A distributed feedback Bragg grating waveguide all-optical switch design relying on the ultrafast cross modulation effect of the intersubband transitions in InGaAs/AlAs/AlAsSb coupled double quantum wells is demonstrated. The pump-induced phase modulation to the signal light is converted to intensity modulation efficiently on chip with the help of the grating structures. To our best knowledge, the switching dynamic characteristics of such design are reported for the first time. With a 400 μm long grating waveguide, 3 dB modulation depth with switching energy of 5.5 pJ and recovery time of 4.5 ps is obtained for the switch-off operation.
© 2011 Optical Society of America