Optical-path difference on-line measurement of multiplexing fiber-optic interferometric sensors using TDM and WDM by improved optical-frequency-domain reflectometry

2019 ◽  
Author(s):  
Shuwang Li ◽  
Guoguang Lu ◽  
Canxiong Lai ◽  
Yun Huang ◽  
Yunfei En
Keyword(s):  
Fiber Optic ◽  
Optical Path Difference ◽  
Path Difference ◽  
Optical Path ◽  
Optical Frequency ◽  
Interferometric Sensors ◽  
Optical Frequency Domain Reflectometry ◽  
Line Measurement ◽  
Frequency Domain Reflectometry ◽  
On Line

scholarly journals THz Signal Generator Using a Single DFB Laser Diode and the Unbalanced Optical Fiber Interferometer

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4862
Author(s):  
Blaž Pongrac ◽  
Denis Đonlagic ◽  
Matej Njegovec ◽  
Dušan Gleich
Keyword(s):  
Optical Fiber ◽  
Laser Diode ◽  
Optical Signal ◽  
Optical Path Difference ◽  
Sweep Rate ◽  
Path Difference ◽  
Optical Path ◽  
Signal Generator ◽  
Optical Frequency ◽  
Frequency Sweep

This paper presents a frequency-modulated optical signal generator in the THz band. The proposed method is based on a fast optical frequency sweep of a single narrowband laser diode used together with an optical fiber interferometer. The optical frequency sweep using a single laser diode is achieved by generating short current pulses with a high amplitude, which are driving the laser diode. Theoretical analysis showed that the modulation frequency could be changed by the optical path difference of the interferometer or optical frequency sweep rate of a laser diode. The efficiency of the optical signal generator with Michelson and Fabry–Perot interferometers is theoretically analyzed and experimentally evaluated for three different scenarios. Interferometers with different optical path differences and a fixed optical frequency sweep rate were used in the first scenario. Different optical frequency sweep rates and fixed optical path differences of the interferometers were used in the second scenario. This paper presents a method for optical chirp generation using a programmable current pulse waveform, which drives a laser diode to achieve nonlinear optical sweep with a fixed optical path difference of the interferometer. The experimental results showed that the proposed signals could be generated within a microwave (1–30 GHz) and THz band (0.1–0.3 THz).

scholarly journals Numerical Analysis and Recursive Compensation of Position Deviation for a Sub-Millimeter Resolution OFDR

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5540
Author(s):  
Yueying Cheng ◽  
Mingming Luo ◽  
Jianfei Liu ◽  
Nannan Luan
Keyword(s):  
Frequency Domain ◽  
Signal To Noise Ratio ◽  
Optical Path ◽  
Optical Frequency ◽  
Spectral Correlation ◽  
Measuring Point ◽  
Compensation Algorithm ◽  
Optical Frequency Domain Reflectometry ◽  
Frequency Domain Reflectometry ◽  
Thermal Optic

We analyze the source of the position deviation and propose a demodulation recursive compensation algorithm to ensure a sub-millimeter resolution in improved optical frequency domain reflectometry. The position deviation between the geometric path and optical path changes with the temperature or strain, due to the elastic-optic and thermal-optic effects. It accumulates along the fiber and becomes large enough to affect the spectral correlation between the measured and reference spectra at the fiber end. The proposed algorithm compensates for the position deviation of each measuring point and aligns the measured spectra with its reference. The numerical and experimental results both reveal that the signal-to-noise ratio of the correlation is improved doubly and a sub-millimeter spatial resolution becomes available at a 30 m fiber end. The recursive compensation algorithm helps to restrain the correlation degeneration at the fiber end and promises an effective approach to a sub-millimeter resolution in optical frequency domain reflectometry.

Optical frequency domain reflectometry: principles and applications in fiber optic sensing

2016 ◽  
Author(s):  
Stephen T. Kreger ◽  
Nur Aida Abdul Rahim ◽  
Naman Garg ◽  
Sandra M. Klute ◽  
Daniel R. Metrey ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Fiber Optic ◽  
Optical Frequency ◽  
Optical Frequency Domain Reflectometry ◽  
Frequency Domain Reflectometry ◽  
Fiber Optic Sensing

Coherent optical frequency domain reflectometry for interrogation of microbend- and macrobend- based fiber optic hydrocarbon sensors

2001 ◽  
Author(s):  
Rosa M. Lopez-Gutierrez ◽  
Vasilii V. Spirin ◽  
Mikhail G. Shlyagin ◽  
Serguei V. Miridonov ◽  
Ileana Marquez Borbon ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Fiber Optic ◽  
Optical Frequency ◽  
Optical Frequency Domain Reflectometry ◽  
Frequency Domain Reflectometry
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