Research On Triangle Wave Pulse Generation Technology Based On Low Phase Noise Oscillator

Low phase noise, high frequency triangular wave pulses have the advantage of waveform uplift linearization and only odd odd harmonics in its spectrum. It has important application value in broadband wireless communication, radar, aerospace and other fields. In this paper, combined with the advanced technology of Opto-Electronic Oscillator (OEO) in the field of microwave photonics, this paper studies the photoelectric oscillator and the triangular wave pulse generation technology based on photoelectric oscillator. The main work is as follows:Firstly, the application technology of Whispering Gallery Mode(WGM) optical microcavity in OEO is studied in this paper. The key point is the combination of optical microcavity and OEO system. The program takes advantage of the optical micro-cavity small size, the advantages of ultra-high quality factor. It overcomes the shortcomings of the traditional OEO long-distance fiber storage link, such as bulky and difficult to control,and reduces the volume of OEO to facilitate integration. In this paper,firstly, the basic characteristics of WGM microcavity and the influence of external environment on its frequency stability are studied. Based on its theoretical research and simulation, the temperature control system based on WGM microcavity is designed. Finally, the feasibility of applying WGM microcavity to OEO system is analyzed.Then, a new type of triangular wave pulse generation technology based on OEO is presented, and the theoretical analysis and experimental verification are carried out. In the new scheme, phase modulator (PM) and Mach-Zehnder interferometer (MZI) are used instead of the key device MZM used in photoelectric modulation in traditional OEO loops.According to MZI in the optical frequency and spectral filter characteristics,set its work in the orthogonal parabolic point, to suppress the system even harmonic. At the same time, through the reasonable adjustment of system parameters, the second harmonic is further suppressed, and finally the generated fundamental and harmonic to meet the triangular wave synthesis required amplitude and phase conditions. Thus, the triangular wave pulse signal is generated. In this paper, the scheme is verified experimentally, and the noise performance of the generated pulse signal is tested. A 5.35G high frequency triangular wave pulse signal was generated in the experiment,and the phase noise performance of the triangular wave pulse signal reached -124dBc/Hz@10kHz.In this paper, the application of microcavity in OEO is studied, and the feasibility is analyzed. Then, the technical scheme of triangular wave pulse signal based on OEO is proposed. Compared with other traditional schemes,the fundamental and odd harmonics required for the triangular wave synthesis in this scheme are generated by OEO itself, and do not need to use other external microwave sources. The system has the advantages of simple implementation and low phase noise.