High-speed Balanced Homodyne Detector for Quantum Information Applications

Abstract

Abstract.We have developed a balanced homodyne detector capable of working with femtosecond pulsed light at a 76MHz repetition rate and 800nm wavelength. It exhibits a common mode rejection ratio of 55dB, and can achieve the shot-noise limit. Provided with good performance, our detector can be used in high speed quantum information applications. IntroductionWith the powerful ability of demonstrating complete characterization of a quantum light state, highspeed balanced homodyne detection is essential for foundational analysis of quantum optics on many areas, such as quantum process tomography, quantum key distribution and quantum precision measurement. By measuring the quadrature operators of the input signal state, the balanced homodyne detector can then obtain the quasi probability distribution or in other words, the Wigner function after kinds of quantum state tomography [1]. The first experiment determining the quantum state of light field was proposed by Smithy, Beck, Cooper, Raymer, et al in 1993 [1,2]. Nowadays, the quantum state tomography with balanced homodyne detector has become a standard method in quantum information field.Over the past decades, remarkable effort has been made to make a balanced homodyne detector with satisfactory performance applying to various applications [3]. Conventionally, researchers use a circuit with a dual-stage amplifier to gain higher magnification and stability, but this design will bring extra noise as well. In our experiments, a single-stage simple-construct amplifier homodyne detector was also found able to satisfy the performance requirements of homodyne detectors: (a) low enough electrical noise competent to beat the shot-noise limit which is the key requirement to make a quantum measurement; (b) high enough bandwidth to distinguish 76 MHz repetition rate femtosecond optical pulse; (c) high common mode rejection ratio (CMRR) to make a balance between the two photodiodes [1].

On-Chip Quantum Communication Devices

“…A maximum shot noise to electrical noise clearance of 28 dB is measured at 100 MHz for a current of 3.14 mA. Compared to previously published works [24][25][29][30], the TIA in this work is able to achieve a high bandwidth while at the same time improving significantly in terms of noise.…”

“…For a CV-QKD receiver, a low-noise transimpedance amplifier (TIA) is used to convert the weak differential current produced by the balanced photodetectors to a sufficient level for processing, without distorting the signal or adding much noise. TIAs in earlier balanced detectors have usually been constructed by using discrete off-the-shelf components [24] or a commercial bare die TIA used in telecom applications [25]. This results in a CV receiver having low bandwidth or poor noise/linearity, causing severe distortion.…”

Noise spectra in balanced optical detectors based on transimpedance amplifiers

“…The subtraction photocurrent is subjected to amplification. The latter, most typically, occurs in an OA set up in a transimpedance scheme, in which the input weak current is converted into a voltage output [4][5][6][7][8][9][10][11][12] .…”