| Wavelength conversion is an important function for future optical networks. Wavelength conversion mitigates signal contention in high traffic networks, allowing for better utilization of the available network bandwidth. Furthermore, wavelength switching has been proposed as the key function for enabling all-optical routing. Developing single-chip wavelength converters through high-functionality photonic integration has become a very attractive solution. Compared with discrete optical components, PICs offer small footprint, simplified packaging, low optical loss, and reduced power dissipation, all of which are necessities for a viable technology.;This work presents a monolithically integrated optical transceiver which combines a widely tunable electroabsorption-based transmitter and a high-power optically-preamplified receiver on a single chip. Wavelength conversion is achieved by the interconnection of a p-i-n photodiode (PD) and electroabsorption modulator (EAM) to form a field-modulated optical gate. Advanced traveling-wave (TW) designs have been implemented to greatly surpass the traditional RC bandwidth limitations. In this work, selectively-undercut-etched waveguides are combined with periodically loaded electrodes to demonstrate high-impedance TW-EAMs with greater than 50 GHz 3-dB bandwidth. The integration of passive microwave terminations has also been developed to improve impedance matching and simplify biasing. These devices demonstrate, for the first time, bit-rate-transparent wavelength conversion up to 40 Gb/s. Error-free operation is achieved over 25 nm of input and output wavelength tuning, with less than 3-dB power penalty. |
