Overlapped Fiber Bragg Gratings With Different Reflectivities

A grating writing system for writing gratings in an optical fiber, comprising:

• a laser source configured to emit ultraviolet light;
• a positioning system configured to adjust at least one pose parameter selected from the group consisting of:
• a position the optical fiber, an orientation of the optical fiber, a position of a part of the laser source, an orientation of the part of the laser source, a position of an optical component associated with the laser source, or an orientation of the optical component;
• and
• a control system comprising one or more processors, the one or more processors comprising circuitry, the control system configured to control the laser source and to cause the positioning system to adjust the at least one pose parameter such that (i) a first ultraviolet light pulse emitted by the laser source is directed to interact with a first portion of the optical fiber to alter a reflectivity of the first portion by a first amplitude and (ii) a second ultraviolet light pulse emitted by the laser source is directed to interact with a second portion of the optical fiber to alter a reflectivity of the second portion by a second amplitude, wherein the first portion partially overlaps with the second portion in an overlap region, and wherein a ratio of the first amplitude in the overlap region and the second amplitude in the overlap region is nonzero and differs from 1.0.

A method for writing overlapping gratings in an optical fiber, the method comprising:

• causing, by a control system comprising one or more processors, an adjustment to at least one pose parameter selected from the group consisting of:
• a position of the optical fiber, an orientation of the optical fiber, a position of a part of a laser source configured to emit ultraviolet light, an orientation of the part of the laser source, a position of an optical component associated with the laser source, or an orientation of the optical component;
• and
• causing, by the control system, the laser source to emit (i) a first ultraviolet light pulse that is directed to interact with a first portion of the optical fiber to alter a reflectivity of the first portion by a first amplitude and (ii) a second ultraviolet light pulse directed to interact with a second portion of the optical fiber to alter a reflectivity of the second portion by a second amplitude, wherein the first portion partially overlaps with the second portion in an overlap region, and wherein a ratio of the first amplitude in the overlap region and the second amplitude in the overlap region is nonzero and differs from 1.0.