Patent ID: 6876786

Claim:
An optical fiber sensor system comprising: a) an optical fiber having the capability transmitting light signals within a first wavelength range and within a second wavelength range, wherein said second wavelength range does not overlap with said first wavelength range, b) a first plurality of sensitive elements said first plurality of sensitive elements being optically and mechanically coupled to said optical fiber, said sensitive elements having a characteristic spectral band occupying said first wavelength range under normal conditions, said characteristic spectral band of at least one sensitive element having the capability of at least partially shifting from said first wavelength range into said second wavelength range, said shifting into said second wavelength range being triggered by a predefined event; c) means for probing integral optical attenuation or integral optical reflection within said second wavelength range of said optical fiber, said means for probing said integral optical attenuation or said integral optical reflection within said second wavelength range of said optical fiber being a light source and a photosensitive apparatus, such that when said integral optical attenuation or said integral optical reflection of said optical fiber in said second wavelength range exceeds a predetermined threshold value, an alarm condition is indicated.