Multi-Vendor Interoperable 800G Optical Communications over 1602-km through 800G-OpenROADM, 800-ZR and 800GBASE-2xFR4 Fiber Links. - Erwan Pincemin; Anna Gueutier; Olivier Renais; Fabrice Herviou; Yves Delisle; Martin Bluethner; Ian Riggs; Anuj Malik; Torben Nielsen; Tom Williams 005; Julia Larikova; Oriol Bertran-Pardo; et al. (OFC, 2026)