Strained-layer multiple-quantum-well InGaAs/GaAs waveguidemodulators operating around 1 μm

Detailed experimental results on the properties of multiple-quantum-well waveguide modulators on strained InGaAs/GaAs layers are presented. Transmission and photocurrent measurements are performed using a tunable Ti-sapphire-laser. The spectra reveal an absorption edge shift as large as 60 nm at 5 V reverse bias. Optimum performance is achieved around a wavelength of 1 μm, where an extinction ratio of up to 20 dB is obtained with an absorption loss of less than 2 dB/cm. The overall insertion loss of the modulator approaches a constant value of 6.5 dB at higher wavelengths (λ⩾980 nm) which is shown to be mainly affected by coupling losses