Currently imposed increasingly high demands not only on the accuracy of the measuring instruments, but also to their size and power consumption. Minimization of the geometric dimensions of the instrument due to their use in industrial complexes and systems of various types. In particular it is known [1], in which the subject is given special attention. Small size systems allow to place within them a greater number of different elements and, thereby, extend the functionality. The most accurate is now a device that measures the velocity of the gas flow and liquid flow, is a laser Doppler anemometer (LDA). For practical implementation of circuits necessary LDA stabilized power and frequency of the radiation source. At the same time minimizing the size of LDA, while maintaining the required parameters is achieved by use as a source of radiation of semiconductor laser diodes (LDs), optimized spectrum and polarization of the radiation power.