Articles Copyright (c) 2013 Dublin Institute of Technology All rights reserved. http://arrow.dit.ie/engscheceart Recent documents in Articles en-us Tue, 21 May 2013 01:06:18 PDT 3600 Investigation and Experimental Measurement of Scissor Blade Cutting Forces Using Fiber Bragg Grating Sensors. http://arrow.dit.ie/engscheceart/124 http://arrow.dit.ie/engscheceart/124 Fri, 30 Nov 2012 05:01:21 PST This paper investigated the application of FBG sensors in the measurement of scissor blade–tissue interaction forces. Sensor placement at the blade–tissue interaction site provides the basis for increased force measurement accuracy, without compromising the functionality of the instrument. This increased accuracy provided the foundation for in-depth analysis of the force components generated during typical scissor cutting cycles. Theoretical analysis and experimental investigation explored the decoupling of the major forces present during cutting. The isolation of tissue-fracture forces from inter-blade friction forces was carried out. This is useful as knowledge of the fracture properties of biological tissues can be diff cult to obtain. Moreover, the force information obtained can be ref ected to the user in a telerobotic application ensuring a greater sense of user immersion. Scissor cutting force data is of particular relevance to those involved in the development of soft tissue models for medical simulation systems. The motivation behind this work is to develop a smart surgical instrument capable of unobtrusively, and with minimal impact on instrument functionality, detecting tissue– instrument interaction forces. Future work will involve the miniaturization of the current technique enabling the development of a laparoscopic prototype instrument capable of acquiring in vivo force and material fracture properties

]]> Dean Callaghan et al. Investigation of Polarization Dependent Loss for a Macrobending Loss http://arrow.dit.ie/engscheceart/123 http://arrow.dit.ie/engscheceart/123 Wed, 21 Nov 2012 04:34:52 PST An investigation of the polarization dependent loss (PDL) of macrobending
loss sensitive single fiber (1060XP) is presented theoretically and experimentally. The
experimental results are in good agreement with the modeling outcomes. Through the
comparison of experimental results of PDL between 1060XP fiber with coatings and
bare 1060XP fiber, it is shown that the fiber coating has significant impact on the PDL
of bend loss sensitive singlemode fiber

]]> Pengfei Wang A Fiber-Optic Voltage Sensor Based on Macrobending Structure http://arrow.dit.ie/engscheceart/122 http://arrow.dit.ie/engscheceart/122 Mon, 12 Nov 2012 10:46:43 PST We propose and demonstrate an optical voltage sensing scheme based on a macrobending optical fiber in a ratiometric power measurement system. This novel approach to sensing has not been utilized before and has the advantage that the sensor involves simple fabrication compared to existing fiber-optic voltage sensors. To prove the feasibility of such a fiber-optic sensor, a sensor for a voltage range from 0 similar to 100 V is demonstrated, with a resolution of 0.5 V. The sensor is robust, linear, and shows a competitive measurement resolution. The sensor can be easily scaled to suit other voltage levels and be effectively combined with optical current sensors.

]]> Pengfei Wang et al. A Simple Ultrasensitive Displacement Sensor Based on a High Bend Loss Single-Mode Fibre and a Ratiometric Measurement System http://arrow.dit.ie/engscheceart/121 http://arrow.dit.ie/engscheceart/121 Mon, 12 Nov 2012 10:46:42 PST An all-fibre displacement sensor with a simple configuration and capable of monitoring sub-50 nm displacements is proposed and investigated experimentally. The proposed fibre displacement sensor consists of a half-loop structure of bare high bend loss single-mode fibre 1060XP and a ratiometric power interrogation system. By measuring the change in transmission ratio in the ratiometric system, a change in displacement can be measured. The displacement sensor is sensitive to temperature and an experimental investigation of this sensitivity is presented. It is found that the peak shift response has a linear variation with temperature; therefore, temperature dependence can be mitigated by a suitable displacement correction process. The proposed macrobending fibre based displacement sensor benefits from simplicity and low cost and achieves a comparable resolution as compared with other conventional fibre optic sensors.

]]> Pengfei Wang et al. Chalcogenide Microsphere Fabricated from Fiber Tapers Using Contact With a High-Temperature Ceramic Surface http://arrow.dit.ie/engscheceart/120 http://arrow.dit.ie/engscheceart/120 Mon, 12 Nov 2012 10:46:40 PST The fabrication 1 and characterization of a 2 chalcogenide glass microsphere resonator has been demonstrated. 3 At wavelengths near 1550 nm, whispering gallery mode 4 resonances can be efficiently excited in a 74-μm-diameter 5 chalcogenide glass microsphere via evanescent coupling using a 6 tapered silica glass fiber with a waist diameter of circa 2 μm. 7 Resonances with Q-factors greater than 105 were observed. 8 Due to the high nonlinearity properties of the chalcogenide 9 material and the ease of fabrication process, chalcogenide 10 microspheres offer the potential for robustly assembled fully 11 integrated photonic devices. 12 Index Terms—Chalcogenide

]]> Pengfei Wang et al. Enhanced Refractometer Based on Periodically Tapered Small Core Singlemode Fiber http://arrow.dit.ie/engscheceart/119 http://arrow.dit.ie/engscheceart/119 Mon, 12 Nov 2012 10:46:39 PST Abstract—An all-fiber 1 refractive index (RI) sensor with a 2 simple configuration of periodical tapers is proposed and inves3 tigated experimentally. The proposed fiber RI sensor consists of 4 a small core fiber sandwiched between two standard singlemode 5 fibers, with tapers periodically fabricated along the small core 6 fiber using a focused CO2 laser beam. Such a structure can be 7 used for RI sensing by measuring the dip wavelength shift of 8 the multimode interference within the small core fiber cladding. 9 An average sensitivity of 226.6 nm/RIU (RI Unit) has been 10 experimentally achieved in the RI range from 1.33 to 1.38. The 11 refractometer is sensitive to temperature and an experimental 12 investigation of this sensitivity is presented. It is found that the 13 peak shift response has a linear variation with temperature; 14 therefore, temperature dependence can be mitigated by a suitable 15 RI correction process. The proposed RI sensor benefits from 16 simplicity and low cost and achieves a competitive sensitivity 17 compared with other existing fiber-optic sensors.

]]> Pengfei Wang et al. High Temperature Performance of an Optical Microfibre Coupler and Its Potential Use as a Sensor http://arrow.dit.ie/engscheceart/118 http://arrow.dit.ie/engscheceart/118 Mon, 12 Nov 2012 10:46:38 PST The dependence of the transmission spectrum of an optical microfibre coupler at high temperatures is investigated experimentally. Results show a temperature sensitivity up to 36.59 pm/oC at a taper waist outer diameter of 2.5 μm; such a temperature-dependent performance can be utilized for temperature sensing up to 1000oC.

]]> Pengfei Wang et al. High-Q Bismuth-Silicate Nonlinear Glass Microsphere Resonators http://arrow.dit.ie/engscheceart/117 http://arrow.dit.ie/engscheceart/117 Mon, 12 Nov 2012 10:46:36 PST The fabrication and characterization of a bismuth-silicate glass microsphere resonator has been demonstrated. At wavelengths near 1550 nm, high-modes can be efficiently excited in a 179-μm diameter bismuth-silicate glass microsphere via evanescent coupling using a tapered silica fiber with a waist diameter of circa 2 μm. Resonances with Q-factors as high as were observed. The dependence of the spectral response on variations in the input power level was studied in detail to gain an insight into power-dependent thermal resonance shifts. Because of their high nonlinearity and high- factors, bismuth-silicate glass microspheres offer the potential for robustly assembled fully integrated all-optical switching devices.

]]> Pengfei Wang et al. A High Sensitivity, Evanescent Feld Refractometric Sensor Based on Tapered Multimode Fiber Interference http://arrow.dit.ie/engscheceart/116 http://arrow.dit.ie/engscheceart/116 Mon, 12 Nov 2012 08:11:36 PST We propose and experimentally demonstrate an enhanced evanescent field fiber refractometer based on a tapered multimode fiber sandwiched between two single-mode fibers. Experiments show that this fiber sensor offers ultrahigh sensitivity [better than 1900 nm/RIU at a refractive index (RI) of 1.44] for RI measurements within the range of 1.33–1.44 , in agreement with the theoretical predictions. This is the highest value reported to date (to our knowledge) in the literature.

]]> Pengfei Wang et al. Lead Silicate Glass Microsphere Resonators With Absorption-Limited Q http://arrow.dit.ie/engscheceart/115 http://arrow.dit.ie/engscheceart/115 Mon, 12 Nov 2012 08:11:34 PST We report the fabrication and characterization of a lead-silicate glass microsphere resonator. We show that at the wavelengths near 1555 nm high Q modes can be efficiently excited from a 109 μm diameter lead-silicate glass microsphere via evanescent coupling using a tapered silica fiber with a waist diameter of 2 μm. Resonances with Q-factors as high as 0.9×107 were observed. This is very close to the theoretical material-limited Q-factor and is the highest Q-factor reported so far from a nonlinear glass microsphere.

]]> Pengfei Wang et al. Investigation of Singlemode-Multimode-Singlemode and Singlemode-Tapered Multitmode-Singlemode Fibre Structures and Their Application for Refractive Index Sensing http://arrow.dit.ie/engscheceart/114 http://arrow.dit.ie/engscheceart/114 Mon, 12 Nov 2012 08:11:33 PST All-fiber in-line single-mode–multimode–single-mode (SMS) and single-mode–tapered-multimode–single-mode (STMS) fiber structures are investigated. A wide-angle beam propagation method in cylindrical coordinates is developed and employed for numerical simulations of the light propagation performance of such fiber devices. The effect of strong mode interference on the performance of the devices is studied and verified numerically; results indicate that the proposed STMS structure can be exploited for measuring a broad refractive index range with reasonable high resolution, compared with the conventional SMS structure.

]]> Pengfei Wang et al. Digital Camera Photographing in Measuring Propagation Loss Properties of Ion2exchange Planar Optical Waveguides http://arrow.dit.ie/engscheceart/113 http://arrow.dit.ie/engscheceart/113 Mon, 12 Nov 2012 08:11:32 PST

The digital photographs of propagation lines of ion-exchange planar glass optical waveguides were taken by a common digital camera.According to the profile of light intensity of propagation lines,the attenuation curves were fitted and the propagation losses of the waveguides were calculated.The waveguides were treated by annealing process,and propagation losses properties were studied before and after annealing,respectively.The results show that the loss of waveguide increases with the mode.The loss in 0 mode decreases from 2.148 9 dB·cm－1 to 0.746 0 dB·cm－1.

]]> Ling-Hua Jia et al. Macrobending Fiber Loss Filter, Ratiometric Wavelength Measurement and Application http://arrow.dit.ie/engscheceart/112 http://arrow.dit.ie/engscheceart/112 Mon, 12 Nov 2012 08:11:30 PST A macrobending standard single-mode fibre (SMF28) is optimized as an edge filter, with the optimal bending radius and length determined according to the bend loss and polarization sensitivity of the bending fibre. An all-fibre ratiometric wavelength system is built and calibrated. The system's accuracy and resolution is discussed with the influence of noise of input signal and photodetectors. Finally, the ratiometric system is employed for the demodulation of FBG strain sensing.

]]> Qian Wang et al. Polarisation Dependence of Bend Loss for a Standard Singlemode Fiber http://arrow.dit.ie/engscheceart/111 http://arrow.dit.ie/engscheceart/111 Mon, 12 Nov 2012 08:11:29 PST Polarization dependence of bend loss caused by the polymer coating layer for a standard singlemode fiber (SMF28) is investigated theoretically and experimentally. Bend loss for SMF28 for both the TE and TM mode is calculated separately. Normalized polarization dependent loss is proposed for the characterization of the polarization sensitivity of bend loss for different bend radii. Corresponding experimental tests are presented, which agree with the theoretical results. Both the theoretical and experimental results show that the polymer coating layer has a significant influence on the polarization dependence of bend loss.

]]> Qian Wang et al. Low-Cost Wavelength Measurement based on a Macrobending Single-mode Fiber http://arrow.dit.ie/engscheceart/110 http://arrow.dit.ie/engscheceart/110 Mon, 12 Nov 2012 08:11:28 PST A low-cost all-fiber wavelength measurement technique is proposed and demonstrated. A macrobending standard single-mode fiber is developed as an edge filter with an optimal design and simple surface processing. A ratiometric wavelength measurement system employing the developed macrobending fiber filter demonstrates a resolution of∼10 pmin a wavelength range from1500to1560 nmwith ease of assembly and calibration.

]]> Qian Wang et al. A Microfiber Coupler Tip Thermometer http://arrow.dit.ie/engscheceart/109 http://arrow.dit.ie/engscheceart/109 Mon, 12 Nov 2012 05:46:20 PST A compact thermometer based on a broadband microfiber coupler tip is demonstrated. This sensor can measure a broad temperature interval ranging from room temperature to 1283 degrees C with sub-200 mu m spatial resolution. An average sensitivity of 11.96 pm/degrees C was achieved for a coupler tip with similar to 2.5 mu m diameter. This is the highest temperature measured with a silica optical fiber device. (C)2012 Optical Society of America

]]> Ming Ding et al. Evanescent Field Coupling Between Two Parallel Close Contact SMS Fiber Structures http://arrow.dit.ie/engscheceart/108 http://arrow.dit.ie/engscheceart/108 Mon, 12 Nov 2012 05:46:19 PST We proposed a novel optical coupling technique based on two parallel singlemode-multimode- singlemode (SMS) fiber structures. This technique utilizes one SMS structure to excite multiple cladding modes within an output singlemode fiber. The excited multiple cladding modes will be coupled to the input SMF in the second SMS structure by placing the two SMS fiber structures in parallel and in close contact each other. The coupled cladding modes will be re-coupled to a guided core mode by the second SMS fiber structure. Theoretical analysis for such technique was provided and experimentally we have achieved a pass band spectral response with an extinction ratio higher than 20 dB and a maximum coupling efficiency of 5.9%.

]]> Qiang Wu et al. Germanium Microsphere High-Q Resonator http://arrow.dit.ie/engscheceart/107 http://arrow.dit.ie/engscheceart/107 Mon, 12 Nov 2012 05:46:18 PST In this Letter, the fabrication and characterization of a microsphere resonator from the semiconductor germanium is demonstrated. Whispering gallery modes are excited in a 46 μm diameter germanium microsphere resonator using evanescent coupling from a tapered silica optical fiber with a waist diameter of 2 μm. Resonances with Q factors as high as 3.8×104 at wavelengths near 2 μm are observed. Because of their ultrahigh optical nonlinearities and extremely broad transparency window, germanium microsphere resonators offer the potential for optical processing devices, in particular at long wavelengths, such as around 2 μm.

]]> Pengfei Wang et al. The Use of a Fiber Comb Filter Fabricated By a CO2 Laser Irradiation to Improve the Resolution of a Ratiometric Wavelength Measurement System http://arrow.dit.ie/engscheceart/106 http://arrow.dit.ie/engscheceart/106 Mon, 12 Nov 2012 05:46:17 PST An edge filter-based ratiometric wavelength measurement system is modeled and analyzed in this paper. The results confirm that the noise of input signal and photodetectors limits the resolution of the wavelength measurement system. The achievable resolution is calculated for a given noise level of the input signal and photodetectors' resolution. An improved ratiometric wavelength measurement system consisting of two fiber comb filters is presented both theoretically and experimentally, which performs coarse and fine wavelength measurements simultaneously. The resolution of the system is significantly improved to better than 5 pm while maintaining the potential for high measurement speed and wide measurable wavelength range.

]]> Pengfei Wang et al. Light Coupling Between a Singlemode-Multimode-Singlemode (SMS) Fiber Structure and a Long Period Fiber Gating http://arrow.dit.ie/engscheceart/105 http://arrow.dit.ie/engscheceart/105 Mon, 12 Nov 2012 05:46:16 PST We propose a novel optical coupling technique based on evanescent field coupling between a singlemode-multimode-singlemode (SMS) fiber structure and a long period fiber grating (LPFG). By parallel placement of the two fiber sections in close proximity to each other, the excited multi-cladding modes from the SMS fiber section can be selectively coupled to the guided mode in the LPFG, and vice versa. A theoretical analysis based for such a structure is undertaken and the simulated results are verified by experiments demonstrating a maximum coupling efficiency of up to 1.66% (which could be improved to 27.5% in theory) over a broadband resonance (42 nm with a 3 dB bandwidth).

]]> Qiang Wu et al.