- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[OSA Optical Fiber Sensors - Lausanne (2018..-..)] 26th International Conference on Optical Fiber Sensors - Mitigation of Output Fluctuations due to Residual State of Input Polarization in a Compact Current Sensor
摘要： We propose and demonstrate a new compact current sensor and technique capable to mitigate the residual state of polarization variation of partially depolarized optical sources. Sensor can operate from 0 to 300A and, is designed to be applied in electric distributed networks to power quality measurement.
关键词： Fiber optics sensors,Fiber optics and optical communications
更新于2025-09-12 10:27:22
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Optimized uni-traveling carrier photodiode and mushroom-mesa structure for high-power and sub-terahertz bandwidth under zero- and low-bias operation
摘要： In this paper, physically-based simulations are carried out to investigate and design uni-traveling carrier photodiode (UTC-PD) for high-power sub-terahertz wave generation at zero- and low-bias operation. The reliability of the physically-based simulation is demonstrated by comparing with our experimental result. Both the bandwidth and RF output power of the proposed UTC-PD is significantly improved by careful design the built-in electric field distribution under high-power input. For the optimized UTC-PD with the mesa diameter of 5 μm, its 3dB bandwidth large than 100 GHz even if the photocurrent reaches 6 mA under zero-bias operation. The device can reach a high bandwidth of 92.4 GHz, 105 GHz, and 119.5 GHz under the reverse bias of 0.5 V, 1 V, and 2 V, respectively, even the input photocurrent as high as 18.2 mA. The peak output-power of the device has enhanced at least 7 dB even at 170 GHz and zero- or low-bias operation. Besides, a novel design of mushroom-mesa UTC-PD (MM-UTC-PD) is proposed which with 4.3% improved high-speed performance. The MM-UTC-PD can trade-off between the external quantum-efficiency and bandwidth when miniaturized junction size is required.
关键词： ultrafast optics,sub-terahertz,optical communications,high-power photodiodes,optical receivers
更新于2025-09-11 14:15:04
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Space division multiplexing in standard multi-mode optical fibers based on speckle pattern classification
摘要： In optical communications the transmission bandwidth of single mode optical fibers is almost fully exploited. To further increase the capacity of a telecommunication link, multiplexing techniques can be applied across 5 physical dimensions: amplitude, quadrature, polarization, frequency and space, with all but the latter being nearly exhausted. We experimentally demonstrate the feasibility of an original space division multiplexing technique based on the classification of speckle patterns measured at the fiber’s output. By coupling multiple optical signals into a standard multimode optical fiber, speckle patterns arise at the fiber’s end facet. This is due to quasi-random interference between the excited modes of propagation. We show how these patterns depend on the parameters of the optical signal beams and the fiber length. Classification of the speckle patterns allows the detection of the independent signals: we can detect the state (i.e. on or off) of different beams that are multiplexed in the fiber. Our results show that the proposed space division multiplexing on standard multimode fibers is robust to mode-mixing and polarization scrambling effects.
关键词： space division multiplexing,mode-mixing,speckle patterns,polarization scrambling,optical communications,multimode optical fibers
更新于2025-09-11 14:15:04
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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - InP-based devices integrating liquid crystals microcells for a tunable laser emission or a wavelength selective photodetection
摘要： Photonic devices with wavelength tuning capabilities are investigated with the use of liquid crystal microcells monolithically integrated onto the surfaces of photodiodes or VCSEL fabricated on InP based materials. For these two devices, we demonstrated that the detected or emitted wavelength can be selected on a tuning range of more than 70 nm in the case of the photodiode, and of more than 20 nm in the case of VCSEL.
关键词： VCSEL,Photodiodes,Liquid-crystal,Optical communications
更新于2025-09-11 14:15:04
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Differential pulse-amplitude modulation signalling for free-space optical communications
摘要： To improve the bandwidth efficiency of free-space optical systems and at the same time to reduce the impact of the background noise, a differential M-ary pulse-amplitude modulation (M-PAM) signalling scheme that uses two laser transmitters is proposed. The authors first consider the condition that the receiver perfectly knows the instantaneous channel coefficient and compare the performance of the proposed differential PAM with the conventional PAM signalling and show the improved performance when the background noise level is relatively high. Second, the practical situation where the receiver has to estimate the channel for signal detection is considered. The authors propose an estimation scheme based on the characteristics of the differential PAM signalling while requiring no pilot symbol transmission. The proposed data-aided channel estimation is performed on a sequence of received PAM symbols. The authors also show that for a sufficiently large observation window, the proposed estimation method allows achieving a performance close to the perfect channel knowledge.
关键词： bandwidth efficiency,channel estimation,background noise,free-space optical communications,differential M-ary pulse-amplitude modulation
更新于2025-09-11 14:15:04
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[IEEE 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Fukuoka, Japan (2019.7.7-2019.7.11)] 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - High-speed High-saturation-power modulation through a 1560nm long-cavity Directly Modulated DFB Laser
摘要： In this work, data modulation of directly modulated DFB laser (DML) of long cavity for high speed and high power has been achieved. With reducing the parasitic capacitance of DML, a high-speed optical modulation can still be obtained, even at long waveguide. The -3dB bandwidth was measured to be 25GHz and 18GHz, where the output power of 5.5mW and 7mW in 1550nm regime for 200μm and 500μm cavity length has been demonstrated. Data modulation speed of 30Gb/s eye diagrams has been also achieved, suggesting that such technique can be applied for high-speed modulation without reducing the device length, also leading to the capability of obtaining high-saturation optical output power.
关键词： Semiconductors,Modulation,Optical communications
更新于2025-09-11 14:15:04
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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - High-speed Avalanche Photodiodes based on III-V Compounds for Optical Communications
摘要： Avalanche photodiodes based on III-V-compounds feature flexibility in designing bandwidth, gain, responsivity, and linearity, which are associated with not only the thickness of each layer but also doping profiles and material options and their combinations. Here, we review the design and performance of our high-speed avalanche photodiodes that feature a unique epitaxial layer structure. Even though the APDs have a vertical illumination structure, which is essential for easy optical coupling and fabrication, their speed is high enough for operation with 100G-PAM4. We also discuss our efforts for improving linearity, which is important for operation with higher-order modulation format.
关键词： Avalanche photodiode,Optical communications systems,high speed
更新于2025-09-11 14:15:04
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[OSA Optical Fiber Sensors - Lausanne (2018..-..)] 26th International Conference on Optical Fiber Sensors - High Pressure FBG Sensor based on Compression Using a Single Point Attached Fiber in a Ferrule
摘要： A compact high pressure FBG sensor using a single point attached fiber in a ferrule was proposed. It was compared theoretically, by simulations and experimentally to FBG fully attached to the ferrule conception. Results show that the proposed conception has 3.2 to 4.2 times higher sensitivity, suited to use in internal combustion chamber engine.
关键词： Fiber optics sensors,Fiber optics and optical communications
更新于2025-09-11 14:15:04
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Controllable Polarization of Lasing Emission From a Polymer Microfiber Laser
摘要： Microlasers with controllable polarization of output emission are vital for on-chip optical communications, optical sensors and optical switches. In this work, we report a high quality (Q) factor, low-threshold polymer microfiber laser and the possibility of achieving laser emission with a desired polarization. The microfiber is fabricated by direct drawing from a dye-doped polymer solution and it can generate whispering gallery mode (WGM) lasing under optical pulse excitation. When the microfiber is pumped from the side with pumping direction perpendicular to the microfiber’s axis, the polarization direction of the output laser is found to be the same as that of the pump laser. Lasing emission with either transverse electric (TE) or transverse magnetic (TM) modes can be obtained and these two polarization states can be switched over by tuning the pumping laser. Furthermore, emission with both TE and TM modes can also be observed by changing the orientation of the microfiber relatively to pumping direction. Our finding provides an effective approach for achieving microlasers that have high Q lasing modes with anticipated polarization.
关键词： microlasers,controllable polarization,polymer microfiber,whispering gallery mode,optical communications
更新于2025-09-11 14:15:04
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - On the Variability of Launching and Detection in POF Transmission Systems
摘要： POF commercial active devices present a variety of designs in which fibre coupling is achieved by different connector types. The particular characteristics and tolerances of transmitter and receiver designs are behind the variability of the fibre input and output angular power distributions, and consequently, we suggest that they are the cause of the high standard deviation usually found in POF measurements. Our aim here is to quantify the impact of the variability of the fibre coupling at the injection and the detection ends on transmission parameters of a POF link. We analysed two different source types and proposed a detector model whose parameters are based on experimental measurements. The standard deviations of power loss and frequency response are calculated using the propagation matrix model for the fibre, and also extracted from experimental measurements, revealing the contribution of both launching and detection conditions.
关键词： statistical analysis,optical communications,plastic optical fibres,experimental characterization
更新于2025-09-10 09:29:36