Silicon photonics have garnered substantial attention in the fields of data and telecommunication. With the demand for power-efficient, faster communication technologies over the past decade, silicon photonics has emerged as a disruptive technology for resolving bottlenecks in the data and telecom fields. This article provides an overview of the evolving trends in silicon photonics that shape the future of the communication landscape.
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What is Silicon Photonics?
Silicon photonics is a technology that is used to prepare photonic integrated circuits (PICs), typically used to generate, detect, transport, and process light. This method uses semiconducting silicon-on-insulator (SOI) wafers as the substrate material and a standard complementary metal-oxide semiconductor (CMOS) semiconductor technology to manufacture them.
The increasing demand for fast and effective communication technologies has led to increased research in silicon photonics. Since its inception, silicon photonics has been rapidly evolving and being adopted as a robust technology by many foundries that manufacture devices, including modulators, photodetectors, and lasers. While the integration of photonics helped enhance the speed of the devices, silicon photonics increased the aggregate bandwidth of these assemblies.
Silicon photonic devices are fabricated using semiconductor fabrication techniques, and the integration of silicon in circuits aids in the construction of hybrid devices, where the optical and electronic components can be integrated on a single chip. This technology is highly useful for enhancing the performance of electronic systems in terms of input/output (I/O) and the power required to drive connections at high speeds.
Silicon Photonics in Telecom and Datacom
Photonics is a viable technology used in intrasystem interconnect in switches, routers, data centers, radio base stations, etc. The advent of big data and the Internet of Things (IoT) has increased the demand for high-performance computing (HPC).
There is a large link capacity for high-speed data communication interconnects between multi-cores or local/distant caches, which cannot be met by conventional electrical interconnects due to the demand for high bandwidth and high power consumption.
Consequently, PICs have come into the limelight because of their cost efficiency, high capacity, and reliability. However, their photonic device integration was fully realized after pioneering work on silicon photonics, especially because of their compatibility with CMOS and the availability of high-quality SOI wafers as waveguides.
Recently, silicon photonics has received considerable attention as a key technology for intra-system and intersystem interconnects for next-generation telecom and datacom. It interconnects electronics and optics, using silicon to construct photonic devices.
In addition to the common advantages of PICs, such as cost and energy efficiency, silicon photonics also have a high miniaturization capacity, aiding in meeting the demand for compact devices with high bandwidth density required in next-generation hardware platforms.
Following are a few silicon photonic devices used in tele- and data communications:
Silicon Integrated Mini-ROADM: These ROADMs are based on silicon photonics with a high implementation potential, low power consumption, high level of integration, and high miniaturization capacity.
Mini-ROADM is designed to connect a central node with peripheral nodes inside a double-ring network. It comprises two structures: an add-bus structure and a one-drop bus structure.
While the former adds wavelength channels from both sides of the bus using cascades of micro-ring resonators, the latter drops wavelength channels from the bus in both directions. Mini-ROADM operates as a network-switching node in a double-ring network.
Silicon-integrated devices for multidirectional ROADM: This type of ROADM is used for extended communication between various ring networks. Because the ROADM is placed between the rings, it has a complex structure that allows multidirectional switching.
A four-directional ROADM consisting of four silicon-integrated wavelength-selective switches (SI-WSS) is used for multidirectional switching. However, the ROADM with more than four directions may limit its practical feasibility.
Silicon Photonics Integrated Transponder Aggregation (TPA): This TPA regulates optical signals using silicon-based components, including:
- An AWG multiplexer/demultiplexer that helps in combining or splitting different wavelengths of light.
- The T1 switching element that handles the drop in certain wavelengths before it passes to the receiver.
- T2 switching element that handles adding wavelengths from transmitters to the system
This method allows the processing of high-speed data using light signals within a silicon-based framework, facilitating cost-effective and efficient communication.
An article recently published in Integrated Optics: Devices, Materials, and Technologies XXVII reported the fabrication of photonic architectures based on a silica-on-silicon planar lightwave circuit (PLC) platform, which is well-known in telecom and datacom due to its ability to control light signals.
The PLC platform fabricated in this study has several advantages, including:
- Ability to control the phase of light signals.
- Very low light loss (<0.009 dB/cm).
- Allows loss-free waveguide bends with a 1 mm radius of curvature.
- Consistent performance due to the combined effect of fiber-matched mode converters and temperature-stable operation
The PLC platform designed in this study can be applied to advanced optical building blocks such as polarization beam splitters, cascaded lattice filters, arrayed waveguide gratings (AWGs), and coherent systems.
The fabrication of an advanced silicon-based device necessitates reliable III–V light sources that can use light to transmit information. These sources must be coupled with Si-based waveguides.
Another article published in the Journal of Applied Physics reported the growth of these III–V materials on a special platform that combined indium phosphide (InP) with silicon-on-insulator (SOI). This method of growing III-V materials provides a promising solution for the design of silicon chip-based lasers and other light-integrated advanced technologies.
Silicon Photonics was valued at $1.6 billion in 2022, which is anticipated to increase to $19.4 billion by 2032 with a compound annual growth (CAGR) of 25.4% from 2023 to 2032. In 2022, North America held a prominent position in the silicon photonics market with a 37% market share. Experts anticipate that Asia-Pacific will witness over 28% CAGR in the silicon photonics market between 2023 and 2032.
Owing to its higher bandwidth and support for faster communication, silicon photonics is attractive in various sectors. In addition, the surge in machine learning (ML) and artificial intelligence (AI) applications has further reinforced its demand.
Overall, silicon photonics stands as a beacon of innovation in the realms of tele- and data communications, offering a cost-efficient and power-efficient solution for faster communication. As we progress in the emerging trends of silicon photonics, it becomes evident that integrating it into high-speed communications will allow the field to witness unprecedented advancements in the coming years.
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References and Further Reading
Shi, Y., Zhang et al. (2022). Silicon photonics for high-capacity data communications. Photonics Research, 10(9), A106-A134. https://opg.optica.org/prj/fulltext.cfm?uri=prj-10-9-A106&id=492831
Testa, F., Bianchi, A., Stracca, S., Sabella, R. (2016). Silicon photonics for telecom and datacom applications. In Silicon Photonics III: Systems and Applications, pp. 421-446. https://doi.org/10.1007/978-3-642-10503-6_15
Bidnyk, S., Yadav, K., Liu, S. H., Balakrishnan, A. (2023). Enabling advanced photonic architectures using state-of-the-art silica-on-silicon planar lightwave circuit platform. In Integrated Optics: Devices, Materials, and Technologies XXVII. 12424, pp. 17-20. https://doi.org/10.1117/12.2647016
Li, J., Xue, Y., Yan, Z., Han, Y., Lau, K. M. (2023). III–V selective regrowth on SOI for telecom lasers in silicon photonics. Journal of Applied Physics, 133(13). https://doi.org/10.1063/5.0144377
Silicon Photonics Market scrutinized in the new analysis. Accessed on November 22, 2023. whatech.com/og/markets-research/industrial/760809-silicon-photonics-market-size-and-forecast-report-2032