Semiconductor coupled-resonator optical waveguide laser

The coupled-resonator optical waveguide (CROW) has been introduced recently as a single-mode waveguiding structure in which the group velocity of light is controllable, and nonlinear interactions between waves can be enhanced by orders of magnitude. A semiclassical description of lasing in CROWs is presented for typical semiconductor media such as GaAs. The threshold conditions for steady-state lasing are presented and evaluated numerically. The lasing threshold can be lowered by reducing the group velocity, thus the CROW laser is an alternative to photonic crystal lasers for realizing lower threshold lasers. Furthermore, the laser wavelength can be tuned with a fine resolution by changing the coupling between the constituent resonators.