Refraction sensor

Claim 1

An index of refraction sensor for monitoring the index of refraction of a material external to a sensing face on the sensor by establishing at least one critical wavelength comprising in combination: a first radiant energy path means comprising a single mode optical fiber waveguide and a second radiant energy path means comprising an optical fiber waveguide, said second optical fiber waveguide capable of being long enough to allow remote detection of the index of refraction; a broad-band radiant energy source means optically coupled to said first radiant energy path means, having a band width chosen to span any of said critical wavelengths expected in a given application; collimating means within the radiant energy path to render the incident radiant energy a parallel beam; sensing means prismatically configured so as to provide a direct reflective path from said first waveguide means, through said sensing means, to said second waveguide means, said sensing means possessing a sensing face which reflects a portion of the broadband incident radiant energy as a function of the index of refraction of the material external to the prism sensor face, the portion including any of said expected critical wavelengths; detecting and monitoring means optically coupled to said second radiant energy path means for simultaneously and continuously detecting the intensities of the separate wavelengths of the broad-band radiant energy that is reflected from the prism sensor face to the detector, the detecting means continuously correlating said at least one wavelengths where the reflected spectral intensity abruptly changes with the index of refraction of the material external to the sensing means.

Claim 10

A method for sensing the index of refraction in the oceans at locations that are remote from a detector having prism sensing means, light source, and optical fiber which are expendable, the method comprising: fabricating an index of refraction sensor from a transparent material having a sensing face with spectral reflection characteristics over a preselected bandwidth which includes at least one expected critical wavelength as a function of the index of refraction of the external fluid, said sensor being prismatically configured so as to provide a second mirrored face to reflect the reflected radiant energy through said sensing means; providing a broad-band radiation source for said preselected bandwidth; optically coupling the sensor to the radiation source with a single mode optical fiber waveguide; providing a detector capable of simultaneously and continuously detecting the intensity change of all the individual wavelengths reflected from the prism sensing face as a function of the index of refraction of the external fluid; optically coupling the sensing means to the detector with an extended, reeled second optical fiber waveguide; unreeling the extended second optical waveguide as the measurement is made; continuously sensing the index of refraction by directing the radiation along a direct reflective path from said first optical fiber waveguide, through said prism sensing means, to said second optical fiber waveguide, and continuously detecting the spectral intensities of the radiation reflected from the sensing means as a function of the index of refraction external to the sensing means; and allowing said second optical fiber waveguide to be severed when the measurement is complete.

Claim 11

A method for sensing the index of refraction in the oceans at locations that are remote from a detector having prism sensing means, light source, and optical fiber which are expendable, the method comprising: fabricating an index of refraction sensor from a transparent material having a sensing face with spectral reflection characteristics over a preselected bandwidth which includes at least one expected critical wavelength as a function of the index of refraction of the external fluid, said sensor being prismatically configured so as to provide a second mirrored face to reflect the reflected radiant energy through said sensing means; providing a broad-band radiation source for said preselected bandwidth; optically coupling the sensor to the radiation source with a single mode optical fiber waveguide; providing a detector capable of simultaneously and continuously detecting the intensity change of all the individual wavelengths reflected from the prism sensing face as a function of the index of refraction of the external fluid; optically coupling the sensing means to the detector with an extended, reeled second optical fiber waveguide; unreeling the extended second optical waveguide as the measurement is made; continuously sensing the index of refraction by directing the radiation along a direct reflective path from said first optical fiber waveguide, through said prism sensing means, to said second optical fiber waveguide, and continuously detecting the spectral intensities of the radiation reflected from the sensing means as a function of the index of refraction external to the sensing means; and allowing said second optical fiber waveguide to be severed when the measurement is complete.