Modification of the second-order optical nonlinearities in AlGaAs asymmetric multiple quantum well waveguides by quantum well intermixing

Abstract

Articles you may be interested inQuasi-phase matched second-harmonic generation in an Al x Ga 1−x As asymmetric quantum-well waveguide using ion-implantation-enhanced intermixing Properties of the second-order nonlinear optical susceptibility χ (2) in asymmetric undoped AlGaAs/InGaAs double quantum wells Quasiphase matched surface emitting second harmonic generation in periodically reversed asymmetric GaAs/AlGaAs quantum well waveguide

Electronic bandstructure of disordered superlattices

“…7 which shows the lowest conduction and highest valence (heavy-hole and light-hole) band states at k x , k y , k z = 0. The various plots correspond to the order at which the Fourier series are truncated: order 1 (chain), 2 (dashed) and higher orders (4,8,16,32) which are indistinguishable from each other on this scale (solid). It can be seen that the bandgap increases towards that of the average alloy composition with the process effectively complete …”

“…In the present approach the z-dependent material parameters and the envelope functions F m l (z) are expanded as Fourier series as in eqns (3) and (8). The z-differential becomes,…”

“…Associated with changes in the absorption coefficient are changes in the refractive index through the Kramers-Kronig relations [6,7] with applications for waveguides and bragg gratings. In addition to these variations in the linear optical properties, it has also been established that quantum well disordering can give rise to a modulation in second-and third-order nonlinear optical coefficients [8][9][10]. This effect can potentially be exploited as a novel quasi-phase-matching technique for wavelength conversion and other second-order nonlinear optical applications.…”

Optical Parametric Generators and Amplifiers

“…The vector q has a direction along the direction of the χ (2) modulation and the length of |q| = l c /Λ, where Λ is the spatial modulation period. The modulation of the nonlinearity can be accomplished by periodically inverting the sign of the χ (2) susceptibility, utilizing a zigzag optical path in slabs of nonlinear material with total-internal reflection [11,35,36] or by modulating the amplitude of the second-order susceptibility by periodically modifying the material properties, for instance, by employing quantum-well intermixing in GaAs-AlAs waveguides [37][38][39]. The latter two QPM methods have rarely been used so far either because of the relatively high losses as in the case of the totalinternal-reflection geometry, or due to the small thickness of the modulation which mandates a waveguide geometry for the frequency conversion device.…”

Design parameters of periodically-switched nonlinear structures for efficient nonlinear process.

“…Notable advantages include larger nonlinear coefficients (∼170 pm/V) [6], higher optical damage thresholds and a larger transparency range with low absorption. Several attempts to fabricate semiconductor QPM devices in bulk [7][8][9][10] or waveguide configurations [11][12][13][14][15][16][17][18][19][20] have been explored already. These include the stacking of thin plates for firstorder QPM, [7,8] epitaxial growth for orientation-patterned GaAs films [9,10] quantum well intermixing induced by ion implantation [13][14][15][16] and periodic domain inversion by wafer bonding [17] and by re-growth techniques [19].…”