Method and apparatus for optically powering and multiplexing distributed fiber optic sensors
First Claim
1. An optical power converter comprising:
- a photodetector for producing an electrical signal;
a storage circuit in parallel with the photodetector to store at least a portion of the electrical signal;
a first chargeable switch;
a second chargeable switch having a different charging time than the first chargeable switch; and
a dual transistor switch coupled to the first chargeable switch and the second chargeable switch, wherein the storage circuit is coupled to the dual transistor switch, and wherein during a storing state the photodetector supplies current to the storage circuit and the dual transistor switch is in an off state, and wherein during a driving state, the storage circuit supplies current to switch the dual transistor switch to an on state wherein at least one of the first chargeable switch or the second chargeable switch is in a conducting state.
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Accused Products
Abstract
An optical power converting apparatus is provided that may be used with remote sensors. A plurality of remote sensors may be coupled to a backbone optical fiber with each sensor having an optical power converter that receives an optical signal from a head end of that fiber. The optical power converters may store electrical energy derived from that optical signal and use that energy to power the remote sensors. The head end'"'"'s optical signal may also include a clock signal, and each remote sensor may be set to sense a measurable parameter after a given number of clock cycles have been counted. In a further example, each of the optical sensors may be synchronized before counting these clock signals via a synchronization signal from the optical power converter. The remote sensors may individually and separately uplink their sensed data to the head end on the optical fiber. The apparatus may be implemented in a vehicle health management system, for example.
72 Citations
36 Claims
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1. An optical power converter comprising:
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a photodetector for producing an electrical signal;
a storage circuit in parallel with the photodetector to store at least a portion of the electrical signal;
a first chargeable switch;
a second chargeable switch having a different charging time than the first chargeable switch; and
a dual transistor switch coupled to the first chargeable switch and the second chargeable switch, wherein the storage circuit is coupled to the dual transistor switch, and wherein during a storing state the photodetector supplies current to the storage circuit and the dual transistor switch is in an off state, and wherein during a driving state, the storage circuit supplies current to switch the dual transistor switch to an on state wherein at least one of the first chargeable switch or the second chargeable switch is in a conducting state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An optically-powered sensor apparatus comprising:
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an optical fiber;
a head end coupled to the optical fiber to provide optical clock signals on the optical fiber; and
at least two sensor modules coupled to the optical fiber and optically powered by the optical clock signals, each sensor module comprising an optical power converter for converting the optical clock signals to electrical clock signals, a timer for counting the electrical clock signals, and a sensor for sensing a measurable parameter, wherein the at least two sensor modules are adapted to sense the measurable parameter after a different number of electrical clock signals have been counted. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A method of time division multiplexing a plurality of sensor modules coupled to an optical fiber, the method comprising:
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transmitting an optical signal on the optical fiber, the optical signal having a clocking portion wherein optical clock signals are provided and a synchronizing portion;
at each of the plurality of sensor modules, receiving the optical signal and converting the optical clock signals of the clocking portion to electrical clock signals;
synchronizing each of the plurality of sensor modules;
counting the electrical clock signals; and
for at least two of the plurality of sensor modules, sensing a measurable parameter after a different number of electrical clock signals have been counted. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. An optically-powered sensor apparatus comprising:
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an optical fiber;
a laser source coupled to the optical fiber for providing optical clock signals on the optical fiber;
a first sensor module coupled to the optical fiber and optically powered by the laser source, the first sensor module having a sleep mode during which the first sensor module is incapable of sensing a first measurable parameter and an awake mode during which the first sensor module is capable of sensing the first measurable parameter, wherein the first sensor module is adapted to switch from the sleep mode to the awake mode after a first number of optical clock signals have been received at the first sensor module; and
a second sensor module coupled to the optical fiber and optically powered by the laser source, the second sensor module having a sleep mode during which the second sensor module is incapable of sensing the second measurable parameter and an awake mode during which the second sensor module is capable of sensing the second measurable parameter, wherein the second sensor module is adapted to switch from the sleep mode to the awake mode after a second number of optical clock signals have been received at the second sensor module, where the second number of optical clock signals is different than the first number of optical clock signals. - View Dependent Claims (33)
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34. A method of diagnosing the state of a vehicle, the method comprising:
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coupling optical clock signals to the plurality of sensor modules via an optical fiber, each sensor module being disposed at a region of interest and each sensor module having a sleep mode and an awake mode;
optically powering the plurality of sensor modules;
at each sensor module, counting the number of optical clock signals received during the sleep mode;
at each sensor module, in response to the counting of the number of optical clock signals received during the sleep mode, switching the sensor module from the sleep mode to the awake mode, where each sensor module is switched from the sleep mode to the awake mode after a different number of optical clock signals have been counted;
at each sensor module, sensing a measurable parameter and producing sensed data; and
diagnosing the sensed data from each sensor module. - View Dependent Claims (35, 36)
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Specification