Rockwell International Corporation

Kenneth A James

Virgil H Strahan

William H Quick

Rudolf R August

Donald K Nichols

A method and, in one embodiment of the invention, the resulting apparatus for implementing a unique multiple beam fringe sensor that is adapted to be interfaced with a low cost, compact fiber optic transmission system in order to provide an accurate digital representation of a physical parameter (e.g. temperature) of a remote sample. The sensor is fabricated so as to include a Fabry-Perot gap formed between the ends of two mated optical fibers. By examining the optical characteristics of light that is transmitted through the Fabry-Perot sensor gap, an indication of gap width can be ascertained. Accordingly, a change in Fabry-Perot sensor gap width is related to a change in the particular physical parameter to be measured. In another embodiment of the invention, a second unique multiple beam fringe sensor having a Fabry-Perot gap is disclosed that is also adapted to provide an accurate digital representation of a physical parameter (e.g. temperature) of a remote sample. The sensor may be fabricated in two segments. A fiber containing segment includes each of a driving optical fiber for supplying incident light signals to the Fabry-Perot gap and a sensing optical fiber for receiving output light signals that have been transmitted twice through the Fabry-Perot gap, the optical characteristics of which output signals provide an indication of the parameter to be sensed. A transducer segment includes the Fabry-Perot gap formed therein and means responsive to the physical parameter for changing the width of the Fabry-Perot gap and, accordingly, the optical characteristics of the light signals passing therethrough.

Method and apparatus for a Fabry-Perot multiple beam fringe sensor

A method of fabrication and the resulting structure for a birefringent transmission line having particular application as an optical waveguide. The instant transmission line is fabricated so as to be adapted to maintain the state (e.g. the polarization vector) of polarized electromagnetic radiation propagating therethrough. Birefringence in the instant transmission line is geometrically generated by producing oblong regions having different indices of refraction through a cross-section of the transmission line. A preferred technique by which to generate birefringence includes the method step of bombarding the transmission line with a supply of atomic particules, such as energetic hydrogen ions, whereby to implant a damaged region of oblong cross-section and thereby cause an internal swelling therein. By way of a preferred example, the transmission line herein described may be a single-mode optical fiber.

Fabrication of birefringent electromagnetic transmission line

This invention relates to a lightweight and compact optical sensor that provides an indication of a deformation (e.g. fatigue, vibration, flex, torsion, bending, slippage) occurring at a monitored area. The sensor includes at least one light transmitting optical fiber and an optical detector that is responsive to the optical characteristics (e.g. amplitude, phase, polarization angle) of a supply of light signals being transmitted through the fiber. In the event that deformation occurs at the monitored region, the optical fiber undergoes a displacement which thereby causes a corresponding change in the optical characteristics of the light signals supplied to the detector. The optical characteristics of the light signals supplied to the detector relative to those of the light signals supplied to the optical fiber provide an accurate indication of the physical parameter.

Optical deformation sensor

1 An inexpensive, light weight fiber optic accelerometer to convert input mechanical motion (e.g. acceleration) into digitized optical output signals. The output of the accelerometer may be connected directly to data processing apparatus without the necessity of space consuming analog to digital interface means.

Fiber optic accelerometer

A method and resulting apparatus for implementing a unique optical sensor that is adapted to be interfaced with a low cost, compact fiber-optic transmission system to provide an accurate indication of a sensed physical parameter (e.g. temperature) of a remote sample. The sensor is fabricated so as to include a semiconductor material that has optical-wavelength-dependent filter characteristics that may be varied as a function of a physical parameter such as temperature. In one embodiment, a graded optical filter fabricated by using thin-film deposition techniques on an amorphous semiconductor material, provides position responsive high-pass filter characteristics. Such filter characteristics are then utilized by moving a light source as a function of a physical parameter and generating an optical signal therefrom having a cutoff frequency dependent upon the position of the light source. In another embodiment, the temperature dependent frequency cutoff characteristics in the absorption edge of amorphous selenium, are utilized more directly in an optical temperature sensor. The optical utilization of amorphous semiconductor material is a particularly advantageous feature of the invention in reducing the cost and complexity of semiconductor optical filters.

Method and apparatus for an optical sensor utilizing semiconductor

Birefringent electromagnetic transmission line that preserves the state

A method and the resulting apparatus for implementing a unique multiple beam fringe sensor that is adapted to be interfaced with a low cost, compact fiber optic transmission system in order to provide an accurate digital representation of a physical parameter (e.g. temperature) of a remote sample. The sensor is fabricated so as to include a Fabry-Perot gap formed between the ends of two mated optical fibers. By examining the optical characteristics of light that is transmitted through the Fabry-Perot sensor gap, an indication of gap width can be ascertained. Accordingly, a change in Fabry-Perot sensor gap width is related to a change in the particular physical parameter to be measured.

An inexpensive, non-obtrusive optical flowmeter is disclosed comprising at least one flexible, light transmitting optical fiber rod having an enlarged (e.g. spherical) terminus formed at a fluid responsive end thereof. The flexible optical fiber is inserted into a fluid channel in such a manner that the enlarged terminus oscillates at a frequency that is a function of the rate of fluid flow. The intensity and frequency of an optical signal being transmitted via the optical fiber to an optical detector are related to the rate at which fluid flows through the channel. By detecting the intensity and frequency of the optical signal at different times for corresponding rates of fluid flow, an accurate (digital) representation of a particular rate of fluid flow can be obtained.

Fluid flowmeter having an optical fiber sensing element

A method and apparatus for holographically processing optical signals in a fiber-optic sensor system. In the present invention, holographic processors are utilized in various combinations with light sources, fiber-optic transmission means, sensors and detectors to provide low cost, compact, sensitive and accurate sensor systems. By means of the holographic processors of the present invention, the aforementioned sensor systems are used to monitor such physical parameters as temperature, pressure, flow-rate, and the like, and to provide output signal indications thereof that are compatible with digital receiving stations and immune to electro-magnetic interference, hazardous atmosphere, and the inimical effects of inadvertent intensity variation due to equipment vibration and the like. In one typical embodiment, a pair of holographic processors are employed in a color multiplex-demultiplex sensor system in which a first holographic processor is employed to color multiplex a sensor signal and a second holographic processor is employed to decode the color-multiplexed signal into a binary pattern that is then transmitted onto a set of photodetectors. In each of the embodiments of the invention disclosed, a unique geometrical orientation of a hologram is utilized to minimize spurious signal interference that would otherwise hamper or totally preclude the holographic processing.

Method and apparatus for holographic processing

An inexpensive, light weight fiber optic accelerometer to convert input mechanical motion (e.g. acceleration) into digitized optical output signals. The output of the accelerometer may be connected directly to data processing apparatus without the necessity of space consuming analog to digital interface means.

An inexpensive, lightweight fiber optic micro-sensor that is suitable for applications which may require remote temperature sensing. The disclosed temperature sensor includes a phosphor material that, after receiving incident light stimulation, is adapted to emit phosphorescent radiation output signals, the amplitude decay rate and wavelength of which are functions of the sensed temperature.

Fiber optic temperature sensor

Optical sensor apparatus and associated means by which to color multiplex optically encoded information signals over a compact fiber optic transmission system. The sensor apparatus includes a movable coded masking means. The masking means is fabricated with a plurality of parallel rows, each of which rows comprising a binary weighted pattern of alternately spaced transparent and opaque areas. Incident white light is spectrally dispersed, so that each of the rows of the masking means receives a respective color. As the masking means is moved in response to an input physical parameter that is to be sensed, the corresponding binary coded output color signals that are transmitted through the transparent areas of the masking means are recombined and multiplexed over either a singel optical fiber or a bundle of incoherent optical fibers. After demultiplexing or spectral dispersion of the multiplexed output signal, a photo-detector means is utilized to receive the individual demultiplexed binary coded output color signals and to provide a numerical equivalent of the position of the masking means and, accordingly, the physical parameter represented thereby.

Means for sensing and color multiplexing optical data over a compact

A temperature sensor comprising an optical transducer member having an array of birefringent crystals. The length and, accordingly, the sensitivity to temperature change of successive birefringent crystals varies according to a particular relationship. The transducer is interconnected with a fiber optic transmission and detecting system. Respective optical output signals that are transmitted from the birefringent crystals via the fiber optic transmission system are detected and decoded so as to correspond to digits of a numbering system, whereby an accurate digital representation of temperature can ultimately be provided.

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Corona Del Mar, CA, United States of America

Kenneth A James