Abstract

Integrated quantum photonic circuits composed of femtosecond laser direct written waveguides (FLDWs) have allowed implementation of several quantum protocols [1], due to their advantages of fast prototyping and ease of 3D fabrication. Adding a single-photon source based on spontaneous four-wave mixing (SFWM) to such circuits on one chip would eliminate coupling loss and promises 3D all-in-one quantum photonic processors. A key issue for such sources is achieving phase-matching in a low index contrast platform. Nevertheless, waveguide form birefringence was recently used to demonstrate this [2]. Here we use a different approach, exploiting stress birefringence introduced with explicit damage structures in the glass [3]. We note that the control of birefringence via stress tracks has great potential for state engineering [4] as the effective nonlinearity can be modulated by adjusting the damage track offset along the propagation direction while keeping the main waveguide optimised for nonlinear interaction.

© 2015 IEEE