On June 24, 2026, Corning unveiled a passive optical component—Corning Glass Bridge, or COR-GlassBridge—for CPO co-packaged optics and high-speed AI data centers at the Seoul AI Optical Communications Conference.

I. What is the Kangning Bridge?

First, the Corning bridge is neither an optical fiber nor an optical module; it is a passive coupling interconnect device between chips and optical fibers. Second, it addresses a key pain point in chip–fiber interconnection:

Optical waveguides within silicon photonics chips (PICs) are on the order of a few hundred nanometers. Whether it’s the 9‑μm core of a single‑mode fiber or the 50‑μm or 62.5‑μm cores of multimode fibers, the mode field diameters differ by several orders of magnitude, resulting in extremely high insertion loss when directly spliced. The Corning Bridge serves as an intermediate “transition bridge” for the optical path, employing wafer‑level ion exchange (IOX) to pre‑fabricate graded‑index buried waveguides within a specialized glass substrate: from the optical fiber → the pre‑fabricated waveguide embedded in the glass → the silicon photonics chip, enabling passive coupling.

II. Key Features

1. Passive alignment: Alignment tolerance has been relaxed to 30 μm (whereas conventional FAU fiber arrays require ±0.5 μm precision active alignment).

2. Low loss: Single-ended coupling loss < 1.5 dB, with a target of ≤ 2 dB;

3. Removable and repairable: No adhesive is used for permanent curing; in contrast, traditional CPO packaging, once sealed, cannot be repaired.

4. High density: Supports a 30 μm channel pitch and is compatible with 1.6T/3.2T/6.4T AI optical engines.

5. Mass production at the wafer level: Reduce assembly costs and improve yield.

III. Compared with the Traditional Approach FAU Fiber Array Comparison

IV. Comparison of Two Solutions for a Complete Link

Option A: Existing mainstream (400G/800G, conventional CPO) 

External optical cable → MPO connector → Pigtail → FAU fiber array → Photonic Integrated Circuit (PIC)

The MPO connector is responsible only for external mating and demating; once inside the module, fiber‑optic precision alignment and active alignment coupling are performed by the FAU. The FAU bonds a fiber bundle at one end and aligns it with the chip’s optical waveguide at the other.

Plan B : Next-generation solution ( 1.6T/3.2T/6.4T  High density CPO ， Kangning Bridge Plan) 

External optical cable → MPO connector → Direct‑plug Corning bridge end face → Glass‑integrated waveguide → Photonic integrated circuit (PIC)

MPO is retained; the interface remains unchanged, with responsibility limited to external plugging and unplugging.

The input end of the Corning Bridge is designed with a standard MT ferrule interface, enabling direct mating with MPO male and female connectors. It maintains full compatibility with MPO‑12, ‑16, and ‑24 in terms of fiber‑core spacing, pin alignment, and polarity, so existing MPO cabling systems require no modifications. Once the Corning Bridge is deployed, it will eventually replace FAU, while MPO remains unaffected. Of course, whether MPO will ultimately be entirely superseded by MMC is a topic we will address later. 。

V. Application Scenarios of the Kangning Bridge 

AI computing‑power switches—CPO—integrate co‑packaged optics, near‑package optics (NPO), and high‑density silicon photonics optical engines, complemented by Corning’s two other key products: TGV glass‑substrate CPO substrates and the GlassWorks AI one‑stop optical interconnect platform.

The Corning Bridge—whether in terms of its technical architecture, application scenarios, or structural design—is a product well worth anticipating. However, following the launch event, Corning clarified that the Corning Bridge is currently still in the laboratory validation stage and has not yet entered mass production; mass production is expected to begin between 2029 and 2030. At present, Corning is still expanding FAU capacity, so demand for FAU will continue to grow in the short term rather than being immediately displaced by the Corning Bridge.

Written by: Guangruyuan Optoelectronics Production Technology Department 
2026 7 month