Abstract
Silicon photonics offers immense potential for developing highly integrated, scalable, and cost-effective photonic devices and systems. This emerging technology leverages existing CMOS fabrication for high-volume manufacturing of photonic integrated circuits (PICs). The most immediate applications are in datacom and telecom, but silicon photonics also shows promise for LiDAR, quantum computing, optical computing, and healthcare. This paper provides an overview of the state of silicon photonics technology, key applications and market outlook, integration approaches, and future roadmap. The industry forecasts strong growth, driven by high data rate transceivers and machine learning, indicating silicon photonics will be pivotal for future optical computing.
Introduction
Silicon photonics integrates photonic components with electronics on silicon substrates by leveraging CMOS manufacturing infrastructure. This enables integration of lasers, modulators, detectors, waveguides, couplers, and other passive optics alongside electronics at a wafer scale. Silicon photonics emerged in the mid-1980s and has since evolved rapidly by incorporating techniques from the electronics industry [1]. This transition to a CMOS-compatible photonics platform makes it highly attractive for high-volume, low-cost production of photonic integrated circuits. While datacom and telecom currently dominate applications, silicon photonics shows immense potential for the future of optical computing.
Silicon Photonics Applications and Market Outlook
The silicon photonics market was valued at $68 million in 2022 and is forecast to grow at a 44% CAGR to over $600 million by 2028 [1]. This growth is largely driven by 800G pluggable modules for high-speed data center interconnects and machine learning applications that demand increased throughput and lower latency.
Intel holds a commanding 61% share in the silicon photonics datacom market, followed by Cisco, Broadcom, and others [1]. In telecom, Cisco (Acacia) leads with 50% market share, trailed by Lumentum (Neophotonics) and Marvell (Inphi). The telecom market is propelled by coherent pluggable modules for long haul networks [1].
While data centers currently dominate silicon photonics applications, the technology shows immense potential in emerging areas like LiDAR, quantum and optical computing, and medical devices. Integrating advanced photonics for healthcare could enable faster and more accurate diagnostics, treatment, and monitoring, though overcoming regulatory hurdles may be necessary. Extending silicon photonics into the visible spectrum also unlocks new possibilities across industries.
PIC Studio for Silicon Photonics Design
Latitude offers full-flow photonic IC design automation via PIC Studio, incorporating pSim simulation, PhotoCAD layout synthesis, and advanced SDL for smooth schematic-to-layout flows, accelerating silicon photonic IC development.
Silicon Photonics Integration Approaches
Despite silicon's poor light emission properties, recent advances have realized monolithic integration of lasers onto silicon substrates for active photonic components. This is significant because efficient light generation necessitates direct bandgap III-V materials. Quantum dot (QD) lasers are a promising approach, offering superior characteristics over quantum well lasers like defect tolerance for epitaxial growth on silicon [1].
Heterogeneous integration can combine dissimilar materials for multifunction photonic circuits but involves complex bonding and limited substrate sizes. Monolithic integration eliminates those challenges by producing light sources and waveguides on a single wafer. For modulation, thin film lithium niobate (TFLN) on silicon provides tight optical confinement and high speeds.
Current silicon photonics operates at the 45nm node, whereas electronics have scaled down to single-digit nanometers. However, the larger geometries are adequate for high-performance silicon photonics devices. Leveraging older technology nodes enables cost-effective manufacturing.
Silicon Photonics Roadmap and Future Outlook
Remarkable progress has occurred over the past four decades across materials, integration techniques, and packaging, cementing silicon photonics as the dominant transceiver technology. Ongoing research, collaborations, and foundry services are making silicon photonics more broadly accessible. Its ability to enhance data transmission while reducing power consumption makes silicon photonics well-positioned to enable future optical computing advances.
Conclusion
Silicon photonics is transitioning from specialized research into a broadly viable industry, spearheaded by high-volume applications in datacom and telecom. However, emerging areas like quantum computing, LiDAR, and medical devices indicate significant potential across industries. With its high-capacity data transfer, low power draw, and potential for dense integration with electronics, silicon photonics will be instrumental in unlocking future optical computing capabilities. The next decade will see silicon photonics progress along the integration roadmap towards efficient lasers, high-speed modulators, and augmented functionality.
Reference
[1] Yole Intelligence, Silicon Photonics 2023, November 2023.
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