The Application of Pseudo-Random Sequence in the Properties Measurement of Polymer Optical Fiber

2013 ◽  
Vol 313-314 ◽  
pp. 653-657
Author(s):  
Yan Chun Wang ◽  
Chang Wei Sun
Keyword(s):  
Optical Fiber ◽  
Output Signal ◽  
Signal To Noise Ratio ◽  
Random Sequence ◽  
Measuring Method ◽  
Optical Signal ◽  
Polymer Optical Fiber ◽  
Photoelectric Conversion ◽  
Noise Interference ◽  
Labview Software

A new method for the properties measurement of polymer optical fiber (POF) using pseudo-random sequence is introduced. The light source modulated by pseudo-random sequence is injected into the POF. The output optical signal after photoelectric conversion is made the correlation detection with pseudo-random sequence, and finally the correlation operation is carried out based on Labview software. Because pseudo-random sequence performs well on randomicity and it has the correlation properties similar to that of white noise, interference and noise have little influence on the peak of correlation function during the measurement, and the signal-to-noise ratio (SNR) of the output signal can be improved obviously. The measuring method is studied both theoretically and experimentally. Experimental results show that the SNR of the output signal can be improved by 25~40dB for the signal with SNR-15dB to 6dB, and the measuring precision is improved by this method.

scholarly journals Microdrilled tapers to enhance optical fiber lasers for sensing

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. A. Perez-Herrera ◽  
M. Bravo ◽  
P. Roldan-Varona ◽  
D. Leandro ◽  
L. Rodriguez-Cobo ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Fiber Lasers ◽  
Signal To Noise Ratio ◽  
Power Level ◽  
Single Mode ◽  
Optical Signal ◽  
Single Mode Fiber ◽  
Output Power Level ◽  
Linear Cavity

AbstractIn this work, an experimental analysis of the performance of different types of quasi-randomly distributed reflectors inscribed into a single-mode fiber as a sensing mirror is presented. These artificially-controlled backscattering fiber reflectors are used in short linear cavity fiber lasers. In particular, laser emission and sensor application features are analyzed when employing optical tapered fibers, micro-drilled optical fibers and 50 μm-waist or 100 μm-waist micro-drilled tapered fibers (MDTF). Single-wavelength laser with an output power level of about 8.2 dBm and an optical signal-to-noise ratio of 45 dB were measured when employing a 50 μm-waist micro-drilled tapered optical fiber. The achieved temperature sensitivities were similar to those of FBGs; however, the strain sensitivity improved more than one order of magnitude in comparison with FBG sensors, attaining slope sensitivities as good as 18.1 pm/με when using a 50 μm-waist MDTF as distributed reflector.

scholarly journals Hybrid Integrated Nanophotonic Silicon-based Structures

2019 ◽  
Vol 29 (4) ◽  
pp. 481
Author(s):  
Thi Hong Cam Hoang ◽  
Thanh Binh Pham ◽  
Thuy Van Nguyen ◽  
Van Dai Pham ◽  
Huy Bui ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Fiber Laser ◽  
Limit Of Detection ◽  
Signal To Noise Ratio ◽  
Optical Signal ◽  
Integrated System ◽  
Laser Structure ◽  
Wavelength Shift ◽  
On Chip ◽  
Silicon Based

We report nanophotonic silicon-based devices for hybrid integration: 1D photonic crystal (PhC) on optical fiber, i. e. fiber Bragg grating (FBG) sensing probe integrated in fiber laser structure for chemical sensors and slotted planar 2D PhC cavity combined with carbon nanotube (CNT) towards light nanosources. The experiments have been carried out by integrating 1D PhC on optical fiber in fiber laser structure. This structure possesses many advantages including high resolution for wavelength shift, high optical signal-to-noise ratio (OSNR) of about 50~dB, the small full width at half-maximum (FWHM) of about 0.014~nm therefore its accuracy is enhanced, as well as the precision and capability are achieved for remote sensing. Low nitrate concentration in water from 0 to 80 ppm has been used to demonstrate its sensing ability in the experiment. The proposed sensor can work with good repeatability, rapid response, and its sensitivity can be obtained of \(3.2\times 10^{ - 3}\) nm/ppm with the limit of detection (LOD) of 3~ppm. For 2D PhC cavity, enhancement of photoluminescence of CNT emission is observed. The semiconducting single-walled carbon nanotubes (s-SWNTs) solution was prepared by polymer-sorted method and coupled with the confined modes in silicon slotted PhC cavities. The enhancement ratio of 1.15 is obtained by comparing between the PL peaks at two confined modes of the cavity. The PL enhancement result of the integrated system shows the potential for the realization of on-chip nanoscale sources.

Investigation of Polymer Optical Fiber Drawing Force and Heat Transfer

2003 ◽  
Author(s):  
Hayden M. Reeve ◽  
Ann M. Mescher ◽  
Ashley F. Emery
Keyword(s):  
Heat Transfer ◽  
Optical Fiber ◽  
Thermal Radiation ◽  
Conjugate Problem ◽  
Optical Signal ◽  
Surface Shape ◽  
Drawing Force ◽  
Polymer Optical Fiber ◽  
Draw Force ◽  
Chain Alignment

In this study, the force required to draw a polymer preform into optical fiber is predicted and measured, along with the resultant free surface shape of the polymer, as it is heated in an enclosed cylindrical furnace. The applied drawing force affects the degree of chain alignment within the polymer. Chain alignment causes orientational birefringence, an unwanted property that attenuates any propagating optical signal. The draw force is a function of the highly temperature dependent polymer viscosity. Therefore accurate prediction of the drawing force requires a detailed investigation of the heat transfer within the furnace. In this investigation, the full axi-symmetric conjugate problem (including both natural convection and thermal radiation) was solved using the commercial finite element package FIDAP. In addition, the location of the polymer/air interface was solved for as part of the problem and was not prescribed beforehand. Results show that thermal radiation accounts for approximately 70% of the total heating experienced by the deforming polymer, but only 15% of the cooling. The draw force is very sensitive to both the furnace wall temperature and to the feed rate of the polymer. Numerical results compared well with the experimentally measured draw tension and neck-down profiles for several preform diameters, draw speeds, and furnace temperatures. The predicted draw forces were typically within 20% of the experimentally measured values.

scholarly journals Implementation of Optical Coherent Communication System between Two Computers

2010 ◽  
Vol 7 (1) ◽  
pp. 41-47
Author(s):  
Baghdad Science Journal
Keyword(s):  
Optical Fiber ◽  
Communication System ◽  
Signal To Noise Ratio ◽  
Single Mode ◽  
Local Oscillator ◽  
Optical Signal ◽  
Coherent Detection ◽  
Heterodyne Detection ◽  
Laser Source ◽  
Coherent Communication

This work represents implementation and investigation of optical coherent communication system between two computers. A single mode optical fiber is selected as transmission medium. The data are sent via the RS-232 standard interface with a bit rate of 9.6 kbps from personal computer (PC1) by line receive to convert the data from electrical levels (-12/+12 V) into TTL level (0/5 V). The modulation of this data was accomplished by internal modulation using laser diode type (HFCT-5208M) 1310 nm wavelength. The optical D-coupler was used to combine the optical signal that come from laser source with optical signal of laser local oscillator (OTS-304XI) at 1310/1550 nm wavelength to obtain coherent (homodyne and heterodyne) detection respectively. A PIN photodetector (HFCT-5208M) is used. Calculations of Signal to Noise Ratio (SNR) and Bit Error Rate (BER) for coherent detection were measured at different length of the optical fiber. Result show that high SNR and low BER for heterodyne detection than for homodyne detection.

scholarly journals A Theoretical Study and Numerical Simulation of a Quasi-Distributed Sensor Based on the Low-Finesse Fabry-Perot Interferometer: Frequency-Division Multiplexing

2017 ◽  
Author(s):  
José Trinidad Guillen Bonilla ◽  
Alex Guillén-Bonilla ◽  
Rodríguez-Betancourtt Veronica M. ◽  
Héctor Guillen Bonilla ◽  
Antonio Casillas Zamora
Keyword(s):  
Optical Fiber ◽  
Frequency Domain ◽  
Signal To Noise Ratio ◽  
Single Mode ◽  
Optical Signal ◽  
Single Mode Fiber ◽  
Wavelength Shift ◽  
Distributed Sensors ◽  
Distributed Sensor ◽  
Fabry Perot

The application of the sensors optical fiber in the areas of scientific instrumentation and industrial instrumentation is very attractive due to its numerous advantages. In the industry of civil engineering for example, quasi-distributed sensors made with optical fiber are used for reliable strain and temperature measurements. Here, a quasi-distributed sensor in the frequency domain is discussed. The sensor consists of a series of low-finesse Fabry-Perot interferometers where each Fabry-Perot interferometer acts as a local sensor. Fabry-Perot interferometers are formed by pairs of identical low reflective Bragg gratings imprinted in a single mode fiber. All interferometer sensors have different cavity length, provoking the frequency-domain multiplexing. The optical signal represents the superposition of all interference patterns which can be decomposed using the Fourier transform. The frequency spectrum is analyzed and sensor´s properties were defined. Following, a quasi-distributed sensor was numerically simulated. Our sensor simulation considers sensor properties, signal processing, noise system and instrumentation. The numerical results show the behavior of resolution vs. signal-to-noise ratio. From our results, the Fabry-Perot sensor has high resolution and low resolutions. Both resolutions are conceivable because the FDPA algorithm elaborates two evaluations of Bragg wavelength shift

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