The UWA-PTB coherent optical-to-microwave frequency chain

This paper reports on the first experimental results of the optical-to-microwave frequency chain that is being constructed in collaboration between the UWA and PTB. The OFCC is being constructed at PTB with the rest of the chain at UWA. The final goal of the experiment is to compare the frequency stability of a cryogenic cavity stabilised Nd:YAG laser to that of a cryogenic sapphire microwave oscillator. Both these sources have demonstrated fractional frequency stabilities better than 1 part in 1015 at 100 seconds integration time. By comparing frequency standards with such excellent stability, the precision of the frequency chain will be verified to a level of 10-15.