Abstract: The present invention provides an optical sensor for monitoring current or power in a monitored element of a device such as a bridge-wire or hot-wire of electro-explosive devices. The optical sensor comprises an optical sensor made of semiconductor material. The semiconductor material comprises an absorption edge which is sensitive to a temperature variation. The semiconductor material is for placing in thermal contact with the monitored element of the device, whereby, when the current or power varies in the monitored element, it causes a variation in temperature in the semiconductor element and hence a spectral shift of the absorption edge which can be measured and which is representative of current and power variation.

Abstract: The invention provides a miniature robust fiber optic pressure sensor. The miniature fiber optic sensor comprises a Fabry-Perot chip bonded to an optical fiber. The invention provides a new sensor design that reduces the amount of adhesive required to bond the optical fiber to the Fabry-Perot sensor such that the sensor is less sensitive to moisture. The invention also provides manufacturing methods of the sensor comprising a method based on etching and a method based on using an excimer laser. The invention also provides a chip design that renders the chip less sensitive to thermal changes. The invention also provides a chip design in which a sensor diaphragm has a well-defined thickness. The invention also provides a chip design that protects the chip from etching.

Abstract: The invention concerns a tandem interferometer for temperature sensing. The low coherence interferometry (LCI) system comprises a polarization-based sensing interferometer comprising a birefringent crystal having a sensor temperature sensitivity and a birefringence dispersion, and a readout interferometer being either a Fizeau interferometer using an optical wedge or a polarization interferometer using a birefringent wedge. In one embodiment of the invention, the birefringent crystal has dispersion properties similar to that of the birefringent wedge or that of the optical wedge of the readout interferometer. The present invention also provides a signal processing method for correcting the dispersion effect and for noise filtering in LCI-based optical sensors of the tandem interferometer arrangement.

Abstract: The invention provides a method and a system for measuring a physical quantity by means of a tandem interferometer optical sensor system based on low-coherence interferometry. The system comprises a light system, a sensing interferometer and a polarization readout interferometer. The invention provides a polarization interferometer comprising a single birefringent wedge. The invention also provides for a dispersion-compensated optical sensor system. The invention also provides an interferometer sensitive to temperature that comprises a trajectory in a LiB3O5 crystal with an x-cut orientation.

Abstract: A method for measuring the cavity length of a remote sensing interferometer by locally replicating the state of the remote sensing interferometer by way of a local interferometer. The local interferometer is produced by micro-electromechanical micro machining techniques, thus obtaining a highly accurate and reliable fiber optic sensing at a cost comparable to electronic sensing devices.