Development of a Pulsed Optical Pumped Rubidium Clock

Since the first ammonia clock in 1949, atomic clocks have been developed to provide improved
frequency stability as well as miniature designs capable of being worn on the wrist. With a small
number of notable exceptions, most research activity has been directed at improving clock accuracy
without regard to power or size, or with very constrained power and volume goals. A design that offers
improved frequency stability, within a moderate volume, and that can be used whilst moving, would
prove a widely useful reference in laboratory, communication, and navigation applications.
To fill this gap, this thesis uses simplified apparatus to achieve the Pulsed Optical Pumping
(POP) technique; proves the viability of an alternative to a conventional cylindrical cavity;
develops a higher-resolution Digital to Analog Convertor (DAC) than anything commercially available;
and does so in a way that can fit within the volume of a shoebox. Limiting factors to the performance
of a 85Rb cell are calculated, and a central Ramsey fringe with 100 Hz Full Width at Half Maximum
(FWHM) is achieved. A route to demonstrating long-term stability of 2x10-14 (τ=100sec) whilst
maintaining -123 dBc/Hz (1Hz offset) close-to-carrier phase noise is provided. The clock’s performance
has not been measured as the laser and microwave locking loops are not fully functional.