Abstract: A sensing system including: a sensor located in an external environment, including: an electrically powered sensor element sensing an environment variable and converting the sensing to a corresponding analog electrical value measure; an electrically powered sensor value conversion system connected to the electrically powered sensor and converting the analog electrical value measure to a digital measure, in addition to encoding the digital measure with sensor identification information; a transducer element for sending the sensed data information over an optical conduit for inputting an optical power signal and outputting optical sensed data information; a coupler splitting a first portion of the optical power signal to an energy storage system; and an energy storage system converting the first portion of the optical power signal into corresponding electrical energy and storing it for on demand usage; said electrically powered sensor value conversion system being supplied with electrical power from said energy

Abstract: A method of measuring fluctuations in electric fields is disclosed, the method comprising the step of: placing a Liquid Crystal Device in communication with the electric field, the device having disparate orthogonal polarization sensitivity to an external electric field; utilizing an optical probe beam having a known polarization state to interrogate the liquid crystal of the liquid crystal device to produce a response beam; and analyzing the polarization state of the response beam to provide an indicator of the corresponding fluctuations in the electric field.

Abstract: A method of measuring fluctuations in electric fields is disclosed, the method comprising the step of: placing a Liquid Crystal Device in communication with the electric field, the device having disparate orthogonal polarization sensitivity to an external electric field; utilising an optical probe beam having a known polarization state to interrogate the liquid crystal of the liquid crystal device to produce a response beam; and analyzing the polarization state of the response beam to provide an indicator of the corresponding fluctuations in the electric field.

Abstract: Output power fluctuations in a distributed feedback laser arrangement are reduced by inducing a saturable absorption grating in a saturable absorption region. Light is coupled into a DFB region and amplified in an amplification region. A feedback loop reflects a portion of the amplified light, and the counter-propagating beams induce an absorption grating in a saturable absorption region which suppresses output oscillations. The amplification region can comprise an erbium doped fiber, and the saturable absorption region can comprise an underpumped portion of such a fiber, or a further length of such fiber, or a planar waveguide.

Abstract: An interferometer (100) for writing Bragg gratings comprising the means for splitting (112) a light beam (114) into two coherent beams (116, 118), and a first optical lens arrangement (106, 108, 110) for bringing the coherent beams to interference for writing the Bragg grating in a photosensitive material (122). The first optical lens arrangement is arraged, in use, to vary an angle &bgr; between the two interfering beams.