Unlocking AI Supercomputing: The Critical Role of Fiber Arrays in CPO and Silicon Photonics

As artificial intelligence supercomputing pushes data rates to exabytes per second, traditional optical interconnect solutions are reaching their limits in latency, power consumption, and density. Co-packaged optics (CPO) and silicon photonics have emerged as the key enablers for next-generation AI clusters, and at the heart of these systems lies an often-overlooked passive component: the fiber array (FA). Hirundo Optics offers a comprehensive line of high-precision fiber arrays designed to bridge the gap between silicon photonic chips and external optical links, delivering the low-loss, low-latency, and high-reliability performance demanded by exascale computing.

What is a Fiber Array?

A fiber array is a passive optical device that precisely aligns multiple optical fibers in a parallel configuration on a substrate—typically a V-groove substrate. It serves as the "optical bridge" between photonic integrated circuits (PICs) and external fiber optic cables. By maintaining micron-level pitch accuracy and end-face geometry control, fiber arrays enable efficient optical coupling with minimal insertion loss and high return loss. They are available in standard single-mode (SM), polarization-maintaining (PM), and multi-fiber MT array variants, as well as custom angled end-face designs (8°, 45°) for specific coupling requirements.

The Pivotal Role of Fiber Arrays in CPO and Silicon Photonics

Co-packaged optics fundamentally changes the architecture of data center switches by placing the optical module in close proximity to the switch ASIC. This “near-package” approach dramatically reduces the distance electrical signals must travel, slashing latency and power consumption. However, the physical integration of optical signals into the chip package creates new challenges: how to efficiently couple light from the silicon photonic chip to the external fiber network? This is where the fiber array becomes indispensable.

1. Optical Bridge for Silicon Photonic Chips

Silicon photonic chips generate and process optical signals through nanometer-scale waveguides. The mode-field diameter of these waveguides is typically only a few microns, whereas standard single-mode fiber has a mode-field diameter of approximately 9µm. To transfer optical signals between the chip and the fiber with minimal loss, a precisely aligned fiber array is required. The FA acts as a “signal relay station,” accurately guiding high-speed optical signals from the chip into the external optical link and vice versa. Hirundo’s fiber arrays are manufactured with sub-micron pitch accuracy and low insertion loss (typical <0.5 dB), ensuring that even the most sensitive signals are preserved during transmission.

2. Enabling Low-Latency, Near-Package Transmission

The core advantage of CPO is “near-package transmission,” which reduces latency by shortening the distance between the optical module and the computing chip. Fiber array, with their compact structural design, can be directly integrated into the CPO package, enabling a “short-distance direct connection” of optical signals between the silicon photonics chip and the optical module. Compared to traditional fiber pigtails, this significantly reduces optical signal transmission losses, amplifying the low-latency benefit and providing a “stutter-free” transmission guarantee for high-frequency data interaction in AI supercomputing.

3. Meeting the Scalability Demands of AI Supercomputing

AI supercomputing centers continue to expand in scale, placing stringent requirements on “large-scale deployment” and “long-term stability” of optical transmission links. Hirundo’s fiber arrays are designed for high reliability and high consistency, enabling mass production with minimal performance deviation. They can meet the needs of large-scale optical link deployment in supercomputing centers while offering flexible array specification designs (e.g., 1CH-64CH) that adapt to the port count of CPO and silicon photonics chips. This scalability reserves expansion space for future computing power upgrades, avoiding bottlenecks caused by transmission link constraints.

Key Design Features of Hirundo Fiber Array

• V-Groove Substrate: The core of the fiber array is a precision-etched V-groove substrate (typically silicon or glass) that holds fibers at exact spacing. Hirundo’s V-groove substrates ensure pitch accuracy within ±0.5µm, guaranteeing consistent coupling efficiency across all channels.
• Polarization-Maintaining (PM) Fiber Array: For applications requiring stable polarization states (e.g., coherent detection, interferometric sensors), Hirundo offers PM FA with a polarization extinction ratio (PER) exceeding 20 dB, ensuring polarization information integrity during transmission.
• Angled End-Face Options: Hirundo offers arrays with 8°, 0°, 45°, and custom angles to meet diverse customer requirements.
• MT Fiber Array (MT-FA): For high-density parallel optical interconnects, Hirundo offers MT-compatible fiber arrays that integrate multiple fibers into a single MPO connector interface. This simplifies cable management and supports up to 24-fiber arrays in a compact footprint.
• Customization: Hirundo can tailor fiber arrays to specific requirements, including fiber type (SM, PM, MM), fiber count, spacing, end-face angle, and housing material. Custom designs are available for unique CPO or silicon photonics packaging configurations.

Why Choose Hirundo for Fiber Array?

Hirundo is a leading supplier of high-performance passive optical components, including fiber array, transceiver, and wavelength division multiplexer. Our fiber array are manufactured in state-of-the-art facilities using advanced fusion tapering and precision micro-assembly techniques. Each unit undergoes rigorous testing for insertion loss, return loss, and positional accuracy to ensure compliance with industry standards. Whether you are developing next-generation CPO switch modules, silicon photonic transceivers, or high-speed optical interconnects for AI supercomputing, Hirundo’s fiber array provide the reliable, low-loss optical bridging your system demands.