James E. Morris

Diffractive optics for packaging of laser diodes and fiber-optics

Diffractive Optical Elements (DOEs) have many advantages over refractive optical elements, including the ability to implement exotic functions (such as flat-tops and line generators), the ability to easily incorporate a variety of functions in one element, lower volume and less weight. In this paper three performance measures of DOEs are examined: diffraction, chromatic aberrations and cost.

Wafer-based diffractive polarizer design for low-reflectivity applications

We present designs of a diffractive polarizer having low zeroth-order reflectivity that is compact, potentially mass-producible and cost-effective, and compatible for high-power applications. It consists of subwavelength grating structures superimposed over a diffraction grating. Using rigorous coupled wave analysis, we optimized the parameters of multilevel grating structures to achieve antireflection for both incident TE and TM polarization states with one polarization passing in the zeroth order and the other into the first and higher orders. We focused on polarizer designs for the 1.31-µm wavelength range, and the theoretical values for zeroth-order reflection were calculated to be 0.01% for TE and 0.29% for TM modes. The zeroth-order transmission efficiencies were 97.2% for TE and 0.01% for TM modes. A prototype of one design was fabricated and tested to verify the functionality of the device, and the zeroth-order reflection was determined to be 1.2% and 3.5% for the two modes.