Abstract

Frequency division in the optical regime is a desirable capability for precision measurement applications. We have recently demonstrated a new approach to tunable frequency division based on an optical parametric oscillator (OPO). By phase locking the signal–idler beat frequency to a microwave frequency source, an input pump frequency is halved. This beat frequency measurement precisely determines the signal and idler frequencies. The method is an efficient one-step process, and OPO dividers can be operated in series or in parallel to measure, compare, and synthesize frequencies from optical to microwave. Our initial results from a cw tunable KTP OPO divider indicate good frequency control and tuning capability, with a signal-idler beat-note linewidth at the hertz level. We will discuss the prospects for an OPO-based optical frequency counter that can accurately measure any optical frequency relative to a microwave frequency standard.

© 1992 Optical Society of America