- Lightmatter officially introduced Passage L20 CPX on September 17 and joined the Open CPX MSA, describing the product as the first bidirectional Open CPX optical engine for AI infrastructure. - Passage L20 CPX uses 1311 nm and 1331 nm wavelengths to carry transmit and receive traffic over the same single-mode fiber, cutting fiber and connector requirements by roughly 50% versus conventional UniDi architectures. - The module is designed for 6.4 Tbps Tx plus 6.4 Tbps Rx, or 12.8 Tbps aggregate bandwidth, using 32 optical lanes per direction at a 212.5 Gbps PAM4 line rate with more than 500 meters of SMF reach. - In Lightmatter's 512-GPU scale-up pod model, the architecture reduces fiber count from roughly 131,072 to 65,536 while eliminating approximately 16,000 connectors and more than 200 miles of fiber. - Lightmatter estimates that BiDi could reduce total scale-up interconnect network spending by roughly 15%, although this figure comes from internal modeling and will vary by topology and deployment configuration. - Importantly, this is not yet a volume-production product. Passage L20 CPX evaluation kits are expected to ship to customers in Q1 2027, and the disclosed specifications remain preliminary. - The announcement follows Lightmatter's June entry into NVIDIA's NVLink Fusion ecosystem and its August launch of an OCP CPO architecture effort targeting AI systems scaling from 72 to more than 1,024 nodes.

Samtech displayed their Co-Packaged Copper (CPC) set-up in the CPX form factor at Taiwan OCP (See the open CPX MSA here: Bandwidth exits the 6.4T pluggable optical engine via a copper connector interface. There are 128 connector pins per module corresponding to 64 differential pairs (DPs) or 32 lanes of 200G. We expect the CPX form factor to present a compelling opportunity for many copper interconnect companies such as TE, Amphenol and Molex even as we see bigger optics TAM in scale-up networking.

A visitor at CIOE in Shenzhen this morning asked a manager on the $ALAB stand whether the value of retimers gets eroded as the industry moves toward optics. I went and put the answer he got next to a specification the company is already helping to write. The answer, as he wrote it down: "The number of high-speed links is going to increase exponentially. Whether it's copper, re-timed optics, or linear optics, all of them are going to increase exponentially. If you think this is crazy right now, 2027 by all accounts is supposed to be where it goes even faster after that. So you cannot go wrong by investing in any of these. You just have to invest in at least one of them." The question was about value per link. The answer is about the number of links. Those are different quantities and only one of them was asked about. I am not going to make much of that on its own. It is a stand manager, unnamed, no title given, at a trade show, and none of that is company guidance. What is worth something is that Astera Labs has already put its name to the thing that decides the answer. Astera Labs is a contributor member of the Open CPX MSA, formed in March this year. What that group is writing, in the words of Credo's own release when it joined on 31 August: common specifications covering "mechanical, thermal, electrical, optical, and management interfaces" for "an optimized optical engine with a defined pluggable socket and electrical connector system." A defined pluggable socket is the whole argument in five words. Once the socket is specified, what goes in it becomes swappable, and swappable is the mechanism by which value per unit gets competed away. That is not a prediction, it is what the MSA is for. The founding members say so directly: the stated goal is to reduce power, cost and latency. The roster is the part I would sit with. Founding members are Ciena, $COHR, $MRVL, Molex, Samtec and TeraHop. Contributors include $ALAB itself, $INTC, $QCOM, $LITE, Source Photonics, TE Connectivity, Accton and Viavi. $CRDO announced it had joined on 31 August and had still not appeared on the published list when I read it this morning. Two names are on neither list: $NVDA and $AVGO. That is the shape of it. The companies without a proprietary scale-up interconnect are standardising the socket between them. The two companies that do have one are not in the room. NVLink is NVIDIA's and nobody sells into it. An open socket is the tool everyone else uses to build domains big enough to compete with it, and the price of that tool is that nothing inside the socket stays scarce for long. So the honest version of the booth answer is that the manager is probably right about volume and the question was about something else. Link counts go with the size of the coherent domain, and in all-to-all topologies links grow faster than accelerators do. Value per link is a separate fight, and the specification his own company is contributing to is the venue for it. Worth saying plainly: absence from a roster is not opposition to a standard, and being in the room is not the same as losing pricing power. Astera is contributing rather than founding, which is a real distinction in how these bodies work. For scale, everything in this chain is up today, which is a CPI day and not a verdict on any of this. $ALAB 294.53, $COHR 310.43, $MRVL 238.11, $LITE 969.09, $CRDO 163.69, all mid-session. What would change my read: watch whether the first Open CPX specification puts the retiming function inside the socket or leaves it on the board outside. If re-timing lives in the module, the module vendors take that content. If it stays outside, the socket standardises the optics and leaves the signal conditioning where it is, and the booth answer holds for reasons better than the one he gave.