INTEGRATED-OPTIC MODE ORDER CONVERTING AND MANIPULATING STRUCTURES IN STRIP WAVE-GUIDES

The design and implementation of new integrated optic strip waveguide elements are reported that are capable of conversion between transverse modes and selective coupling and separation of transverse modes. The mode converting element utilises a periodic serpentine structure to achieve mode conversion, and a novel type of three-guide coupler is used to separate the resulting zeroth and first order modes. Devices were fabricated in a polymer/glass waveguide system for a wavelength of 1.3 mum. 94% conversion was observed in a convertor of length of 1.59 mm, with a loss in the convertor of 1.3 dB. The mode separator performs separation of the first order mode with an efficiency of 60% and a zeroth order mode rejection of greater than 20 dB. It is predicted that improved design should yield near 100% conversion with 0.4 dB loss in the convertor, and separator efficiencies near 100%.