A 2x2 wavelength selective switch array comprising: a plurality of optical input ports configured to receive one or more optical input beams, each of the one or more input optical beams having one or more wavelength channels, and a plurality of optical output ports configured to receive one or more-optical output beams each having one or more wavelength channels based on a switching state, wherein the plurality of optical input ports and optical output ports form an array of 2x2 optical port pairs each including a pair of optical input ports and a pair of optical output ports; an optical assembly having optical power to convert the one or more optical input beams into collimated beams; one or more optical conditioning and wavelength dispersion elements, including a polarization conditioning assembly and a half wave plate, configured to align the one or more optical input beams that have been converted into collimated beams by the optical assembly into a common polarization direction and to separate the respective wavelength channels of the one or more input optical beams traveling in a first direction and to combine two or more separate optical beams having different wavelength channels into particular output beams; an optical assembly including a focusing optic element having optical power to focus the optical input beams that have been converted into collimated beams by the optical assembly and have separated respective wavelength channels onto a polarization modulator array, the polarization modulator array having a plurality of polarizing modulation cells, each cell configured to independently change a polarization orientation of a focused optical input beam passing through the cell and associated with a particular wavelength channel of a particular 2x2 switch; and one or more polarization-selective beam-routing optical elements configured to route each particular focused optical input beam that has been reflected from the polarization modulator array to either a first output port or a second output port of a corresponding 2x2 optical port pair according to polarization orientation; wherein the polarization conditioning assembly is coupled to a collimating optical element and a half wave plate such that input light beams having a random polarization become light beams having a common polarization, and wherein a grating is optically coupled between the collimating optical element and the focusing optic element and wherein the grating is located at the front focus plane of the collimating optical element and the back focus plane of the focusing optic element. a plurality of optical input ports configured to receive one or more optical input beams, each of the one or more input optical beams having one or more wavelength channels, and a plurality of optical output ports configured to receive one or more-optical output beams each having one or more wavelength channels based on a switching state, wherein the plurality of optical input ports and optical output ports form an array of 2x2 optical port pairs each including a pair of optical input ports and a pair of optical output ports; an optical assembly having optical power to convert the one or more optical input beams into collimated beams; one or more optical conditioning and wavelength dispersion elements, including a polarization conditioning assembly and a half wave plate, configured to align the one or more optical input beams that have been converted into collimated beams by the optical assembly into a common polarization direction and to separate the respective wavelength channels of the one or more input optical beams traveling in a first direction and to combine two or more separate optical beams having different wavelength channels into particular output beams; an optical assembly including a focusing optic element having optical power to focus the optical input beams that have been converted into collimated beams by the optical assembly and have separated respective wavelength channels onto a polarization modulator array, the polarization modulator array having a plurality of polarizing modulation cells, each cell configured to independently change a polarization orientation of a focused optical input beam passing through the cell and associated with a particular wavelength channel of a particular 2x2 switch; and one or more polarization-selective beam-routing optical elements configured to route each particular focused optical input beam that has been reflected from the polarization modulator array to either a first output port or a second output port of a corresponding 2x2 optical port pair according to polarization orientation; wherein the polarization conditioning assembly is coupled to a collimating optical element and a half wave plate such that input light beams having a random polarization become light beams having a common polarization, and wherein a grating is optically coupled between the collimating optical element and the focusing optic element and wherein the grating is located at the front focus plane of the collimating optical element and the back focus plane of the focusing optic element.