Salience Labs has raised $125 million in Series B funding to expand the manufacturing and deployment of its integrated optical switching technology for artificial intelligence data centres. The Oxford company intends to increase production of photonic networking hardware, develop higher-capacity switches and extend its commercial and engineering presence in the United States.
The oversubscribed round was led by Bullhound Capital, with participation from AMD Ventures, Intel Capital, SBI Group, Hudson River Trading and the British Business Bank, which invested £10 million. Existing shareholders, including Applied Ventures, Oxford Science Enterprises, Cambridge Innovation Capital and Silicon Catalyst Ventures, also participated.
The investment follows Salience’s demonstration of a 64-port all-optical circuit switch at the European Conference on Optical Communication in September 2026. The company plans to use the new funding to develop 128- and 256-port devices and scale the manufacturing processes required to produce integrated photonic switching hardware in larger quantities.
Founded in 2021, Salience emerged from research associated with the University of Oxford and the University of Münster. Its technology addresses the connections between graphics processing units used in large AI computing systems, where the rate at which information can move between processors influences the performance of the complete installation.
In an AI cluster, processors exchange data during the execution of connected workloads. When transfers take longer than the computing operations they support, some processors may have to wait for information before continuing. Increasing the number of GPUs can therefore place additional demands on the network connecting them.
Conventional electronic packet switches examine incoming traffic and direct it towards the appropriate destination using electrical processing circuitry. Optical circuit switching takes a different approach by establishing configurable paths through which optical signals can travel between selected endpoints.
The optical method can avoid some of the optical-to-electrical and electrical-to-optical conversions associated with conventional switching arrangements. However, this does not remove the need for electronic control, network management or conversion at other parts of a computing system. Its performance depends on the complete network architecture and the way traffic is allocated between connections.
Circuit switching is particularly suited to communication patterns that can make effective use of established high-bandwidth paths. A connection must be configured before it is used, and changes in the required destinations may necessitate adjustments to the optical switching arrangement. Control mechanisms therefore remain important when workloads demand different communication patterns over time.
Salience’s architecture combines silicon photonic circuitry with proprietary optical amplification. Integrating switching functions onto a semiconductor device is intended to reduce the amount of discrete optical equipment needed to construct a larger system, while amplification helps manage signal losses within the optical path.
Optical signals lose power as they pass through components and connections. Each additional interface or switching element can contribute to that loss, and a receiver must still obtain a signal of sufficient quality to recover the transmitted information reliably. Increasing the number of supported connections therefore creates requirements for optical power management, component consistency and system testing.
The company’s 64-port demonstration provides evidence of an integrated device operating at that scale. Salience describes the achievement as an industry first for silicon photonics optical circuit switching, although that characterisation is its own. The demonstration is a technical milestone rather than confirmation of commercial shipments of equivalent systems.
The proposed 128- and 256-port products would extend the number of connections supported by future devices. Higher port counts introduce further engineering challenges involving packaging, optical connections, control of signal paths and the thermal behaviour of the completed assembly.
Optical packaging is an important consideration because semiconductor chips must be connected to external fibres and associated equipment with sufficient accuracy to maintain reliable signal transmission. Small differences in alignment or component dimensions can influence optical coupling and the repeatability of the manufacturing process.
Integrated photonics can make use of established semiconductor manufacturing techniques, but the completed product requires more than fabrication of the underlying chip. Assembly, optical alignment, electrical interfaces, testing and final packaging each contribute to manufacturing yield and unit cost.
The relationship between chip performance and production yield becomes increasingly important when a manufacturer moves beyond prototype quantities. A device that performs successfully during laboratory testing must also be produced with sufficiently consistent characteristics across multiple manufacturing batches.
Salience intends to continue working with Keysight Technologies and Tower Semiconductor as it scales its manufacturing operations. Keysight provides electronic and optical testing capabilities, while Tower operates semiconductor manufacturing facilities. The company’s announcement identifies both organisations as part of its development relationships without disclosing new production volumes or specific manufacturing commitments arising from the funding round.
Testing requirements increase as optical devices become more complex. Manufacturers need to establish whether each assembled unit meets its intended optical and electrical specifications, including the performance of different switching paths and the consistency of connections between external equipment and the integrated circuit.
Manufacturing scale also creates demands for handling, inspection and process control. If a product relies on precise alignment during packaging, small differences between production operations can affect the proportion of completed devices that meet specification. Equipment capability and stable assembly procedures are therefore important to achieving repeatable output.
The company is targeting both scale-up and scale-out networking applications. Scale-up systems connect processors that work closely together on a common computing task, often requiring high-bandwidth communication over short distances. Scale-out networks connect larger groups of computing resources, creating different requirements for network management, physical connectivity and traffic distribution.
Salience’s technology is intended to address these arrangements through configurable optical paths. Whether an individual switching product is suitable for a particular network will depend on the traffic pattern, supported interfaces, circuit configuration behaviour and overall system design.
Vaysh Kewada, chief executive and co-founder of Salience Labs, described the company’s technology as “a fully integrated on-chip solution that scales well to high-volume manufacturing”. The investment is intended to support the transition towards production and customer deployment at greater scale.
Strategic participation from AMD Ventures and Intel Capital connects the company with investors involved in processor and computing infrastructure development. Their investment does not, by itself, establish that either organisation has placed an equipment order or committed to using Salience switches in a commercial computing system.
The company also plans to establish a further West Coast office as part of its expansion in Silicon Valley. That activity will support customer and partner engagement alongside product development, while the locations and capacities of any additional manufacturing facilities remain undisclosed.
The $125 million round provides capital for Salience to develop the next generation of its optical switching products and expand production capability. Its 64-port demonstration establishes a technical starting point; manufacturing yield, system reliability, customer integration and the performance of future higher-capacity devices will determine how successfully the technology progresses into wider industrial use.
