QND Measurement of the Photon Number Using Kerr Effect in Optical Fibres

Nobuyuki Matsuda, Ryōsuke Shimizu, Yasuyoshi Mitsumori +2 more

Hans Martens, Willem M. de Muynck

The authors study a quantum non-demolition (QND) set-up for the measurement of photon number, employing the optical Kerr effect. A method for the compensation of the negative effects of self-phase modulation is discussed. Losses are taken into account. It is seen that the performance of the device is limited in the first place by losses, rather than by self-phase modulation.

Hans Martens, Willem M. de Muynck

Yun‐Feng Xiao, Şahin Kaya Özdemir, Venkat Gaddam +3 more

We theoretically investigate a quantum nondemolition (QND) measurement with optical Kerr effect in an ultra-high-Q microtoroidal system. The analytical and numerical results predict that the present QND measurement scheme possesses a high sensitivity, which allows for detecting few photons or even single photons. Ultra-high-Q toroidal microcavity may provide a novel experimental platform to study quantum physics with nonlinear optics at low light levels.

P. M. Alsing, Gerard J Milburn, Daniel F. Walls

We analyze schemes for performing quantum nondemolition (QND) measurements in optical cavities. We consider three schemes: (1) measurement of a quadrature phase amplitude using a parametric process, (2) measurement of a quadrature phase amplitude using the optical Kerr effect in a nonlinear fiber, and (3) measurement of the photon number also using the Kerr effect in a fiber. We show that in the second scheme an enhancement of the QND effect may be obtained by making the cavity finesse for the signal larger than that for the probe.

N. Imoto, S. Watkins, Yutaka Sasaki