Siemens Aktiengesellschaft

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Siemens Aktiengesell Schaft

Gerhard Schiffner

Ekkehard Klement

Dieter Rosenberger

An apparatus for detecting intensity-modulated light signals is provided that exhibits higher sensitivity in comparison to prior apparatus and which is composed of an optical detector for detecting an intensity-modulated optical signal and a mixer stage in the form of an electronic mixing device having a subsequent lock-in amplifier. The mixer stage comprises an optical mixing device into which the optical signal can be coupled and from which the mixed signal can be taken as an optical signal and the mixed signal is fed to an optical detector device.

Apparatus for detecting intensity-modulated light signals

A ring interferometer which has a light waveguide with two ends which act as the two separate coupling points so that light from a source can be coupled into each of the ends to travel in the light waveguide to be uncoupled from the opposite end as an output beams characterized by the source of light emitting light pulses whose duration is smaller than the transit time of the light in the light waveguide and whose time interval between pulses is greater than the transit time.

Ring interferometer with an arrangement to eliminate false indications

A ring interferometer, which has a coiled waveguide having two ends with each end being provided with means for coupling light from a first source into the waveguide and for uncoupling light coupled into the opposite end of the waveguide, a first optical arrangement for superimposing the uncoupled light from the two ends of the waveguide and forming two portions, an optical arrangement for directing one of the portions of the output coupled light at a first light receiving surface over a common path in a direction opposite to a direction of light from said first source characterized by a mode diaphragm being arranged in the common path to receive the one portion of the superimposed beam and the light from the first source to reduce the number of modes being transmitted therein. Preferably, a second mode diaphragm is arranged in the path of the other portion and both diaphragms are preferably a monomode waveguide such as an optical glass fiber having a core surrounded by a cladding. Preferably, the interferometer includes a second light receiving surface arranged to receive light coupled out of the second mode diaphragm. In an embodiment, a second light source is provided which may have a different wavelength than the wavelength of the first mentioned light source and filters are provided in the path of the light directed at each light receiving surface so that only light from the second source is received by the first receiving surface and only light from the first source is received by the second receiving surface.

Ring interferometer with a mode diaphragm

A sensing device which includes a sensing element in the form of an optical fiber, a device for coupling light into the fiber and a device for measuring changes in the specific physical parameters of the light passing through the fiber to determine special physical influences applied to the fiber characterized by the fiber being a multicore fiber having at least two adjacently extending cores surrounded by a common cladding and the means for measuring the changes in the parameter of the light measuring the alterations in the light passing through each of the cores. To make the device sensitive to bending and deformation in all directions, the fiber may have two cores and be twisted through 90.degree. or the fiber may have three or more cores which are not disposed in the same plane. The measuring of the amount of change may be by measuring the interference pattern from superimposed beams of the output from the two cores or by measuring the intensity of each of the output beams separately.

Sensing device having a multicore optical fiber as a sensing element

A sensor is disclosed which utilizes a ring interferometer for receiving light with a polarizer provided in each of the paths of the superimposed beams exiting the interferometer so that only light polarized in a fixed direction relative to the direction of polarization of the light being coupled into the interferometer is detected. The sensor is particularly adapted to determining influences such as pressures, tensions, torsion, and heat in addition to rotation. In one embodiment, the Faraday effect is utilized to compensate for transit time differences and the amount of energy required to compensate by the Faraday effect is measured to determine the amount of influence.

Sensor which is sensitive to pressure, tension, torsion and heat and a

A device has a waveguide, such as monomode fiber, for receiving a light beam and retransmitting specific portions of the light in a reemitted beam, which reemitted beam can be moved in space. To move the reemitted beam, the device has an arrangement for moving an end portion of the light waveguide adjacent the outlet surface to change the direction of the reemitted beam. The waveguide, such as the cladded optical fiber, can be either provided with a mode stripper or is of a sufficient length so that cladding modes will be eliminated before reaching the outlet surface. To move the end of the waveguide, various arrangements, which can utilize either an electro-magnet, a piezoelectric device or other suitable movement devices, are utilized. The device usually includes outlet optics for the reemitted beam and these optics can either be a gradient lens secured on the outlet surface of the waveguide or a lens which is spaced a distance from the outlet surface.

Device for producing a moving light beam

An interferometer with single-mode optical waveguide wound in a coil which waveguide has a surface at each end for the acceptance of light into the waveguide and for the display of light in the waveguide characterized by at least one polarizing filter being arranged in the path of light emerging from each end surface of the waveguide. Preferably, the interferometer includes a light source such as a laser, at least one beam dividing element which is arranged in the path of a light beam and a coupling arrangement for coupling the light of one of the partial beams into one of the end surfaces and the other partial beam into the other end surface. While the interferometer utilizes a device for detecting the superimposed images of the light exiting both end surfaces of the waveguide, preferably two devices are utilized which can be either a screen or a light sensitive element such as a photo diode.

Optical directional coupler and method of manufacture

A ring interferometer which has a light waveguide with two ends which act as the two separate coupling points so that light from a source can be coupled into each of the ends to travel in the light waveguide to be uncoupled from the opposite end as an output coupled light traveling in a separate output path characterized by the separate output paths of the output coupled light from the coupling point to a unification point where components are superimposed into a superimposed path directed to the light receiving surface have different lengths and the amount of the difference exceeds the coherence length of the coherent light employed in the ring interferometer.

Ring interferometer with an arrangement for reducing the influence of

A ring interferometer which has at least one single mode light waveguide wound in a coil characterized by the light waveguide maintaining one polarization state. If the interferometer includes directional couplers or additional light waveguides, each of these are constructed of waveguides which conduct only one polarization state.

Ring interferometer comprising a single-mode light waveguide

An interferometer with a single-mode optical waveguide wound in a coil which waveguide has a surface at each end for the acceptance of the light into the waveguide ends and for the display of light in the waveguide characterized by an improvement comprising at least one optical directional coupler having four input/output ends being provided. One of the four input/output ends is coupled into one of the pair of ends of the waveguide forming the coil and a second of the input/output ends is coupled to the other end of the pair of ends of the waveguide forming the coil. Preferably, the coupling of light from a light source utilizes a second additional directional coupler, which has an input/output end coupled to a third input/output end of the first mentioned coupler and the device preferably has a pair of light sensitive elements with one of said elements receiving a superimposed image from the fourth input/output end of the first mentioned coupler and the other receiving light from one of the input/output ends of the second or additional coupler.

Interferometer with a single-mode waveguide coil

An interferometer with a single mode optical waveguide wound in a coil, which waveguide has an end surface at each end for the acceptance of light into the waveguide and for the emitting of light that is in the waveguide, a beam dividing element for superimposing a portion of light from each of the end surfaces of the waveguide into two separate superimposed beams of light characterized by a polarizer arranged in the path of each of the superimposed beams of light for filtering the light as it is received by a beam receiver, which may be a screen or a light sensitive element such as a photo diode. The beam splitting element may be a beam splitting element having a reflective surface such as a partially reflective mirror or a beam splitting cube or may be optical directional couplers.

Interferometer with a coil composed of a single mode waveguide

A device for optically pumping a solid state laser consisting of a rod of a laser material, and at least one light pumping source having a point form or shape characterized by a waveguide arranged between each pumping light source and the laser rod for coupling the pumping light into the rod. Preferably, the waveguides are either glass rods or a prism and the optical axis of the waveguide extends at an angle .delta. with a normal to a flat surface of the rod of laser material which angle .delta. has a relation of 2 arc sin (1/n.sub.1) .ltoreq. .delta. &lt; .pi./2 wherein n.sub.1 is the index of refraction of the light waveguide.

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Munich, Germany

Gerhard Schiffner