Rickface: I am trying to understand if that is a limit in terms of speed. Beyond 50 Gb/s would it be necessary to duplicate transceivers rather than continue in increasing speed? Is it possible to extend this technology beyond 50 Gb/s to 100 Gb/s? 500 Gb/s? etc.

You have two choices that can be combined:

• Sending/receiving data faster over each channel.
• Adding more channels to transmit data in parallel, which overall leads up to a higher throughput.

The key point is that adding more channels comes virtually without extra manufacturing costs, because with POET the laser is monolithically integrated. In silicon photonics, each extra channel requires an extra laser, leading up to extra manufacturing costs.