An investigation was made of the distribution of the delay of the phase of modulated radiation in the near zone of (GaAl)As heterolasers. The maximum fluctuations in the delay time at a modulation frequency of 750 MHz varied from 10 to 100 psec and depended on the pumping conditions. The regions with a higher radiation intensity in the heterojunction plane were characterized by a shorter phase delay, whereas the reverse was true in the perpendicular direction.