An optical phase standard includes a coupler dividing an applied optical signal between a measurement interferometer and a frequency reference branch. Resulting signals at the outputs of the measurement interferometer and the frequency reference branch are sampled. The samples acquired at the output of the frequency reference branch are mapped to optical frequencies that are traceable to a frequency standard provided by an absorption cell. This mapping determines the optical frequencies at which the samples acquired are at the output of the measurement interferometer. From the acquired samples at the output of the measurement interferometer, phase characteristics of a device under test (DUT) are extracted. Aspects of the optical phase standard are alternatively implemented according to an optical phase standardization method.