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10 pages, 2364 KiB

Open AccessArticle

Spectral Self-Compression of Chirp-Free Pulses in Anomalously Dispersive Optical Fibers

by Minas Sukiasyan, Vardan Avetisyan and Aghavni Kutuzyan

Photonics 2023, 10(11), 1207; https://doi.org/10.3390/photonics10111207 - 29 Oct 2023

Viewed by 866

Abstract

In this work, we demonstrated, both experimentally and numerically, the existence of a chirp-free pulse propagation regime within a standard single-mode fiber. We found numerically that the pulse spectrum can undergo self-compression by more than a hundredfold, resulting in the creation of a [...] Read more.

In this work, we demonstrated, both experimentally and numerically, the existence of a chirp-free pulse propagation regime within a standard single-mode fiber. We found numerically that the pulse spectrum can undergo self-compression by more than a hundredfold, resulting in the creation of a spectrally limited pulse. In this regime, we experimentally achieved a 5× spectral self-compression, reducing the spectral width from 75 nm to 15 nm within the 1.3–1.5 μm spectral range. This was achieved with a standard telecommunication fiber with constant dispersion. Full article

(This article belongs to the Special Issue Fiber Optics and Its Applications)

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10 pages, 4935 KiB

Open AccessCommunication

An All-Fiber FLRD System for SO₂ Detection Based on Graphene-Coated Microfiber

by Dibo Wang, Ran Zhuo, Yin Zhang, Wenwen Yu, Zhiming Huang, Mingli Fu and Xiaoxing Zhang

Photonics 2023, 10(8), 863; https://doi.org/10.3390/photonics10080863 - 25 Jul 2023

Cited by 1 | Viewed by 680

Abstract

The accurate and effective detection of SF₆ decomposition components inside a gas-insulated switchgear (GIS) is crucial for equipment fault diagnosis and condition assessment. The current method for detecting SF₆ decomposition components involves gas extraction at the GIS inlet, which only provides [...] Read more.

The accurate and effective detection of SF₆ decomposition components inside a gas-insulated switchgear (GIS) is crucial for equipment fault diagnosis and condition assessment. The current method for detecting SF₆ decomposition components involves gas extraction at the GIS inlet, which only provides limited information on the decomposition component content. Therefore, there is a need to explore more effective ways to obtain internal gas component information within GIS. In this study, we propose a graphene-coated microfiber gas detection method for SO₂. We establish a physical simulation model of the microfiber and analyze the sensing mechanism of the microfiber diameter and cladding refractive index changes in its evanescent field. A graphene-coated microfiber gas sensor was prepared using a drop-coating method, and a fiber loop ring-down (FLRD) gas detection system was constructed for the experimental studies on SO₂ gas detection. The results demonstrated that the graphene-coated microfiber exhibits an excellent gas-sensitive response to SO₂ and achieves trace-level detection at room temperature. The concentration range of 0 to 200 ppm showed good linearity, with a maximum detection error of 4.76% and a sensitivity of 1.24 ns/ppm for SO₂. This study introduces an all-fiber method for detecting SF₆ decomposition components, offering a new approach for online monitoring of SF₆ decomposition components in GIS equipment using built-in fiber-optic sensors. Full article

(This article belongs to the Special Issue Fiber Optics and Its Applications)

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11 pages, 2092 KiB

Open AccessArticle

Parameter Optimization for Modulation-Enhanced External Cavity Resonant Frequency in Fiber Fault Detection

by Xiuzhu Li, Min Zhang, Haoran Guo, Zixiong Shi, Yuanyuan Guo, Tong Zhao and Anbang Wang

Photonics 2023, 10(7), 822; https://doi.org/10.3390/photonics10070822 - 14 Jul 2023

Viewed by 695

Abstract

Fiber fault detection is crucial for maintaining the quality of optical communication, especially in well-established optical access networks with extended distances and a growing number of subscribers. However, the increasing insertion loss in fiber links presents challenges for traditional fault-detection methods in capturing [...] Read more.

Fiber fault detection is crucial for maintaining the quality of optical communication, especially in well-established optical access networks with extended distances and a growing number of subscribers. However, the increasing insertion loss in fiber links presents challenges for traditional fault-detection methods in capturing fault echoes. To overcome these limitations, we propose a modulation-enhanced external-cavity-resonant-frequency method that utilizes a laser for fault echo reception, providing improved sensitivity compared to traditional photodetector-based methods. Our previous work focused on analyzing key parameters, such as sensitivity and spatial resolution, but did not consider practical aspects of selecting optimal modulation parameters. In this study, we develop a model based on Lang–Kobayashi rate equations for current-modulated optical feedback lasers and validate it through experimental investigations. Our findings reveal that optimal detection performance is achieved with a modulation depth of 0.048, a frequency sweeping range of 0.6 times the laser relaxation oscillation frequency, and a frequency sweeping step of 0.1 times the external cavity resonant frequency. Full article

(This article belongs to the Special Issue Fiber Optics and Its Applications)

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8 pages, 1499 KiB

Open AccessCommunication

Research on the Linear Demodulation Range and Background Noise of Fiber-Optic Interferometer System

by Weitao Wang, Chen Wang, Shuai Qu, Haifeng Qi, Zhiqiang Song, Pengbo Jiang, Jian Guo, Ying Shang, Jiasheng Ni and Gangding Peng

Photonics 2023, 10(3), 283; https://doi.org/10.3390/photonics10030283 - 07 Mar 2023

Cited by 1 | Viewed by 1304

Abstract

The linear demodulation range and background noise of the Michelson interferometer system are investigated with a laser phase noise measurement system. We have theoretically and experimentally analyzed the performance of the interferometer system by changing the frequency modulation amplitude of the laser and [...] Read more.

The linear demodulation range and background noise of the Michelson interferometer system are investigated with a laser phase noise measurement system. We have theoretically and experimentally analyzed the performance of the interferometer system by changing the frequency modulation amplitude of the laser and the optical path difference (OPD) of the interferometer, respectively. It is shown that the linear demodulation range of the Michelson interferometer system is finite, which depends on the parameters of the system, such as the sample frequency, the delay time between two interferometer arms, and the system bandwidth. Furthermore, the experimental results indicate that the background noise of the interferometer system can be reduced by using a sufficiently long OPD so that the smaller true phase information can be detected with the demodulation system. The parameters of the measurement system could be optimized to satisfy the demand of the phase demodulation with different levels, which is of great significance for the phase monitoring interrogator, such as fiber-optical interferometer sensors and distributed acoustic sensors. Full article

(This article belongs to the Special Issue Fiber Optics and Its Applications)

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7 pages, 2328 KiB

Open AccessCommunication

Optimum Design of Glass–Air Disordered Optical Fiber with Two Different Element Sizes

by Jiajia Zhao, Changbang He, Haimei Luo, Yali Zhao, Yiyu Mao and Wangyang Cai

Photonics 2023, 10(3), 259; https://doi.org/10.3390/photonics10030259 - 28 Feb 2023

Viewed by 922

Abstract

This paper presents a detailed study investigating the effect of the material refractive index distribution at the local position of a glass–air disordered optical fiber (G-DOF) on its localized beam radius. It was found that the larger the proportion of the glass material, [...] Read more.

This paper presents a detailed study investigating the effect of the material refractive index distribution at the local position of a glass–air disordered optical fiber (G-DOF) on its localized beam radius. It was found that the larger the proportion of the glass material, the smaller its localized beam radius, which means that the transverse Anderson localization (TAL) effect would be stronger. Accordingly, we propose a novel G-DOF with large-size glass elements doped in the fiber cross-section. The simulation results show that the doped large-size glass elements can reduce the localized beam radius in the doped region and has a very tiny effect on the undoped region, thus contributing to reducing the average localized beam radius of G-DOF. Full article

(This article belongs to the Special Issue Fiber Optics and Its Applications)

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6 pages, 2272 KiB

Open AccessCommunication

Fabrication Method for the High-Accuracy Optical Fiber Delay Line with Specified Length

by Ruoxian Liu, Shiyuan Zhao, Yiying Gu, Runze Yu, Pengcheng Deng and Mingshan Zhao

Photonics 2023, 10(2), 176; https://doi.org/10.3390/photonics10020176 - 07 Feb 2023

Viewed by 1084

Abstract

We propose a novel scheme for fabricating high-accuracy optical fiber delay lines (OFDLs). The fabrication system integrates a self-designed optical fiber cutting device and a high-accuracy fiber length measurement module based on optical frequency domain reflectometry. The optical fiber cutting device can cleave [...] Read more.

We propose a novel scheme for fabricating high-accuracy optical fiber delay lines (OFDLs). The fabrication system integrates a self-designed optical fiber cutting device and a high-accuracy fiber length measurement module based on optical frequency domain reflectometry. The optical fiber cutting device can cleave optical fibers to a specific length with the help of the motorized stage. The accuracy of fiber-cutting was determined by the positional accuracy of the motorized stage, which can reach several microns or even lower. This integrated design significantly reduces the errors and uncertainties introduced by fiber-cutting. To test, a set of OFDLs of a certain length was fabricated by this system. The deviation from the desired fiber length was kept below 50 μm, thus proving high fabrication accuracy and repeatability. Full article

(This article belongs to the Special Issue Fiber Optics and Its Applications)

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8 pages, 2913 KiB

Open AccessCommunication

1.73 kW CW Amplification ASE Source Based on Yb³⁺ Ions-Doped All-Fiber System

by Xin Li, Zhe Zhang, Xinyang Xu, Junjie Liu and Xiaolei Bai

Photonics 2023, 10(1), 81; https://doi.org/10.3390/photonics10010081 - 10 Jan 2023

Viewed by 1308

Abstract

The all-fiber ASE source is an intriguing tool in the fields of super-fluorescence detection, coherent measurement and spectrum analysis technology. We experimentally demonstrate a continuous all-fiber amplified spontaneous emission (ASE) source based on amaster-oscillator power amplifier (MOPA) system, which aims at achieving high [...] Read more.

The all-fiber ASE source is an intriguing tool in the fields of super-fluorescence detection, coherent measurement and spectrum analysis technology. We experimentally demonstrate a continuous all-fiber amplified spontaneous emission (ASE) source based on amaster-oscillator power amplifier (MOPA) system, which aims at achieving high power and frequency stability. The seed source is homemade ASE low power super-fluorescence source with 200 mW. The system employs large-mode-area Yb³⁺-doped double-clad fiber (LMA-DCF), and the maximum power can reach 1.73 kW at a center wavelength of 1079.36 nm, and can maintain an optical-to-optical conversion efficiency of 79.13%. During 30 min of real-time monitoring, the ASE source system did not generate a nonlinear effect, and power fluctuation was less than 2%. Full article

(This article belongs to the Special Issue Fiber Optics and Its Applications)

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14 pages, 26542 KiB

Open AccessArticle

Research on Temperature Compensation of Optical Fiber MEMS Pressure Sensor Based on Conversion Method

by Guozhen Yao, Yongqian Li, Qiufeng Shang and Hanbai Fan

Photonics 2023, 10(1), 22; https://doi.org/10.3390/photonics10010022 - 25 Dec 2022

Cited by 1 | Viewed by 1398

Abstract

The characteristics of optical fiber MEMS pressure sensors are easily affected by temperature, so effective temperature compensation can improve the accuracy of the sensor. In this paper, the temperature characteristics of optical fiber MEMS pressure sensors are studied, and a temperature compensation method [...] Read more.

The characteristics of optical fiber MEMS pressure sensors are easily affected by temperature, so effective temperature compensation can improve the accuracy of the sensor. In this paper, the temperature characteristics of optical fiber MEMS pressure sensors are studied, and a temperature compensation method by converting the wavelength is proposed. The influence of target temperature and data point selection on the compensation effect is studied, and the effectiveness of the method is verified by the temperature compensation of sensors before and after aging. When the converted target temperature is 25 °C, the pressure measurement accuracy of the sensor is improved from 1.98% F.S. to 0.38% F.S. within the range of 5–45 and 0–4 MPa. The method proposed in this paper can not only improve the accuracy but also make the regular calibration more operable. Full article

(This article belongs to the Special Issue Fiber Optics and Its Applications)

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Review

Jump to: Research

21 pages, 12451 KiB

Open AccessReview

High-Spatial-Resolution Dynamic Strain Measurement Based on Brillouin Optical Correlation-Domain Sensors

by Yahui Wang, Jing Chen, Jinglian Ma, Lintao Niu and Mingjiang Zhang

Photonics 2023, 10(11), 1255; https://doi.org/10.3390/photonics10111255 - 13 Nov 2023

Viewed by 821

Abstract

Brillouin-scattering-based sensors have been widely applied in distributed temperature or strain measurement in recent 20 years. Brillouin optical correlation-domain technology has extensive development and application prospects because of its millimeter-level spatial resolution, distribution measurement, and high accuracy. Traditional Brillouin-scattering-based sensors, requiring a time-consuming [...] Read more.

Brillouin-scattering-based sensors have been widely applied in distributed temperature or strain measurement in recent 20 years. Brillouin optical correlation-domain technology has extensive development and application prospects because of its millimeter-level spatial resolution, distribution measurement, and high accuracy. Traditional Brillouin-scattering-based sensors, requiring a time-consuming frequency-sweep process, struggle to achieve dynamic strain measurement. In this article, Brillouin optical correlation-domain analysis and reflectometry based on fast-sweep frequency and slope-assisted methods will be reviewed. The main merits, drawbacks, and performances of these schemes are compared, and the avenues for future research and development of these two technologies are also explored. Full article

(This article belongs to the Special Issue Fiber Optics and Its Applications)

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