Compact wavelength selective switch

An optical device, comprising:

• an optical port array having a plurality of optical ports for receiving optical beams;
• an optical arrangement for allowing optical coupling between (i) any optical ports in a first subset of the plurality of optical ports for light in a first polarization state but not in a second polarization state and (ii) any optical ports in a second subset of the plurality of ports for light in the second polarization state but not in the first polarization state, wherein the first and second polarization states are orthogonal to one another;
• a dispersion element for receiving an optical beam from any of the optical ports after traversing the optical arrangement and spatially separating the optical beam into a plurality of wavelength components;
• a focusing element for focusing the plurality of wavelength components;
• a programmable optical phase modulator for receiving the focused plurality of wavelength components, the programmable optical phase modulator being configured to steer the wavelength components to a selected one of the optical ports;
• a beam directing optical arrangement for coupling the plurality of wavelength components from the focusing element to the programmable optical phase modulator and from the programmable optical phase modulator to the focusing element, the beam directing optical arrangement including:
• a first prism including an input surface, an output surface and an oblique surface;
• a second prism including an input surface and an oblique surface, the input surface of the second prism being positioned to face the oblique surface of the first prism;
• an optical element disposed between the input surface of the second prism and the oblique surface of the first prism, the optical element being configured to reflect the wavelength components in the first polarization state and transmit the wavelength components in the second polarization state;
• a polarization converting reflector positioned to receive the wavelength components reflected from the optical element in the first polarization state and reflect the wavelength components in the second polarization state so that the wavelength components are directed through the first prism, the optical element and the second prism in the second polarization state and to the programmable optical phase modulator,
• wherein the wavelength components in the second polarization state that are focused by the focusing element and directed through the first prism and the optical element are directed through the oblique surface of the second prism and to the programmable optical phase modulator.