Druk69, Ranovus uses Senko Advanced Components for their optical connectivity solutions.
Senko's pdf below has their coupling insertion loss numbers. Their CWDM, and DWDM products are on pages 15 -22. The index is on page 3.
Possibly this will give us some insight into a competitors dB signal loss as compared to POET's?
https://www.senko.com/literature/Passive-Devices-catalogue.pdf