Abstract

We demonstrated a transmission electroabsorption modulator operating near 1.3 µm grown on GaAs. This achievement has technological applications, particularly for fiber optic communication. The longest wavelength modulation previously achieved in InGaAs/GaAs was 1.06 µm.¹ We achieved sharp excitonic resonances near 1.3 µm in InGaAs/GaAs with molecular beam epitaxy using a slowly graded InGaAs buffer. The p-i-n structure included 30 75-Å In_{0 5}Ga_{0 5} As quantum wells with 35-Å Al_{0 33}Ga_{0 67}As barriers. Room temperature I-V measurements show excellent leakage characteristics. 300-K absorption spectra show a clear exciton at 1.25 µm at zero bias and pronounced quantum confined Stark effect. The device functions as a transmission modulator with an insertion loss of 3 dB and a maximum ΔT/T of 17% at 1.25 µm and 12% at 1.3 µm. Photocurrent measurements exhibit negative differential conductivity, which is useful for operation as a self-electro-optic device at 1.25 µm.

© 1992 Optical Society of America