Abstract

New fabrication techniques have recently achieved sub-micrometer poling periods in ferroelectric second-order nonlinear crystals which allows phase-matching for counter-propagating twin photons. Because of the presence of distributed feedback, the optical system has been shown to behave as a Mirrorless Optical Parametric Oscillator (MOPO) and exhibits peculiar spectral properties which strongly differ from those found in more common geometries involving co-propagating beams [1]. Moreover, the spectral properties of the counter-propagating interaction lend themselves to novel applications such as the transfer of coherent phase modulation from the pump beam into the co-propagating signal wave [3] and the production of slow light [4]. In addition, the use of type 0 quasi-phase matching exploited in KTiOPO₄ (KTP) or LiNbO₃ crystals (pump, signal and idler waves are all extraordinarily polarized) allows the use of the strong non-linear χ⁽²⁾ coefficient characterizing this configuration.

© 2015 IEEE