Modulation on silicon for datacom: Past, present, and future

Abstract

Datacenters become an important part of technical infrastructure. The Datacom traffic grows exponentially to satisfy the demands in IT services, storage, communications, and networking to the growing number of networked devices and users. High bandwidth and energy efficient optical interconnects are critical to improve overall productivity and efficiency in data centers. Mega-data centers are expected to address the power consumption and the cost in which optical interconnects contribute quite a large part. Silicon photonics is a promising platform to offer savings in power and potential increase in bandwidth for Datacom. Several modulation techniques are developed in silicon photonics to reduce the optical mode volume or enhance the light matter effect to further improve the modulation efficiency. Many other materials such as III-V and LiNbO3 are integrated on silicon photonics to maximize the optical link performance. This paper reviews several modulation techniques for Datacom, from vertical-cavity surface-emitting laser (VCSEL) direct modulation to silicon photonics modulators then to hybrid silicon modulators.