MEASUREMENT SYSTEM AND THE METHOD FOR CHROMATIC DISPERSION IN OPTICAL FIBERS

摘要

PURPOSE: A system and a method for measuring color dispersion of an optical fiber are provided to accurately measure the color dispersion of a long optical fiber and a short optical fiber. CONSTITUTION: A color dispersion measurement system comprises a multi-mode laser diode(100), an optical fiber amplifier(120), a high dispersion optical fiber(140), an optical spectrum analyzer, a test optical fiber(160), a high-speed photodetector(180), and an RF(Radio Frequency) spectrum analyzer(200). Upon gain-switching the multi-mode laser diode, an optical pulse of 20-30ps is obtained. The optical pulse is amplified by the optical fiber amplifier. The amplified optical pulse is passed through the high dispersion optical fiber to obtain mode separation of the multi-mode laser diode. The high dispersion makes possible the measurement in the range of maximum resolution by adjusting the length. By using the pulse streams of respective wavelengths as reference signals, a test optical fiber is connected. According to the color dispersion characteristic of the test optical fiber, pulse stream interval is changed. The change is measured by the high-speed photodetector and the RF spectrum analyzer. Therefore, the color dispersion of the test optical fiber is measured.