Sub-picosecond modulation by intersubband transition in ridge waveguide with GaN/AlN quantum wells

Optical modulation due to the intersubband transition in GaN/AlN multiple quantum wells has been characterised for the first time with a ridge waveguide structure. An ultrafast response of as short as 0.36 ps for the full width at half maximum is reported with 1.55 (mu)m signal and 1.7 (mu)m control wavelengths.