Novel plastic optical-fiber connector

Application of highly concentrated sunlight transmission and daylighting indoor via plastic optical fibers with comprehensive cooling approaches

Study on thermal protection and temperature of PMMA plastic optical fiber for concentrated sunlight transmission in daylighting

Cerenkov radiation, which is produced by charged particles that pass through optical fibers with a velocity greater than that of light, is frequently regarded as a severe noise signal in a fiber-optic radiation sensor consisting of a scintillator and an optical fiber. Since the spectral range of Cerenkov radiation is very broad and covers that of light outputs from a scintillator, Cerenkov radiation generated in optical fibers is also acquired by a photodetector. However, Cerenkov radiation can be a significant signal when we measure the intensities of Cerenkov radiation generated from fixed length of optical fibers because it is one of the signals induced by interactions between radiations and optical fibers. In this study, gamma-ray induced Cerenkov radiation generated in silica and plastic optical fibers was measured in order to select an efficient optical fiber for producing Cerenkov radiation. The intensities and the spectra of Cerenkov radiation generated in the optical fibers were measured using a spectrometer. As the results, the intensities of Cerenkov radiation generated in silica and plastic optical fibers have peak wavelengths at approximately 500 nm. Also, the intensity of Cerenkov radiation obtained using a plastic wavelength shifting fiber was the highest among all sample optical fibers.

Scintillation dosimeters consisting of a scintillating fiber coupled to an optical fiber and read with a CCD camera have shown accurate dose measurement in external beam radiotherapy. This work presents the next step, which is to investigate the development of a multi‐channel dosimeter array in conjunction with a CCD camera for dose measurement that includes small fields. The light collection of the CCD camera was studied to evaluate the number of detectors that can be read simultaneously. We also looked at possible sources of dose perturbation with a single‐fiber detector surrounded by other optical fibers. We then constructed a prototype array with 10 detectors and compared with measurements taken with small ion chambers. No dose perturbations were seen when a plastic optical fiber was used to transmit the scintillation light to the CCD. Depth dose curves measured in water with a scintillation dosimeter with up to 75 plastic optical fibers in the beam showed no discrepancy to within 0.3% when compared to the same curve taken with an ion chamber and without the plastic fibers. Agreement within 0.6% was seen for output factor measured with the scintillator and the A16 Exradin chamber for fields of 1×1 cm 2 and 5×0.5 cm 2 . The ten‐fiber prototype allowed precise evaluation of profile and depth dose curves in a single irradiation. This work has shown that use of a multi‐channel scintillation dosimeter is feasible. The prototype of 10 detectors produced excellent results and could be extended up to 3000 detectors in the near future.

A new type of analog data transmission system using a plastic fiber is proposed, where a direct intensity modulation scheme has been employed together with a differential amplifier to compensate for the transmission error caused by the optical fiber bending loss. This system was experimentally applied to transmit analog data of dimensions detected by the displacement sensor attached to the robot arm tip to the robot basement through the plastic optical fiber installed in the robot arm body.

When the charged particle travels in transparent medium with a velocity greater than that of light in the same medium, the elec-tromagnetic field close to the particle polarizes the medium along its path, and then the electrons in the atoms follow the waveform ofthe pulse which is called as Cerenkov light or radiation. This type of radiation can be easily observed in a spent fuel storage pit. In opticalfibers, the Cerenkov light also can be generated due to their dielectric components. Accordingly, the radiation-induced light signals canbe obtained using optical fibers without any scintillating material. In this study, to measure the intensities of Cerenkov radiation inducedby gamma-rays, we have fabricated the fiber-optic Cerenkov radiation sensor system using silica optical fibers, plastic optical fibers,multi-anode photomultiplier tubes, simulated spent fuel assembly and a scanning system. To characterize the Cerenkov radiation gen-erated in optical fibers, the intensities of Cerenkov radiation generated in the silica and plastic optical fibers were measured. Also, wemeasured the longitudinal distribution of gamma rays emitted from the Ir-192 isotope by using the fiber-optic Cerenkov radiation sensorsystem and simulated spent fuel assembly.Keywords: Cerenkov radiation, Fiber-optic sensor, Gamma ray, Ir-192 isotope, Simulated spent fuel assembly

The main objectives of this paper is to improve knowledge of multimode fiber transmission over step-index plastic optical fiber SI POF with 1000 μm core. The thick SI POF fibers seem a very attractive alternative in local computer networks for the “classic” (thin) single- and multimode fibers because of their low price and easy installation. In the paper we show measurements of bandwidth and attenuation of various SI POF optical paths. In particular, there was investigated a cascade of passive components (couplers, patchcords) which can be part of transparent (passive) optical networks. Keywords : plastic optical fibre, passive optical network, multimode coupler. 1. INTRODUCTION Recently there has been publish a number of papers concerning optical data transfer over plastic optical fiber [1][2]. Both point-to-point and WDM passive network configurations are considered. The concept of passive network is well known as it comes to the access networks based on single mode fiber. Such networks were proposed in several standards (APON, BPON networks). Commercial solution have been developed and deployed since. We would like to extend benefits of this network type to home networks based on multimode optical fiber. We consider such networks as a viable solution of the optical home network architecture. Along with a multimode optical cable only multimode compatible elements (couples/splitters, connectors, etc.) may be used in the network. Once deployed the upgrade of such a network should be relatively easy. Unlike to the single mode PON where the bandwidth is not an issue, the multimode network maximum operational range is defined by the fiber bandwidth (related to the intermodal dispersion) rather than by the fiber attenuation [3]. The relation among the modal bandwidth of the fiber, the launching condition and mode coupling is fairly well known for silica GI optical fibers (

For mass information transfer, the optical communication using optic fiber has been widely used. Especially, in the field of medical image, the large data is digitalized based on the standard image and it is used for telemedicine with this method. Therefore, to transfer the large amount of data fast and effectively POF (Plastic Optical Fiber) can be used and the development of optic connector for connection between POFs is very important. In this study, for stable optical coupling of POF optic fiber Ferrule and Sleeve were designed and produced by considering the bond stability and the insertion loss according to the physical contact and roughness profile was evaluated. As a result of examining the insertion loss by physical contact method of two optic fibers, it showed the loss was about 1.895dB. According to the results from studying the condition of grinding section for POF mass production, the mass production condition was established as POF profile roughness of 6nm and the loss of 0.2dB or lower by controlling the film size and time step by step.

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.

최근의 철도차량은 안전성 향상 및 승객에의 멀티미디어 서비스 제공을 위해 광대역 열차통신네트워크를 설치하고 있다. 플라스틱 광섬유(POF)는 일반 광섬유에 비해 직경이 크고 내구성 및 유지보수성이 우수하기 때문에, 진동 및 온도변화가 큰 환경에서 운행하는 철도차량에 적합하다. 이에 따라, 철도차량내 모든 장치를 POF를 이용하여 All-IP 방식으로 접속하는 1Gbps급 열차통신네트워크를 구현하기 위한 연구를 수행하였다. 한국철도규격에 의거한 특성 시험을 통하여 POF가 철도차량의 진동 및 온도변화 환경에 적합하다는 것을 확인하였으며, POF 인터페이스를 갖는 전용의 Layer-2 스위치를 개발하였다. 개발된 Layer-2 스위치와 POF를 이용하여 시운전중인 도시철도차량에 1Gbps급 열차통신네트워크를 구성하고 데이터 전송률과 손실률을 측정하여 성능을 검증하였다. POF는 경제성도 우수하며, 향후 철도차량용 통신네트워크는 POF 기반으로 광대역화될 것으로 기대된다. Recent trains have broadband train communication networks to improve train operation safety and to provide passengers with multimedia services. Compared to glass optical fiber, plastic optical fiber (POF) has a large diameter; it also provides the good durability and maintainability necessary to railway applications. This paper suggests an All-IP broadband train communication network that connects all devices in the train through a POF interface. Performance tests according to Korean railroad standards shows that this POF interface is usable in the range of vibration and temperature conditions encountered in trains. A dedicated Layer-2 switch with the POF interface is developed for the construction of the All-IP train communication network. A prototype 1Gbps train communication network was set up in a trial-run of train on a metro line using the developed Layer-2 switch and POF. On-track tests indicated the feasibility of the POF train communication network. POF has an additional advantage of economic feasibility, and it is expected to start a trend toward broadband train communication networks using POF.

Soil moisture has an essential role in agriculture. The growth of specific vegetation requires a certain level of soil moisture. Therefore, monitoring soil moisture is very important for farmers. In monitoring, the first essential component is the sensor. Nevertheless, the existing proper soil moisture sensor is an electric-based system sensor with low water resistance. It easily damaged in extreme environments which can reduce sensor ability. Based on these problems, we developed a soil moisture sensor based on plastic optical fibre with a U-bend structure. Optical fibre was developed as an alternative sensor due to low prices, immunity to water, and resistance to extreme conditions. U-bend optical fibre can measure soil moisture depends on changes in the refractive index. The changes of refractive index caused by changes in external force which causes a decrease in the optical fibre output power are following the concentration of water contained in the soil. Plastic material is used because of its high durability and high responsiveness in refractive index-based measurements. In this experiment, a plastic optical fibre with a U-bend radius of 30 mm and a wavelength of 930 nm is used. The result shows that the U-Bend structure plastic optical fibre sensor is highly potential to use as a soil moisture sensor with sensor sensitivity of 2.885x10 W/%VWC, R of 97.14%, and standard deviation of 0.6%.

The paper reports the numerical analysis and some experimental results relative to an optical sensor system based on Surface Plasmon Resonance (SPR) at the interface of a liquid sample and a sandwiched structures realized starting from the exposed core of a Plastic Optical Fiber (POF). The advantages of POF sensors is that they are simpler to manufacture than those based on silica optical fibers. In the scientific literature there are only simple POF sensors based on laterally polished bent structures prepared along a plastic optical fiber [1]. In this paper different POF sensor configurations are simulated and experimentally tested. The classical geometry of sensors based on SPR in silica optical fiber is adapted and borrowed for Plastic Optical Fibers [2], so representing a simple approach to low cost plasmonic sensing.

Raman distributed optical fiber sensing has the unique ability to measure the spatially distributed profile of temperature that are of great interest to numerous field applications. However, the sensing performance is severely limited by the signal-to-noise ratio (SNR). The existing SNR enhancement schemes have drawbacks such as increased system complexity, degradation of sensor performance metrics such as spatial resolution, poor denoising performance, etc. Here, we report the Raman residual composite dual-convolutional neural network (RRCDNet), a novel convolutional neural network-based denoising model for one-dimensional signals specifically tailored to Raman distributed fiber sensing. The RRCDNet-enhanced Raman distributed fiber sensor system dramatically improves the temperature precision by more than a factor of 100, from 7.57°C to 0.06°C, without hardware modification or degradation of other performance metrics. At the same time, RRCDNet can also enhance other optical fiber sensor systems with one-dimensional signals, such as Rayleigh and Brillouin sensing systems.

An optical actuator has some interesting characteristics, such as no generation of magnetic noise and receiving the energy remotely. A novel micromanipulator using photothermal effect is proposed. It consists of three optical fibers. One end of the fiber is cut for a bevel and painted with black color. A photothermal effect is occurred responding to the incident beam at the end of optical fiber. This effect makes the end of fiber stretching vibration. It can release a ball with 2.5 mm of diameter and a microlens currently held by light energy. The mechanism of photothermal vibration is also studied.

Astronomical instruments with hundreds of optical fibers are increasingly common in the setup of the modern telescopes. Multi-fibers connectors assure precise connection among several optical fibers, providing flexibility for instrument exchanges. In fact, highly multiplexed instruments require a fiber connector system that can deliver excellent optical performance and reliability. In this paper, we present a multi-fiber connector developed to assure strong and accurate connection. MULEC is a multi-fibers connector where each fiber end, suitably polished, is coupled at a microlens such that the beam of light from one end of the optical fiber can be collimated and then, focused by another microlens coupled with another optical fiber end. Given the optical magnification inferred by the microlens, the optical accuracy of the coupling is significantly increased. MULEC is easy to coupling using powerful micro magnets and also, has devices for adjustment in x, y, z and rotation. The optical fiber arrangements on both sides of the connector are constructed with a special dark composite, made with refractory oxide, which is able to sustain its polishing with minimum quantities of abrasives during the polishing process. In other words, when in polishing, the detachment of the refractory oxide nanoparticles reinforces gently the polishing process and increases the efficiency of this procedure. The bench tests with these connector systems will be implemented in a near future and the chosen fibers should measure the throughput of light and the stability after many connections and disconnections. In this paper, we describe some optical features and mechanical details.