Both Luxtera and Elenion (now Nokia Optical Subsystems Group) have focused their efforts on building and selling transceivers:  Luxtera was successful in building transceivers for the short distance links within

hyperscale datacenters.

 

Elenion built both  transceivers for 400G intra-datacenter applications, and transceivers using coherent techniques that went into metro and long-haul telecommunication systems.