Abstract: In an optical microphone including a light source, a fiber optic cable and a Fabry-Perot interferometer with two reflectors, wherein one end face of the fiber optic cable forms a first reflector and the second reflector is arranged at a distance therefrom and is displaceable by fluctuations in the sound air pressure, the second reflector is the end face of a glass fiber section which is displaceable by induced air pressure by means of a separate diaphragm that is coupled thereto. The light source may be a super luminescent diode (SLD).

Abstract: An arrangement for measuring acceleration and vibration employs a fiber-optic interferometer comprising a monomode optical fiber through which light is guided and, having exited the fiber, is then reflected back therethrough, the exit end of the fiber being capable of transverse vibrations.

Abstract: A light source supplies light to an interferometer or polarimetric sensor and a beam divider divides the emerging light into two or more beam paths. Interference filters having different central wavelengths are provided in the beam paths and can be used to bring the two uncoupled interference signals into quadrature, e.g. by suitable adjustment of the tilting angle. In each beam path, a measuring device for quantitatively measuring the received light is disposed, and the data from the measuring devices are supplied to a data-processing device.

Abstract: A photoelectric beam device comprises a light source, a monomode optical fibre, a transmitting optical unit, a reflector and a photodetector, where the transmitting optical unit comprises a collimation optical unit, e.g. in the form of a graded index lens or rod lens and a beam expansion optical unit e.g. in the form of a telescopic optical unit. A fibre-optic directional coupler, arranged between the light source and the monomode fibre, conducts to the photodetector the optical signal reflected back from the reflector to the transmitting optical unit and refocused into the fibre.

Abstract: An interferometer strain sensor or gauge comprises a laser diode coupled to an interferometer with an opto-electric output converter, the output of which is supplied via a differentiating unit to an interference-fringe counter and via a feedback amplifier to the current supply of the laser diode to vary the wavelength thereof, the interference signal being in the form of a saw-tooth pattern with steep edges to produce rapid transitions for the differentiating unit.

Abstract: In an optical switching arrangement comprising a laser, an electrooptical phase modulator formed as a two-arm interferometer, and a second two-arm interferometer as a multistable element, the second interferometer is formed with interferometer arms having optical pathlength differences of the order of magnitude of 10.sup.4 times the wavelength of the light from the laser and has at least one signal output arranged parallel to a further output; the further output is connected to a photodiode the output voltage of which is amplified and then used to control the current supply of the laser. The wavelength of the light emitted by the laser is variable by changing the control voltage of the modulator or the bias voltage of the current supply of the laser so that the output signal alternates between two stable interference signals.

Abstract: An opto-electronic A/D converter comprises an input light source, an input nterferometer, and a plurality of parallel multistable interferometers the optical lengths of which are controlled by respective electrodes, the outputs of the parallel interferometers being converted by photodiodes into electrical signals which are used both to supply a digital output of the converter and as feedback signals to both the respective and an adjacent one of the parallel interferometers.

Abstract: A description is given of a tactile sensor for measuring force with fine resolution which is based on a network of glass fiber optic interferometers. The counting of interference fringes as readout method makes available an inherently digital (incremental) output signal which allows the measured signal to be passed on optically free of interference to evaluation electronics and to data processing. In conjunction with a suitable elastic skin to accept the glass fiber network, the small glass fiber diameter (125 .mu.) and the user of the strain measurement technique employing glass fiber interferometers should make possible a tactile sensor comparable with the human sense of touch. The fields of application for such tactile sensors are robotics, prostheses and advanced controls at the man-machine interface.