- 标题
- 摘要
- 关键词
- 实验方案
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All-optical regenerative technique for width-tunable ultra-wideband signal generation
摘要： We demonstrate all-optical generation of width-tunable mono-cycle pulses for ultra-wideband communication. It has been shown that the width of the mono-cycle pulses can be tuned dynamically by simply varying the power of the optical signal. We also investigate the regenerative property of the nonlinear medium-based technique for the generation of mono-cycle pulses. For the purpose of comparison, ultra-wideband mono-cycle pulses are also generated through the optical delay line-based technique. It has been demonstrated through numerical simulations that the nonlinear medium-based technique is highly resilient to amplified spontaneous emission noise that is induced over the optical signal. Furthermore, we have shown that the highly nonlinear fiber-based nonlinear medium performs better than the semiconductor optical amplifier-based medium. Bit error rate measurements are taken for different values of optical signal-to-noise ratios in order to elaborate our work.
关键词： Gaussian mono-cycle pulses,Ultra-wideband over fiber,Semiconductor optical amplifier,Pulse width tuning,Highly nonlinear fiber
更新于2025-09-23 15:22:29
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Analogue Wireless Beamforming Exploiting the Fiber-Nonlinearity of Radio Over Fiber Based C-RANs
摘要： As a key technique of supporting the fixed backbone network, radio over fiber (RoF) systems transmit the radio frequency signals over optical fiber in order to take advantage of their large available bandwidth. In this context, optical fiber aided phased antenna array (PAA) based beamforming techniques have attracted substantial research interest with the goal of improving the cell-edge coverage of cellular base stations. In this paper, we conceive a novel optical fiber aided beamforming technique based on the fiber's nonlinearity to be applied in cloud radio access network (C-RAN). In our proposed technique, the PAA elements are fed by the phase-shifted signals introduced by our highly nonlinear fiber (HNLF) aided phase-shifting solution, which results in an angular beamsteering range of around 90°. This can be exploited by sectorization in cellular networks to reduce the cochannel interference imposed. Furthermore, we exploit the proposed RoF-aided phase shifting technique in C-RAN, where our proposed system takes advantage of the centralized signal processing capability of the RoF system to conceive an all-optical processing based tunable beamforming system. While our flexible HNLF-aided phase-shifting process is confined to the central office of the C-RAN, the end users in the C-RAN cellular networks are capable of flexibly choosing the serving remote radio heads (RRHs) and employing diverse wireless transmission techniques. Through integrating our HNLF-aided phase-shifting design into the proposed C-RAN, we impose as little as 0.1 dB signal-to-noise Ratio (SNR) degradation compared to its traditional electronic counterpart, which requires extra phase-shifters.
关键词： phase-shifter,self-phase modulation,phased array antenna beamforming,C-RAN,cross-phase modulation,highly nonlinear fiber,Optical fiber,optical nonlinearity
更新于2025-09-23 15:22:29
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Repetition Rate Adjustable Dual-wavelength Solitons Fiber Laser Based on Highly Nonlinear Fiber
摘要： A dual-wavelength soliton ?ber ring laser with adjustable repetition rate was reported. Through adding highly nonlinear ?ber (HNLF) as nonlinear medium in the ?ber ring cavity, the dual-wavelength bright-dark soliton pair can be formed. The 1st to 4th, 5th to 8th and 9th to 11th harmonics bright-dark solitons pairs were obtained by rotating the Polarization controller (PC) when the power are 160 mW, 230 mW and 340 mW, respectively. To investigate the in?uence of loss on the laser system, a variable optical attenuator (VOA) was embedded in the ring laser cavity. Then the dual-wavelength with Kelly sidebands was obtained by properly adjusting the PC and VOA. The center wavelengths of the dual-wavelength laser were located at 1557.8 nm and 1568.5 nm and the 3 dB bandwidths of two wavelengths are 2.2 nm and 2.1 nm, respectively. The spacing between the two wavelengths was 10.7 nm. Due to the existence of nonlinearity, the 1st to 22th harmonics bright solitons sequence (corresponding to the repetition rate tunable from 196.8 kHz to 4.33 MHz) was obtained by increasing the pump power. The intervals of bright-dark solitons pair and bright solitons all were 5.08 μs, which corresponds to fundamental repetition rates are 196.8 kHz. The signal-to-noise ratio of the bright solitons was approximately 58 dB, which means the operation of laser was stable.
关键词： harmonic solitons,dual-wavelength soliton,adjustable repetition rate,fiber ring laser,highly nonlinear fiber,bright-dark soliton pair
更新于2025-09-19 17:13:59
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H-shaped pulse generation with tunable leading edge from a Tm-doped mode-locked fiber laser
摘要： A novel h-shaped pulse train with a tunable leading-edge (resembling a h-shaped pulse merging with a weak square pulse) is experimentally generated in a Tm-doped mode-locked fiber laser (MLFL) incorporating a 100 m highly nonlinear fiber. Through carefully adjusting the pump power and cavity polarization states, the leading-edge duration of the obtained h-shaped pulse can be widely tuned from zero (corresponding to the typical conventional h-shaped pulse train) to 567.8 ns (equivalent to the cavity roundtrip time). Our results can further facilitate understanding the intrinsic mechanism and characteristics of novel h-shaped pulse dynamics in MLFLs.
关键词： nonlinear polarization rotation,Tm-doped mode-locked fiber laser,tunable leading-edge,h-shaped pulse,highly nonlinear fiber
更新于2025-09-16 10:30:52
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Stability investigation of a multi-wavelength fiber linear cavity laser using a highly nonlinear fiber
摘要： A stable multi-wavelength fiber linear cavity laser based on cascaded four-wave mixing in a highly nonlinear fiber is proposed and experimentally demonstrated. In this scheme, the instability caused by model competition between comb filtering of the Sagnac interferometer loop mirror and self-seeded cascaded stimulated Brillouin scattering in the fiber cavity is successfully mitigated by the self-stability mechanism in the highly nonlinear fiber. Fifteen stable laser lines within 3 dB flatness are obtained at a pump power of 550 mW. We believe this can be further improved and the cavity structure further simplified by optimizing the design of the erbium-doped fiber and improving pump efficiency. However, stable multi-wavelength operation cannot be obtained by using a similar linear cavity structure. Therefore, the stability mechanism of multi-wavelength fiber linear cavity lasers using highly nonlinear fiber is investigated in detail.
关键词： fiber lasers,highly nonlinear fiber,nonlinear optics,four-wave mixing
更新于2025-09-11 14:15:04