Metamaterials have opened up a new field of electromagnetic wave stealth that can achieve cross-band electromagnetic wave stealth through high electromagnetic wave absorption and low infrared emission. However, traditional cross-band stealth metamaterials make covering the terahertz band challenging and have certain design flaws. This Letter introduces an innovative cross-band electromagnetic wave stealth metasurface design that can achieve cross-band stealth in the infrared, microwave, and THz bands.
View Article and Find Full Text PDFMeasurement device independent quantum key distribution (MDI QKD) has attracted growing attention for its immunity to attacks at the measurement unit, but its unique structure limits the secret key rate. Utilizing the wavelength division multiplexing (WDM) technique and reducing error rates are effective strategies for enhancing the secret key rate. Reducing error rates often requires active feedback control of wavelengths using precise external references.
View Article and Find Full Text PDFThe quantum-classical coexistence can be implemented based on wavelength division multiplexing (WDM), but due to Raman noise, the wavelength spacing between quantum and classical signals and launch power from classical channels are restricted. Space division multiplexing (SDM) can now be availably achieved by multicore fiber (MCF) to reduce Raman noise, thereby loosening the restriction for coexistence in the same band and obtaining a high communication capacity. In this paper, we realize the quantum-classical coexistence over a 7-core MCF.
View Article and Find Full Text PDFIn this study, we report a simple method to improve the thermal conductivity of epoxy resin by using new magnetic composites as fillers. The rGO@FeO nanocomposite has been prepared by a solvothermal method, and its morphology and chemical structure were characterized and analyzed by various characterization methods. Afterwards, the rGO@FeO/EP composite material was obtained in an external magnetic field, in which the rGO@FeO is uniformly dispersed in the epoxy resin matrix, arranged along the direction of the magnetic field.
View Article and Find Full Text PDFThe demand for the integration of quantum key distribution (QKD) and classical optical communication in the same optical fiber medium greatly increases as fiber resources and the flexibility of practical applications are taken into consideration. To satisfy the needs of the mass deployment of ultra-high power required for classical optical networks integrating QKD, we implement the discrete variable quantum key distribution (DV-QKD) under up to 25 dBm launch power from classical channels over 75 km on an ultra-low-loss (ULL) fiber by combining a finite-key security analysis method with the noise model of classical signals. To the best of our knowledge, this is the highest power launched by classical signals on the coexistence of DV-QKD and classical communication.
View Article and Find Full Text PDFThere is an increasing demand for multiplexing of quantum key distribution with optical communications in single fiber in consideration of high costs and practical applications in the metropolitan optical network. Here, we realize the integration of quantum key distribution and an optical transport network of 80 Gbps classical data at 15 dBm launch power over 50 km of the widely used standard (G.652 Recommendation of the International Telecom Union Telecom Standardization Sector) telecom fiber.
View Article and Find Full Text PDFWe investigate quantum random number generation based on backward spontaneous Raman scattering in standard single-mode fiber, where the randomness of photon wavelength superposition and arrival time is simultaneously utilized. The experiment uses four avalanche photodiodes working in gated Geiger mode to detect backward Raman scattering photons from four different wavelength channels and a time-to-digital converter placed behind the detectors to record their arrival time. Both information of the wavelength and arrival time interval of photons from different channels are applied to generate random bits.
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