XKL is still here ...
Some caveats on 400G ZR/ZR+ devices:
- They are power hungry, cooling is a challenge. 800G even more so. The OSFP package for 800G looks like the better choice than QSFP-DD for this reason. We'll see, we need more mileage on this.
- For the ZR devices, not all vendors are equal. Some support 4x100GE as well as 400GE, if that matters to you. Some have integrated BERT and encryption, some do not.
- Do not plan on inter-operating different vendors of ZR+ devices. They will interoperate only in ZR mode.
- Plenty of filter options out there if you are putting the ZR/ZR+ in your router. I'll throw a plug in for the Coherent free space DWDM filter. Free space technology has the best IL and isolation numbers. Coherent hasn't packaged it in a module for easy racking yet (XKL can provide that). So if you aren't adding an EDFA, the lowest IL you can get helps your reach.
- If you have at least a few 400G channels, add an EDFA and use the Tx = -10dBm devices, rather than the Tx = 0dBm devices. This is cost effective. The EDFA also extends the reach considerably. You can launch each channel up to +10dBm or more, for a modest number of channels, without getting in trouble with fiber non-linearities (four-wave mixing).

Chad

On 10/7/23 10:35 PM, Mark Tinka wrote:

Finally, the name came to me :-):

https://www.xkl.com/

Looks like they are still in business.

Mark.

On 10/6/23 16:02, Mark Tinka wrote:

On 10/6/23 15:52, Dave Bell wrote:

Smartoptics?

https://smartoptics.com/

Not them.

I want to say they had an "X" in their name, but memory is fuzzy.

Mark.