Taiwan's silicon photonics push is hitting a wall at the testing stage rather than the factory floor, and that is good news for the two Taiwanese equipment makers positioned to fix it.

• Silicon photonics (CPO) chips entered mass production this year, but the choke point turns out to be testing, not manufacturing.
• Even chips that pass early screening can fail after final assembly, so post-packaging checks of optical links and signal paths have become essential.
• Cathay Futures sees back-end testing rising in value and names Hon Jin (7769) and Chroma ATE (2360) as winners, with a target price on Hon Jin of NT$8,400.
• Hon Jin plans to deliver production-grade verification machines in October; Chroma's optical test gear starts shipping in the second half of this year.

Outlook: The fourth quarter is the test — watch whether customers accept and order these machines, which would confirm the shift of value toward back-end testing.