The rapid buildout of data centers with co-packaged optics (CPO) and near-packaged optics (NPO) is pushing photonic device testing from lab-scale characterization to high-volume manufacturing, but the industry is not ready. Test vendors say the challenge is not just adding optical instruments; it's automating optical alignment and building test cells that can scale across a factory floor.
Unlike electronics, photonics lacks design-for-test. Engineers must test each waveguide, ring, modulator, or photodiode individually, which is slow and laborious. Optical components are also extremely sensitive to slight offsets: a small x-y or pitch mismatch causes more signal loss than an equivalent electrical probe offset, making thermal expansion and warpage especially problematic.
The ecosystem is still maturing. Customers are still choosing connector technologies and laser sources, so test equipment makers are aiming at a moving target. Experts from Teradyne, Advantest, ISE Labs, and Keysight broadly agree on the test insertion points—PIC testing, wafer-level optical engine, die-level optical engine, module test, and system-level test—but they stress the need for hybrid engineers who understand both optical and electrical test. One suggested addition is wafer-level burn-in for lasers to weed out infant mortality.