Abstract: An optical fiber temperature thermometer uses a thermochromic substance having optical absorption peaks which vary with temperature within a first waveband, and having substantially constant absorption with temperature in a second waveband. The radiation employed is in a wide band to include the first and second wavebands, and the radiation, reflected and attenuated as a result of the passage through the thermochromic substance, is split into two selected beams and filtered in narrow band pass filters for the first and second wavebands, to supply optical signals to respective detectors whose outputs are divided to produce a ratio signal representative of the temperature. The sensor is sufficiently compact for biomedical use, and, being unaffected by electromagnetic fields, is useful in regions of high tension or in microwave heating.

Abstract: A device for transferring the energy emitted by a high power laser onto a target characterized in that it comprises two guides of optical fibre having a step index refraction distribution and at least a plastic material coating. The first guide, stiffly coupled to the laser source, is a variable section fibre with an input face of larger diameter. The second guide is a uniform or variable section fibre with a larger diameter near the output terminal. The two guides are joined by a low leakage optical fibre connector, and between them an adapter can be interposed if the output section of the first guide of fibre does not coincide with the input section of the second guide of fibre. The variable section fibre can be drawn from a pre-molded or melted material, with the speed controlled by an electronic circuit. Different kinds of pots can be utilized in order to obtain the fibre plastic coating.