Reflection and Emission of Brillouin zone edge states for active photonic crystal waveguides

A one-dimensional photonic crystal is patterned into an active planar waveguide containing multiple InGaAs quantum wells. External coupling reflectivity is used to map out the photonic band structure, revealing a clear anti-crossing at similar to 1.37 eV in the 45 degrees TM polarized spectrum. The band structure is compared to and confirmed by scattering-matrix calculations. Photoluminescence measurements are performed in the same geometry on the patterned and unpatterned regions of the sample. The latter shows conventional quantum-well emission and GaAs emission with increasing pump power. In contrast, the spectra from the patterned sample contain a sharp mode from the dielectric-like band of the anti-crossing, corresponding to the Brillouin zone edge. Power-dependent excitation shows this mode to be strongly super-linear, indicative of band edge lasing.