Dual-wavelength photometer and fiber optic sensor probe

A dual wavelength optical sensor for measuring chemical properties based on the optical characteristics of thin sensing films which are responsive to at least two distinct wavelengths of light, the optical sensor comprising:

• light source means for producing light outputs at the at least two distinct wavelengths;
• a single optical fiber receiving the at least two distinct wavelengths of light from the light source means and carrying the light to a sensor probe;
• the sensor probe transmitting the at least two distinct wavelengths of light to and from a thin sensing film associated with the sensor probe, the thin sensing including optical characteristics which produce responses at the at least two distinct wavelengths which, when combined, provide a self-calibrated measurement of the chemical properties being measured;
• sample detecting means receiving the at least two distinct wavelengths of light transmitted from the thin sensing film and measuring the optical characteristics of the thin sensing film in response to the at least two distinct wavelengths of light;
• and
• means combining the measurements of the optical characteristics of the thin sensing film from the sample detecting means for providing the self-calibrated measurements which account for changes in the optical characteristics of the thin sensing film that otherwise contribute to instability in the sensor response.

A method of measuring chemical properties of a particular quantity based on the optical characteristics of thin sensing films which are responsive to at least two distinct wavelengths of light, the method comprising:

• producing light at the at least two distinct wavelengths;
• conveying the light through a single optical fiber to a thin sensing film;
• subjecting the thin sensing film to the chemical properties to be measured to produce responsive optical characteristics at the at least two distinct wavelengths which, when combined, provide a self-calibrated measurement of the chemical properties being measured;
• receiving the at least two distinct wavelengths of light from the thin sensing film and measuring the optical characteristics of the thin sensing film in response to the at least two distinct wavelengths of light;
• and
• combining the measurements of the optical characteristics of the thin sensing film for providing the self-calibrated measurement which accounts for changes in the optical characteristics of the thin sensing film that otherwise contribute to instability in the sensing response.

A dual wavelength optical sensor for measuring the optical characteristics of thin sensing films which are responsive to the chemical properties of a particular quantity to be measured, the optical sensor comprising:

• light source means for producing light at two distinct wavelengths;
• a time-shared optical fiber receiving the two distinct wavelengths of light from the light source means and carrying the two distinct wavelengths on a time-shared basis to a sensor probe;
• the sensor probe transmitting the two distinct wavelengths of light to and from a thin sensing film associated with the sensor probe, the optical characteristics of the thin sensing film being responsive to the chemical properties of the quantity at the two distinct wavelengths in such a way that when the responses to the two distinct wavelengths are combined, a self-calibrated measurement of the measured chemical properties is provided;
• sample detecting means receiving the two distinct wavelengths of light transmitted from the thin sensing film and measuring the optical characteristics of the thin sensing film in response to the two distinct wavelengths of light;
• and
• means combining the measurements of the optical characteristics of the thin sensing film in response to each of the two distinct wavelengths for providing the self-calibrated measurement which accounts for changes in the optical characteristics of the thin sensing film that otherwise contribute to instability in the sensor response.

A dual wavelength optical sensor for measuring chemical properties of a particular quantity comprising:

• a sensor probe including a thin sensing film whose optical characteristics are responsive to the chemical properties of the quantity at at least two distinct wavelengths of light in such a way that when the responses to the at least two distinct wavelengths are combined, a self-calibrated measurement of the measured chemical properties is provided;
• a wide spectrum light source generating multiple wavelength light over a wide spectral range, the at least two distinct wavelengths of light being included in said wide spectral range;
• a single optical fiber for carrying the light from the light source to the sensor probe;
• sample detecting means receiving the light from the sensor probe after it has passed to and from the thin sensing film, the sample detecting means filtering the at least two distinct wavelengths of light from the multiple wavelength light to produce light intensity readings at the respective wavelengths of light;
• and
• output means for combining the light intensity readings from the sample detecting means to produce the self-calibrated measurement which accounts for changes in the optical characteristics of the thin sensing film that otherwise contribute to instability in the sensor response.