By Gaylord Hart, Infinera
The cable industry is beginning to migrate to 100G core optical transport waves, which greatly improve fiber utilization while lowering transponder count for equivalent transport bandwidth. However, transporting 100G waves requires complex optical modulation to preserve performance and increase spectral efficiency. These modulation methods require several additional discrete optical components per lambda, so the migration to 100G waves alone does not fully address the scalability issues of increasing cost, power, space, and heat as bandwidth requirements continue to grow.
Optical networks are rapidly approaching the point where continual scaling of higher bit rate optical lambdas using discrete optical components is reaching its limits. Photonic integration, which combines multiple optical subsystems on a single IC, can efficiently support complex modulation schemes without increasing component counts and can offer significant improvements over discrete designs, providing a scalable path for future growth.
This paper provides an overview of complex optical modulation methods for 100G waves and higher. An analysis of discrete component solutions and photonic integration solutions is provided which demonstrates the impact of photonic integration in reducing component counts, heat, space, and optical coupling requirements.