Modulation on Silicon for Datacom: Past, Present, and Future (Invited Review)

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 LiNbO 3 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.

Wafer-Scale Integration of Graphene-Based Photonic Devices

“… 29 However, these have intrinsic wavelength selectivity. 29 InP technology provides modulators with size similar to SiPh, 30 large BW (>50 GHz), 31 but with a higher cost of manufacturing, 31 due to the greater cost of InP wafers with respect to Si ones. 14 , 32 , 33…”

“…29 However, these have intrinsic wavelength selectivity. 29 InP technology provides modulators with size similar to SiPh, 30 large BW (>50 GHz), 31 but with a higher cost of manufacturing, 31 due to the greater cost of InP wafers with respect to Si ones. 14,32,33 Graphene-based photonics is very promising, as graphene is fully compatible with SiPh, 2 it has electro-absorption 2,34 and electro-refraction properties, 2,34 and it can be used for light modulation 2 and photodetection.…”

High-speed Si-Ge avalanche photodiodes

“…The development trend is towards higher integration for higher bandwidth density and lower cost per gigabit. Silicon photonics is a promising technology that has been widely used for applications in optical communication [8,9], optical switch [10,11], optical computing [12,13], light detection and ranging (LIDAR) [14,15], optical sensing [16][17][18], and so on and so forth. Due to the complementary metal-oxide-semiconductor (CMOS) compatible process and the high integration capability, silicon photonics has shown superior performance in aforementioned applications.…”

Linear Dual-Series Mach Zehnder Modulator Employing Electrostatic Doping for Photonic Integrated Circuits

“…Although silicon MRM offers a very high extinction ratio (ER) and low device footprint, its performance is severely dependent on operating wavelength (λ) and temperature [9]- [11]. On the other hand, silicon based MZM suffers from large device footprint and significant power consumption [12]- [14]. To reduce the footprint of MZM, compact and highly efficient optical phase shifters (PS) are required.…”