High-Gain Er3+:Al2O3 On-Chip Waveguide Amplifiers

Abstract

In this work, high-gain on-chip Er3+ doped Al2O3 single-mode ridge waveguide amplifier device is reported. The growth of the active layer is realized using atomic layer deposition (ALD) compatible with Si processing technology. Optimization of the Al2O3 and Er2O3 growth conditions for fine-tuning the optical properties is systematically investigated. In order to optimize the active ion concentration, heterocycle structures consisting of separately optimized Al2O3 and Er2O3 are deposited. The structural and optical properties of the active layers were characterized by spectroscopic ellipsometry, X-ray photoelectron spectroscopy, time-resolved photoluminescence, and optical gain measurements. We demonstrated up to 2.74 ± 0.40 dB total gain and 13.71 ± 1.97 dB/cm internal optical net gain per unit length at 1550 ± 12 nm using a 2-mm-long device, pumped using a 980 nm laser diode at 23-mW. This work can be expanded to other rare-earth ion doping processes, paving the way to significant improvements of active on-chip applications.