Power Coupling

The power coupling ratio between step-index multimode fibers caused by combined transversal and angular misalignment is calculated. A theoretical description of the coupling efficiency between two optical fibers based on geometrical optics is provided. The theoretical calculations are collaborated by experiments, determining the power coupling ratio between three output fibers with an axial offset and angular misalignment with a single input fiber. The calculation results are in good agreement with experimental results obtained using a previously fabricated optical fiber sensor for monitoring physiological parameters in clinical environments. The theoretical results are particularly beneficial for optimizing the design of optical fiber bending sensors that are based on power coupling loss (intensity) as the measurement interrogation requires either axial displacement, angular misalignment, or both.

Fabrication of Lensed Plastic Optical Fiber Array Using Electrostatic Force

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Yih-Tun Tseng ◽  
Jhong-Bin Huang ◽  
Che-Hsin Lin ◽  
Chin-Lung Chen ◽  
Wood-Hi Cheng
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Electrostatic Force ◽  
Coupling Efficiency ◽  
Numerical Aperture ◽  
Uv Curing ◽  
Power Budget ◽  
Fiber Array ◽  
Plastic Optical Fibers ◽  
Efficient Coupling

The GI (graded-index) POFs (Plastic optical fibers), which has been proven to reach distances as long as 1 km at 1.25 Gb/s has a relatively low numerical aperture . Therefore, the efficient coupling of GI POFs to the light source has become critical to the power budget in the system. Efficient coupling for a POFs system normally involves either a separate lens or the direct formation of the lens at the end of the fiber. Forming the lens-like structure directly on the fiber end is preferred for simplicity of fabrication and packaging, such as polishing and fusion, combine different fibers with the cascaded fiber method and hydroflouride (HF) chemical etching. These approaches are well established, but applicable only to glass. Optical assembly architecture for multichannel fibers and optical devices is critical to optical fiber interconnections. Multichannel fiber-pigtail laser diode (LD) modules have potential for supporting higher data throughput and longer transmission distances. However, to be of practical use, these modules must be more precise. This work proposes and manufactures lensed plastic optical fibers (LPOF) array. This novel manipulation can be utilized to fabricate an aspherical lens on a fiber array after the UV curing of the photo-sensitive polymer; the coupling efficiency (CE) is increased and exceeds 47% between the LD array and the fiber array.

Enhancement of Coupling Efficiency of Butterfly Package Laser Modules Based on Post-Weld-Shift Compensation

2011 ◽  
Vol 145 ◽  
pp. 109-113
Author(s):  
Jao Hwa Kuang ◽  
Tsung Pin Hung ◽  
Shian Huan Chiou ◽  
Chao Ming Hsu
Keyword(s):  
Optical Fiber ◽  
Laser Diode ◽  
Optical Design ◽  
Coupling Efficiency ◽  
Welding Process ◽  
Central Wavelength ◽  
Power Coupling ◽  
Finite Element Software ◽  
Numerical Predictions ◽  
Welding Sequence

When fabricating laser diode transceiver modules, the coupling efficiency can be improved via a laser hammering process, in which additional, calculated spot welds are performed at key locations within the package in order to compensate for post-weld shift. The present study performs a numerical investigation into the post-weld-shift compensation of a butterfly laser module package incorporating a lensed optical fiber and a laser diode with a central wavelength of 980 nm. In performing the simulations, the deformation of the package components during the welding process is modeled using Marc finite element software. Furthermore, the laser power coupling efficiency is estimated using the commercial Zemax optical design program. It is shown that the numerical predictions for the coupling power in the laser diode transceiver module are in good agreement with the experimental results. The optimal welding sequence which minimizes the post-weld shift of the optical fiber relative to the laser diode is determined. It is shown that the corresponding coupling efficiency is equal to 69%. Finally, it is shown that by performing an optimized laser hammering process, the coupling efficiency can be improved to around 99%.

scholarly journals Comparative Experimental Study of a High-Temperature Raman-Based Distributed Optical Fiber Sensor with Different Special Fibers

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 574 ◽  
Author(s):  
Ismail Laarossi ◽  
María Quintela-Incera ◽  
José López-Higuera
Keyword(s):  
Experimental Study ◽  
High Temperature ◽  
Optical Fiber ◽  
Optical Fibers ◽  
Optical Fiber Sensor ◽  
Time Domain Reflectometry ◽  
Fiber Sensor ◽  
Mechanical Resistance ◽  
Distributed Optical Fiber Sensor ◽  
Distributed Optical Fiber

An experimental study of a high temperature distributed optical fiber sensor based on Raman Optical-Time-Domain-Reflectometry (ROTDR) (up to 450 °C) and optical fibers with different coatings (polyimide/carbon, copper, aluminum and gold) is presented. Analysis of the distributed temperature sensor (DTS) measurements determined the most appropriate optical fiber to be used in high temperature industrial environment over long periods of time. To demonstrate the feasibility of this DTS for an industrial application, an optical cable was designed with the appropriate optical fiber and it was hermetically sealed to provide the required mechanical resistance and isolate the fiber from environmental degradations. This cable was used to measure temperature up to 360 °C of an industrial furnace during 7 days.

Integrated Fiber Optic Sensors For Nondestructive Characterization Of Concrete Structures

1997 ◽  
Vol 503 ◽  
Author(s):  
F. Ansari
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Optical Fiber Sensor ◽  
Fiber Optic Sensors ◽  
Fiber Sensors ◽  
Fully Integrated ◽  
Integrated Optical ◽  
Concrete Elements

ABSTRACTIt is possible to monitor the initiation and progress of various mechanical or environmentally induced perturbations in concrete elements by way of fully integrated optical fiber sensors. Geometric adaptability and ease by which optical fibers can be embedded within concrete elements has led to the development of a number of innovative applications for concrete elements. This article is intended for a brief introduction into the theories, principles, and applications of fiber optic sensors as they pertain to applications in concrete.. However, due to the fact that the transduction mechanism in optical fibers is invariant of the materials employed, the principles introduced here also correspond to other structural materials. The only application related differences among various materials pertain to sensitivity and choice of optical fiber sensor types.

Lensed Plastic Optical Fiber with a Convexo-Concave Fiber Endface for Coupling Laser Diodes With Plastic Optical Fiber

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Yih-Tun Tseng ◽  
Shu-Ming Chang ◽  
Sheng-He Huang ◽  
Wood-Hi Cheng
Keyword(s):  
Optical Fiber ◽  
Light Source ◽  
Optical Fibers ◽  
Transmission Rate ◽  
Coupling Efficiency ◽  
Small Diameter ◽  
Plastic Optical Fiber ◽  
Graded Index ◽  
Coupling Laser ◽  
Working Distance

This work presents a novel lensed plastic optical fiber (POF), efficiently coupled with a light source. A convexo-concave plastic lens (CCPL) was bound to a flat-end plastic optical fiber using laser transmission welding (LTW) to form a convexo-concave-shaped fiber endface (CCSFE). The novel lensed plastic optical fiber has a longer working distance and a higher coupling efficiency than conventional lensed plastic optical fibers. 850 nm fiber is often used in high-power 2.5 Gb/s transmission rate. Experimental POF is perfluorinated POF, 62.5–500 μm diameter, 850∼1300 μm wavelength, 10 dB/km power loss rate, 2.5 Gb/s transmission rate. Because of the small diameter of POF, it is difficult to couple between the light source and POF. Therefore, it is important to develop a lensed fiber structure to increase the coupling efficiency. Experiments indicate that the coupling efficiency between a laser diode at a wavelength of 850 nm and a graded-index POF is as high as 85% with a long working distance of 250 μm. The measured tolerance, in relation to the lateral and vertical displacements and tilt, are satisfactory for practical active alignment.

scholarly journals Smartphone-Based Optical Fiber Sensor for the Assessment of a Fed-Batch Bioreactor

2020 ◽  
Vol 2 (1) ◽  
pp. 26
Author(s):  
Marco César Prado Soares ◽  
Thiago Destri Cabral ◽  
Pedro Machado Lazari ◽  
Matheus dos Santos Rodrigues ◽  
Gildo Santos Rodrigues ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Sucrose Concentration ◽  
Low Cost ◽  
Optical Fiber Sensor ◽  
Refraction Index ◽  
Fed Batch ◽  
Pixel Intensity ◽  
Batch Bioreactor ◽  
Sensing Platform

Industry is currently in a period of great expansion, the so-called “Industry 4.0”. This period relies on the development of new sensor technologies for the generation of systems capable of collecting, distributing, and delivering information. Particularly in chemical and biochemical industries, the development of portable monitoring devices can improve many process parameters, such as safety and productivity. In this work, the design of a smartphone-based optical fiber sensing platform for the online assessment of fed-batch fermentation systems is reported. The setup is comprised of a smartphone equipped with a 3D-printed case that couples optical fibers to the phone, and of an application for collecting images from the camera and then analyzing the pixel intensity. Finally, the obtained intensities are correlated to the broth refraction index, which is function of the sucrose concentration. We calculated the sensitivity of this sensor as 85.83 RIU−1 (refractive index units), and then compared its performance to results obtained with a handheld refractometer and with Monod model predictions. It showed to be a reliable, portable, and low-cost instrument for the online monitoring of bioreactors that can be easily reproducible on-site by simply printing it.

Stress optical fiber sensor using light coupling between two laterally fused multimode optical fibers

1998 ◽  
Vol 37 (16) ◽  
pp. 3417 ◽  
Author(s):  
Rachid Gafsi ◽  
Pierre Lecoy ◽  
Abdelrafik Malki
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Optical Fiber Sensor ◽  
Fiber Sensor ◽  
Light Coupling

Stress Analysis of Composite Material Embedded with Optical Fiber Sensor

2006 ◽  
Vol 326-328 ◽  
pp. 59-62
Author(s):  
Shiuh Chuan Her ◽  
Bo Ren Yao
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Electromagnetic Interference ◽  
Optical Fiber Sensor ◽  
Local Stress ◽  
Smart Structure ◽  
Fiber Optic Sensor ◽  
Host Material ◽  
Concentric Cylinders ◽  
Host Structure

Fiber optic sensor with small size, light weight and immunity to electromagnetic interference can be embedded and integrated into the host material to form a smart structure system. One must recognize that optical fibers are foreign entities to the host structure, therefore will alter the stress state in the vicinity of the embedded sensor irrespective of the small size of the fiber. This is a result of the material and geometric discontinuity introduced by the embedded optical fiber. In this study, the local stress fields in the vicinity of the embedded fiber are examined. The host material is considered to be a composite with reinforced fiber parallel to the optical fiber. The geometry in the vicinity of the embedded fiber is modeled by four concentric cylinders which represent the optical fiber, protective coating, resin and host material, respectively. In this investigation, the host structure is subjected to longitudinal normal stress and transverse hydro-static stress. The effects of the coating and host material on the stress distribution in the vicinity of the embedded optical fiber are presented through a parametric study.

Optical Fiber Hydrogen Sensor Based on Magnetron Sputtered Pd/V2O5 Films

2010 ◽  
Vol 663-665 ◽  
pp. 898-901
Author(s):  
Ling De Zhou ◽  
Jin Shan Huang ◽  
Yong Shi ◽  
Yin Wei Wu ◽  
Hai Hu Yu
Keyword(s):  
Thin Films ◽  
Optical Fiber ◽  
Response Time ◽  
Optical Fibers ◽  
Hydrogen Sensor ◽  
Hydrogen Gas ◽  
Multimode Fibers ◽  
Glass Substrates ◽  
Reflected Light ◽  
20 Nm

Laminated thin films composed of V2O5 and Pd (or Pt-Pd) layers were deposited on glass substrates and the end faces of multimode optical fibers, and the sensitive behaviors of the thin films to hydrogen gas were studied using a UV-visible spectrophotometer and an optical fiber sensor’s experimental setup. Both the thickness of the V2O5 layer and that of the Pd layer have obvious influences on the sensitivity performance of the Pd/V2O5 films. The Pd (30 nm)/V2O5 (280 nm) film deposited on a glass substrate is sensitive to 0.1% hydrogen and the highest change in relative transmittance is about 25% when exposed to 4% hydrogen. Pd/V2O5 films were coated onto the end faces of multimode fibers to form optical fiber sensors. The response time of the Pd (20 nm)/V2O5 (280 nm) sensor is about 50 s and the change in relative reflected light intensity is about 18% upon exposure to 4% hydrogen. Deposition of Pt-Pd double layer instead of Pd signal layer over V2O5 can reduce the response time of the sensor. The response time of the Pd (20 nm)/V2O5 (280 nm) sensor is about 50 s, while that of the Pt (10 nm)-Pd (10 nm)/V2O5 (280 nm) sensor is about 25 s.

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