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Fiber Optic Fabry Perot Vector Sensor Arrays
Navy SBIR FY2007.3
| Sol No.: |
Navy SBIR FY2007.3 |
| Topic No.: |
N07-215 |
| Topic Title: |
Fiber Optic Fabry Perot Vector Sensor Arrays |
| Proposal No.: |
N073-215-0434 |
| Firm: |
VIP Sensors
302 Calle Paisano
Suite 1523
San Juan Capistrano, California 92673 |
| Contact: |
Alexis Karolys |
| Phone: |
(949) 429-3558 |
| Web Site: |
www.vipsensors.com |
| Abstract: |
Conventional accelerometers are non-optimal for many submarine sensor applications, especially for hydrophone towed arrays. Limitations include size and weight, need for heavy copper conductors, susceptibility to electromagnetic interference and electrical cross talk, and limited cable drive capability. VIP Sensors proposes to develop a sensor measuring system consisting of optical MEMS vector sensors distributed on a single optic fiber, each working at different frequency ranges. A broadband high intensity LED is used as a light source for the serially connected accelerometers. Each optical sensor, tuned to work at a unique frequency of the spectrum, shifts (modulates) its corresponding input signal frequency proportional to the measured pressure and lets pass all other frequency signals. The light at the end of the optic fiber contains the information for all sensors at different preset frequency slots, in a scheme similar to Wave Division Multiplexing. An optical demultiplexer located at the fiber end separates the signal spectrum. A photodiode array converts the photons to electrons and specialized circuitry quantifies the frequency shift corresponding to each sensor. The sensor is sculptured on silicon wafer using MEMS processes. It consists of a mass hanging on a flexure hinge. A strand of optical fiber is attached on the surface of the sensor chip with an intrinsic Fabry Perot cavity laid between the mass and the rigid frame. The inertia force rotates the hanging mass about the flexure hinge. The mass displacement stretches or compresses the fiber. The strain in the fiber changes the length of the Perot cavity, which causes the shift of the incoming light wavelength. The shift of wavelength is thus proportional the inertia force or acceleration. |
| Benefits: |
Micro-miniature Size - Optical MEMS vector sensors are non-intrusive, very small units. Cumbersome electrical cables typical of traditional transducers are replaced by one optic fiber. The sensor die itself is not much bigger than the optic fiber. The vector sensor is expected to measure 3.5 x 5.0 x 0.8 mm Light Weight - Optical MEMS vector sensors are basically a tiny block of silicon; the final transducer is packaged in a cylinder with two hemispherical end caps, and is less than 15 mm in length, 10 mm in diameter and weights less than 2 grams. This sensor is neutrally buoyant in water to produce the best motion coupling with the acoustic waves in the water. Passive Sensor - The proposed optical MEMS vector sensor does not require any electrical signal; modulated photons provide the needed information. This intrinsic feature makes these sensors highly stable. Network - The proposed optical sensors can be serialized in a network with one central light source and one detection system. Different type of sensors such as accelerometers, pressure transducers, etc. may be connected serially. Vector sensor arrays may be formed that can be very beneficial when measuring underwater sound profiles. Sensitivity / Accuracy - The optical sensors are able to measure displacements on the scale of the wavelength of light, which allows for highly accurate, highly sensitivity devices. Resistance to RFI/EMI - The optical sensor is inherently robust and highly resistant to electromagnetic interference and radio frequency interference The high performing micro-miniature fiber optic accelerometers and its innovative technology are not only applicable underwater sound in towed array, but also to many other fields where accelerometer of small size, high accuracy, robustness and ease of instrumentation use is important. Some of these applications are: Medical - Their small size makes them ideal for motion sensing, etc. Sales potential: $20M /year Structure Monitoring - The networking feature facilitates structure monitoring of ships, aircrafts, satellites, etc. Sales potential: $20M /year Machinery Health Monitoring - Military (ships, aircrafts) and industrial applications. Sales potential: $10M /year Laboratory Testing - Sales potential: $10M /year Aerospace - Aircraft and satellite monitoring. Sales potential: $4M to $6M /year |
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