Polarization control using diffraction gratings in VCSEL waveguide grating couplers

A waveguide grating coupler comprising:

• first and second mirrors, wherein the first mirror is positioned with respect to the second mirror so that light travels within a resonant cavity defined between said first and second mirrors;
• a waveguide comprising a core and a cladding;
• a first grating formed as a part of said waveguide and proximate to the waveguide core, wherein said first grating couples light in a first polarization mode to the waveguide;
• and
• a second grating, wherein said second grating creates a loss of light in a second polarization mode different from the first polarization mode within said resonant cavity, such that the light traveling within said resonant cavity lases preferentially in said first polarization mode;
• wherein said first grating and said second grating are orthogonal to each other.

A method for coupling light comprising:

• forming a resonant cavity between a first and a second mirror;
• causing light to lase within said resonant cavity;
• positioning a waveguide to couple light out of said resonant cavity;
• forming a first grating as a part of said waveguide proximate to a core of the waveguide, wherein said first grating couples light having a first polarization mode to the waveguide;
• and
• forming a second grating, wherein said second grating is orthogonal to the first grating, and wherein said second grating reduces light having a second polarization mode different from the first polarization mode within said resonant cavity, such that said light lasing within the resonant cavity lases preferentially in said first polarization mode.