Patent ID: 7515275

Claim:
An optical sensor for determining a distance between a target and a probe head, the sensor comprising: a low-coherence light source delivering a broadband spectrum; a fiber-optic Michelson interferometer (FOMI) for creating an interterogram; and an analyzer unit for determining the distance to the target and comprising a Fourier transform unit for calculating a Fourier transform of the spectral distribution of the interferogram, the distance being determined by finding a value of the distance corresponding to a maximum in the Fourier transform; the FOMI comprising: a probing optical fiber having at a first end the probe head and coupled at a second end to the light source such that a first amplitude portion of the broadband spectrum is to propagate from the second end towards the probe head and such that a measuring signal resulting from a reflection of the first amplitude portion on the target is to propagate back in the probing optical fiber from the first end toward an output of the FOMI, the probe head being an integral element having a first end surface and a second end surface, the first end surface being in contact with the first end of the probing optical fiber to receive the first amplitude portion, and the first amplitude portion exiting the probe head from the second end surface to directly illuminate the target; and a reference optical fiber coupled at one end to the light source such that a second portion of amplitude of the broadband source is to propagate along a reference optical path of fixed length to provide a reference signal at the output, the probing optical fiber and the reference optical fiber being coupled such that the measuring signal and the reference signals are to be combined to form the interferogram.