For those experiencing thin or dry SQ from optical I too have experienced this. The issue may arise in some systems due to incompatibility with generic FMC and/or SMPS or lesser quality LPS. Upgrading to Sonore OpticalModules with nice LPS will solve this issue.
And then we have optimizing of these modules or any optical converter or device, this https://audiophilestyle.com/forums/topic/62352-finisar-sfp-modules-for-audio-grade-network-switch-group-buy-for-audiophilestylecom/#comments
I just purchased the two reference grade Constellation cables with the Finisar enterprise grade optical transceivers. These will install into Sonore OM and OR, I'll soon discover the efficacy of these!