Experts At The Table: The steep data center build-out contains an increasing amount of near-packaged optics (NPO) and co-packaged optics (CPO), putting pressure on test manufacturers to produce high-volume manufacturing tooling. Semiconductor Engineering sat down with Matt Griffin, senior product manager for optoelectronics test at Teradyne; Ira Leventhal, vice president of research and venture at Advantest America; Dave Armstrong, fellow at ISE Labs, a subsidiary of ASE Group; and Kazuo Yamaguchi, silicon photonics researcher and engineer at Keysight Technologies.

Fig. 1: (L-R): Teradyne’s Griffin; Keysight’s Yamaguchi; ISE Labs’ Armstrong; Advantest’s Leventhal.

SE: Some people liken the testing of optical devices to testing electronic devices several decades ago. What are the most significant challenges associated with testing photonic devices?

Griffin : There are two key changes we’re making to the test cells to support co-packaged optics. One is the optical instrumentation itself at the wafer, optical engine, or package level. The second is the automation. So how do I optically interface with the device under test (DUT)? That could be a fiber alignment at wafer, a connector alignment, or receptacle alignment at the package or optical engine level. This is what needs to change to enable high volume. Some of the photonics engineers will say, ‘Well, what’s the big deal? I’ve been testing optical transceivers for 20 years. ’ The difference is the scale of going to high-volume manufacturing, where you’re deploying many testers on a test floor. You want to support high-volume software, data analysis, and test programming capabilities, so it’s not as simple as bringing rack-and-stack instrumentation onto a test cell or designing your own custom optical alignment system like you would in your characterization lab.

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