Research On Nonplanar Ring Oscillator And Its Noise Properties

The non-planar ring oscillators with excellent single mode property and low noisehave been extensively applied to coherent optical communication, coherent laserdetection, and optically controlled phased array radar. Besides, with the developmentof coherent homodyne optical communication technology, the better performances oflasers are required. So it is very important for us to investigate the monolithicnon-planar ring oscillator, which has the performance features such as low noise andnarrow linewidth. And the main content of this thesis is:1. The intrinsic polarization state of non-planar ring cavity is analyzed in Jonesmatrix, and the principle of laser is explained. Meanwhile, the stability of non-planarring resonator is analyzed by ABCD matrix.2. For the first time to our knowledge, the relative intensity noise transfer functionof non-planar ring Nd:YAG oscillator is deduced by means of the full quantum theory.By theoretical analysis and simulation, it is obtained that the pump noise, andspontaneous emission noise will influence on the low frequency intensity noise, andcontribute to the relaxation oscillation peak relatively weak; The vacuum fluctuation,dipole fluctuation and cavity loss will influence on the whole frequency range, andcontribute to the relaxation oscillation peak relatively large; With the increase of pumppower, the relaxation oscillation peak shifted to the high frequency region, the peakvalue is relatively reduced. By the experimental measure, the result shows that thetheoretical analysis with the experimental results is consistent.3. The intensity noise transfer function of optoelectronic negative feedback isdeduced by means of the full quantum theory. And the transfer function of laser anddriving circuit is measured, the result shows that the measured phase of the transferfunction changes by180°across the resonance, confirmed the theoretical simulationresults. Based on the intensity noise transfer function of optoelectronic negativefeedback, an optoelectronic negative feedback circuit is designed which has a maximum phase advance85.8°. The transfer function of whole loop system ismeasured, and the result shows that the feedback loop is stability.4. In the experiment, the linewidth is measured, and the result shows that thelinewidth less than1kHz in the scanning time of1.00ms. Meanwhile, the performanceparameter of laser is measured, and the maximum single-frequency output power is1.04W, optical conversion efficiency is52.97%, slope efficiency is59.65%. By use ofa suitable optoelectronic feedback circuit, satisfied noise suppression results areachieved in the whole spectrum range, especially when the pump power is1.00W, arelative intensity noise level below-150dB/Hz is achieved.