<正>Square microcavity laser with an output wavegnide is proposed and analyzed by the finite-difference time-domain(FDTD)technique.For a square resonator with refractive index of 3.2,side length of 4μm,and output wavegnide of 0.4-μm width,we have got the quality factors(Q factors)of 6.7×10~2 and 7.3×10~3 for the fundamental and first-order transverse magnetic(TM)mode near the wavelength of 1.5μm,respectively.The simulated intensity distribution for the first-order TM mode shows that the coupling efficiency in the waveguide reaches 53%.The numerical simulation shows that the first-order transverse modes have fairly high Q factor and high coupling efficiency to the output waveguide.Therefore the square resonator with an output wavegnide is a promising candidate to realize single-mode directional emission microcavity lasers.
