SYSTEM AND METHOD FOR MEASURING PHYSICAL, CHEMICAL AND BIOLOGICAL STIMULI USING VERTICAL CAVITY SURFACE EMITTING LASERS WITH INTEGRATED TUNER
First Claim
1. An optical sensor diagnostic system, comprising:
- a tunable VCSEL incorporating an integrated MEMS wavelength tuner for providing wavelength-tunable light in response to a tuning control signal, said tunable light being launched into an optical waveguide, said tunable VCSEL including a movable tuning mirror and at least one optical, capacitive, piezoelectric or magnetic detector for detecting the position of the movable tuning mirror and providing feedback;
at least one optical sensor, disposed in the path of said tunable light, said at least one sensor providing a transmitted light having at least one associated characteristic amplitude feature selected from the group consisting of a minimum, a maximum or a slope located at a particular wavelength within the transmitted wavelength range, said wavelength at each minimum, maximum or sloped transmission amplitude being responsive to an environmental stimulus imposed upon said at least one sensor;
said tunable VCSEL individually illuminating said at least one sensor in a wavelength range spanning said wavelength location of said associated characteristic transmission amplitude feature;
an optical isolator, disposed in the path of said tunable light between said tunable VCSEL and said at least one sensor, said optical isolator isolating said tunable light source from light reflected from said at least one sensor;
an optical detector disposed in the path of said transmitted light, said optical detector detecting said transmitted light from said at least one sensor and providing an electrical detection signal indicative of the power of said transmitted light throughout a predetermined wavelength range;
a controller for providing a variable tuning control signal to said tunable VCSEL indicative of the desired wavelength of said tunable light;
at least one wavelength reference independent of said tuning control signal and moveable mirror position detector disposed in the path of the light; and
a signal processor responsive to said electrical detection signal, for detecting a wavelength defined on the characteristic transmission amplitude feature in order to quantitatively detect the effect on said at least one sensor due to said environmental stimulus, changes in said wavelength at the characteristic transmission amplitude feature caused by changes in said environmental stimulus, and for providing a signal indicative of said stimulus or change therein.
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Accused Products
Abstract
An optical sensor diagnostic system uses a tunable Vertical Cavity Surface Emitting Laser (VCSEL) that incorporates an integrated MEMS tuning mechanism. The system provides variable wavelength light into an optical fiber with improved wavelength scanning speed and greater simplicity of construction. Sensors, such as Bragg gratings, are disposed along the fiber in the light path. Each sensor reflects or transmits light exhibiting a characteristic amplitude feature with respect to wavelength, the wavelength position of which is affected by an environmental stimulus imposed thereon. The reflected light is converted to an electrical signal by a simple detector and monitored by circuitry that detects changes. The system provides output signals indicative of the environmental stimulus for each sensor.
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Citations
65 Claims
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1. An optical sensor diagnostic system, comprising:
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a tunable VCSEL incorporating an integrated MEMS wavelength tuner for providing wavelength-tunable light in response to a tuning control signal, said tunable light being launched into an optical waveguide, said tunable VCSEL including a movable tuning mirror and at least one optical, capacitive, piezoelectric or magnetic detector for detecting the position of the movable tuning mirror and providing feedback;
at least one optical sensor, disposed in the path of said tunable light, said at least one sensor providing a transmitted light having at least one associated characteristic amplitude feature selected from the group consisting of a minimum, a maximum or a slope located at a particular wavelength within the transmitted wavelength range, said wavelength at each minimum, maximum or sloped transmission amplitude being responsive to an environmental stimulus imposed upon said at least one sensor;
said tunable VCSEL individually illuminating said at least one sensor in a wavelength range spanning said wavelength location of said associated characteristic transmission amplitude feature;
an optical isolator, disposed in the path of said tunable light between said tunable VCSEL and said at least one sensor, said optical isolator isolating said tunable light source from light reflected from said at least one sensor;
an optical detector disposed in the path of said transmitted light, said optical detector detecting said transmitted light from said at least one sensor and providing an electrical detection signal indicative of the power of said transmitted light throughout a predetermined wavelength range;
a controller for providing a variable tuning control signal to said tunable VCSEL indicative of the desired wavelength of said tunable light;
at least one wavelength reference independent of said tuning control signal and moveable mirror position detector disposed in the path of the light; and
a signal processor responsive to said electrical detection signal, for detecting a wavelength defined on the characteristic transmission amplitude feature in order to quantitatively detect the effect on said at least one sensor due to said environmental stimulus, changes in said wavelength at the characteristic transmission amplitude feature caused by changes in said environmental stimulus, and for providing a signal indicative of said stimulus or change therein. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. An optical sensor diagnostic system, comprising:
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a VCSEL incorporating integrated MEMS wavelength tuner for providing wavelength-tunable light in response to a tuning control signal, said tunable light being launched into an optical waveguide, wherein is provided at least one optical sensor, disposed in the path of said tunable light, each providing a reflected light having at least one associated characteristic amplitude feature selected from the group, a minimum, a maximum or a slope located at a particular wavelength within the reflected wavelength range, said wavelength at each minimum, maximum or sloped reflection amplitude being responsive to an environmental stimulus imposed upon a corresponding sensor;
said tunable VCSEL for individually illuminating each of said sensors in a wavelength range spanning said wavelength location of said associated characteristic reflection amplitude feature;
optical detector, disposed in the path of said reflected light, for detecting said reflected light from each of said sensors and for providing an electrical detection signal indicative of the power of said reflected light throughout the appropriate wavelength range;
an arrangement including at least one of an optical circulator and an optical splitter, said optical circulator or optical splitter being optically coupled to with an optical isolator, said arrangement being disposed in the path of said tunable light between said tunable VCSEL and said sensor, for isolating said tunable light source from light reflected from said sensor and directing the light to said detector;
voltage or other controller for providing a variable tuning control signal to said tunable VCSEL indicative of the desired wavelength of said tunable light;
at least one capacitive, optical, piezoelectric or magnetic detector that detects the position of the movable tuning mirror and providing feedback; and
at least one wavelength reference independent of said tuning control signal and moveable mirror position detector disposed in the path of the light, and signal processor responsive to said electrical detection signal, for detecting a wavelength defined on the characteristic reflection amplitude feature in order to quantitatively detect the effect on said sensor due to said environmental stimulus, changes in said wavelength at the characteristic reflection amplitude feature caused by changes in said environmental stimulus, and for providing a signal indicative of said stimulus or change therein for each of said sensors. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62)
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63. In a sensing system of the type including an optical fiber sensor or optical waveguide having a radiation reflectance or transmissivity characteristic that varies in response to a stimulus, an optical path being defined between a coupler and said optical fiber sensor or optical waveguide, a sensing method comprising:
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(1) operating a Vertical Cavity Surface Emitting Laser to generate radiation;
(2) tuning the Vertical Cavity Surface Emitting Laser to vary the wavelength of said Vertical Cavity Surface Emitting Laser-generated radiation;
(3) coupling at least some of the radiation emitted by said Vertical Cavity Surface Emitting Laser to said coupler; and
(4) analyzing radiation transmitted or reflected by said sensor or waveguide for variations of said characteristic caused by said stimulus.
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64. A sensing system including an optical fiber sensor or optical waveguide, said system comprising:
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a coupler being coupled to the optical fiber sensor or optical waveguide having a wavelength-selective radiation transmissivity characteristic that varies in response to a stimulus;
a Vertical Cavity Surface Emitting Laser coupled to said coupler, said Laser operated to generate radiation and supply said radiation to said coupler;
a tuning device that tunes the Vertical Cavity Surface Emitting Laser to vary the wavelength of said Vertical Cavity Surface Emitting Laser-generated radiation;
a detector that detects radiation transmitted or reflected by the optical fiber sensor or waveguide; and
an analyzer that analyzes said detected radiation for at least one variation caused by said stimulus.
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65. A sensing system including an optical fiber sensor or optical waveguide, said system comprising:
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coupling means being coupled to the optical fiber sensor or optical waveguide having a wavelength-selective radiation transmissivity characteristic that varies in response to a stimulus;
Vertical Cavity Surface Emitting Laser means coupled to said coupler, said Laser means for generating radiation and for supplying said radiation to said coupler;
tuning means for tuning the Vertical Cavity Surface Emitting Laser means to vary the wavelength of said generated radiation;
detecting means for detecting radiation transmitted or reflected by the optical fiber sensor or waveguide; and
analyzing means for analyzing said detected radiation for at least one variation caused by said stimulus.
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Specification