The initial method proposed for creating qubits in a photonic quantum computer is path encoding, introduced by [1]. In this approach, the positions of the photons—referred to as spatial modes—define the state of the qubit. Spatial modes can, for example, correspond to optical fibers. In this chapter, we adopt the term "mode" to specifically refer to spatial modes for the sake of clarity and simplicity in notation. The state of the system is represented by where denote the spatial modes occupied by photons, respectively, thereby representing a Fock state. The concept of polarization enables the design of novel quantum photonic circuits that do not require the inclusion of CNOT gates. To emphasize the significance of polarization, we present a comparative study between the non-polarized formulation of Grover's algorithm and its polarized counterpart. However, polarization does not inherently provide an advantage in photonic circuits, as the readout process necessitates specialized operations that rely on additional spatial modes essential for extracting the results.