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Coherent 400G 800G QSFP-DD OSFP OpenZR+ OpenROADM Optical Networking Pluggable Supply Chain

Pluggable Coherent in 2026: What's Shipping, What's Vaporware

800G ZR modules are announced. 1.6T is on the roadmap. Meanwhile, half the 400G ZR+ SKUs take 14 weeks to ship. Here's what's real in pluggable coherent today.

Rene Fichtmueller / 2026-05-07 / ~2 min read min read
Optical Networking CPO Co-Packaged Optics 800G Data Center QSFP-DD OSFP Pluggable Optics Silicon Photonics Thermal Management Hyperscale Power Efficiency 1.6T

CPO Won't Save You — Co-Packaged Optics and the Modularity Trade-Off

Co-Packaged Optics will cut power consumption in half. CPO will eliminate transceiver inventory headaches. CPO will redefine data center design. You have heard the pitch. The pitch skips the parts

Rene Fichtmueller / 2026-04-27 / ~3 min read min read
400G Firmware CMIS QSFP-DD EEPROM DSP Optical Transceiver Troubleshooting Network Engineering State Machine Optics Compatibility DataPathActivated Coherent Optics Flexbox Programmer Optical Networking

Firmware Hell — Why Your Optics Break After Upgrade

A system runs stable for months, then starts showing intermittent link resets after a routine update. Nothing is technically broken. The system behavior has changed.

Rene Fichtmueller / 2026-04-14 / ~3 min read min read
400G 400ZR 400ZR+ Coherent Optics QSFP-DD OSFP DWDM Optical Networking Data Center Network Design Supply Chain Capacity Planning Lead Time DP-16QAM Indium Phosphide Optical Transceiver ECMP

Coherent 400G ZR+ — When Lead Time Becomes a Design Problem

The design is complete. Procurement comes back: 400ZR+ optics are not available for four to five months. That is not a supply chain problem. It is a design assumption problem.

Rene Fichtmueller / 2026-04-13 / ~3 min read min read
Optical Networking 800G 400G Deployment Data Center Optical Transceiver OSFP QSFP-DD PAM4 Network Design TCO Fiber Infrastructure

800G: The Upgrade That Exposes Everything

A $350 optic turned into an $18,000 problem. Not because the optic failed — because nobody cleaned the connector.

Rene Fichtmueller / 2026-04-05 / ~1 min read min read