There is a critical need for new metrology tools for bridging the gap between mechani
cal profilometry and high-resolution Interterometry in the manufacture of advanced optical
components. A new class of instruments is becoming available because of the rapid
advances In laser diode technology. Properties of modern index-guIded laser diodes
include wavelength tunability, multiple wavelength operation, excellent spatial coherence
and low unit cost. These properties can be used for absolute distance measurement on
polished and unpolished optical surfaces during fabrication.