Optical phase-change memory shows 40 dB loss but a 2D VCSEL array
jwt0625 · x · 2026-07-23
The post comments on an optical-readout phase-change memory bank that suffers from severe loss and variability — about 40 dB insertion loss, 10 dB port-to-port variation, and another 5 dB variation across 20 nm of bandwidth.
What makes the setup interesting is the hardware packaging: it uses a 2D addressable VCSEL array and flip-chip packaging with the memory chip. The writer still flags the write energy per bit as too high, so the architecture looks promising on integration but weak on write efficiency.
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