Efficient All-Optical Interband Light Modulation by Ultrafast Manipulation of Intersubband Transitions in an Asymmetric Quantum Well*
Arup Neogi, Haruhiko Yoshida, Teruo Mozume +1 more
An efficient modulation scheme at relatively lower control light intensities is proposed using ultrashort interband and intersubband-resonant coupling light pulses in a novel asymmetric In x Ga1-x As/AlAs semiconductor quantum well structure. The shape of the intersubband-control light pulses can manipulate the interband-signal light pulse absorption. The carrier relaxation rate of the quantum well system can be estimated from the interband nonlinear optical parameters induced by the intersubband control light field. The modulation efficiency in the proposed structure is twice than in a conventional symmetric quantum well structure. This reduces the threshold optical energy below 1 pJ in a 100-µm2 waveguide structure on using 500 fs control light pulses owing to the enhanced optical nonlinearities in the proposed structure.
Japanese Journal of Applied Physics•Feb 1, 1999•4 citations