2-d optical beam splitter using diffractive optical elements (DOE)

A novel approach for optical beam distribution into a 2-dimensional (2-D) packaged fiber arrays using 2-D Dammarm gratings is investigated. This paper focuses on the design and fabrication of the diffractive optical element (DOE) and investigates the coupling efficiencies of the beamlets into a packaged Vgrooved 2x2 fibre array. We report for the first time experimental results of a 2-D optical signal distribution into a packaged 2x2 fibre array using Dammann grating. This grating may be applicable to the FTTH network as it can support sufficient channels with good output uniformity together with low polarization dependent loss (PDL) and acceptable insertion loss. Using an appropriate optimization algorithm (the steepest descent algorithm in this case), the optimum profile for the gratings can be calculated. The gratings are then fabricated on ITO glass using electron-beam lithography. The overall performance of the design shows an output uniformity of around 0. 14 dB and an insertion loss of about 12.63 dB, including the DOE, focusing lens and the packaged fiber array.