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Quantum parameter estimation has many applications, from gravitational wave detection to quantum key distribution. The most commonly used technique for this type of estimation is quantum filtering, using only past observations. We present the first experimental demonstration of quantum smoothing, a time-symmetric technique that uses past and future… (More)
—This brief introduces a delayed differential feedback chaos generator with a programmable feedback element. The pro-grammable feedback allows us to implement an arbitrary nonlin-earity or modulate the feedback delay time. Delayed differential feedback systems have been suggested for secure communications, and the flexibility of the programmable system is… (More)
We present a method for synchronization of chaos generators based on transmission of an analog chaotic waveform in a digital form. Experimental comparisons between digital and analog transmission of chaos from a delayed differential feedback system are performed. Synchronization is demonstrated to be between 18 and 39 dB (or equivalently 63 to 7943 times)… (More)
We experimentally performed adaptive phase estimation using time-symmetric quantum smoothing for a stochastically varying phase on continuous wave coherent beam. We demonstrate better accuracy than conventional methods.
Homodyne locking is a new approach to frequency-locking an OPO-based squeezed-vacuum source and its driving laser. It is cheap, easy to implement, subsequent measurements are automatically phase-locked, and it is uniquely a sub-QNL frequency discriminator.
Frequency locking of an optical cavity using a time-varying kalman filtering approach, " IEEE Trans. Control Syst. Tech., 2013. In print.  S. Z. Sayed Hassen, " A robust approach to the load frequency control problem with speed regulation uncertainty, " Int. Optimal frequency regulation of a two-area power system, " in IEEE Inter. A time-varying Kalman… (More)
We demonstrate the measurement of a “squeezing comb”, the time-resolved homodyne detection of the first twelve vacuum squeezing sidebands of an optical parametric oscillator, and propose its use as a multiplexed quantum communications channel.
We propose and demonstrate a pump-phase locking technique that makes use of weak pump depletion (WPD) - an unavoidable effect that is usually neglected - in a sub-threshold optical parametric oscillator (OPO). We show that the phase difference between seed and pump beam is imprinted on both light fields by the non-linear interaction in the crystal and can… (More)
We demonstrate squeezing-enhanced adaptive optical phase estimation for a stochastically varying phase. By using a continuous-wave phase squeezed beam, estimation accuracy is improved by a factor of 1.4 compared to a coherent beam case.
We demonstrate a device that allows for the coherent analysis of a pair of optical frequency sidebands in an arbitrary basis. We show that our device is quantum noise limited, and hence applications for this scheme may be found in discrete and continuous variable optical quantum information experiments.