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Article
Publication date: 29 July 2020

Abdelhak Boukharouba

Fast iterative algorithms for designing birefringent filters with any specified spectral response are proposed. From the Jones formalism, we derive two polynomials…

Abstract

Fast iterative algorithms for designing birefringent filters with any specified spectral response are proposed. From the Jones formalism, we derive two polynomials representing the transmitted and rejected response of the filter, respectively. Once the coefficients of the filters are obtained, the orientation angle of each birefringent section and the phase shift introduced by each compensator can be determined by an iterative algorithm that gives an efficient solution to the birefringent filter design problem. Afterward, some design examples are presented to demonstrate the effectiveness of the proposed approach. In comparison with results reported in the literature, this approach provides the best performance in terms of accuracy and time complexity.

Details

Applied Computing and Informatics, vol. 17 no. 2
Type: Research Article
ISSN: 2634-1964

Keywords

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Article
Publication date: 1 October 2018

Ke Kou, Tianhong Lian, Cuo Wang and Guanlei Zhang

As an emerging measurement technique with the merit of easy alignment and high sensitivity, laser self-mixing interferometry (SMI) has wide applications in the detection…

Abstract

Purpose

As an emerging measurement technique with the merit of easy alignment and high sensitivity, laser self-mixing interferometry (SMI) has wide applications in the detection of physical quantities. Considering that the characteristics of lasers have a determining influence on sensors’ performance, the authors have established an open cavity solid-state laser (SSL) with more adjustment flexibility to act as a laser source.

Design/methodology/approach

The fundamental structure of a SSL has been presented with an Nd:YAG rod severing as an active material and a birefringent filter inserted in the resonator as a mode selecting element. The power stability has been tested by a power meter, while the mode pattern has been inspected with a scanning Fabry–Perot interferometer, and the linewidth has been observed through a wavelength meter. A loudspeaker driven by a function generator is located in the extracavity to introduce phase modulation for SMI signal observation.

Findings

The established Nd:YAG SSL operates in a single longitudinal mode with the power stability of 0.2 mW and the linewidth less than 10 MHz. The SMI phenomenon occurs in the SSL, and the SMI signal obtained shows a fine signal-to-noise ratio of about 30 dB.

Originality/value

To the authors knowledge, SMI sensors using SSLs, especially in open cavity type, have rarely been reported, and they can find significant applications in designing high performance SMI sensors and instruments.

Details

Sensor Review, vol. 39 no. 2
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 1 March 2005

M. McSherry, C. Fitzpatrick and E. Lewis

There are various temperature measuring systems presented in the literature and on the market today. Over the past number of years a range of luminescent‐based optical…

Abstract

Purpose

There are various temperature measuring systems presented in the literature and on the market today. Over the past number of years a range of luminescent‐based optical fibre sensors have been reported and developed which include fluorescence and optical scattering. These temperature sensors incorporate materials that emit wavelength shifted light when excited by an optical source. The majority of commercially available systems are based on fluorescent properties.Design/methodology/approach – Many published journal articles and conference papers were investigated and existing temperature sensors in the market were examined.Findings – In optical thermometry, the light is used to carry temperature information. In many cases optical fibres are used to transmit and receive this light. Optical fibres are immune to electromagnetic interference and are small in size, which allows them to make very localized measurements. A temperature sensitive material forms a sensor and the subsequent optical data are transmitted via optical fibres to electronic detection systems. Two keys areas were investigated namely fluorescence based temperature sensors and temperature sensors involving optical scattering.Originality/value – An overview of optical fibre temperature sensors based on luminescence is presented. This review provides a summary of optical temperature sensors, old and new which exist in today's world of sensing.

Details

Sensor Review, vol. 25 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

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Article
Publication date: 1 August 1960

J.R. Linge

The technique described in this paper consists of the examination of surface strains in a metal component with optically sensitive material bonded to the component and the…

Abstract

The technique described in this paper consists of the examination of surface strains in a metal component with optically sensitive material bonded to the component and the analysis of the photoelastic pattern produced under load by means of polarized light reflected from the surface of the metal. The original investigations cover in considerable detail the development of the technique and the results obtained, using the photoelastic materials Catalin 800, C.R.39, and the Marco Resin, S.B.26C, and S.B.28C, in conjunction with light alloy, magnesium and mild steel. The fundamental problem of producing good adhesion between the photoelastic material and the metal surface coupled with satisfactory light reflexion from the latter comprised the major part of the initial investigations. Results of the measurement of both elastic and plastic stress concentrations at holes in plates subjected to uniform tension are presented, together with a qualitative analysis of the effect on stress distribution of the variation of the pin to hole clearance in lugs. Owing to the fairly extensive nature of the original investigations it has only been possible to outline the more salient features of the work undertaken. The term ‘Metaplastic’ is suggested to describe concisely the use of compound specimens for the photoelastic applications considered.

Details

Aircraft Engineering and Aerospace Technology, vol. 32 no. 8
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 January 1989

Robert Woodrough

Pressing problems in optical‐disc manufacture need to be quickly and precisely identified.

Abstract

Pressing problems in optical‐disc manufacture need to be quickly and precisely identified.

Details

Sensor Review, vol. 9 no. 1
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 27 June 2008

James Hunt

The purpose of this paper is to look at fibreoptic sensing techniques and applications.

Abstract

Purpose

The purpose of this paper is to look at fibreoptic sensing techniques and applications.

Design/methodology/approach

The paper provides information on fibreoptic sensing technologies, instrumentation, advantages and applications.

Findings

Fibreoptic sensing, especially fibreoptic Bragg gratings, provide a highly effective means of monitoring internal changes in structural and other components that were previously impossible or very difficult to detect. Such systems are now approaching full commercialisation.

Originality/value

The paper provides a useful overview of how fibreoptic sensors work, and the advantages they provide when used in instrumentation applications ranging from compact devices to large and complex structures, where they may be structurally integrated.

Details

Sensor Review, vol. 28 no. 3
Type: Research Article
ISSN: 0260-2288

Keywords

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Article
Publication date: 1 July 1962

This book is a paperback republication of the original edition published in 1950. (Reviewed in Aircraft Engineering, Vol. 22, p. 243). It opens with a section on…

Abstract

This book is a paperback republication of the original edition published in 1950. (Reviewed in Aircraft Engineering, Vol. 22, p. 243). It opens with a section on Fundamental Theory which covers the main thermodynamic principles and kinematics of motion. The mathematical derivations of divergence and circulation are then discussed. The potential equation is introduced, and the solutions of its linearized form are described for two dimensional and axisymmetrical flows. The theory of characteristics is deduced and applied to plane and axisymmetrical cases. The basic normal and oblique shock relationships are first established for plane flows with emphasis on the shock polar and are then extended to the case of the cone at zero incidence. The hodograph transformation is outlined without particular application.

Details

Aircraft Engineering and Aerospace Technology, vol. 34 no. 7
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 July 2006

Christine Connolly

To examine the range of fibre‐optic sensors available for monitoring the integrity of buildings and civil engineering structures.

Abstract

Purpose

To examine the range of fibre‐optic sensors available for monitoring the integrity of buildings and civil engineering structures.

Design/methodology/approach

Explains the need for structural monitoring and reviews the types of fibre‐optic sensors. Concentrating on elongation and temperature sensing, shows how each technology works, which companies supply the products, and gives an overview of their technical specifications.

Findings

Fibre optics are able to provide integrated, single‐point and distributed sensor systems. The fibre is a communication channel as well as a sensor, and in some systems, carries highly multiplexed data over considerable distances to a central monitoring station. The take‐up of this technology in structural sensing is helped by appropriate packaging that assists attachment to buildings. Durability and measurement stability give a continuity of measurement that was not previously possible.

Originality/value

An introduction to the range of sensors applicable to structural monitoring, of general interest to scientists, but particularly to civil and constructional engineers.

Details

Sensor Review, vol. 26 no. 3
Type: Research Article
ISSN: 0260-2288

Keywords

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Article
Publication date: 1 March 1986

Plessey's Roke Manor research centre was one of the first organisations to become involved in fibre optic sensing. Jack Hollingum visited the laboratory and learned about…

Abstract

Plessey's Roke Manor research centre was one of the first organisations to become involved in fibre optic sensing. Jack Hollingum visited the laboratory and learned about current developments.

Details

Sensor Review, vol. 6 no. 3
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 23 February 2018

Yage Zhan, Ziyang Shen, Zeyu Sun, Qiao Yu, Hong Liu and Yong Kong

The purpose of this paper is to theoretically analyze and experimentally demonstrate the investigation of and present a kind of sensing system for monitoring simultaneous…

Abstract

Purpose

The purpose of this paper is to theoretically analyze and experimentally demonstrate the investigation of and present a kind of sensing system for monitoring simultaneous temperature and strain measurements based on highly nonlinear fiber (HNLF) and single mode fiber (SMF).

Design/methodology/approach

First, the stimulated Brillouin scattering (SBS) characteristics of the HNLF have been studied, including the Brillouin gain bandwidth, Brillouin gain center frequency and SBS threshold. Second, based on the Brillouin gain center frequency, the Brillouin frequency shift coefficients of strain and temperature in HNLF have been studied. Third, the sensing and signal interrogation scheme for simultaneous monitoring of temperature and strain with high resolution has been presented.

Findings

It is found that the HNLF has a wider Brillouin gain bandwidth. The SBS threshold of HNLF is 78 mW, which is much larger than 7.9 mW of SMF. Also, the Brillouin frequency shift coefficients of strain and temperature in HNLF are 0.0308 and 0.413 MHz/°C, respectively.

Originality/value

The larger threshold of SBS is useful to avoid SBS under certain situations that Spontaneous Brillouin Scattering is necessary and should be applied. The technique is based on the fact that the Brillouin frequency shift coefficients of strain and temperature in HNLF are different from those in SMF. Therefore, the two-parameter monitoring can be achieved by producing SBS and obtaining the back-scattering Brillouin signal light simultaneously in HNLF and SMF.

Details

Sensor Review, vol. 39 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

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