Quantum-Noise Measurement in Difference Frequency Generation

Mark S. Hillery, Marlan O. Scully

Peter C. Strassmann, Anthony Martin, Nicolas Gisin +1 more

We report a detailed study of the noise properties of a visible-to-telecom photon frequency converter based on difference frequency generation (DFG). The device converts 580 nm photons to 1541 nm using a strong pump laser at 930 nm, in a periodically poled lithium niobate ridge waveguide. The converter reaches a maximum device efficiency of 46 % (internal efficiency of 67%) at a pump power of 250 mW. The noise produced by the pump laser is investigated in detail by recording the noise spectra both in the telecom and visible regimes and measuring the power dependence of the noise rates. The noise spectrum in the telecom is very broadband, as expected from previous work on similar DFG converters. However, we also observe several narrow dips in the telecom spectrum, with corresponding peaks appearing in the 580 nm noise spectrum. These features are explained by sum frequency generation of the telecom noise at wavelengths given by the phase-matching condition of different spatial modes in the waveguide. The proposed noise model is in good agreement with all the measured data, including the power dependence of the noise rates, both in the visible and telecom regimes. These results are applicable to the class of DFG converters where the pump laser wavelength is in between the input and target wavelength.

Colin J. McKinstrie, Anjali Agarwal, T.C. Banwell +1 more

In this paper, the coupled-mode equations for sum-frequency generation (SFG) and difference-frequency generation (DFG) driven by multiple pumps are solved, and the noise figures of idler generation are determined. For SFG, the (common) noise figure is n, the number of pumps (and idlers), whereas for DFG, the (common) noise figure is 2, independent of n. Thus, DFG driven by multiple pumps enables the generation of multiple low-noise idlers.

François Chapeau-Blondeau

P. Nee, N. C. Wong

We report on the demonstration of optical frequency division by 3 via two successive stages of difference frequency generation. Two input sources at 532 nm and 798 nm generated an output at 1596 nm and the mixing between the 798-nm input and the 1596-nm output generated a second 1596-nm output. Both difference frequency mixing stages were implemented in a single piece of quasi-phase matched periodically poled lithium niobate. By measuring the beat frequency between the two 1596-nm an exact frequency ratio of 3:2 was obtained between two input sources. A signal-to-noise ratio of 27 dB was obtained for a resolution bandwidth of 100 kHz.