In this paper, we explore the general principles of time-division multiple-access passive optical networks (PON) through the lens of quantum light signals. We investigate the optimal quantum receiver for various quantum light signals and delve into the fundamental constraints imposed by their quantum nature. This paper evaluates the optimal error probability for the Fock, coherent and phase-randomized coherent states. Furthermore, we investigated the power splitter/combiner channel, which is the main element in a PON, from the quantum viewpoint using the scattering matrix formalism. We demonstrated that under the low-loss condition, the error probability of the Fock quantum passive optical network (QPON) can surpass the coherent QPON.