A central component of a sideband separating (2SB) receiver is the quadrature hybrid which splits the incoming radio frequency signal into two branches with a 90 degrees-phase shift. Its fabrication, however, is one of the factors limiting the operational bandwidth and the maximum frequency at which a 2SB can be built. In this paper a 100%-photonic approach to produce this split is presented. In this way, wider operational bandwidth and a higher maximum operational frequency could be achieved. We also present the first experimental results of a proof-of-concept implementation at 55 MHz that studied the phase stability and controllability of this approach using a commercial 90-degree optical hybrid.