Fiber optic remote sensor

An oscillating resonant element measurand sensor apparatus energized solely by unmodulated radiant energy carried by a single optical pathway, comprising:

• (a) a mechanical resonator subjected to a stress force, said stress force being related to said measurand, said resonator having reflective means for reflecting radiant energy at a location on the surface thereof;
• (b) motive means for vibrating said mechanical resonator;
• (c) optical pathway means for communicating radiant energy from a first point to a second point in a first direction;
• (d) radiant energy source means located apart from said resonant element apparatus, said radiant energy source means providing radiant energy to said optical pathway at said first point, wherein the radiant energy provided by the radiant energy source means is substantially steady and unmodulated;
• (e) terminal end means terminating said optical pathway at said second point, located adjacent sad mechanical resonator such that radiant energy exiting said optical pathway is directed toward said mechanical resonator at said reflective location;
• (f) transducer means for converting radiant energy to electrical energy, located opposite said mechanical resonator from said terminal end of said optical pathway, in which the transducer, mechanical resonator, and terminal end means are displaced one from the other with the mechanical resonator positioned at least partially between said terminal end means and said transducer means;
• (g) electric communication means for communicating electrical current from said transducer means to said motive means, for initiating vibratory motion of the mechanical resonator;
• and
• (h) radiant energy modulation detection means located along said radiant energy optical pathway means apart from said first point;
• wherein vibratory motion of said mechanical resonator modulates said radiant energy incident on said transducer means to produce electrical current modulated at said resonant frequency to energize said motive means and said mechanical resonator motion positions said reflection means such that at least a portion of the radiant energy is reflected back along said optical pathway in a second direction towards said first point ot said radiant energy modulation detection means for determination of said measurand.

In a self-sustaining resonant oscillator apparatus energized solely by radiant energy carried by a single pathway, and which includes a vibratable mechanical resonator, motive means for vibrating said mechanical resonator, and single fiber optic pathway means for communicating radiant energy from a first point to a second point, the method of energizing said oscillator which comprises:

• (a) generating unmodulated radiant energy at a radiant energy source apart from said resonant oscillator,
• (b) introducing said radiant energy into said optical pathway at a first end thereof;
• (c) directing radiant energy from a terminal point at the second end of said optical pathway onto a transducer, the space between said transducer and said terminal point including a vibratable mechanical resonator;
• (d) generating power via said transducer to energize said motive means;
• and
• (e) vibrating said mechanical resonator via said motive means such that said mechanical resonator alternately at least partially passes and shutters radiant energy passing between said terminal point and said mechanical resonator.

In an oscillating resonant element measrand sensor apparatus energized solely by unmodulated radiant energy carried by a single optical pathway, the measurand sensing method comprising:

• (a) subjecting a source end of a radiant energy pathway means to a steady beam of such radiant energy;
• (b) communicating said steady radiant energy along said pathway in a first direction to a self-sustaining resonant oscillator device;
• (c) alternately using only said communicated radiant energy to intermittently drive the resonant element in an oscillatory mechanical vibration mode and to reflect at least a portion of the radiant energy partially along said pathway in a second, reverse direction, wherein electrical energy is derived from the radiant energy by a transducer during periods when the radiant energy is not bein reflected and is used to sustain oscillation of said resonant element;
• and
• (d) detecting the reflected radiant energy variations and relating same to the measurand.

In an oscillating resonant element measurand sensor apparatus energized solely by unmodulated radiant energy carried by a single optical pathway, including plural resonant elements subjected to stress forces related to measurands, radiant energy drive source, and means to return a plurality of signal values related to the stress forces, the method comprsiing:

• (a) subjecting a source end of a radiant energy pathway means to a steady beam of radiant energy which includes a plurality of wavelengths including at least first and second wavelengths,
• (b) communicating said steady beam of radiant energy along said pathway in a first direction to a splitter, said splitter dividing the radiant energy into a plurality of discrete paths,
• (c) communicating the radiant energy from at least one of said plurality of discrete paths to a resonant element device, and
• (d) alternately using only said communicated radiant energy to intermittently drive at least one resonant element in an oscillatory mechanical vibration mode and reflecting energy of a wavelength selected from at least a portion of the radiant energy along at least a portion of said pathway in a second, reverse direction wherein electrical energy for energizing the sensor is derived from the radiant energy by a transducer during periods when the radiant energy is not being reflected and is used to sustain oscillation of said resonant element;
• and
• (e) detecting the reflected radiant energy variations and relating same to the measurand.

An oscillating resonant element measurand sensor apparatus energized solely by unmodulated radiant energy carried by a single optical pathway for a portion of the pathway length, for remotely sensing a plurality of stress forces related to at least one measurand, comprising:

• (a) radiant energy source means located apart from said resonant element sensor apparatus, said radiant energy source means providing radiant energy to said optical pathway at said first point, wherein the radiane energy provided by the radiant energy source means is substantially steady and unmodulated;
• (b) a plurality of vibratable mechanical resonators subjected to at least two stress forces related to at least one measurand, disposed apart from said radiant energy source means;
• (c) single communicating optical pathway means to channel the radiant energy in a first direction from said radiant energy source means;
• (d) means to divide said single communicating pathway into a plruality of communicating pathways each of a separate wavelength;
• (e) terminating end point means associated with each of said resonators for terminating a radiant energy pathway adjacent each of said resonators;
• (f) plural communicating pathway means for communicating radiant energy to the corresponding individual terminal points adjacent each of said resonator elements;
• (g) individual transducer means associated with each pathway and each terminating point, adjacent each of said resonator elements and opposite the respective corresponding terminating point, for generating electrical power from the radiant energy emanating from the respective corresponding terminating point;
• (h) individual electric motive means for inducing movement of each resonator element transversely between its corresponding transducer and respective terminating point to shutter the radiant energy reaching the transducer at frequencies related to the stress forces;
• (i) a reflective surface on each of said resonator elements for modulating the radiant energy by reflecting at least a portion of the radiant energy back along at least a portion of the communicating pathway in a second direction opposite said first direction,
• (j) means for selectively separating the radiant energy returned from each of said resonant elements by wavelength;
• and
• (k) means for detecting the modulation frequency of the returned radiant energy associated with each of said resonant elements.