An optical sensor includes an optical fiber inscribed with a repeated refraction pattern such that light scattered from a location on the optical fiber is scattered at multiple frequencies in a range of frequencies. The inscribed patterns overlap at every measurement point along at least a portion of the length of the sensor. An optical sensing system including control circuitry coupled to the optical fiber detects measurement scatter data from the optical fiber over the range of frequencies, determines a change in the detected measurement scatter data over the range of frequencies, and extracts a parameter describing a state of the optical fiber from the determined change in the detected measurement scatter data. The sensor may be made by inscribing a first light refracting pattern on the optical fiber at every measurement point along at least a portion of the length of the sensor and inscribing a second light refracting pattern on the optical fiber that overlaps the first inscribed light refracting pattern at every measurement point along at least that portion of the length of the sensor.

A system for producing an optical fiber with inscribed grating array is described. The system comprises a fiber drawing apparatus for drawing an optical fiber, a writing system for inscribing a grating in the optical fiber during the drawing process of the optical fiber and a controller for controlling the driving of the writing system. According to the present invention the fiber drawing apparatus also comprises a fiber length and/or drawing detecting means for determining the fiber length and/or fiber drawing speed and/or a fiber drawing parameter during the drawing process. The controller thereby is configured for capturing information from the fiber length and/or drawing detecting means and for controlling the writing system based on the captured information captured from the fiber length and/or drawing detecting means.

A system for producing an optical fiber with inscribed grating array is described. The system comprises a fiber drawing apparatus for drawing an optical fiber, a writing system for inscribing a grating in the optical fiber during the drawing process of the optical fiber and a controller for controlling the driving of the writing system. According to the present invention the fiber drawing apparatus also comprises a fiber length and/or drawing detecting means for determining the fiber length and/or fiber drawing speed and/or a fiber drawing parameter during the drawing process. The controller thereby is configured for capturing information from the fiber length and/or drawing detecting means and for controlling the writing system based on the captured information captured from the fiber length and/or drawing detecting means.

A system for producing an optical fiber with inscribed grating array is described. The system comprises a fiber drawing apparatus for drawing an optical fiber, a writing system for inscribing a grating in the optical fiber during the drawing process of the optical fiber and a controller for controlling the driving of the writing system. According to the present invention the fiber drawing apparatus also comprises a fiber length and/or drawing detecting means for determining the fiber length and/or fiber drawing speed and/or a fiber drawing parameter during the drawing process. The controller thereby is configured for capturing information from the fiber length and/or drawing detecting means and for controlling the writing system based on the captured information captured from the fiber length and/or drawing detecting means.

A method for producing a protected optical fiber with distributed sensors includes heating an optical fiber preform and drawing the heated optical fiber preform to form a drawn optical fiber. The method also includes coating the drawn optical fiber with a carbon coating after the optical fiber is drawn to provide a carbon coated optical fiber and then writing a series of fiber Bragg gratings (FBGs) into the carbon coated optical fiber to provide a carbon coated optical fiber with FBGs. The method further includes coating the carbon coated optical fiber with FBGs with one or more layers of a polymer to provide the protected optical fiber with distributed sensors, wherein the heating, drawing, carbon coating the drawn optical fiber, writing, coating the carbon coated optical fiber are performed in that sequence while the protected optical fiber is being produced.

An optical sensor includes an optical fiber inscribed with densely-overlapping, chirped-frequency fiber Bragg gratings at multiple locations along the optical fiber such that light reflected from a location on the optical fiber is reflected at multiple frequencies in a range of frequencies. An entire length of the optical sensor includes densely-overlapping, chirped-frequency fiber Bragg gratings. At least two of the densely-overlapping, chirped-frequency fiber Bragg gratings overlap at every measurement point along the entire length of the optical sensor. An optical sensing system uses the optical sensor. A method of making the optical sensor is described.