Photonic integrated tunable receivers with optical preamplifiers for direct detection

Abstract

We propose and demonstrate a photonic integrated tunable receiver which cascades a traveling-wave optical preamplifier, a passive tunable grating-assisted codirectional coupler filter, and a waveguide photodetector. The devices contain three strained InGaAs quantum wells and operate around λ=0.98 μm. The spectral responses have been measured using the broadband spontaneous emission from the integrated amplifier. Optical filters ∼4-nm wide, ∼10-nm apart with grating pitches ranging from 7.4 to 10.6 μm were observed. Wavelength selective photodetection of a channel ∼3-nm wide, tunable over 4.3 nm with a reverse bias is in relatively good agreement with theory.