A shearing interferometer with a Kitty-type self-pumped phase-conjugat
e mirror is developed. The measurement of the focal length of a lens i
s demonstrated with a standard deviation of 1.5%. In addition, we meas
ured the microdisplacement in the range of tens of micrometers with an
error less than 2% by using the interferometer. (C) 1996 Optical Soci
ety of America