title: Nonlinear optical waveguides based on near-infrared intersubband transitions in GaN/AlN quantum wells.
abstract: We present the design, fabrication, and characterization of III-nitride quantum-well waveguides optimized for nonlinear-optical switching via intersubband transitions. A dielectric structure consisting of an AlN lower cladding and a GaN cap layer allows minimizing the propagation losses while maintaining a large modal overlap with the quantum-well active layer. A strong nonlinear saturation of the intersubband absorption near 1.55 mum is demonstrated at record low input powers for these materials; in particular, a 3-dB saturation pulse energy of less than 10 pJ with 240-fs pulses is measured. Combined with the well established sub-picosecond recovery lifetimes of intersubband absorption in III-nitride quantum wells, these results are very promising for all-optical switching applications in future ultrafast fiber-optic communication networks.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Anirban
authors.initials: A
authors.lastname: Bhattacharyya
authors.forename: Christos
authors.initials: C
authors.lastname: Thomidis
authors.forename: Theodore D
authors.initials: TD
authors.lastname: Moustakas
authors.forename: Roberto
authors.initials: R
authors.lastname: Paiella