Continuously tunable, precise, single frequency optical signal generator.

To realize a genuine CW optical frequency synthesizer, a continuously tunable single-frequency CWlaser has been employed to track precisely any arbitrary component of a wide bandwidth phase-stabilized optical comb. We demonstrate experimentally two fundamental aspects of optical frequency synthesis, namely, precise setting of the laser frequency at an arbitrary pre-determined value, and continuous tuning of the laser frequency with the digital precision known in radio frequency synthesis. A typical computer-automated search-and-lock procedure finishes on oneminute time scale.