Fiber Optic Thermometer

A fiber optic thermometer comprising:

• a hollow body made of material of low thermal expansion,
• an intermediate support made of material of high thermal expansion,
• an optical fiber having a first end and a second end remote from the first end, said optical fiber being supported toward the second end inside the hollow body and affixed to intermediate support so as to form a cantilever section,
• a fiber optic splitter coupled to the first end of the optical fiber,
• a light source for directing light into the optical fiber via a first branch of the optical splitter,
• a photo detector arranged for receiving light conveyed through the optical fiber via a second branch of the optical splitter and measuring an intensity of the received light, and
• a reflective target disposed within and supported at a second end of the hollow body so as to be axially aligned with the second end of the optical fiber at room temperature whereby upon changes of the ambient temperature changes the height of the intermediate support and thus cantilever section moves such that its position relative to the reflective target changes thereby changing the instantaneous intensity of light reflected by the target into the second end of the optical fiber and measured by the photo detector.