Du, WeiJia, JunChen, J. F.Ou, Z. Y.Zhang, Weiping2018-10-122018-10-122018Du, W., Jia, J., Chen, J. F., Ou, Z. Y., & Zhang, W. (2018). Absolute sensitivity of phase measurement in an SU(1,1) type interferometer. Optics Letters, 43(5), 1051–1054. https://doi.org/10.1364/OL.43.001051https://hdl.handle.net/1805/17536Absolute sensitivity is measured for the phase measurement in an SU(1,1) type interferometer, and the results are compared to that of a Mach–Zehnder interferometer operated under the condition of the same intra-interferometer intensity. The interferometer is phase locked to a point with the largest quantum noise cancellation, and a simulated phase modulation is added in one arm of the SU(1,1) interferometer. Both the signal and noise level are estimated at the same frequency range, and we obtained 3 dB improvement in sensitivity for the SU(1,1) interferometer over the Mach–Zehnder interferometer. Our results demonstrate a direct phase estimation and may pave the way for practical applications of a nonlinear interferometer.enPublisher Policyabsolute sensitivityphase measurementSU(1,1) type interferometerArticle