A spectroscopy wavelength and amplitude referencing system comprises an optical bench receiving a tunable optical signal from a tunable signal source, a wavelength reference detector on the bench for determining a wavelength of the tunable optical signal, an amplitude reference detector on the bench for determining an amplitude of the tunable optical signal and an output optical signal fiber for transmitting the tunable optical signal to a sample. Also, spectroscopy system controller determines a spectral response of the sample to the tunable optical signal by determining an instantaneous wavelength of the tunable optical signal by reference to the wavelength reference detector.