Research On Jitter Measurement Based On The Photonics Time Stretch

Time is one of the seven fundamental physical quantities,ultra-stable time signals are widely used in the fields of communication,navigation and positioning,aerospace,astrophysics and metrology.High-resolution time measurement capability is a key mark of the development in science and technology.In the information field,time information is often transmitted by electrical pulses.The parameter that measures the timedomain stability of an electrical pulse signal is called timing jitter.How to measure tinier timing jitter has become a hot research at present.Traditional electrical instruments are difficult to further improve the measurement resolution of timing jitter due to electronic bottlenecks.The all-optical measurement methods,such as optical cross-correlation method and optical self-difference method,can achieve ten femtoseconds level resolution of timing jitter measurement,but they only work for optical time signals and are incompatible with the widely used electrical time signals.In this paper,we first use the photonics time stretch technique on the high-resolution jitter measurement for stable time signals.We have performed theoretical derivations,simulation,experiment and quantitative calculation respectively around the jitter magnification model,highresolution jitter measurement system,the influence of temperature variations and dispersion penalty.The main research content are as follows:1.A mathematical model ofjitter magnification is constructed based on the photonic time stretch technique.Through deviating the jitter variation of the time signals in each expression in the model,the correctness and validity of the jitter magnification model are demonstrated.2.For the application demand of resolution improvement of timing jitter measurement,we propose and design a jitter measurement method based on photonic time stretch technique according to the above jitter magnification model.The main research contents include the simulation and experiment of the timing jitter measurement system based on photonic time stretch technique.We propose an acousto-optic modulator-based pulse picker to reduce the repetition rate of optical pulses,thus eliminate the time domain aliasing;The nonlinearity of MZM is avoided by controlling it bias at the quadrature point;An improved time stretch module is used to eliminate optical carrier while outputting electrical information,which avoids the influence of optical carrier in timing jitter measurement.This proposed method consists of an optically assisted front-end and an electrically processed back-end,which improves the jitter measurement’s resolution by 11.24 times with a measurement error of 3.2%.3.Aiming at the problem that the jitter measurement’s resolution is limited with increasing noise,we analyze the impact of the output noise from mode-locked laser on the jitter measurement system.And we also analyze the limitation of jitter measurement’s resolution caused by temperature variation.The variation of jitter magnification factor due to temperature shift is discussed and simulation.The impact of the dispersion penalty characterized by frequency fading occurs at a null point on this experiment is derived and analyzed in detail.The third-order groupvelocity dispersion can not affect the jitter measurement.