Silicon photonics
Which is a correct challenge of CPO (Co-Packaged Optics), which mounts the optical transmit/receive components in the same package as the switch IC?
- AFailed optical components cannot be replaced as modules, so high reliability and thorough pre-assembly testing are required
- BThe electrical path between the switch IC and the optical components becomes longer, increasing power consumption compared with pluggables
- CThe step of attaching optical fiber to the package is eliminated, but communication reach is limited to a few cm
Show answer and explanation
Answer: A. Failed optical components cannot be replaced as modules, so high reliability and thorough pre-assembly testing are required
In CPO, the optical engines sit right next to the switch IC, so the electrical paths are short, lowering energy per bit and allowing many optical links to be packed densely. On the other hand, a failed optical component cannot be swapped out by unplugging it from the front panel, and the failure affects the entire package. Therefore, testing at the wafer or chip level before assembly and using only good parts, and moving the failure-prone lasers outside the package, become important. Operating optical components near the hot switch IC and precisely connecting many fibers are also challenges.