Patent ID: 8120759

Claim:
A method for sensing strain in a component in a wind turbine comprising an optical sensor system, said method comprising: inputting an input optical signal into a plurality of optical fibers of said sensor system, each of said optical fibers comprising one or more fiber Bragg grating sensors; measuring a spectral intensity distribution of a transmitted output optical signal influenced by said one or more sensors, in response to the input optical signal, with a plurality of light detectors, said light detectors being operatively connected to the optical fibers with first and second detectors connected to respective first and second fibers, and with said first and second detectors being located downstream relative to said one or more sensors of said respective first and second fibers; and processing the measured output optical signal in a control unit in order to establish a value of a strain in the component wherein the output optical signal comprises at least one notch representing a minimum light intensity, and the strain value is established by determining a spectral location of the at least one notch in the measured spectral intensity distribution.