Multi-mode optical fiber sensor

A method for sensing one of vibration, temperature, and strain, the method comprising:

• stretching a multimode optical fiber at an out of band frequency such that it operate at a point at which an output is a linear function of a displacement of the multimode optical fiber;
• powering a laser source coupled to a first end of a first single mode optical fiber;
• propagating light through said first single mode optical fiber, a second end of said first single mode optical fiber being coupled to a first end of the multimode optical fiber;
• exciting a plurality of modes in said multimode optical fiber by coupling said light propagating through said first single mode optical fiber into said multimode optical fiber;
• spatially filtering an output of said multimode fiber to obtain an interference pattern;
• and
• detecting a variation of said interference pattern when one of said vibration, temperature, and strain is applied to said multimode optical fiber.

A musical instrument comprising:

• a housing having a neck and a body;
• a plurality of tuning pegs at one end of said neck;
• a bridge on the body;
• and
• a multimode fiber having a plurality of segments stretched at an out of band frequency and operated at a point at which an output is a linear function of a displacement of the multimode fiber, each one of said segments extending from one of said tuning pegs to the bridge, the bridge holding the multimode fiber in place on the body, the multimode optical fiber being wrapped around each one of the tuning pegs, the tuning pegs adjustable for tensioning each of the segments of the multimode optical fiber.