Physics and Technology for VCSEL-related Devices

Fumio Koyama,

Microsystem Research Center, P&I Lab.
Tokyo Institute of Technology

Our recent research activities on surface emitting semiconductor lasers and related functional optical devices will be reviewed.  We will present the wavelength engineering of microcavity surface emitting lasers for use in high speed short-reach systems, which includes the wavelength expansion, the wavelength integration and wavelength control based on fully monolithic VCSEL technologies.  In addition, new functions on VCSELs for optical signal processing are addressed, which include optical inverters, optical regenerators and novel polarization controllers based on an injection-locked VCSEL.  Also, we present a novel optical nonlinear phase shifter based on a VCSEL saturable absorber. A large nonlinear phase shift was observed in both modeling and experiment. The device would be useful for mitigating fiber nonlinearities in optical domain.  In addition, we propose a tunable hollow waveguide with highly reflective periodic mirrors for manipulating light in an air core. We present our latest results on widely tunable hollow waveguide devices. 
Toward other applications including optical storages and sensing, we will present metal nano-aperture VCSELs for near-field optics.  We demonstrate a metal nano-aperture GaAs VCSEL for sub-wavelength optical near-filed probing, which exhibits strong plasmon enhancement of both optical near-field intensity and voltage signals by introducing a metal nano-particle in the nano-aperture.  The maximum power density reaches in the range of 1 MW/cm2 with low power consumption below 10 mW.