Patent ID: 6400450
Filing Date: 2002-06-04
Classification: G01M

Abstract:
A method of qualifying a multimode optical fiber for bandwidth performance when used with a laser source that excites a modal power distribution (MPD) comprising an optical power in various mode fields of the multimode optical fiber, said multimode fiber having a core surrounded by a cladding and having an input end and an output end, the method comprising the following steps:measuring a differential mode delay (DMD) characteristic of the multimode fiber; combining the MPD excited by the laser source with the DMD of multimode fiber to estimate the fiber's impulse response; performing a time-domain-to-frequency-domain transformation of the impulse response to determine the distribution of optical power as a function of frequency; and assigning a measure of bandwidth performance to the multimode fiber, said measure being the frequency difference between a pair of band-edge frequencies where the magnitude of the optical power distribution is less than the maximum magnitude of the optical power distribution by a predetermined amount.