Optical Frequency Counting and Synthesis

A novel method of optical frequency counting and synthesis has been proposed based on a parallel network of optical parametric oscillators. The scheme utilizes the generation of precise frequency ratios by nonlinear optical techniques to phase lock a calibration optical frequency to the primary frequency standard at 9.2 CHz. By operating entirely in the visible to near IR regions and taking advantage of advances in nonlinear crystals, detectors and modulators in this spectral region, an optical to microwave frequency chain can be operated efficiently and compactly. The proposed frequency chain can be used to provide the highest frequency accuracy in the visible for applications such as optical frequency standards, precision spectroscopy, and measurements of fundamental constants. Moreover, the method is applicable to producing a commercial optical frequency counter and synthesizer for use in laboratory and field environments. In addition, the proposed frequency counter can be used to provide accurate frequency markers in the important 1.55-micron optical communication band. The main focus of this work has been to develop the various technologies that are needed for a prototype optical frequency counting and synthesis apparatus.