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It is important to monitor wrist four direction movements (flexion, extension, adduction and abduction) for hand healthcare, wrist rehabilitation and upper limb exercise, and so on. The purpose of this study is to develop a quadri-directional optical bending sensor that integrated wearable device technology in a smart glove to detect wrist four direction movements.

The quadri-directional optical bending sensor was designed with a microcontroller board, a Bluetooth wireless module, a side-emitting polymeric optical fibre (POF), an infrared light emitting diode and four phototransistors. A linear equation was deduced to calculate bending angle from detecting sensor value of Arduino microcontroller. The bending angle values could be seen by the smartphone screen, so the system has a good human–machine interface function.

The light emission by macro-bending of the side-emitting POFs that the transmittance of the outer side is greater than the inner. The bending POFs lateral emission phenomenon integrated with phototransistors on the edge is suitable for the development of bending sensors.

This study is to develop a novel quadri-directional optical bending sensor to replace two bi-direction sensors or four uni-direction sensors for wrist four direction movements monitoring.

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

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

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.

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.

Tipped to be a major technology of the next decade, fibre‐optic sensors are already making some waves in the laboratory, as Stephen McClelland explains.

Fibre optic sensors offer many potential advantages for the measurement of physical parameters in process plants

Optical sensor companies in the UK are getting together to organise their own research and development.

To describe a new technique, developed in Korea, which extends the operational length of fibre Bragg grating strain and temperature sensors to approximately 50 km. It is based on distributed Raman amplification.Design/methodology/approach – The system uses a single pump source to achieve distributed Raman amplification in the transmission optical fibre and does not employ an additional broadband light source, as the residual pump power after the transmission fibre is recycled to generate broadband amplified spontaneous emission in an erbium‐doped fibre.Findings – The temperature and strain response of the system was tested by measuring changes in reflection from the sensor which were captured on an optical spectrum analyser, located at the end of a 50 km length of fibre. The thermal sensitivity was found to be 8.2 pm/°C over the range 30‐100°C and a strain sensitivity of 1.1 pm/με was exhibited between 0 and 1,700 με. The measurement resolutions of the system for temperature and strain were estimated at 0.7°C and 8.64 με, respectively. The signal‐to‐noise ratio was approximately 11 dB.Originality/value – This work has shown that the use of distributed Raman amplification can extend the operational length of fibre Bragg grating sensors from around 25 km to at least 50 km, whilst achieving good strain and temperature sensitivities.

Deals with the optical responses of fibre Bragg grating (FBG) sensors under different modes of deformation. It derives both the polarisation states and reflection spectra of FBGs based on coupled mode equations by considering the deformation perturbations. It conducts numeric simulations, finds that the experimental results agree well with the simulated ones for normal germano‐silicate FBGs under different individual modes of deformations.

A distributed fibre‐optic sensor could be many miles long, as an expert explains.

A review of integrated optical circuit technologies [OIC] and their relevance to potential OIC sensor application. Describes the manufacture of OICs and the varied range of material technologies used. Active Silicon Integrated Optical Circuits have been developed which may have applications for many optical sensor and fibre optic sensor systems. Concludes however that silicon integrated optics will not enjoy large‐scale success until their manufacturing costs have been dramatically reduced.

Looks at the use of non‐contact displacement and vibration sensors and notes their value for difficult sensing measurements. Mentions various situations which may dictate the use of a non‐contact sensor. Focuses on fibre‐optic sensors and laser triangulation sensors. Concludes that practical uses for such devices are rapidly expanding.