Novel design of multiplexed sensors using a dual FBGs scheme (original) (raw)
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Novel tunable Fabry-Perot filters for FBG sensing system
2009
ABSTRACT Tunable filters with a wide tunable rang have been found wide applications and be the key component in fiber optical communication system and fiber sensor system. It is hard to fabricate a fiber Fabry-Perot tunable filter. In this paper, the principles of Fabry-Perot filter is introduced, and a novel tunable Fabry-Perot filter is designed and fabricated. The fabricated process of the tunable filter is described and the transmission spectrum of tunable FP filter in experiment is given and discussed.
A high-resolution tunable fiber Bragg grating filter
Microwave and Optical Technology Letters, 2004
A tunable fiber Bragg grating (FBG) filter with a tuning resolution of less than one picometer (pm) is demonstrated. The FBG is embedded in carbon-fiber composite material, which is bent by using a simple mechanical setup. A tuning range of 2 nm and repeatability of less than 0.4% are obtained.
Demodulation of the FBG temperature sensor with the tunable twin-core fiber
Microwave and Optical Technology Letters, 2010
A novel linear edge filter based on a piece of tunable twin-core fiber is proposed in this article. The transmission spectrum of the twin-core fiber can be adjusted by pulling and twisting the twin-core fiber to match the central wavelength of the Fiber Bragg Grating (FBG) used for the temperature sensor. The feasibility of the method is analyzed and demonstrated experimentally. This demodulation filter, which is based on the all-fiber component, can be designed and adjusted according to the measurement sensitivity and range of FBG temperature sensor, so its characteristics of compact scheme and low cost would make this method more applicable. V
Demodulation system for fiber Bragg grating sensors using digital filtering technique
Transactions of Tianjin University, 2008
： A discrimination measurement method and demodulation technique for fiber Bragg grating (FBG) sensors were presented using digital filtering technique. The system can control a tunable fiber Fabry-Perot filter with sawtooth wave voltage generated by digital clock to interrogate FBG sensors. Using the analogue digital converter (ADC), the reflected FBG signals were sampled with synchronous digital clock. With the aid of digital matched filtering technique, the sampled FBG signals were processed to obtain the maximum signal-to-noise ratio (SNR) and the Bragg wavelength shift from the FBG signals was recovered. The results demonstrate that this system has a scanning range of 1 520 nm-1 575 nm,and the wavelength detection accuracy is less than 2 pm with 1.5 Hz scanning frequency.
Wide Range FBG Displacement Sensor Based on Twin-Core Fiber Filter
Journal of Lightwave Technology, 2000
In this paper, we present a wide range displacement sensor system using the fiber Bragg grating (FBG), spring, and a twin-core fiber. The quantitative analysis of the theory of the cascaded FBG-spring system for displacement measurement is introduced together with the basic working principle of a twin-core fiber filter. The feasibility of the method is demonstrated in experiments which shows the output optical intensity linear relation with the displacement. The characteristics of the wide range, high resolution, low cost, and compact scheme would make this method more applicable. Index Terms-Displacement sensor, edge filter, fiber Bragg grating (FBG), fiber filter, twin-core fiber. I. INTRODUCTION S ENSORS based on fiber Bragg grating (FBG) have been widely investigated since they were first demonstrated for strain and temperature measurement about two decades ago. The major advantages for FBG are its unique wavelength multiplexing capacity and the narrow-band reflection wavelength, of which by demodulating it we can get the sensing information. So it is an ideal candidate for structural health monitoring and impact detection. Many researchers have discussed the FBG applications such as strain, temperature, corrosion, state of cure, and vibration [1]-[5]. To accompany the wide use of FBG as the sensing element, recently, the demodulation methods of FBG feedback signal have also attracted great interests. The major demodulation techniques to extract the outside information are edge filter [6]-[10], tunable filter [11]-[13], interferometer [14]-[17], and wavelength scanning laser [18], [19]. The edge filter, which the output intensity closely relates to the central wavelength of input signal, has some advantages such as quick response, simple structure, good for static and dynamic measure etc.[20], a viable candidate for demodulating wavelength signal. But this method still bears some shortcomings, for instance, the inconvenience of fixed wavelength of the filter that can correspond to the central wavelength of the FBG sensor, which limits the practical applications.
Multi-channel monolithic integrated optic fiber Bragg grating sensor interrogator
Photonic Sensors, 2011
Fiber Bragg grating (FBG) is a mature sensing technology for the measurement of strain, vibration, acoustics, acceleration, pressure, temperature, moisture, and corrosion. It has gained rapid acceptance in civil, aerospace, chemical and petrochemical, medicine, aviation and automotive industries. The most prominent advantages of FBG are: small size and light weight, distributed array of FBG transducers on a single fiber, and immunity to radio frequency interference. However, a major disadvantage of FBG technology is that conventional state-of-the-art FBG interrogation system is typically bulky, heavy, and costly bench top instruments that are typically assembled from off-the-shelf fiber optic and optical components integrated with a signal electronics board into an instrument console. Based on the industrial need for a compact FBG interrogation system, this paper describes recent progress towards the development of miniature fiber Bragg grating sensor interrogator (FBG-Transceiver™) system based on multi-channel monolithic integrated optic sensor microchip technology. The integrated optic microchip technology enables monolithic integration of all functionalities, both passive and active, of conventional bench top FBG sensor interrogator system, packaged in a miniaturized, low power operation, 2 cm×5 cm small form factor (SFF) package suitable for long-term structural health monitoring in applications where size, weight, and power are critical for operation.
A combined fiber Bragg grating and interferometric based sensor
Proceedings of SPIE - The International Society for Optical Engineering
A novel combined fiber Bragg grating (FBG) and interferometric based sensor is proposed and demonstrated. The sensor is based on two overlapped Michelson interferometers working at different wavelengths in a Sagnac loop and two FBGs used as wavelength selective mirrors. The advantage of the system is that it combines the benefit of point measurement with FBG and the high sensitivity of long gauge interferometric sensor.
2007
Fiber Bragg grating sensors (FBGs) have gained rapid acceptance in aerospace and automotive structural health monitoring applications for the measurement of strain, stress, vibration, acoustics, acceleration, pressure, temperature, moisture, and corrosion distributed at multiple locations within the structure using a single fiber element. The most prominent advantages of FBGs are: small size and light weight, multiple FBG transducers on a single fiber, and immunity to radio frequency interference. A major disadvantage of FBG technology is that conventional state-of-the-art fiber Bragg grating interrogation systems are typically bulky and heavy bench top instruments that are assembled from off-the-shelf fiber optic and optical components integrated with a signal electronics board into an instrument console. Based on the need for a compact FBG interrogation system, this paper describes recent progress towards the development of a miniature fiber Bragg grating sensor interrogator (FBG-Transceiver™) system based on multi-channel integrated optic sensor (InOSense) microchip technology. The hybrid InOSense microchip technology enables the integration of all of the functionalities, both passive and active, of conventional bench top FBG sensor interrogators systems, packaged in a miniaturized, low power operation, 2-cm x 5-cm small form factor (SFF) package suitable for the long-term structural health monitoring in applications where size, weight, and power are critical for operation. The sponsor of this program is NAVAIR under a DOD SBIR contract.