- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2018 Asia Communications and Photonics Conference (ACP) - Hangzhou, China (2018.10.26-2018.10.29)] 2018 Asia Communications and Photonics Conference (ACP) - A code-free optical undersampling technique for broadband microwave spectrum measurement
摘要： A novel broadband microwave (MW) spectrum measurement (BMSM) scheme based on code-free optical undersampling and homodyne detection is proposed. The fully analog generation of optical pulses with a far-less-than-Nyquist rate is only through modulating cascaded electrooptical modulators by a single RF tone instead of any high-speed coding sequence modulation. Homodyne detection will reduce the analysis bandwidth of BMSM and enhance the detection performance of weak signal. A multi-band signal with 20 GHz spectral range and SNR = 61 dB is used to investigate the BMSM performance of this scheme, and the results show good performance for BMSM. The potentials for further optimization in practice are also discussed.
关键词： homodyne detection,optical undersampling,microwave spectrum measurement
更新于2025-09-23 15:22:29
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Continuous-variable entanglement distillation between remote quantum nodes
摘要： The development of quantum network relies on high-quality entanglement between remote quantum nodes. In reality the unavoidable decoherence limits the quality of entangled quantum nodes, however, entanglement distillation can overcome this problem. Here we propose an experimentally feasible scheme of continuous-variable entanglement generation, storage, and distillation between distant quantum nodes, which only requires the atomic ensemble quantum memory and balanced homodyne detection (BHD). Initially one copy of a bipartite entangled state of light, suffering phase fluctuations during the distributions, is stored in two distant atomic ensembles so that the atomic ensembles are entangled. Within the storage lifetime, by distributing and storing another copy of entangled optical modes in these two atomic ensembles, the distillation on entangled atomic spin waves can be implemented based on the post-selection of the BHD result. Our scheme provides a highly entangled state between remote quantum nodes for downstream applications, and enables the extension to multipartite entanglement distillation in a large-scale quantum network.
关键词： balanced homodyne detection,continuous-variable,entanglement distillation,quantum network,atomic ensemble
更新于2025-09-23 15:21:01
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functions
摘要： We propose a quantum optical device to experimentally realize quantum processes, which perform the regularization of the—in general highly singular—Glauber–Sudarshan P functions of arbitrary quantum states before their application and/or measurement. This allows us to produce a broad class of nonclassical states with regular P functions, also called nonclassicality quasiprobabilities. For this purpose, the input states are combined on highly transmissive beam splitters with specific Gaussian or non-Gaussian classical states. We study both balanced and unbalanced homodyne detections for the direct sampling of the output states of the implemented processes, which requires no further regularization or state-reconstruction. By numerical simulations we demonstrate the feasibility of our approach and we outline the generalization to multimode light.
关键词： quantum processes,Glauber–Sudarshan P functions,homodyne detection,nonclassical states,quantum optics
更新于2025-09-23 15:21:01
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A Coherent Homodyne TO-Can Transceiver as Simple as an EML
摘要： The introduction of low-cost coherent signal reception in optical telecommunications is one of the great challenges since its opto-electronic sub-systems are associated to a high degree of complexity. In this work we propose a disruptive approach: the re-use of widely deployed direct-detection technology for simultaneous coherent homodyne reception and transmission. We first show that an externally modulated laser (EML) is sufficient to perform both, coherent reception and transmission functionality. Second, we prove that homodyne detection applies to the EML-based scheme in virtue of an injection-locked local oscillator, which for low input power levels is pulled to the optical carrier frequency of the incident data signal. The proposed methodology for coherent reception enables a greatly simplified transceiver as optical-layer hardware. As we will demonstrate it just requires single fiber access, a single radio frequency port and can be implemented in a transistor-outline package. Full-duplex transmission with coherent homodyne reception is experimentally validated, showing 2.5 Gb/s transmission over 27.5 km reach and a loss budget of 28 dB, and coherent Gigabit Ethernet connectivity – without use of optical-layer digital signal processing functions.
关键词： Externally modulated laser,Optical signal detection,Optical communication terminals,Homodyne detection,Optical fiber communication
更新于2025-09-19 17:15:36
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Solution-Process ZnO-Mediated Semiconductor Bonding for Photovoltaic Applications
摘要： We propose and demonstrate frequency-comb regeneration using injection locking and a parametric mixer. We theoretically evaluate the effect of the dispersive walk-off between the two unmodulated carriers from which the comb is regenerated. We calculate the maximum number of carriers which can be regenerated as a function of the laser linewidth and transmission distance when considering dispersion-unmanaged links. Experimentally, we demonstrate a 70 line comb generation without major linewidth degradation from two carriers with 15 dB optical signal-to-noise ratio (OSNR). The low OSNR operation is achieved by the use of optical injection locking. We also evaluate the degradation in the comb regeneration when the carriers are temporally decorrelated in order to emulate the effect of dispersive walk-off. When the temporal delay is 1.5 ns, the comb regeneration does not suffer from major degradation but when the delay is 10 ns, only 30 carriers can be regenerated without linewidth degradation, which agrees with our theoretical analysis.
关键词： parametric devices,optical fiber communications,Homodyne detection
更新于2025-09-19 17:13:59
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Continuous Wave THz System Based on an Electrically Tunable Monolithic Dual Wavelength Y-Branch DBR Diode Laser
摘要： We analyse the use of a tunable dual wavelength Y-branch DBR laser diode for THz applications. The laser generates electrically tunable THz difference frequencies in the range between 100 and 300 GHz. The optical beats are tuned via current injection into a micro-resistor heater integrated on top of one of the distributed Bragg reflector (DBR) section of the diode. The laser is integrated in a homodyne THz system employing fiber coupled ion-implanted LT-GaAs log spiral antennas. The applicability of the developed system in THz spectroscopy is demonstrated by evaluating the spectral resonances of a THz filter as well as in THz metrology in thickness determination of a polyethylene sample.
关键词： Homodyne detection,CW THz source,Semiconductor laser
更新于2025-09-19 17:13:59
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Performance of grey-coded IQM-based optical modulation formats on high-speed long-haul optical communication link
摘要： In this article the performance of grey-coded advanced optical modulation formats is evaluated on a single-channel high-speed long-haul optical communication link and are compared to the respective differential-coded modulation formats. Polarisation division multiplexed optical in-phase quadrature modulator (IQM) structure and homodyne detection scheme are used to realise 100 Gbps quadrature phase-shift keying (QPSK), 120 Gbps 16-ary quadrature amplitude modulation (16-QAM), 360 Gbps 32-QAM and 480 Gbps 64-QAM modulation formats. Advanced digital signal processing unit with various pre-processing and recovery stages such as direct current blocking, normalisation, low-pass Bessel filter, resampling, quadrature imbalance compensation, chromatic dispersion compensation, non-linear compensation, timing recovery, adaptive equalisation, down-sampling, frequency offset estimation, and carrier phase estimation is used at the receiving end to compensate for signal impairments during propagation. Maximum transmission distances of 7200, 1050, 560, and 360 km have been achieved at an acceptable bit error rate for QPSK, 16-QAM, 32-QAM, and 64-QAM, respectively. The grey-coded systems outperformed the differential-coded systems regarding optical signal-to-noise ratio requirement, receiver sensitivity, and transmission distance.
关键词： grey-coded,optical modulation formats,high-speed long-haul optical communication,homodyne detection,IQM,digital signal processing
更新于2025-09-16 10:30:52
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Excess Loss in Homodyne Detection Originating from Distributed Photocarrier Generation in Photodiodes
摘要： The distributed absorption of photons in photodiodes induces an excess noise in continuous-wave photodetection above the transit-time roll-off frequency. We show that it can be treated as a frequency-dependent excess optical loss in homodyne detection. This places a limit on the bandwidth of high-accuracy homodyne detection, even if an ideal photodetector circuit is available. We experimentally evaluate the excess loss in two ways: a comparison of signal gain and shot-noise gain of one-port homodyne detection and a balanced homodyne detection of squeezed light at a 500-MHz sideband. These results agree with an analytic expression we develop, where the randomness of the photoabsorption is directly modeled by an intrusion of vacuum field. At 500 MHz, we estimate the excess loss at 14% for a Si photodiode with 860-nm incident light, while the numerical simulation predicts much smaller excess loss in (In, Ga)As photodiodes with 1550 nm light.
关键词： squeezed light,photodiodes,excess noise,homodyne detection,quantum measurement
更新于2025-09-09 09:28:46