We propose and demonstrate a polarization-based truncated SU(1,1) interferometer that outputs the desired optical joint-quadrature of a two-mode squeezed vacuum field and allows its measurements using a single balanced homodyne detector. Using such a setup, we demonstrate up to approximate to 2 dB of quantum noise suppression below the shot-noise limit in intensity-difference and phase-sum joint-quadratures, and confirm entanglement between the two quantum fields. Our proposed technique results in a better balance between the two ports of the detector and, consequently, in better common noise suppression for differential measurements. As a result, we are able to observe flat joint-quadrature squeezing and entanglement at a wide range of detection frequencies: from several MHz (limited by the photodiode gain bandwidth) down to a few hundred Hz (limited by electronic noises). (C) 2019 Optical Society of America
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