Optical-gain enhancement in two-dimensional active photonic crystals

Optical-gain-enhancement effects are numerically investigated in detail for two-dimensional photonic crystals with active (gain) lattice points. First , this gain enhancement is shown to occur in the vicinity of every photonic band edge. A thorough examination is carried out to isolate the leading fa ctors that determine this enhancement on the basis of a number of (more tha n 1000) numerically calculated data points. The gain-enhancement factor is uniquely determined by the product of the time for light to pass a gain rod and the confinement factor of the field energy in the gain rod, irrespecti ve of the choice of dielectric constants, wave numbers, band indices, and p olarization directions of light. In designing photonic crystals, therefore, more gentlly sloped bands and a greater contrast in the dielectric constan t between gain and background materials are essential in order to intensify optical gain more effectively. (C) 2001 American Institute of Physics.