1. Purpose of the gate
The last-time buy is a promise: customers order once more, and the supplier delivers. For photonic products that promise depends on several suppliers who may themselves be withdrawing parts, so the gate confirms that every supplier can support the last builds before the notice goes out.
It also checks that customers have somewhere to go: a documented replacement or migration path, and the support period after the last shipment.
Optical products are often withdrawn because a faster generation replaces them, while customers still run installed systems that use the old one. The gate therefore looks at the installed base as well as new orders: how many spares those systems may need, whether repairs will be offered, and whether the replacement interoperates with the old product so mixed installations can work.
Where the product is co-packaged with a host chip, its last-time buy is aligned with the host product's own end of life, and the two notices are coordinated.
What done means at this gate: customers receive a final date to order before the product is withdrawn, with the supply of lasers, fibres and wafers checked against the last builds.
The gate opens the End of Life stage, which covers withdrawing the product in an orderly way: a last-time buy, last builds while laser, fibre, wafer and assembly supply still exist, support for customers moving to the next generation of optics, and an archive of the design, test and qualification data so questions about shipped parts can still be answered.
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