Black solitons in dispersion-managed fiber transmission systems

In an ideal continuous exponential varying-dispersion fiber, black solitons, like their bright counterparts, can propagate over long distances without being broadened when the weakened nonlinearity that is due to the fiber loss is compensated for by the decreasing dispersion. It is found, however, that in a practical stepwise decreasing-dispersion fiber with N steps the number of steps N required for well-behaved evolution of black solitons in a lossy fiber with negligible distortion and broadening is fewer than for bright solitons. This finding indicates that the stepwise-varying-dispersion in fibers can be more effective for extending the amplifier spacing or reducing amplifier numbers in the high-bit-rate black soliton transmission system than in the corresponding bright soliton transmission system.     

Dark pulse generation in a dispersion-managed fiber laser

We report an experimental observation of dark pulse generation in a dispersion-managed erbium-doped fiber laser with net anomalous cavity group-velocity dispersion. It is found that apart from the bright soliton pulses, dark pulses with spectral sidebands could be obtained in the laser under appropriate operating conditions. The generation of dark pulses may be attributed to soliton shaping in the cavity.     

Noise evolution and soliton internal modes in dispersion-managed fiber systems

We perform a linear stability analysis of the Ablowitz-Biondini equations to explain the dynamic evolution of the noise squeezing, caused by the interplay among optical solitons and noise components, of initially uncorrelated statistics in fiber systems with dispersion management.     

色散管理掺铥光纤激光器高能量脉冲的产生

设计了一种基于色散管理的掺铥光纤激光器。通过调节泵浦功率以及腔内偏振态，首先实现了稳定的展宽脉冲输出，中心波长和脉冲宽度分别为1 939.4 nm和482 fs。最大输出功率为15 mW，对应的单脉冲能量为0.52 nJ。增加泵浦功率到645 mW时，通过适当调节偏振控制器可以实现类噪声脉冲锁模，中心波长为1 940.1 nm。所实现的锁模脉冲具有飞秒量级的尖峰以及皮秒量级的基底。最大输出功率为20.4 mW，相对应的单脉冲能量为0.7 nJ。相比于传统孤子，采用色散管理所实现的锁模脉冲具有更高的脉冲能量。此外，所设计的掺铥光纤激光器可作为理想的主振荡功率放大以及啁啾脉冲放大结构的种子源，进一步提高脉冲能量，拓展2 μm高能光纤激光器的实际应用。     

Interactions of dispersion-managed solitons in wavelength-division-multiplexed optical transmission lines

We investigate interactions between pulses in dispersion-managed multichannel wavelength-division-multiplexed soliton systems, using an improved variational approximation. The frequency shifts are found to be smallest for moderate, i.e., relatively short-scale, dispersion management. The position shifts increase monotonically with map strength.     

Optical bistability in tunable fiber laser using fiber Mach-Zehnder interferometer

In this letter, a novel mechanism of hybrid optical bistability is proposed by using nonlinear mechanism in the frequency domain. This device is based on electro-optical feedback through the fiber Bragg grating on piezoelectric transducer (PZT) to tune continuous wave (CW) fiber laser. The optical bistable characteristics for two manners of separately alternating input power and bias voltage are discussed. The smallest wavelength shift of the order of 0.001 nm needed to realize a switching process in this optical bistability device is estimated. The potential applications of this device in the optical fiber sensor technique are also discussed.     

Black solitons in dispersion-managed fiber transmission systems: errata

In the referenced Letter,1 a word was misprinted with the opposite meaning. On the fourth line of the left column of p. 158, the second word of the second sentence should be independence, not dependence as printed.     

Observation of dark pulse in a dispersion-managed fiber ring laser

The observation of dark pulse in a dispersion-managed fiber ring laser with net negative cavity group velocity dispersion (GVD) is reported. Both bright and dark pulses can be obtained in our fiber laser. When we appropriately adjust the cavity birefringence to achieve triple-wavelength mode-locked operation in the laser by rotating the polarization controller, the bright pulse could be switched to dark pulse. It is believed that the dark dispersion-managed (DM) pulse generation is caused by the linear and nonlinear intermodulation effects among the three wavelength pulses.     

Gain-guided solitons in dispersion-managed fiber lasers with large net cavity dispersion

Gain-guided solitons are experimentally observed in dispersion-managed fiber lasers with large net positive group-velocity dispersion. It is shown that formation of the soliton is a robust feature of the lasers. Numerical simulations also confirmed the experimental results.     

Optical bistability and temporal symmetry-breaking instability in nonlinear fiber resonators

In this work we analyze two different behaviors in a nonlinear passive fiber ring cavity with a synchronously pulsed pump iterating the infinite-dimensional Ikeda map. First, we show optical bistability with normal and anomalous dispersions. The obtained numerical results are compared with the cw pump case. Secondly, these cavities are subject to a temporal symmetry-breaking instability with anomalous dispersion. This instability is described and the range of parameters for its appearance is shown and discussed.     

Controllable optical bistability and multistability in a rare-earth-ion-doped optical fiber

We investigated the optical bistability and multistability in an Er³⁺-doped ZrF₄–BaF₂–LaF₃–AlF₃–NaF optical fiber inside an optical ring cavity. It is found that the optical bistability and multistability can be easily controlled via adjusting properly the parameters of the corresponding system. Our scheme may provide some new possibilities for technological applications in optoelectronics and optical-fiber communication.     

Optical bistability in fiber ring resonator containing an EDFA

In this paper, we study on optical bistability behaviors in a double-coupler ring resonator, in which an erbium-doped fiber amplifier (EDFA) is inserted into the ring for counteracting the loss by the gain of EDFA. The two groups of transmitted and reflected optical bistability loops under different parameters are investigated symmetrically. According to our optimum design of this new optical bistable device, the switching power can be less than 60 mW.     

Coupler-loss and coupling-coefficient-dependent bistability and instability in a fiber ring resonator

In this paper, we demonstrate the dynamic simulation of light traveling in a fiber ring resonator with a single coupler. Optical nonlinear phenomena including bistability, the Ikeda instability, bifurcation and chaos are studied. The Ikeda instability in ring resonator arises from the ring-cavity lifetime being much longer than the Kerr-effect response time of the fiber. The transmission curves of the bistability and the instability as function of the insertion losses (γ) and the coupling coefficients (κ) of the coupler are derived.     

超高斯型光脉冲在色散管理光纤系统中的传输

从描述超短光脉冲在光纤中传输的高阶非线性薛定谔方程入手,使用傅里叶变换的分裂算符法,通过计算机模拟,研究了超高斯光脉冲在色散管理光纤系统中的传输特性,并考察了超高斯光脉冲在加入随机噪声后传输的稳定性以及脉冲间的相互作用.     

Optical bistability and signal processing in a microstructured fiber ring resonator

We explore theoretically the effects of bistability in a microstructured fiber-based ring resonator. Numerical simulations indicate that bistable behavior of the fiber cavity can be observed with a short length of fiber. Feasibility of all-optical processing using this type of cavity is also investigated. In particular, we show that a ring cavity including a microstructured fiber should allow one to perform flip-flop and time-division demultiplexing functions. The analysis presented here will be useful for future design of bistable microstructured fiber device.     

Optical bistability and multistability via quantum interference in an Er-doped optical fiber

The optical bistability and multistability in an Er³⁺-doped ZrF₄-BaF₂-LaF₃-AlF₃-NaF optical fiber inside a ring cavity are investigated. The underlying mechanism shows some new characteristics that other schemes do not have. Thus, it may provide some new possibilities for technological applications in optoelectronics and quantum information science.     

Period-doubling of dispersion-managed solitons in an Erbium-doped fiber laser at around zero dispersion

Period-doubling of dispersion-managed solitons in an Erbium-doped fiber ring laser operating at the near zero net cavity group velocity dispersion region was experimentally observed. The generated dispersion-managed solitons of the laser are characterized by their near Gaussian spectral profiles and no sidebands. Numerical simulations verified our experimental observations and showed that the period-doubling could occur both in the positive and negative near zero net cavity group velocity dispersion regions, which suggests that the occurrence of the period-doubling is an intrinsic feature of the mode-locking fiber lasers and independent of the concrete mode-locked pulse profile.     

Hybrid optoelectronic bistability in a fiber Bragg grating by use of a tunable fiber laser

We report the observation of hybrid optoelectronic bistability in a fiber Bragg grating (FBG) by use of an electro-optically tuned cw fiber laser in which another wavelength-matched FBG is employed to constitute a tunable resonant cavity. The potential application of such a device as a fiber-optic sensor is also discussed.     

Dual-wavelength-switching operation based on optical bistability in pump-bypassed ytterbium-doped fiber laser

The bistable feature of residual pump in a pump-bypassed Yb-doped fiber laser offers the potential to pump Er/Yb co-doped fiber in a bifurcated cavity for the lasing of the 1537 nm line. The results of our proof-of-concept demonstration show that the oscillations at 1040 nm and 1537 nm are operated in the wavelength-switching mode, and this suggests that the combination of optical bistability in a pump-bypassed fiber laser cavity with a bifurcated cavity could be one simple and efficient method for switchable dual-wavelength operation. PACS 42.55.Wd; 42.65.Pc; 42.79.Ta     

Laws, Symmetries, and Reality

It is argued that quantum mechanics follows naturally from the assumptions that there are no fundamental causal laws but only probabilities for physical processes that are constrained by symmetries, and reality is relational in the sense that an object is real only in relation to another object that it is interacting with. The first assumption makes it natural to include in the action for a gauge theory all terms that are allowed by the symmetries, enabling cancellation of infinities, with only the terms in the standard model observable at the energies at which we presently do our experiments. In this approach, it is also natural to have an infinite number of fundamental interactions.