EugenLight readies external lasers for CPO

EugenLight Technologies, the optical-interconnect business backed by USI, has introduced high-power external laser modules for near-packaged and co-packaged optical systems, with pilot production planned during the second half of 2026.

The ELSFP devices follow the OIF-ELSFP-02.0 specification and use dual 12-fibre MT connectors to deliver optical power into the surrounding photonic system. EugenLight specifies connector insertion loss below 0.3dB, low-bend-loss polarisation-maintaining fibre, and polarisation extinction ratio above 20dB.

External lasers address one of the more awkward thermal and serviceability problems surrounding co-packaged optics. Silicon photonic engines can sit increasingly close to high-power switch ASICs, but the semiconductor lasers supplying those engines are temperature-sensitive devices that do not necessarily benefit from sharing the same thermal environment.

Separating the laser source allows it to be cooled and serviced independently from the switch package. The ELSFP format is also hot-pluggable, reducing the risk that a laser failure forces replacement of a substantially more expensive package containing the switch silicon and optical engines.

That separation creates another set of engineering constraints. Optical power has to travel from the external module through fibres and connectors before reaching the photonic device, making insertion loss, polarisation stability, alignment, connector cleanliness, and repeatability central to the available link budget.

EugenLight says its latest design keeps connector insertion loss below 0.3dB while using polarisation-maintaining fibre across the channels. Polarisation control is important because many silicon-photonic devices are designed around a specific optical mode, and variation can reduce coupling efficiency or disturb the behaviour of downstream modulators and waveguides.

The company has also developed automated lens and fibre-array-unit coupling and curing equipment for the modules. It reports coupling repeatability variation below 3%, channel-to-channel deviation below 3%, and post-curing movement below 5%, with batch chip-to-fibre coupling efficiency above 85%.

Those figures matter because coupling is one of the manufacturing steps most capable of turning a viable photonic design into an expensive assembly problem. Aligning a laser, lens, fibre array, and photonic structure in a laboratory is manageable; reproducing the same optical efficiency quickly across production volumes requires automated equipment capable of maintaining micron-scale relationships through adhesive cure, thermal cycling, handling, and final assembly.

The ELSFP modules use a socket-based connector arrangement intended to shorten internal connection paths and allow the optical source to be removed from the printed-circuit assembly. EugenLight has also placed the principal thermal interface against the module cover to give the laser assembly a more direct route for heat removal.

For its higher-power configuration, the company reports optical output above 23dBm per path while holding individual-channel drive current below 1A. Total module consumption has been measured as low as 13.5W, according to its launch material.

Power efficiency becomes increasingly important as the number of optical channels rises. A data-centre switch may require several external laser modules, so electrical power consumed by each source adds directly to the thermal load surrounding the network equipment even before power used by the switch ASIC, optical engines, drivers, and cooling hardware is considered.

The modules are aimed at 51.2Tbit/s and 102.4Tbit/s switching platforms, high-performance-computing interconnects, and spine or core network layers. These are among the systems pushing optical conversion closer to switching silicon because board-level electrical links become increasingly difficult to operate efficiently as signalling rates and aggregate bandwidth rise.

Open co-packaged-optics architectures are simultaneously defining how external lasers, optical engines, fibres, and switch packages should interact. Standardisation matters because a replaceable external laser has limited value if every switch platform requires a proprietary optical, electrical, or mechanical interface.

Manufacturing compatibility is therefore becoming as important as optical output. External laser modules need predictable connectors, management interfaces, thermal behaviour, and lifetime characteristics if system manufacturers are to treat them as field-replaceable infrastructure rather than custom components tied to one optical engine.

EugenLight has already demonstrated ELSFP technology alongside 800G and 1.6T optical engines, but the latest programme provides a firmer path towards manufacturing. Engineering samples from its VPH and UPH product series were completed between the fourth quarter of 2025 and the second quarter of 2026, with pilot runs scheduled through the third and fourth quarters of this year.

Volume production is targeted for the first quarter of 2027. USI intends to support customer-specific development and manufacturing transfer through production capability in Chengdu and Hai Phong, giving the programme a route from optical-module engineering into higher-volume assembly.

The timetable places EugenLight alongside the broader transition from co-packaged-optics demonstrations towards manufacturable systems. Optical bandwidth attracts the headline figures, but external laser modules will ultimately be judged on considerably less glamorous measurements: insertion loss, alignment yield, thermal stability, field replacement, and production repeatability.

If those characteristics hold through pilot production, ELSFP provides a practical way to keep the most temperature-sensitive part of the optical link outside the switch package without surrendering the shorter electrical paths that make CPO attractive in the first place.