Abstract

Guided wave χ⁽²⁾ nonlinear frequency conversion via cascaded processes such as frequency doubling and different frequency generation (cSHG/DFG) is an attractive means for wavelength conversion in high bit rate WDM-systems [1, 2]. The efficiency of corresponding devices strongly increases with the nonlinear interaction length (Fig. 1a). Therefore, longer devices are more efficient provided (quasi-) phase matching can be maintainned over the whole length. As alternative, a double-pass approach may be used to increase the interaction length. Such a configuration requires a broadband dielectric mirror on one end face of the waveguide. As it induces wavelength dependent phase-shifts of the reflected waves, the direction of energy transfer by the nonlinear interactions may be reversed in backward direction after reflection unless appropriate phase control allows readjustment.

© 2009 IEEE