September 20, 2012

Design and Challenges in a 100 Gb/s Hybrid-Integrated Photonic Circuit

Hybrid-integrated, 10×10.7-Gbps WDM transmitters and receivers are built upon DML arrays and APD arrays combined with electronic dispersion compensation. 80-km unamplified transmission is 2 demonstrated with devices 32.5 cm in size and power dissipation under 17 W. Introduction The increasing demand for smaller and lower power consuming transceivers is driving the development of more integrated devices. Hybrid integration offers excellent opportunities to combine sophisticated functionalities in a more compact form by consolidating multiple parts onto fewer substrates, each one optimized for a specific task. This technology is less affected by tradeoffs in device performance, fabrication yield and complexity than for e.g. a full monolithic approach. While packaging may lessen some of the advantages above, the additional flexibility in terms of devices' evolution currently make hybrid integration more appealing than either fully discrete or fully monolithic approaches. We present an example of 10-channel parallel transmitter and receiver optical sub-assemblies (TOSA & ROSA) with an aggregated capacity of 107 Gbps. They consist of arrays of DFB lasers and avalanche photodiodes (APD) combined with silica arrayed waveguide gratings as multidemultiplexers. A free-space assembly is also included for wavelength-locking purposes and signal filtering required by the used transmission format. The compact TOSA-ROSA pair delivers a power budget in excess of 22 dB that can support unamplified transmission over 80-km standard single-mode fiber (SSMF).