Balanced homodyne detector (BHD) has been widely used in quantum information processing. In this paper, we design a wide bandwidth BHD and implement an optical layout to test the performance of our BHD. The test results show that the bandwidth is about 600 MHz, the quantum to classical noise ratio (QCNR) is 15.2 dB and the common mode rejection ratio (CMRR) is 41.16 dB. The performance of BHD shows that it can meet the requirements of high-speed applications in quantum information processing.
Balanced homodyne detector (BHD) has been widely used in quantum information processing. In this paper, we design a wide bandwidth BHD and implement an optical layout to test the performance of our BHD. The test results show that the bandwidth is about 600 MHz, the quantum to classical noise ratio (QCNR) is 15.2 dB and the common mode rejection ratio (CMRR) is 41.16 dB. The performance of BHD shows that it can meet the requirements of high-speed applications in quantum information processing.
We study a relatively excellent BHD(Balanced Homodyne Detector)with large bandwidth and low noise pre-amplification, which is different from the specific BHD implementation scheme and can better adapt to the subsequent cascade scheme, thereby achieving the implementation of BHD with specific needs. Specifically, we optimize our BHD performance by compromising various parameters of BHD, focusing on optimizing and increasing BHD bandwidth, and choosing a more reasonable BHD implementation solution. Judging from the test results, the produced BHD has good performance in extracting effective signals. The bandwidth reaches about 2GHz, which meets the requirements of detection applications. It has a high signal-to-noise ratio of 10 dB and a common-mode rejection ratio (CMRR) of 20 dB near the 2 GHz frequency point.
Balanced homodyne detector (BHD) that can measure the field quadratures of coherent states has been widely used in a range of quantum information technologies. Generally, the BHD tends to suffer from narrow bands and an expanding bandwidth behavior usually traps into a compromise with the gain, electronic noise, and quantum to classical noise ratio, etc. In this paper, we design and construct a wideband BHD based on radio frequency and integrated circuit technology. Our BHD shows bandwidth behavior up to 1.2 GHz and its quantum to classical noise ratio is around 18 dB. Simultaneously, the BHD has a linear performance with a gain of 4.86 k and its common mode rejection ratio has also been tested as 57.9 dB. With this BHD, the secret key rate of continuous-variable quantum key distribution system has a potential to achieve 66.55 Mb/s and 2.87 Mb/s, respectively, at the transmission distance of 10 and 45 km. Besides, with this BHD, the generation rate of quantum random number generator could reach up to 6.53 Gb/s.
We present a high-performance, fully discrete balanced homodyne detector (BHD) with a 2.5 GHz bandwidth, exceptional gain flatness, and superior common-mode rejection ratio. The design leverages a Rogers 4350B-based printed circuit board, a broadband multi-section RF choke bias network, and inter-stage π-section attenuators, complemented by precise photodiode matching and phase-magnitude compensation to ensure signal integrity and suppress common-mode noise. Experimental results show a -3 dB bandwidth of 2.5 GHz and 1 dB gain flatness up to 2.4 GHz-significantly exceeding our prior 1.55 GHz/1.4 GHz implementation and representing state-of-the-art performance among discrete BHDs. At 16 mW optical input, the detector delivers a 16.5 dB signal-to-noise ratio at 2 GHz while maintaining excellent linearity, and achieves a 66 dB common-mode rejection ratio at the same frequency. This cost-effective and flexible BHD is ideally suited for high-speed continuous-variable quantum key distribution and quantum random number generation.
Performance of linear avalanche photodiode-based balanced homodyne receiver (APD BHD) is examined and compared to reference BHD based on PIN photodiodes, in terms of common mode rejection ratio (CMRR), quantum-to-classical noise clearance (QCNR) and sensitivity in coherent reception of quadrature phase shift keying (QPSK) modulation format. NIST randomness validation was performed on sampled data for quantum random number generator (QRNG). Achieved CMRR values were 50 dB and 30 dB at 100 MHz and 1 GHz, respectively. QCNR of 20 dB at low input power of −20 dBm was demonstrated. Optical sensitivity of APD BHD coherent receiver compared to its PIN BHD counterpart can be improved by 3 dB at low local oscillator (LO) powers, whereas for high LO powers the sensitivity of APD BHD approaches the values for PIN BHD.
Abstract The rapid development of quantum technology has driven the need for high-performance quantum signal processing modules. Balanced homodyne detector (BHD) is one of the most promising options for practical quantum state measurement, providing substantial advantages of cost-effectiveness, no cooling requirement, and system compactness. However, due to the stringent requirements in BHD design, it typically suffers from a relatively small operating bandwidth which limits the overall speed of a quantum system. In this study, we propose comprehensive modelling for the BHD in quantum applications and enhance the performance of BHDs based on our modelling. Specifically, we utilise a photonic chip approach and optimise the electronic design to create the integrated BHD, which significantly boosts the 3 dB bandwidth to 4.75 GHz and achieves a shot-noise-limited bandwidth of 23 GHz. We demonstrate the capability of this setup to generate quantum random numbers at a rate of 240 Gbit s−1, highlighting its potential for ultra-high-speed quantum communication and quantum cryptography applications.
In this paper, a model for simulating the shot noise power and the electronic noise power of a balanced homodyne detector (BHD) using cascaded low noise amplifiers (LNAs) is presented. Moreover, the factors influencing the enhancement of BHD gain flatness are analyzed. Based on these theories, a BHD with a large clearance between shot noise and electronic noise, along with a flat broadband frequency response, is designed using LNAs and an optimized printed circuit board design. According to the experimental measurements, the bandwidth for 1 dB flatness reaches 1.4 GHz with the -3 dB bandwidth extending up to 1.55 GHz. With a 4 mW optical signal input, a signal-to-noise ratio of 12 dB is obtained at 1 GHz. The BHD exhibits excellent linearity for shot noise output up to an 8 mW optical signal input and a tested common mode rejection ratio of 63 dB. This developed BHD is well-suited for applications in high-speed continuous variable quantum key distribution and quantum random number generation.