On 5/9/23 20:37, Phil Bedard wrote:

[phil] These are already available today and have been for some time and in use in production networks for over a year now. This is with 400G links running up to 600km in routers with QDD ports. 400G-16QAM using 60Gbaud (the OpenZR+ standard) can reach around 1300km. These optics are being used in both routers and xponders on the line side.

Right... I've not been keeping in touch with this development on the terrestrial side, as our focus is mainly on the submarine end of things. But this is good to know.

In our case, the majority of our customers are still seeking 10Gbps and 100Gbps services over long distances (so 200km and over).

Neither they (nor us) have a requirement for 400Gbps in the metro. That said, we do have the capability to do this on terrestrial spans where we are able to carry 600Gbps per channel across 700km or so. We are looking forward to the next generation of tech. with our vendor that could get us to about 700Gbps per channel for the same distance.

[phil] 800Gbps and 1.2Tbps are not really positioned for long haul use cases yet. It requires lowering the modulation to something like QPSK which at those speeds requires baud rates which are not yet commercially available.

I meant more in terms of the capabilities of the 800G/1.2T embedded option to improve spectral efficiency for more capacity over long haul use-cases, and not necessarily that they can actually get to 800Gbps or 1.2Tbps for that length of span.

The next generation of 5nm CMOS with the potential for close to 150 Gbaud is quite intriguing, although I'm not expecting anything more than 15% - 18% improvement in performance compared to the current 7nm 100 Gbaud systems.

Will keep you posted, especially on our submarine application of this.

Mark.