Device and method of calibrating fiber Bragg grating based fiber optic overheat systems

A method of calibrating a fiber optic system, the method comprising:

• emitting, by a first optical transmitter disposed in a first interrogator connected to an optical fiber, a first optical signal into the optical fiber, wherein the optical fiber comprises:
• a plurality of overheat fiber Bragg gratings disposed in the optical fiber;
• and
• a plurality of calibration fiber Bragg gratings disposed in the optical fiber;
• reflecting the first optical signal with at least one of the plurality of calibration fiber Bragg gratings to create a first response signal;
• receiving, by a first optical receiver in the first interrogator, the first response signal from the optical fiber based upon the reflected first optical signal;
• detecting the received first response signal to identify presences of each of the plurality of calibration fiber Bragg gratings;
• emitting, by a second optical transmitter disposed in a second interrogator that is different from the first interrogator, a second optical signal into the optical fiber;
• reflecting the second optical signal with at least one of the plurality of calibration fiber Bragg gratings to create a second response signal;
• receiving, by a second optical receiver in the second interrogator, a second response signal from the optical fiber based upon the second optical signal;
• detecting the received second response signal to further identify presences of each of the plurality of calibration fiber Bragg gratings;
• and
• determining a calibration value based upon the identified presences of the plurality of calibration fiber Bragg gratings.

A detection system comprising:

• a line replaceable unit comprising:
• first and second connectors in optical communication;
• and
• an optical fiber extending between the first and second connectors, the optical fiber with first and second ends, wherein the first end of the optical fiber is connected to the first connector, wherein the optical fiber comprises:
• a plurality of overheat fiber Bragg gratings disposed in the optical fiber;
• a first timing fiber Bragg grating disposed in the optical fiber, wherein the first timing fiber Bragg grating is configured to indicate at least one of a start point and end point of the line replaceable unit;
• a plurality of calibration fiber Bragg gratings located in a pattern that provides information related to a calibration value of the line replaceable unit based upon a center wavelength of each of the first plurality of overheat fiber Bragg gratings;
• a first interrogator connected to the line replaceable unit at the first end of the optical fiber, wherein the first interrogator is configured to provide a first optical signal to the optical fiber and to receive a first optical response signal from the optical fiber;
• a second interrogator different from the first interrogator, wherein the second interrogator is connected to the second end of the same optical fiber that the first interrogator is connected to, wherein the second interrogator is configured to provide a second optical signal to the optical fiber and to receive a second optical response signal from the optical fiber;
• and
• a controller operatively connected to the first interrogator and configured to determine the calibration value of the line replaceable unit based on the first optical response signal.