Some recent advances in fibreoptic sensors

Batchellor, C.R.; Edge, C.

doi:10.1049/ecej:19900042

Cited by 3 publications

(2 citation statements)

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“…Fiber optic hydrophones using Bragg reflectors and fiber lasers have been explored as an alternatives to conventional ceramic based hydrophones due to its many advantages such as high sensitivity to strain, immunity to electromagnetic interference, intrinsic safety to water leakage, ease of multiplexing and remote measurement capability. [1][2][3] The fiber laser based hydrophone (FLH) technology has been fast developing and it may soon replace the existing mandrel wound fiber optic hydrophones due to their high sensitivity and compact size. Though not widely addressed in open literature, an important area that requires special attention is in the design of a suitable encapsulation for these hydrophones so that they can be safely deployed in seawater.…”

Section: Introductionmentioning

confidence: 99%

Pressure compensated fiber laser hydrophone: Modeling and experimentation

Chandrika

Pallayil

Lim

et al. 2013

The Journal of the Acoustical Society of America

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A pressure compensated metal diaphragm based fiber laser hydrophone configuration that can provide good sensitivity, large bandwidth, and sea state zero noise floor is proposed in this paper. A simplified theoretical model of the proposed sensor configuration is developed in which the acoustic elements of the sensor configuration are modeled using a four-pole acoustic transfer matrix and the structural elements are modeled as second order single degree of freedom elements. This model is then used to optimize the design parameters of the sensor system to achieve the performance objectives. An axisymmetric finite element analysis of the sensor configuration is also carried out to validate the results from the simplified theoretical model. Prototype sensors were fabricated and hydrostatic testing in a pressure vessel validated the static pressure compensation performance of the sensor. Frequency dependent sensitivity of the sensor system was measured through acoustic testing in a water tank. The prototype sensor gave a flat frequency response up to 5 kHz and experimental results compared well with theoretical predictions. The sensor has an acceleration rejection figure on the order of 0 dB ref 1 m/s(2) Pa and the pressure compensation approach worked reasonably well up to a hydrostatic pressures equivalent to a depth of 50 m.

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Section: Introductionmentioning

confidence: 99%

Pressure compensated fiber laser hydrophone: Modeling and experimentation

Chandrika

Pallayil

Lim

et al. 2013

The Journal of the Acoustical Society of America

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“…Recent developments in optical systems led the development not only of high performance transmission systems, but also of numerous optical monitoring and control systems using the same optical components 1 . Fiber-optic sensors were produced for explosive environments and for EMI immunity 2,3 . Optical actuators appeared recently for control-by-light systems for hazardous or electromagnetically noisy environments 4 .…”

Section: Introductionmentioning

confidence: 99%

Optical implementation of closed loop controllers for mechatronic systems

Necsulescu

Bhagia

2002

Optomechatronic Systems III

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The paper investigates the implementation of closed loop controllers of optomechatronic systems using optical components for signal transmission and control loop implementation. The system used for illustration is a DC position servomotor under state feedback control. The comparison is carried out between electric-electronic implementation and optical implementation for an environment with significant electromagnetic noise. For the optical implementation a photodiode is used for converting analog voltage output from position and velocity sensors into modulated 900 nm light, transmitted over a significant distance by a multi mode glass fiber (MMGF) to a controller implemented with a tunable optical amplifier. As an alternative, attenuators can also be used for controller implementation. The signal from controller is again transmitted 1550 nm MMGF to a photodetector that converts the signal into an analog voltage input to motor driver. Experimental results will illustrate the performance of the proposed optical implementation and advantages vs. electric-electronic implementation using a Lab View platform for data acquisition and display.

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