The photon class is a full sized starship approximately the same size as a sovereign class but containing a single nacelle like the Freedom class. It can be used as a standalone multimission ship but is generally used as the primary saucer section of the Mjolnir/Exodus class.
When used in the Exodus class, the Photon class serves as both primary and battle bridge, and is used a secure are to contain the fucntions of command, security and tactical ops.