I think technically Silorix could also be an end user for LWLG. I believe LWLG has their own slot modulator development outside of what they’re doing with Silorix. If Silorix has their own end users, they’d have to order the LWLG/foundry wafers themselves. The water gets a bit muddy here.
End users in general for the slot modulator based PICs are transceiver makers.