The SYCATUS Optical Noise Analyzer with Keysight signal analyzers is used for evaluation of optical frequency noise of lasers as a power spectrum density. This instrumentation system provides analysis of 1/f noise, spurious noise (from electrical control circuitry or EMI), white noise, the Lorentzian, as well as the conventional self heterodyne linewidth of lasers used in digital coherent transmission systems. ITLA, plus other performance-critical laser development is streamlined by the advanced detection of spurious noise caused by dither or EMI and no other solution can isolate the white noise and Lorentzian line width as required by OIF for the ITLA MSA. No reference laser source or frequency tuning is required for easy, stable and high-speed measurement.