Method and apparatus for a polarization insensitive arrayed waveguide grating (AWG)

1. A method for forming an arrayed waveguide grating (AWG) with at least two free space regions coupled by a plurality of grating arms with a passivstion layer overlying the AWG and having a plurality of inputs to receive a plurality of channel signals separated by a predetermined channel spacing, comprising the step of choosing the depth of the passivation layer over the grating arms of the AWG to be defined by the TE-TM wavelength shift between TE and TM modes propagating through the arrayed wavc guide grating being approximately less than or equal to 20% of a magnitude of the channel spacing.

2. The arrayed wavegoide grating (AWG) of claim 1 wherein said AWG is Group III–V-based or silicon based AWG.

3. The arrayed waveguide grating (AWG) of claim 2 wherein said AWG is InP-based AWG.

4. The arrayed waveguide grating (AWG) of claim 1 wherein said channel spacing is 50 GHz, 100 GHz or 200 GHz.

5. An arrayed waveguide grating (AWG) comprising:

at least two free space regions;

a plurality of grating arms extending between said at least two space regions;

a pass ivation layer formed over the arrayed waveguide grating;

a plurality of inputs at least to one of said free space regions to receive a plurality of channel signals separated by a predetermined channel spacing;

a depth of said passivation layer chosen by providing a TE to TM wavelength shift between TE and TM modes propagating through the arrayed waveguide grating being approximately less than or equal to 20% of a magnitude of the channel spacing.

6. The arrayed waveguide grating (AWG) of claim 5 wherein said AWG is Group III–V-based or silicon based AWG.

7. The arrayed waveguide grating (AWG) of claim 6 wherein said AWG is InP-based AWG.

8. The arrayed waveguide grating (AWG) of claim 5 wherein said channel spacing is 50 GHz, 100 GHz or 200 GHz.