Optically-injected Semiconductor Laser Based Microwave Photonics Filter And Upconversion System

Due to the low loss and large bandwidth capabilities of the optoelectronics system,which makes it attractive for the processing and transmission of microwave signals.At the same time,people’s demand for high-capacity communication systems also makes microwave technology widely used in optical transmitters and receivers.These two trends have prompted the development of microwave photonics.Microwave photonics uses optical processing methods instead of electric domain processing methods with advantages of low loss,large bandwidth,light weight,and immunity to electromagnetic interference。Therefore,it has important applications in military communications,civil communications,commercial communications,cable television,astronomy exploration,optical signal processing,optical switching networks and other fields.The optical injection technique can optimize the performance of distributed feedback(DFB)semiconductor lasers,allowing semiconductor lasers to exhibit a wide variety of optical characteristics.Semiconductor lasers have an increased modulation bandwidth,enhanced resonant peaks,reduced modulated signal frequency chirps and reduced system noise in the case of optical injection locking.In addition,when light having a plurality of frequency components is injected into the semiconductor laser,the semiconductor laser selectively amplifies light of a specific wavelength in the injected light,which has important practical value in the field of microwave photonics.The paper is guided by the application of microwave photonics and explores the characteristics of light-injected semiconductor lasers.And based on light injection into semiconductors,new microwave photonic filters and all-optical signal upconversion schemes have been proposed.The overall structure of this paper is as follows:1.The first chapter mainly introduced the research field and significance of microwave photonics,and then theoretically analyzed and summarized the light injection semiconductor laser.2.An efficient photonic microwave upconversion scheme is proposed and experimentally demonstrated using injection-locking-based optical single sideband(SSB)modulation and an embedded optoelectronic oscillator.Through the injection-locking in a directly-modulated DFB laser,an optical SSB is successfully realized with optical carrier-to-sideband ratio(OCSR)of around 0 dB.The embedded optoelectronic oscillator operated at 10.66 GHz provides a RF clock signal as a local oscillator(LO)for the photonic upconversion with a phase noise of around-103 dBc/Hz at a 10-kHz frequency offset,lower than that obtained using a RF synthesizer,-92 dBc/Hz,featuring low phase noise.It makes the upconversion system free of costly RF synthesizer,thus offering a potentially low cost solution.In the experiment,the OEO was oscillated at 10.66GHz,a baseband signal with data rates of 2.5 Gb/s are successfully up-converted.Owing to the SSB modulation,no RF power fading is observed in the converted signal after fiber transmission,showing the tolerance against chromatic dispersion of the scheme.3.A novel scheme to realize a microwave photonic filter(MPF)with a widely tunable passband based on an optical-injected Fabry-Perot laser diode is proposed and experimentally demonstrated.The principle is due to the wavelength-selective amplification of the FP semiconductor laser in the case of optical injection locking.By apply the optical signal from a tunable laser source(TLS)to the PM,a phase-modulated optical signal is generated,which injects into the slave laser by the circulator.The overall operation corresponds to a single passband MPF with the central frequency of the single passband widely by changing the injection locking parameters of the TLS.The proposed MPF is experimentally evaluated.A single passband MPF with the bandwidth of 275 MHz and a frequency tunable range of 23 GHz is achieved.The insertion loss and out-of-band suppression ratios are 27.9 dB.These are useful in applications where high frequency and wideband tunability are required.In addition,we added a tunable laser to the system to lock another wavelength of the F-P semiconductor laser,thus implementing a tunable dual pass microwave microwave photonic filter.4.This chapter is the summary and prospect of this thesis.