We present two different laser ranging systems under development, both based on the use of a high frequency modulated beam. The first range meter makes no use of interferometry: only the phase of the return beam is detected, in a way that rejects cyclic errors due to optical and electronic crosstalk. An Allan deviation slightly better than 10nm has been obtained with this simple system. The other range meter should provide better resolution, at the expense of a somewhat more sophisticated procedure, as it involves both time-of-flight and interferometry measurements.
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