Font Size: a A A

Researches On The Characteristics Of Vertical-Cavity Surface-Emitting Lasers In High Speed Optical Fiber Communication Systems

Posted on:2008-11-30Degree:DoctorType:Dissertation
Country:ChinaCandidate:J Q ChengFull Text:PDF
GTID:1118360215483693Subject:Physical Electronics
Abstract/Summary:PDF Full Text Request
This work was supported by the National "863" High Technology Project of China (No. 2003AA311070) and the Open Project of the State Key Laboratory on Integrated Optoelectronics.Vertical-Cavity Surface-Emitting Laser (VCSEL) has become one of the key elements of information systems and optoelectronics. This novel laser has many advantages such as ultralow threshold, single longitudinal mode operation, narrow beam divergence, easy two-dimensional integration. Those advantages enable the wide applications of VCSELs in various fields, such as optical fiber communication, optical interconnect and integrated optical component. Great improvements have been achieved in researches and applications of VCSEL in recent years.In this dissertation, we take into account the interactions between the most important physical processes in the operation of VCSEL. The characteristics such as Relative Intensity Noise (RIN), temperature variety, modulation, modes competition of VCSELs in high-speed optical fiber communication systems are investigated. At last, we also make a research on Second-Harmonic Generation (SHG) of biaxial crystal KNbO3 (KN) of semiconductor laser ultrashort pulse in high-speed optical fiber communication systems. The details are described as follows:1. The theoretic foundation and interactions among various physical processes of VCSEL are studied. A series of phenomena having important influence on operation of VCSEL, such as diffusion of current carriers, leakage current of active region, spatial profiles of current carriers and modes and temperature are investigated. The simulation model is built up and the influence of configuration parameters, operation condition and temperature on the performance of VCSEL are analysed.2. A spatially temperature model based on rate equations is put forward. The intrinsic mechanism of thermal effect is analysed using temperature correlated gain and current carriers' leakage model and expressions of temperature and electrical properties are obtained. The transient characteristics, light current and modulation characteristics, the dependence of threshold current on temperature and roll-over of optical output power are investigated.3. We found a two-dimensional rate equations model using Runge-Kutta Method taking the spatial distribution and transverse diffusion of carriers into consideration. The influence of the shape and situation of electrodes and the intensity of injection cunent on the characteristic of transverse mode competition are analysed. Further taking into account the nonuniformity of optical mode in azimuthal direction, the influence of azimuthal distribution of injection current on the mode selection of VCSEL is discussed.4. The transverse mode characteristics of VCSELs are presented using analytical calculation based on Green's function and numerical simulation based on rate equations. The steady state solution of a model that takes into account the spatial dependence of the electrical field and the carrier density profiles is calculated. We obtained the power of the transverse modes by solving a linear set of equations involving modal and injection current density profiles. The comparison shows good agreements among the analytical, simulation and experiment results.5. The characteristics of RIN in VCSELs are investigated using analytical calculation and numerical simulation. We obtain analytical expressions of VCSEL corresponding to the spatial dependence of electrical field and carrier density profiles. The simulation of RIN based on the rate equations and the comparison with the theoretical result are performed. The analysis shows that noise spectras depend on the spatial mode profiles and the degree of spatial overlapping between the modes. The analytical results show that the resonance peaks of the noise spectra at frequencies that correspond to the relaxation oscillation frequencies of the multimode laser. The results are in good agreement with experiments.6. The SHG characteristics of biaxial crystal KN in high speed optical fiber communication systems were studied. We calculated, for the first time to the best of our knowledge, the phase-matching angles and effective second-order nonlinear coefficients for the communication wavelength of 1550nm and obtained the optimum phase-matching parameters. The influences of walk-off angle on effective second-order nonlinear coefficient and SHG efficiency were also analyzed.
Keywords/Search Tags:optical fiber communication, Vertical-Cavity Surface-Emitting Laser, rate equations, mode competition, Relative Intensity Noise, Second-Harmonic Generation
PDF Full Text Request
Related items