Device and method for increasing white light interference measurement link length

Abstract

The invention discloses a device and method capable of increasing the length of a DUT link measured based on the white light interference principle, and belongs to the field of optical measurement, one path of optical signal is divided into N paths of signals, each path of optical signal is subjected to frequency shift in different ranges and then is combined into one path, and the optical path of an optical fiber link is changed; the other path enters a DUT link, and beat frequency interference occurs between echo signals returned from the DUT and white light mixed signals with different frequencies; performing difference frequency detection on the beat frequency signal; converting the difference frequency signal into a return loss-position curve of the DUT link to be tested; the length difference of each path is controlled to be equal to the delayed movable range, and the measurement range of the white light interference measurement link signal is improved by N times. According to the invention, through a frequency domain multiplexing thought, superposed mixed signals obtained by simultaneous interference of multiple paths of signals are separated in a frequency domain, then are inversely transformed into time domain signals, and are spliced front and back, so that a total signal obtained by sequential splicing of N paths of beat frequency signals can be obtained, and the total signal can realize N times of a measurement range during original single-path interference.

Description

technical field [0001] The invention belongs to the technical field of optical measurement, and more specifically relates to a device and a method for increasing the length of a white light interferometric measurement link. Background technique [0002] White light interferometry is an effective means and solution for measuring weak optical signals and precise positioning. Using the extremely short coherence length of white light, the detection and accurate positioning of distributed extremely weak echo signals can be realized. White light interference usually uses optical fiber delay line scanning to increase the optical path distance, observe the presence and height of the interference peak of the beat frequency spectrum in this increased optical path length, and judge whether there is an event point, the position of the event point, and the echo power of the event point . [0003] However, due to the technological limitations of optical devices such as fiber optic delay...

AI Technical Summary

Problems solved by technology

[0004] In view of the above defects or improvement needs of the prior art, the present invention proposes a device and method for increasing the length of the white light interferometry link to solve the solution for measuring the distributed return loss of the link by white light interferometry. The link length is very short, which is limited by the technical problem of the maximum delay range constraint of the fiber delay line

Images