Study On Characteristics Of Optically Injected Semiconductor Lasers In The Frequency Domain

Semiconductor lasers have become one core type of today's optoelectronic devices.The application of semiconductor lasers covers almost the entire fields of optoelectronics.Their characteristics in the frequency domain are complex,and it commonly uses frequency response,phase noise,linewidth,relative intensity noise(RIN)and linewidth enhancement factor(?)to characterize and describe their performance.Therefore,accurate measurement of these parameters can not only judge the performance of lasers in practical applications,but also help to find out the factors affecting these parameters from the test process and then find ways to improve the performance of lasers.It has been widely investigated that semiconductor lasers under optical injection experience a variety of nonlinear behaviors,and these nonlinear states have been widely used in various fields of microwave photonics.Previous study shows that the technology of the optical injection not only provides a new method for measuring relevant parameters of optically injected semiconductor lasers,but also provides a new choice for improving characteristics of semiconductor lasers in the frequency domain.It is of great significance to select an appropriate and accurate method to study characteristics of optically injected semiconductor lasers in the frequency domain.In this thesis,some main parameters of optically injected semiconductor lasers in the frequency domain are theoretically analyzed and experimentally measured.Characteristics in the frequency domain are studied for semiconductor lasers with and without optical injection.The improvement of these performance due to optical injection is analyzed.The main work is as follows:1.The main parameters in the frequency domain,their measurement methods and basic theories are introduced for optically injected semiconductor lasers.The reasons for the asymmetric distribution of the injection locking bandwidth regards to the injection parameter are analyzed by adding optically injection term to the rate equations.The ?factor of a semiconductor laser is measured.2.The frequency response characteristics under different injection conditions are measured by use of vector network analyzer.The influences of the frequency detuning and the injection power are analyzed.Results show that the frequency response in the injection locking state can be significantly increased by more than 10 GHz compared with in the free running operation.3.Based on the delayed self-homodyne method with optical coherent receiver,the phase noise and linewidth of the semiconductor laser are measured with and without optical injection.Its frequency stability is analyzed in the free running operation and in the process of the injection locking.It is verified that the injection locking can significantly improve the frequency stability,phase noise and linewidth characteristics of the semiconductor laser.4.By use of RIN measurement method based on the microwave optical link,the RIN of the semiconductor laser is measured with and without optical injection.Experiment results show that the RIN of the semiconductor laser in the optical injection locking state gets improved by nearly 10 dB in the low frequency range compared with in the free running operation.