Output characteristics of square and circular resonator microlasers connected with two output waveguides

Square and circular resonator microlasers connected with two output waveguides are investigated for correlation of output powers from the two output ports. The square resonator microlasers with two output waveguides connected at the midpoint of one side and one vertex are fabricated and tested by measuring the output power versus injection current and the laser spectra of the two ports. The laser spectra indicated that the output power correlation between the two output ports is very weak because of different lasing modes in different ports of the square microlaser. Circular resonator microlaser with two output waveguides can realize single mode operation and has good output correlation from the two ports. So the output power from one port of the circular microlasers can be monitored by that of another port.