Microdrilled tapers to enhance optical fiber lasers for sensing

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.

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Study of Microbending Loss Single Mode Optic Fiber in Sand Powder Against Pressure

Journal of Technomaterials Physics ◽

10.32734/jotp.v3i1.5549 ◽

2021 ◽

Vol 3 (1) ◽

pp. 65-73

Author(s):

Bambang Widiyatmoko ◽

Mefina Y. Rofianingrum

Keyword(s):

Optical Fiber ◽

Optical Fibers ◽

Voltage Drop ◽

Signal Transmission ◽

Single Mode ◽

Optical Signal ◽

Single Mode Fiber ◽

Mechanical Pressure ◽

Optical Attenuation ◽

Load Sensor

Research has been carried out to further investigate specifically the effect of sand powder, both the size of the sand grains and the thickness of the sand powder on the photodetector output as an advanced study of the single-mode optical fiber microbending loss theory in sand grains to pressure. This was done to investigate the response of optical fibers due to microbending loss to the load and determine the size of the sand particles that are most effectively used as a compiler of load sensors. The principle works to test the response of load sensors based on single-mode fiber optic microbending loss in the form of photodetector output when given a large variety of pressure. The method used in this research is to observe the reduction in the intensity of the light transmitted through optical fibers in the form of a voltage drop that is read by MMD that is connected to the photodetector. The reduced light intensity shows that the load sensor experiences optical attenuation of the laser as a light source with a wavelength of 1550 nm and a power of 1.47 mW. Microbending loss is caused by mechanical pressure that can change the direction of optical signal transmission and the radius of the curve is equal to or less than the diameter of a bare optical fiber. Observations were made using 12 load sensors with variations in the size of the sand grains in each diameter of the hose. The results of this study obtained the size of the most effective grains of sand providing microscopic curvature in the optical fiber that is 0.05 mm in terms of the correlation between the response of sensors with various diameters to changes in pressure.

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

10.20944/preprints201704.0001.v1 ◽

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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Switchable and tunable linear cavity erbium-doped fiber laser based on FBGs embedded in Sagnac rings

Laser Physics ◽

10.1088/1555-6611/ac3512 ◽

2021 ◽

Vol 32 (1) ◽

pp. 015101

Author(s):

Gangxiao Yan ◽

Weihua Zhang ◽

Peng Li ◽

Qiuhao Jiang ◽

Meng Wu ◽

...

Keyword(s):

Fiber Laser ◽

Low Cost ◽

Single Mode ◽

Optical Signal ◽

Single Mode Fiber ◽

Hole Burning ◽

Linear Cavity ◽

Erbium Doped ◽

Optical Fiber Sensing ◽

Birefringence Effect

Abstract A switchable and tunable erbium-doped fiber laser with a linear cavity based on fiber Bragg gratings embedded in Sagnac rings is proposed and experimentally verified. Due to the stress birefringence effect and the polarized hole burning effect, which are introduced into the single-mode fiber in the polarization controllers (PCs) by the PCs, the designed laser can achieve seven kinds of laser-states output including three kinds of single-wavelength laser states, three kinds of dual-wavelength laser states and one kind of triple-wavelength laser state. The optical signal-to-noise ratios of the output wavelengths are all higher than 52 dB, and the wavelength shifts are all less than 0.04 nm. Furthermore, the temperature tuning of the wavelength range is also researched, which is about 1.2 nm. Due to advantages, such as low cost, simple structure, easy switching and multiple laser states, the designed laser has great application potential in laser radar, optical fiber sensing and so on.

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Dual Polarization-Based Transmitter Configuration Improving Q-Factor for a Single-Mode Fiber Link

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.e7018.018520 ◽

2020 ◽

Vol 8 (5) ◽

pp. 4286-4289

Keyword(s):

Optical Fibers ◽

Power Level ◽

Phase Variation ◽

Single Mode ◽

Single Mode Fiber ◽

Spectrum Efficiency ◽

Q Factor ◽

Nonlinear Optical Effect ◽

Communication Range ◽

Fiber Link

The requirement of the modern application is to transmit wide bandwidth of signal with the low latency. The optical fibers provide wide transmission bandwidth along with very little delay as well as choice on choosing transmission medium for high data rate. However, Stimulated Brillouin Scattering (SBS) is a nonlinear optical effect that restricts power level into a fiber to few milliwatts. It degrades the Q-factor and consequently the bit error rate of an optical fiber link. For suppression of SBS, various approaches have been used previously such as PSK, ASK, FSK, CSRZ-DQPSK etc. Among all the previous techniques, CSRZ-DQPSK transmitter is considered as the most efficient one for suppression of SBS. However, it consists of some drawbacks such as low spectrum efficiency, susceptibility to phase variation and short communication range, due to which requirement arises of upgrading the previous work. Therefore, in the proposed work (i.e. CSRZ-DP-QPSK), DP-QPSK scheme is used which makes the system more efficient as it has high spectrum efficiency and improved sensitivity. Also, the communication range is elongated in present work. The performance evaluation of CSRZ-DP-QPSK approach has been performed in terms of Q-Factor, BER, and threshold. Also, the comparative analysis of the proposed approach with conventional approaches has been performed and from the obtained results it has been demonstrated that proposed work is more efficient than conventional one as it has better SBS tolerance and improved BER.

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Efficient Blind Adaptive CSE to Reduce Cyclic Prefix Length in Direct Detection Optical OFDM Systems

Journal of Optical Communications ◽

10.1515/joc-2018-0165 ◽

2019 ◽

Vol 0 (0) ◽

Author(s):

Asmaa Benieddi ◽

Sid Ahmed Elahmar

Keyword(s):

Orthogonal Frequency Division Multiplexing ◽

Direct Detection ◽

Group Velocity Dispersion ◽

Signal To Noise Ratio ◽

Single Mode ◽

Optical Signal ◽

Single Mode Fiber ◽

Cyclic Prefix ◽

Ofdm Systems ◽

Blind Adaptive

AbstractDirect detection optical orthogonal frequency division multiplexing (DDO-OFDM) systems for a long-reach of standard single mode fiber (SSMF) require a large length of cyclic prefix (CP) to avoid the inter-symbol interference (ISI) effect caused by group velocity dispersion (GVD). Unfortunately, this method is inefficient due to the energy wasted in CP samples. In order to reduce the CP length and to mitigate the residual ISI, a novel blind adaptive channel shortening equalizer (CSE) is proposed in this paper. Based on the orthogonality between subcarriers in the fast Fourier transform (FFT) property, the proposed algorithm attempts to minimize the sum-squared correlation (SSCM) between each sample located in a well-defined window to update the CSE coefficients. Thus, the combined channel-CSE response is shortened. Therefore, it can cancel the residual ISI effect due to the GVD and the short CP length. The performance of the system is evaluated on basis of bit error rate (BER) versus optical signal to noise ratio (OSNR) for different CP lengths. The simulation results validate the new algorithm SSCM and show that it can reduce the CP length with a much better system improvement than existing algorithms.

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Hybrid Raman-Erbium Random Fiber Laser with a Half Open Cavity Assisted by Artificially Controlled Backscattering Fiber Reflectors

10.21203/rs.3.rs-192136/v1 ◽

2021 ◽

Author(s):

R. A. Perez-Herrera ◽

P. Roldan-Varona ◽

M. Galarza ◽

S. Sañudo-Lasagabaster ◽

L. Rodriguez-Cobo ◽

...

Keyword(s):

Fiber Laser ◽

Output Power ◽

Signal To Noise Ratio ◽

Power Level ◽

Laser Cavity ◽

Gain Medium ◽

Optical Signal ◽

Open Cavity ◽

Output Power Level ◽

Erbium Doped

Abstract A hybrid Raman-erbium random fiber laser (RFL) with a half-open cavity assisted by chirped artificially controlled backscattering fiber reflectors (ACBFRs) is presented. A combination of 2.4 km of dispersion compensating fiber (DCF) with two highly erbium-doped fiber (EDF) pieces of 5 m length was used as gain medium. A single random laser emission line centered at 1553.8 nm with an output power level of -6.5 dBm and an optical signal to noise ratio (OSNR) of 47 dB was obtained when pumped at 37.5 dBm. A full width at half maximum (FHWM) of 1 nm and a 100% confidence level (CL) output power instability as low as 0.08 dB were measured. The utilization of the new laser cavity as a temperature and strain sensor is also experimentally studied.

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Carrier-Assisted Phase Retrieval

10.36227/techrxiv.17170814 ◽

2021 ◽

Author(s):

Qi Wu

Keyword(s):

Phase Retrieval ◽

Forward Error Correction ◽

Signal To Noise Ratio ◽

Single Mode ◽

Local Oscillator ◽

Optical Signal ◽

Single Mode Fiber ◽

Critical Parameters ◽

Hardware Complexity ◽

Full Field

Phase-retrieval (PR) schemes based on the modified Gerchberg-Saxton (GS) algorithm capture the full-field employing a dispersive element and intensity-only measurements to eliminate the use of a local oscillator. In this work, we propose two carrier-assisted PR schemes, namely central carrier-assisted PR (CCA-PR) and edge carrier-assisted PR (ECA-PR), to improve the comprehensive performance of PR receiver in terms of convergence speed, redundancy, and computational complexity. The proposed CCA-PR recovers the electrical field employing a reference carrier at 0 GHz with several iterations between two projection planes. It avoids pilot symbols and digital backpropagation to the transmitter and offers a flexible electrical bandwidth requirement compared with conventional PR schemes. To lower the carrier-to-signal power ratio (CSPR) requirement and enable faster convergence for the carrier-assisted PR schemes, the ECA-PR is proposed to obtain the initial phase for the GS algorithm. We numerically characterize the performance of the two schemes and experimentally demonstrate them for 30 GBaud 16-quadrature amplitude modulation (16-QAM) transmission over 80 km single-mode fiber with a bit error rate (BER) below the threshold of 7% hard-decision forward error correction (HD-FEC). Several critical parameters are analyzed, including the applied dispersion value, CSPR, and electrical bandwidth. Moreover, we compare the hardware complexity and optical signal-to-noise ratio (OSNR) sensitivity of proposed PR schemes with mainstream field recovery schemes.

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Analysis of secured Optical Orthogonal Frequency Division Multiplexed System

Journal of Optical Communications ◽

10.1515/joc-2016-0075 ◽

2017 ◽

Vol 38 (2) ◽

Cited By ~ 1

Author(s):

Harsimranjit Singh Gill ◽

Kamaljit Singh Bhatia ◽

Sandeep Singh Gill

Keyword(s):

Signal To Noise Ratio ◽

Average Power ◽

Single Mode ◽

Optical Signal ◽

Data Encryption ◽

Single Mode Fiber ◽

Frequency Division ◽

Ofdm Systems ◽

Ofdm Signal ◽

Coded Ofdm

AbstractIn this paper, security issues for optical orthogonal frequency division multiplexed (OFDM) systems are emphasized. The encryption has been done on the data of coded OFDM symbols using data encryption standard (DES) algorithm before transmitting through the fiber. The results obtained justify that the DES provides better security to the input data without further bandwidth requirement. The data is transmitted to a distance of 1,000 km in a single-mode fiber with 16-quadrature amplitude modulation. The peak-to-average power ratio and optical signal-to-noise ratio of secure coded OFDM signal is fairly better than the conventional OFDM signal.

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

Sensors ◽

10.3390/s18124150 ◽

2018 ◽

Vol 18 (12) ◽

pp. 4150 ◽

Cited By ~ 1

Author(s):

Soongho Park ◽

Sunghwan Rim ◽

Ju Kim ◽

Jinho Park ◽

Ik-Bu Sohn ◽

...

Keyword(s):

Optical Fiber ◽

Optical Fibers ◽

Single Mode ◽

Spot Size ◽

Single Mode Fiber ◽

Fiber Probe ◽

Optical Fiber Probe ◽

Working Distance ◽

Physical Sensing ◽

Fabrication Parameters

A method for adjusting the working distance and spot size of a fiber probe while suppressing or enhancing the back-coupling to the lead-in fiber is presented. As the optical fiber probe, a lensed optical fiber (LOF) was made by splicing a short piece of coreless silica fiber (CSF) on a single-mode fiber and forming a lens at the end of the CSF. By controlling the length of the CSF and the radius of lens curvature, the optical properties of the LOF were adjusted. The evolution of the beam in the LOF was analyzed by using the Gaussian ABCD matrix method. To confirm the idea experimentally, 17 LOF samples were fabricated and analyzed theoretically and also experimentally. The results show that it is feasible in designing the LOF to be more suitable for specific or dedicated applications. Applications in physical sensing and biomedical imaging fields are expected.

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Tunable Linear Fiber Laser Cavity Based on a Twisted Mechanical Long Period Grating

Revista Mexicana de Física ◽

10.31349/revmexfis.64.615 ◽

2018 ◽

Vol 64 (6) ◽

pp. 615

Author(s):

Julian Moises Estudillo-Ayala

Keyword(s):

Fiber Laser ◽

Laser Emission ◽

Signal To Noise Ratio ◽

Laser Cavity ◽

Single Mode ◽

Optical Signal ◽

Long Period Grating ◽

Dual Emission ◽

Linear Cavity ◽

Long Period

The present manuscript shows linear cavity fiber laser experimental analysis. The fiber laser arrangement, use an all fiber mechanical long period grating (MLPG) to control single and dual laser emission. Here, single laser emission centered at 1562nm with a signal to noise ratio of 27dB and a linewidth less than 0.1nm is obtained and tuned from 1562nm to 1546nm, by twisted a conventional section of single mode fiber that was set into the MLPG. Thus, when the twist is around 120º dual emission is obtained with centered wavelengths at 1533nm and 1546nm, these emissions can be switched between them when the twist is incremented and the peak centered at 1546nm is tuned in backward direction. The proposed laser offers wavelength and power stability with minimal variations of 0.5dB and 0.5nm respectively. This laser can be applied in several fields such as sensing, optical signal analysis and optical communications.

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