Claims
- 1. A progressively monitorable fire alarm system, comprising:
- one or more thermally switchable fiber reflectors disposed along a continuous length of optical fiber, said reflectors being comprised of two optical fiber ends fused together, one of said fiber end having a reflective surface consisting of a vanadium oxide, the combination optical fiber and reflector having a thermally sensitive or an electrically resistive medium deposited along its length;
- a pulsed light source disposed at one end of the optical fiber, and a receiver disposed to detect reflections of the pulsed light source such that a change in the general refractive index of each reflector may be individually monitored.
- 2. A progressively monitorable fire alarm system, comprising:
- multiple low finesse Fabry-Perot cavities disposed in a continuous length of optical fiber, said cavity having a thermally sensitive or an electrically resistive medium deposited along the length of the cavity;
- a pulsed light source disposed at one end of the optical fiber, and a receiver disposed to detect reflections of the pulsed light source, such that the change in the general refractive index of each cavity may be monitored.
- 3. A progressively monitorable fire alarm system comprising:
- multiple low finesse Fabry-Perot cavities positioned in a continuous length of optical fiber such that the general reflectivity of the cavity will vary dependent upon temperature;
- a pulse light source disposed at one end of the optical fiber, and an optical receiver disposed to detect reflections of the pulsed light source such that the general reflectivity of each cavity may be monitored.
- 4. The fire alarm system of claim 2 where the Fabry-Perot cavities are constructed by forming two optical mirrors along a continuous length of optical fiber such that the mirrors are separated by a length of optical fiber.
- 5. The fire alarm system of claim 4 where the mirrors are formed by fusion splicing.
Parent Case Info
This is a divisional of application Ser. No. 108,270 filed Oct. 13, 1987 now U.S. Pat. No. 4,848,999.
US Referenced Citations (18)
Non-Patent Literature Citations (3)
Entry |
Miyauchi, E., Compact Wavelength Multiplexer using Optical-Fiber Pieces, Optical Society of America, vol. 5, No. 7, (1980). |
Epworth, Model Noise-Causes and Cures, Laser Focus, vol. 17 (1981) pp. 224-230. |
Kuwahara, H., A Semi-Transparent Mirror-Type Directional Coupler for Optical Fiber Applications, IEEE Transactions of Microwave Theory & Techniques, pp. 179-180. |
Divisions (1)
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Number |
Date |
Country |
Parent |
108270 |
Oct 1987 |
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