Method and apparatus for detecting and compensating for a kink in an optic fiber

摘要

A method and apparatus are provided for detecting and compensating for a kink in an optical fiber. A distal sensor (11) monitors a level of a parameter in an environment in which the distal sensor is immersed. The distal sensor is disposed at a tip of the optical fiber (17) and the optical fiber conveys green light signals and near infrared (NIR) light signals to and from the distal sensor. A photodetector (59') records the signal and reference values for the green light signals and the NIR light signals conveyed by the optical fiber at consecutive data points. A microcontroller (42) is electronically coupled to the photodetector and receives the signal and reference values for the green light signals and the NIR light signals. A kink in the optical fiber is detected when a change between NIR signal values recorded at a pair of consecutive data points recorded by the photodetector is greater than a predetermined threshold. After the kink is detected, a true level of the parameter in the environment is calculated that compensates for the kink. More specifically, a true green signal value is determined based on a linear relationship between green and NIR signal values recorded at the pair of consecutive data points. The true green signal value is then used to calculate the true level of the parameter. In an alternative embodiment of the present invention, a warning is issued when the kink is detected and monitoring of the level of the parameter is discontinued.