Patent ID: 7659969

Claim:
A method for determination of the bandwidth of at least one optical fiber from attenuation of two optical signals at two frequencies, the method comprising: injecting light at a first optical power level and at a first frequency of the two frequencies into the at least one optical fiber; measuring a first signal level as a function of the optical power level of the light which is passing through the at least one optical fiber and is at the first frequency; injecting light at a second optical power level and at a second frequency of the two frequencies into the at least one optical fiber, wherein the second frequency is different than the first frequency; measuring a second signal level as a function of the optical power level of the light which is passing through the at least one optical fiber and is at the second frequency; and determining the bandwidth of the at least one optical fiber as a function of the first and second optical power levels and/or of the measured first and second signal levels using a predetermined rule which describes a frequency-dependent attenuation response of the at least one optical fiber.