Applied Physics Letters · 1991 · 10 citations · 11 references
EngineeringElectrical EngineeringMaterials ScienceOpticsOptoelectronicsPhotonicsInfrared Optical MaterialsIntegrated OpticsOptical ModulationOptical Properties Of SemiconductorsOptical WaveguidesRefractive IndexBand GapBand Gap EnergyChannel WaveguidesInfrared OpticsLight-induced Refractive Index ChangePhase ModulationPhoton EnergyRefractive Index Changes
An optically activated guided-wave Mach–Zehnder interferometer has been constructed and used to study photoinduced phase modulation in GaAs channel waveguides. A π radian phase shift at the optical wavelength of 1.15 μm has been achieved with modulating pulse energy of 320 pJ at an interaction length of 22 μm. Our experiment also indicates that for infrared (IR) light with photon energy far below the band-gap energy of the semiconductor material, the free carrier-induced refractive index changes are much more significant than the free carrier-induced absorption changes.
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