Multiport wavelength-selective optical switch

1. An optical switch comprising

one or more input and one or more output ports structured to be able to receive and transmit multi-wavelength optical signals;

a diffractive element structured and arranged to be able to spread the wavelengths of incoming optical signals from the one or more input ports in a wavelength-spreading direction and to combine the wavelengths of outgoing optical signals traveling to the output ports;

an angular-beam directing device structured and positioned to be able to selectively alter, in an angular-directing direction optically orthogonal to said wavelength-spreading direction, an angle of beams transmitted from said angular-beam directing device; and

an anamorphic optical system so structured and arranged such that a multi-wavelength input signal, arriving at one of said one or more input ports, is transformed by said anamorphic optical system so as to provide, after diffraction by said diffractive element, at said angular beam-directing device, for a portion of said signal corresponding to a selected wavelength of that signal, an elliptical Gaussian-beam waist having a larger waist in the angular-directing direction of the beam-directing device than in the wave-length spreading direction of the diffractive element.

2. The optical switch of claim 1 wherein the anamorphic optical system comprises a planar emitter/receiver.

3. The optical switch of claim 2 , wherein the planer emitter/receiver comprises an individual waveguide region corresponding to respective input or output ports for guiding the optical signals in the angular-directing and wave-length spreading directions and a slab waveguide region in which the optical signals spread or diffract in the angular-directing direction plane, while remaining guided in the wavelength spreading direction.

4. The optical switch of claim 3 wherein the individual waveguide region comprises channel waveguides.

5. The optical switch of claim 1 , wherein said anamorphic optical system includes a cylindrical lens for focusing the optical signals in wave-length spreading direction.

6. The optical switch of claim 1 , wherein said anamorphic optical system comprising a linear array of expanded core fibers for increasing a mode field diameter of the optical signals, and a cylindrical lens for focusing the optical signals in wave-length spreading direction.

7. The optical switch of claim 1 , further comprising an arcuate array of expanded core fibers for correcting aberrations of diffracted skew rays.

8. The optical switch of claim 1 , wherein said anamorphic optical system comprises planar waveguides corresponding to respective input or output ports, a slab waveguide region in which the optical signals spread or diffract in the angular-directing direction plane, while remaining guided in the wavelength spreading direction, and a planar power lens in the slab waveguide region, for collimating the optical signals.

9. The optical switch of claim 1 , wherein the anamorphic optical system is structured and arranged such that any multi-wavelength signals that propagate in the emitter/receiver are overlapped at the exit plane of the emitter/receiver, such that individual multi-wavelength signals enter or exit the emitter/receiver at the same location but at different angles.

10. The optical switch according to claim 8 , wherein the planar power lens collimates the optical signals, whereby waists of the optical beams are coincident at an edge of the slab waveguide region for both the angular-directing and wave-length spreading directions.

11. The optical switch according to claim 1 , wherein the anamorphic optical system comprises mode field expanding means for increasing a mode field diameter of the optical signals, and a cylindrical lens for focusing the optical signals in wave-length spreading direction.

12. The optical switch according to claim 11 , wherein the mode field expanding means comprises a plurality of collimating lenses for increasing a mode field diameter of the optical signals.