Design Of Ultrashort Optical Pulses Measuring System

Ultrashort optical pulses show tremendous application foreground,so they develop pretty rapidly.The picosecond magnitude's laser has been quite common.Now the attosecond magnitude's laser has also been commercialized.Pulse width is an important parameter to lasers which produce ultrashort optical pulses.Many measuring systems have very stringent requirements on lasers' pulse width.For example,in laser ranging measuring system,pump-probe measuring system and all-optical measuring system,lasers' pulse width plays a decisive role in overall system performance.Therefore,pulse width measurement for this kind of lasers is a very important and meaningful work.This thesis introduces basic theory,generation technique of and measurement methods for ultrashort optical pulses.Meanwhile it discusses sampling principle and optical heterodyne and gives a theoretical derivation on the propagation of ultrashort optical pulses in fiber.Simulation of measuring principle has also been analyzed in this thesis.On that basis,all fiber ultrashort optical pulses measuring system,which establishes on the optical link of delayed self-heterodyne and uses interferometric autocorrelation and sequential equivalent sampling,has been designed to measure pulse width of high repetition rate ultrashort optical pulses of picosecond fiber lasers.This system connects the photodetector with variable optical delay line to measure pulse width of ultrashort optical pulses,uses the oscilloscope as data acquisition equipment and fits the curve of interferometric autocorrelation intensity and delay time to obtain information about pulse width of optical pulses under test.Experimental results show this system operates at 1550nm and covers repetition rate from 8 to 10GHz.Its measuring range is between 1.3 and 10ps.The maximum relative error of this system is 23 percent and its resolution is 0.01 ps.This system meets design requirements and is characterized by simple structure,easy operation and wide measuring range.Hence,it has good engineering application value.