Our work is devoted to the analysis of a power spectral density (PSD) of amplitude and phase fluctuations of the laser and the laser optoelectronic oscillator (LOEO) with direct modulation. Using the control operator equation of the laser, the amplitude and phase fluctuations of the laser covered by positive optoelectronic feedback were analyzed for the two-level model. Systems of differential stochastic equations of laser and LOEO are compiled, and analytical dependencies of spectral power density of amplitude and phase fluctuations in approximation of small phase noise are determined. The obtained design relationships were compared with experimental PSD of amplitude and phase fluctuations of the laser and LOEO. Shown to achieve in LOEO, the PSD of phase fluctuations less than −140 dB/Hz at the F=10 kHz offset 10 GHz radio frequency (RF) oscillation, it is necessary to use highly coherent laser PSD phase fluctuations less than −100 dB/Hz at the F=10 kHz offset and achieve noise reduction by synchronizing the longitudinal laser modes by directly modulating the laser with a harmonic RF signal of LOEO generation. Our results make it possible to construct the theory of LOEO and the coupled LOEO based on a system of operator differential equations of a laser with fluctuations covered by a positive feedback circuit on the variable component of the pumping current. The content used in this document is only for preview purposes.