Dispersion and Modulation of the Linear Optical Properties of GaAs–AlAs Superlattice Waveguides Using Quantum-Well Intermixing

Abstract

Abstract-We report on the large modulation of the optical properties of a 14:14 monolayer GaAs-AlAs superlattice waveguide following quantum-well intermixing. Low-temperature photoluminescence measurements illustrate a large 169-meV differential blue-shift obtained between the disordering-suppressed and disordering-enhanced materials. Effective index measurements are presented as a function of polarization, for both the as-grown and disordered material for near-bandedge and half-bandedge wavelengths, which is the wavelength range 775-1550 nm. The largest effective refractive index shift observed was 9 10 2 which exceeds that previously reported for disordered AlGaAs ternary multilayer structures, and illustrates the potential of the superlattice for the fabrication of etch-free, planar optical components with large index contrast.

Difference Frequency Generation by Quasi-Phase Matching in Periodically Intermixed Semiconductor Superlattice Waveguides

“…The phase matching wavelengths at which SHG efficiency was highest were measured for various QPM grating periods and are shown in Figure 4. The dashed lines indicate the phase-matching wavelengths based on the refractive index measurements reported in [16]. Note that there are significant differences between the samples used in the refractive index measurements from which the expected tuning curves were obtained, and those in the current frequency mixing experiments: (1) the wafer composition is different with the superlattice AlAs barriers replaced with Al 0.85 Ga 0.15 As; (2) the QWI technique was replaced with a high-resolution ion-implantation induced method; (3) slab waveguides were replaced with rib waveguides providing lateral optical confinement.…”

Polarization-dependent nonlinear refraction and two-photon absorption in GaAs/AlAs superlattice waveguides below the half-bandgap

“…Predicted values of the tensor components vary in magnitude and lead to a highly polarization-dependent nonlinear index of refraction [9]. Significant birefringence in the linear index of refraction has already been experimentally verified for a superlattice [10]. Furthermore, the degeneracy between the light-and heavy-hole valence bands is lifted in quantum heterostructures, and therefore the bandgaps involving the heavy-and light-hole bands differ in energy.…”

Recent advances in phase matching of second‐order nonlinearities in monolithic semiconductor waveguides

“…5. The shift in the phase-matching wavelengths relative to the type I process corresponds with the known material birefringence of the superlattice [81]. Output second-harmonic powers of over 2.0 μW and type II conversion efficiencies as high as 350 % W 1 cm 2 were recorded in a 0.5 mm long sample.…”