Abstract

A crucial aspect in current telecommunications research is the search for network components and technologies of reduced size and fabricated from functional materials suitable for operation around 1550 nm. Most current modulation technologies are based on Lithium Niobate crystals using optical indiffused waveguides, which allows optimal light coupling with crystal lengths close to 10 cm. In LiNbO3, the r₃₃ coefficient is around 30 pm/V, resulting in waveguide lengths of ~10cm in order to obtain sufficient electro-optic effect for high modulation rate. The electrodes need however to be carefully designed (travelling wave electrodes), in order to allow also for a broad modulation bandwidth. However, for highly doped SBN, r₃₃ is significantly higher from 400 to 1400 pm/V which yields comparable electro-optic effect using sub-cm interaction lengths. A smaller device also reduces the difficulty of broadband electrode design. Also another alternative material was investigated in this context with similar dimensions, KTN crystal, which is exhibiting a nonlinear Kerr effect instead of the linear Pockels one. In this paper, we report the development of micro-modulator technology using bulk SBN and KTN crystals, materials which exhibit giant electro-optical coefficients r₃₃.

© 2009 IEEE