Efficient zone plate array accessor for optoelectronic integrated circuits: design and fabrication

A spatially divided beam splitter is designed, by which the laser diode light couples into multiple fibers using a cylindrical lens and a phase type linear zone plate array. Using skew ray tracing, the focusing characteristics of a spatially divided beam splitter are predicted. A three-section linear zone plate array with the linewidth changing from 1.1 to 2.05 microm was fabricated by holographic mask patterning and deep UV printing. In oblique incident conditions close to the Bragg angle, the diffraction efficiency reached 60%. By combining the linear zone plate array with a cylindrical lens, simultaneous focusing and separation of the laser output are achieved.