The co-packaged optics (CPO) market is experiencing rapid growth, driven by the increasing demand for high-speed data transmission and the exponential expansion of data centers and cloud services. According to data from LightCounting, demand for network speeds powered by artificial intelligence is more than ten times higher than current levels. LightCounting expects CPO technology to begin shipping with 800G and 1.6T ports, with commercialization beginning between 2024 and 2025 and large-scale deployment occurring between 2026 and 2027. This technology will mainly be applied in short-term data communications scenarios. distances for hyperscale cloud. service providers.
CPO development roadmap
Co-Packaged Optics (CPO) is a photoelectric co-packaging technology that packages the optical engine and switching chip together, achieving high integration and reducing costs and energy consumption. The optical engine (OE) refers to the part of the optical transceiver module responsible for processing optical signals. CPO assembles the optical engine and the switching chip on the same socket to form a joint package of the chip and the module. The closer the optical engine is to the switching chip, the shorter the optical signal distance is, leading to lower SerDes power consumption.
NVIDIA’s latest product roadmap highlights its plan to launch a CPO version of the Quantum 3400 X800 InfiniBand switch in Q3 2025, followed by the Spectrum4 Ultra interfaces, supporting 36 3.2T CPO modules, with four 28.8T switching chips inside, giving a total switching power of 115.2T.
The architecture of these switches uses a multi-plane design, allowing efficient distribution of optical signals. After entering through the MPO optical ports, the fibers are split by a shufflebox into four separate paths, each connected to a different switch chip. This approach effectively segments the signal source into smaller units, which are then aggregated on the CX8 network card. The multi-plane arrangement allows independent aircraft to operate simultaneously, optimizing throughput and reducing signal congestion. The shufflebox plays a central role in this architecture, performing crucial signal routing and processing functions.
Shuffle Box – Between front panel and optical engines (OE)
Fast CPO switches are expected to require thousands of internal fiber optic connections. Managing the routing of these fibers within the compact structure of the switch poses several challenges, including maintaining uniform fiber lengths despite varying distances between optical engines and the front panel, and preventing excessive bending that could lead to signal degradation . To overcome these obstacles, advanced solutions such as flexible optical backplane shuffle technology are used. Combined with high-density connectors and adapters, this approach effectively minimizes length variations and ensures robust, high-quality signal transmission.
Flexible fiber circuit products enable higher density optical routing solutions. Conventional 1U optical patch panels typically support up to 24 fiber connections for splicing and distribution. In a 40U cabinet (with a height of 2 meters), this results in a total fiber capacity of only 960 fibers. By integrating optical fiber flex circuits with high-density MT connectors, a 1U optical panel can contain up to 600 fibers (12*50). When scaled up to a 40U cabinet, the total fiber capacity increases dramatically to 24,000 fibers, representing a twenty-fold increase in density compared to conventional solutions. This significant improvement in density is a key benefit for high-speed, high-capacity data centers and network systems.
High density fiber optic connectors – on front panels
The shufflebox uses high-density connectors, such as MPO and MMC connectors, to enable high-speed, high-density signal connections and transmissions, meeting network performance and equipment integration requirements in data center applications. CPO switches require extensive fiber deployment internally, and using high fiber count MPO connectors can significantly reduce the number of ports required on the front panel.
For example, a 51.2T CPO switch may require 1,152 optical fibers, including 1,024 standard single-mode fibers and 128 polarization maintenance fibers. Using 16-fiber MPO connectors requires 64 MPO adapter ports (16 x 64 = 1,024), streamlining deployment and improving integration efficiency.
But if LC connectors are used instead of MPO connectors, 1,024 fibers would require 512 connectors (512 × 2 = 1,024), resulting in 512 adapter ports on the CPO front panel. A standard 1U chassis would not be able to accommodate such a large number of ports. This comparison highlights the critical need for high-density connectors.
PM fiber assemblies between external laser source (ELS) and OE
There are two types of laser sources for CPO: Integrated Laser Source (ILS) and External Laser Source (ELS).
Integrated Laser Source (ILS): This refers to the integration of the laser source with the Photonic Integrated Circuit (PIC) within the same package, creating a one-package solution.
External Laser Source (ELS): In this configuration, the laser source and PIC are separated into separate modules. Although this arrangement takes up more space, its benefits include simpler manufacturing processes, lower costs, and a reduced impact of the ASIC chip’s heat dissipation on the laser’s stability.
Due to its ease of maintenance and wide accessibility, the External Laser Source (ELS) is currently one of the most widely used solutions for CPO light sources. The performance of optical CPO engines is very sensitive to the polarization state of the incident light from the ELS, which requires the laser polarization state to remain stable during signal transmission. To achieve this, Polarization Maintaining Fiber (PMF) is used to connect the light source to the switching chip. PMF ensures that light propagates within the fiber in a single polarization direction, ensuring signal stability and transmission reliability.
Photonics Integrated Circuit (PIC) connections
Optical interconnection between silicon-based optoelectronic chips and external optical fibers is a critical packaging technology that requires low-loss signal transmission and high-precision micrometer-scale alignment. Due to the high refractive index of silicon-based materials, the waveguide mode field diameter is typically much smaller than that of single-mode optical fibers, leading to high insertion losses during mode conversion.
3D optical waveguides overcome the limitations of traditional planar waveguide technologies by enabling flexible light guidance and coupling in three-dimensional space, meeting the demands of more complex packaging configurations. Fabricated using advanced techniques such as photolithography and direct laser writing, 3D optical waveguides provide precise geometric control and superior optical performance, providing a reliable solution for the efficient interconnection of next-generation silicon-based optoelectronic chips.
With more than 20 years of expertise in passive optical device manufacturing, HYC can provide tailor-made optical interconnect solutions for future CPO connectivity:
Fiber Flex Circuit: Supports the automated design and cabling of fiber optic routing, helping to meet high-volume production requirements.
MPO/MTP Assemblies: Using high-precision mold design and advanced injection molding technology, HYC provides high-density, high-reliability fiber optic connectivity solutions for AI data centers.
Polarization-Maintaining (PM) Assemblies: With mature process technologies and automated manufacturing capabilities for key processes, HYC ensures large-scale supply and consistency of PM products.
Optics Design Platform: Equipped with space optics design and coupling capabilities, sub-micron alignment, precision optical back-end processing and optical analysis capabilities, HYC provides design-in and co-development support for Photonic Integrated Circuit (PIC) connections.
HYC’s optical interconnect solutions not only meet the high performance requirements of CPO modules, but also support the future trends of optical module integration and rapid interconnect development.
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For more information, https://www.hyc-system.com
This release was published on openPR.
