  We describe a chip-scale, telecommunications-band frequency conversion
interface designed for low-noise operation at wavelengths desirable for common
single photon emitters. Four-wave mixing Bragg scattering in silicon nitride
waveguides is used to demonstrate frequency upconversion and downconversion
between the 980 nm and 1550 nm wavelength regions, with signal-to-background
levels >10 and conversion efficiency of approximately -60 dB at low continuous
wave input pump powers (<50 mW). Finite element simulations and the split-step
Fourier method indicate that increased input powers of approximately 10 W
(produced by amplified nanosecond pulses, for example) will result in a
conversion efficiency >25 % in existing geometries. Finally, we present
waveguide designs that can be used to connect shorter wavelength (637 nm to 852
nm) quantum emitters with 1550 nm.
