Abstract
This research focuses on the development of a feedback system that provides effective control of the output frequency of a frequency divide-by-three optical parametric oscillator (OPO). This work will facilitate the use of the OPO to ultrafast waveform synthesis. Simulation shows that if the idler frequency of a divide-by-three OPO has an offset of Δω from exactly one-third of the pump frequency waveforms synthesized with this OPO output will be distorted periodically because the frequencies are not commensurate. Therefore, we need an effective feedback system to minimize Δω and stabilize the output frequencies of the OPO. The first part of this thesis is an introduction to the OPO and the past development of frequency stabilization techniques. Then the basic principle of the scheme used in controlling a divide-by-three OPO output frequency is described. The third part of the thesis provides details of the OPO setup and the feedback system used in this project. Results of measurements performed on the free-running OPO to characterize its frequency fluctuation and tests on the feedback electronics to ensure that they function as expected are then presented. The test results are used to set the electronic and optical parameters for controlling the frequency drift/fluctuation to achieve a minimum offset for the divide-by-three objective and are described in the next and final section. At this moment the OPO can be locked to operate so that the one-standard deviation fluctuation around zero offset frequency is less than 1.4 MHz. The output power of the idler and signal is 1.6 W and 1.2 W, respectively. The offset frequency fluctuation can be reduced further in the future by improving the response of the electronic feedback circuit and the stability of the OPO.