Propose here unique wavelength and hybrid wavelength-polarization and wavelength-polarization-time-multiplexed heterodyne optical interferometers using an internal self-referencing scheme enabling Angstrom level sensitivity optical path-length measurements. As a first step, a proof-of-concept wavelength multiplexed scanning heterodyne interferometer is built to test the surface quality of a test mirror, demonstrating +/- 100 angstrom profile variations with a 0.9 angstrom accuracy. The hybrid wavelength-polarization and wavelength-polarization-time-multiplexed interferometers can be used to form spectrally coded distributed sensors. (c) 2006 Society of Photo-Optical Instrumentation Engineers.Propose here unique wavelength and hybrid wavelength-polarization and wavelength-polarization-time-multiplexed heterodyne optical interferometers using an internal self-referencing scheme enabling Angstrom level sensitivity optical path-length measurements. As a first step, a proof-of-concept wavelength multiplexed scanning heterodyne interferometer is built to test the surface quality of a test mirror, demonstrating +/- 100 angstrom profile variations with a 0.9 angstrom accuracy. The hybrid wavelength-polarization and wavelength-polarization-time-multiplexed interferometers can be used to form spectrally coded distributed sensors. (c) 2006 Society of Photo-Optical Instrumentation Engineers.