Research On Technology Of Control Frequency Of Monolithic Non-planar Ring Nd:YAG Laser

With the continuous development of the inter-satellite communication technology,the traditional microwave communication is gradually difficult to meet therequirements of higher communication bandwidth. Homodyne coherent opticalcommunication technology will become an important direction of development ofouter space communication, which has the advantages of high sensitivity,anti-interference ability and long distance communication ability. In space applications,more particularly in the case of the Doppler shift, the frequency difference between thelocal oscillation light and signal light could reach GHz. In order to capture thefrequency of the signal light, the optical phase-lock loop should be designed for thesignal light and the local light to lock phase. The local oscillator laser is required to hasability of great stability and fast tunability.In this thesis, the frequency control technology on monolithic non-planar ring Nd:YAG laser is discussed, the principles of the stability and tunability of the laser areanalysed and the corresponding system is designed:1. The technology of frequency control of the monolithic non-planar ring Nd:YAGlaser is analysed. After contrasting several methods of tuning technologies, PZT tuningand temperature tuning are chosed and their principles are analysed; the stability of theoutput power and frequency of the single frequency laser is analysed and its stablesystem is designed.2. With the thermistor detecting the temperature, the high-precision temperaturecontrol system and the pump source drive system are designed to achieve the stability ofthe laser. The stability of the constant current source of pump sources was tested, whenthe applied current reached to1.541A and the output power of the NPRO laser was247mW, the stability of output laser power reached to±0.2%in an hour which basiclymeet the requirements of pumping LD. By changing the temperature of the pumping LDand the laser crystal, the curve was obtained between the output power and the pumping LD’s and the laser crystal’s temperature. When the temperature of the LD is changed10℃, the max output power is changed45mW. With the temperature accuracy of±0.01℃the temperature control system, the temperature of the laser crystal was changedfrom10℃to47℃, high tuning range is achieved and the maximum tuning rangereaches to61GHz.3. The tunability of the monolithic non-planar ring Nd: YAG laser is studied. Athin PZT slice is affixed to the laser crystal. the PZT response bandwidth could reachedto100kHz. By changing the signal on the PZT, the frequency of the NPRO laser isachieved to tune. In the PZT tuning experiments, when the amplitude of the signalapplied to the PZT is170V, the laser frequency is fastly tuned and the tuning rangeexceeds200MHz.