Enhancing the measurement accuracy of a cavity-enhanced fiber chemical sensor by an adaptive filter

Ni, N.; Chan, Chi Chiu; Chuah, Tong Kuan; Xia, Li; Shum, Ping

doi:10.1088/0957-0233/19/11/115203

Cited by 18 publications

(8 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another problem is the high level of ASE noise introduced by the EDFA, causing accuracy problems similar to those seen in free space systems. Ni et al have used a digital adaptive filter to reduce the ASE noise, improving their system sensitivity by a factor of 8 and giving a limit of detection of 100 ppm acetylene at 1.531 μm (pathlength not stated) [328] . Page 63…”

Section: High Finesse Optical Fibre Cavitiesmentioning

confidence: 99%

Optical gas sensing: a review

Hodgkinson

Tatam

2012

Meas. Sci. Technol.

1,311

858

View full text Add to dashboard Cite

The detection and measurement of gas concentrations using the characteristic optical absorption of the gas species is important for both understanding and monitoring a variety of phenomena from industrial processes to environmental change. This article reviews the field, covering several individual gas detection techniques including non-dispersive infrared (NDIR), spectrophotometry, tunable diode laser spectroscopy and photoacoustic spectroscopy. We present the basis for each technique, recent developments in methods and performance limitations. The technology available to support this field, in terms of key components such as light sources and gas cells, has advanced rapidly in recent years and we discuss these new developments. Finally, we present a performance comparison of different techniques, taking data reported over the preceding decade, and draw conclusions from this benchmarking.

show abstract

Section: High Finesse Optical Fibre Cavitiesmentioning

confidence: 99%

Optical gas sensing: a review

Hodgkinson

Tatam

2012

Meas. Sci. Technol.

1,311

858

View full text Add to dashboard Cite

show abstract

“…This filter reduced the error of the ring-down measurement by 9 dB at a ring-down time of 2.7 μs. With a newer system [ 62 ] the same group obtained ring-down times up to 101.2 μs corresponding to a round-trip loss of 0.218 dB. Measurements of acetylene (C 2 H 2 , at 1531.54 nm) were performed and a detection limit of 70.1 ppm and an accuracy of 15 ppm was determined.…”

Section: Amplified Crdsmentioning

confidence: 99%

Chemical Sensing Using Fiber Cavity Ring-Down Spectroscopy

Waechter

Litman

Cheung

et al. 2010

Sensors

105

View full text Add to dashboard Cite

Waveguide-based cavity ring-down spectroscopy (CRD) can be used for quantitative measurements of chemical concentrations in small amounts of liquid, in gases or in films. The change in ring-down time can be correlated to analyte concentration when using fiber optic sensing elements that change their attenuation in dependence of either sample absorption or refractive index. Two types of fiber cavities, i.e., fiber loops and fiber strands containing reflective elements, are distinguished. Both types of cavities were coupled to a variety of chemical sensor elements, which are discussed and compared.

show abstract

“…Another approach is to compensate the inherent cavity loss by introducing an erbium-doped fiber amplifier (EDFA) to the fiber cavity. As the EDFA is served as the gain source, this new FCRD is usually named as time-domain active FCRD or amplified FCRD [8][9][10][11][12][13][14][15][16][17][18]. In 2001, the active FCRD technique was firstly proposed by George Stewart and the sensitivity was improved because the inherent cavity loss can be sufficiently compensated by the EDFA [8].…”

Section: Introductionmentioning

confidence: 99%

“…One is the gain fluctuation of the EDFA, which results in the nonexponential decay of the ringdown signal and thus degrades the measurement precision and long-term stability [17,18]. Another is the amplified spontaneous emission (ASE) noise produced by EDFA, which causes the baseline drift of ring-down signal and reduces the stability of the sensing system [9,10,14]. To minimize the impact of gain fluctuation, a gain clamped EDFA was used in the fiber cavity to reduce the gain fluctuation effect [11,12], but the gain fluctuation still exists because the pulsed laser was used in time-domain active FCRD to excite the fiber cavity and thus it cannot provide the power stabilization in the fiber cavity, so the stability was usually only about 10% which was not suitable for the practical application [15].…”

Section: Introductionmentioning

confidence: 99%

Optical Sensor Using Space-Domain Active Fiber Cavity Ringdown Technique

Chen

Zhu

et al. 2021

Preprint

View full text Add to dashboard Cite

A novel active fiber cavity ringdown (FCRD) technique using frequency-shifted interferometry (FSI) is proposed for the first time. Using this scheme, external parameters can be monitored in the space domain by measuring the ringdown distance instead of ringdown time. A bidirectional erbium-doped fiber amplifier (Bi-EDFA) is employed to compensate the inherent cavity loss for achieving higher sensitivity. And two band-pass filters are used to reduce the amplified spontaneous emission (ASE) noise of the Bi-EDFA. Compared with the well-known time-domain active FCRD scheme, our proposed method enables us to avoid using pulsed laser needed in time-domain active FCRD, it uses continuous-wave laser to inject into the fiber cavity and stabilize the optical power in the fiber cavity, which can suppress gain fluctuations of the EDFA and thus improve the detecting precision. Moreover, this novel method enables us to use differential detection method for further reducing the ASE noise, and thus eliminating the baseline drift of ringdown signal. A magnetic field sensor was developed as a proof-of-concept demonstration. The experimental results demonstrate that the proposed sensor with a sensitivity of 0.01537 (1/km·Gs) was achieved. This is the highest magnetic field sensitivity compared to the time-domain active FLRD method. Due to the reduced ASE noise, the stability of the proposed sensing system was also greatly improved.

show abstract

Enhancing the measurement accuracy of a cavity-enhanced fiber chemical sensor by an adaptive filter

Cited by 18 publications

References 15 publications

Optical gas sensing: a review

Optical gas sensing: a review

Chemical Sensing Using Fiber Cavity Ring-Down Spectroscopy

Optical Sensor Using Space-Domain Active Fiber Cavity Ringdown Technique

Contact Info

Product

Resources

About