In this work, we study the characteristics of semiconductor microlasers based on the heterostructure with two coupled waveguides intended to improve heat dissipation in cw regime. We analysed total output optical loss of the microlasers, their spectral characteristics, output power, emission pattern and thermal resistance. We observed that the use of the principle of two coupled resonant planar waveguides, active and passive, as well as p-side down bonding, significantly reduces the thermal resistance of microlasers and improves their performance.