Articles you may be interested inMaximum and overlapped photonic band gaps in both transverse electric and transverse magnetic polarizations in two-dimensional photonic crystals with low symmetry

The threshold gain (gth) of a two-dimensional (2D) photonic crystal distributed-feedback (DFB) laser composed of 8×8 dielectric cylinders was one order of magnitude smaller than that of an 8-pair 1D DFB laser with the identical refractive indexes. In the 2D finite-width photonic crystal laser, gth using the 1st photonic band was smaller than that using the higher photonic band, contrary to the expectation from the flatness of the photonic band structures. This unexpected gth is probably due to the longer optical path caused by the reflection at the side boundary. Moreover, gth using the 1st photonic band was the smallest in the Γ–X direction of the square-lattice photonic crystal. The gain-enhancement using the 1st–3rd photonic bands were 10–30 in the 2D photonic crystal and that using the 3rd band was the largest. The gain-enhancement using the 1st photonic band of the 2D photonic crystal consisting of dielectric cylinders was larger than that of air cylinders.

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Articles you may be interested inPolarization-independent large field-induced refractive index change in a strained five-step GaAs-InAlGaAs asymmetric coupled quantum well Appl.Effects of an electric field on exciton recombination in threestep asymmetric coupled quantum wells J. Appl. Phys. 75, 2105 (1994); 10.1063/1.356315 Enhanced refractive index change in asymmetrical quantum wells with an applied electric field J. Appl. Phys. 74, 6872 (1993); 10.1063/1.355089 Improvement in electroabsorption and the effects of parameter variations in the threestep asymmetric coupled quantum well J. Appl. Phys. 73, 932 (1993); 10.1063/1.353306 Enhancement of change in the refractive index in an asymmetric quantum well Appl.A scheme for enhancing the refractive index change An in the wavelength region longer than that for an n = 1 heavy-hole exciton peak, where the absorption coefficient a is small, is proposed and three-step GaAs/AlGaAs quantum wells (QWs) are numerically analyzed as an example. The basis of this scheme is that an electric-field-dependent oscillator strength can be controlled by designing a QW structure which yields either positive or negative absorption change, Aa at all wavelengths, resulting in an increase in the An in the longer wavelength region and a reduction in the operating electric field. The numerical analysis predicts that the electric field for the three-step QW that yields a An of -lo-' is as small as 5-15 kV/cm which is about one order of magnitude smaller than that for a conventional square-potential QW. In addition, the An and the figure-of-merit, which is defined as An/a, are larger than those for the conventional QW in the longer wavelength region. 8463