Micron Optics, Inc.

Stephen K Ferguson

Yufei Bao

Donald Q Snyder

The current invention relates to optical gages designed to measure strain on the surface of a test specimen. The gages of this invention is designed to be installed and used in a manner similar to conventional electronic foil strain gages, but to have the advantages of an all-optical gage. The gage of this invention is constructed to allow surface strain on the test specimen to be transferred to a length of optical fiber containing a fiber Bragg grating (FBG). As strain is applied to the fiber, the optical spectrum center wavelength reflected by the Bragg grating shifts in wavelength. This shift in wavelength can be converted directly to units of strain. The current invention provides a gage carrier design for use with fiber optic strain sensors comprising one or more FBGs which provide the benefits of a carrier for ease of handling and mounting without degrading gage performance. The gage carrier provides features that allow the FBG to be precisely positioned and securely bonded to the test specimen in a controlled manner. The carrier additionally provides fiber protection to the installed FBG.

Fiber optic strain gage and carrier

The invention relates generally to optical interference filters and interferometers. Methods, devices and device components for fiber Fabry-Perot (FFP) filters and ferrule holders are provided. The invention provides ferrule holders for FFP filters capable of good radial and longitudinal alignment. An exemplary ferrule holder of the present invention is capable of substantially constraining the motion of a pair of ferrules in all directions except a direction parallel to the longitudinal axis, thereby allowing the resonance cavity of a FFP filter to be adjusted while maintaining good radial alignment. The invention further provides temperature compensated ferrule holders and FFP filters that are stable with respect to wavelength drift over a useful range of device operating conditions. In addition, the present invention provides ferrule holders and FFP filters which are particularly useful for monitoring ambient conditions and measuring physical properties and mechanical phenomena.

Selectable and tunable ferrule holder for a fiber Fabry-Perot filter

Improved fiber Fabry-Perot (FFP) filter configurations are provided in which at least one of the mirror-ended fiber ends forming the FFP has a concave fiber core end. The mirror at that fiber core end is thus concave. The invention provides waferless FFP configurations in which the FFP cavity is an air-gap cavity formed by two highly reflective dielectric mirrors deposited directly on optical fiber ends. The air gap cavity can be tuned using various methods to tune the filter. Use of a concave mirror at the fiber core enables filters with improved performance characteristics: including very wide FSR (&#x3e;12000 GHz), very high finesse (&#x3e;5,000), and high glitch-free dynamic range (GFDR) (&#x3e;40 dB). The invention also provides improved wafer-based FFP fixed and tunable filters that incorporate a concave mirror at a fiber core forming the FFP cavity and a fiber (SMF) waveguide within the cavity.

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Lawrenceville, GA, United States of America

Stephen K Ferguson