Optical waveguides for 1064 nm and chip pigtailing with PM fibers

The purpose of this project was to develop optical waveguide technology to offer polarization maintaining (PM) components for a Nd:YAG laser wavelength at 1.064 μm. The silicon oxynitride waveguide layers were grown with a PECVD method on a silicon wafer. The waveguide height and width are 3.5 μm and 6.0 μm, respectively. A well balanced 3 dB operation was achieved with a 2´2 MMI coupler. The excess loss of the coupler was 2 dB. The polarization maintaining properties were studied by measuring the polarization extinction coefficient (PXR) of the straight waveguides and pigtailed chips. Typical PXR for a 15 mm waveguide was <18 dB. Waveguide crossings at different crossing angles were characterized in terms of excess loss and PXR. Both passive and active fiber alignment was studied to achieve low-loss pigtailing with a polarization maintaining fiber.