温度调谐型均匀光纤光栅级联进行色散补偿

本文提出使用级联的温度调谐均匀光纤光栅对光纤进行宽带色散补偿,对所需光纤光栅的变迹函数和耦合长度进行了优化设计,并讨论了光纤光栅的温度增敏措施。     

Dispersion compensation with SBS-suppressed fibre phase conjugator using synchronised phase modulation

204 km, 10 Gbit/s standard optical fibre transmission is successfully demonstrated using the mid-span spectral inversion technique with a stimulated Brillouin scattering suppressed fibre phase conjugator, proposed recently by Tani and Yamashita. Transmission performance has been improved compared with a conventional phase conjugator.     

光子晶体光纤的色散特性

本文用有效折射率模型 ,分析了光子晶体光纤的色散特性 ,定量给出了光子晶体光纤双折射特性与光纤参数之间的关系 ,指出了光子晶体光纤具有多个零色散波长 ,对相关现象作出了合理的解释。     

Dispersion compensation for optical fiber systems

Much of the currently embedded optical fiber was originally designed for light with a wavelength of 1.3 microns. If this fiber is to be used with tomorrow's optically amplified, high-speed, long span-length lightwave system operating at 1.5 microns, the chromatic dispersion in the fiber must be compensated. Dispersion compensation will be required in long-haul l0 Gb/s systems using conventional fiber. Many compensation techniques have been demonstrated and they exhibit a variety of different and often complimentary properties. Transmitter compensation techniques are the most easily implemented but provide a limited amount of compensation. The most commercially advanced technique is negative dispersion fiber. Chirped Bragg gratings are advancing rapidly, but will always be hampered by their narrow bandwidth. The adoption of any particular technique for use in a high-speed network will depend on the constraints imposed by the, as yet, undefined network architecture     

Dispersion compensation with phase-sensitive optical amplifiers

Recently, we proposed a novel approach to combating the pulse-broadening effect of group-velocity dispersion (GVD) in a fiber-optic communication link (IEEE Photon. Technol. Lett., vol. 5, pp. 669-672, 1993). In our scheme, linear loss in the fiber is balanced by a chain of periodically spaced, phase-sensitive optical amplifiers. In this paper, we present a detailed analysis of pulse propagation in such a fiber line showing that, due to attenuation in the quadrature orthogonal to the amplified quadrature, it is possible for a pulse to propagate without significant broadening over lengths many times longer than the usual dispersion length of the fiber. An averaged equation for pulse evolution over distances longer than the amplifier spacing is derived. The effect of optical-phase fluctuations between the propagating pulse and the amplifiers is also considered. Since our proposed scheme does not rely on the formation of solitons in the fiber, it can be implemented in both the positive and negative GVD regions, and it does not require a minimum peak power for the pulses     

Dispersion compensation by differential time delay

A technique for optical pre- or postdistortion in order to compensate for fiber dispersion is discussed theoretically, The dispersion compensation device is based on differential time delay for the upper and the lower sideband of the modulated signal. The proposed scheme is primarily intended for high bit rate (>10 Gbit/s) time division multiplexed transmission, and in an ideal case the transmitting distance could be enhanced by a factor of 4 in a dispersive limited system. With more realistic demands on the dispersion compensation device, the gained distance is in the order of 2.5     

Dispersion statistics in concatenated single-mode fibers

Dispersion measurement data from two sets of fiber cable lengths were employed to determine the histograms of slope and wavelength of zero chromatic-dispersion in concatenated single-mode fibers. We use a Monte-Carlo technique under two concatenating scenarios, depending on whether those fibers being concatenated are or are not manufactured by the same process. Results show that the variances of slope and wavelength of zero dispersion are inversely proportional to the numberNof fiber cable lengths being concatenated. The average and standard deviation of zero-chromatic dispersion wavelength changes less than 0.005 percent or 1 percent, respectively, when the actual dispersion slopes of individual fiber lengths being concatenated are replaced by random quantities distributed with uniformity within 0.08-0.1 ps/km . nm².     

Dispersion compensation with photonic crystal line-defect waveguides

A concept for dispersion compensation in transmission is proposed, based on modes anti-crossing in photonic crystal (PC) line-defect waveguides. Quasi-constant positive and negative dispersion is possible in order of 100 ps/nm/mm on the bandwidth of 100 GHz. An adiabatic taper is proposed for efficient coupling into PC structure.     

Dispersion compensation by active predistorted signal synthesis

Techniques for the synthesis of an optical signal predistorted to compensate for fiber dispersion are discussed theoretically. A scheme for very high bit rate (>10 Gbit/s) time-division-multiplexed transmission is proposed which neither requires extremely short pulse sources nor suffers from their inherent dispersion limitations. The rudimentary aspects of the techniques have been verified experimentally by demonstrating both enhanced and degraded transmission of a 4-GHz modulated signal at 1.55 μm over 10-30 km of optical fiber.     

光通信技术讲座--(十二):光纤通信系统色散补偿和管理

介绍现在广泛使用的色散补偿和管理的方法、基理及其进展.     

线性啁啾光纤光栅使色散补偿超过100km

报告了用简单的应力方法使均匀光栅成为线性啁啾光纤光栅的技术,并推导出了相应理论。在常规单模光纤Ｇ．６５２、１０Ｇｂ／ｓ系统中实现超过１００ｋｍ的色散补偿。     

Dispersion and bandwidth spectra in single-mode fibers

Bandwidth spectra of single-mode fibers are calculated from experimentally obtained chromatic-dispersion-versus-wavelength curves. Results include second-order effects on bandwidth which depend on the curvature of the dispersion curves. Examples illustrate how bandwidth spectra change as a function of source power spectra. They also show how small changes in fiber dimensions and refractive-index differences can cause significant bandwidth changes at 1.3 μm wavelength.     

Dispersion measurement on fluoride glasses and fibers

An overview is given of dispersion measurements on fluoride glasses and fibers, and the dispersion compensating capability of fluoride fibers is discussed. The temperature dependence of refractive-index dispersion and material dispersion of fluoride glasses is measured. These measurements indicate that fluoride glasses can compensate for temperature-dependent changes of refractive indices and material dispersion in silica glasses and fibers     

Dispersion compensation of 16 ps pulses over 100 km of step-indexfibre using cascaded chirped fibre gratings

The propagation of 16 ps data pulses over 100 km of step-index fibre using two cascaded chirped fibre gratings to achieve dispersion compensation is presented. At the output, the pulses are broadened slightly to 20 ps, indicating the potential for 50 Gbit/s operation     

Dispersion of optical fibers with far off-resonance gratings

We derive analytic expressions for the quadratic and cubic dispersion of optical fiber Bragg gratings, at frequencies far from the Bragg condition, where the usual coupled-mode theory (CMT) fails. We use these to design fibers that have no quadratic dispersion at a particular wavelength, but find that the cubic dispersion then increases. We also show that it is possible to design a fiber link with vanishing average quadratic and cubic dispersion by combining a length of standard fiber and a length of dispersion compensating fiber with an off-resonance grating     

Dispersion compensation over 270 km at 10 Gbit/s using anoffset-core chirped fibre Bragg grating

A 120 mm long fibre Bragg grating, adjustably chirped by an offset-core technique, compensates for dispersion in a 10 Gbit/s optical communication system operating at 1054 μm over 270 km of non-dispersion-shifted fibre. Simultaneous compensation of fibre dispersion and source chirp in a directly modulated system is also described     

超高速光传输系统使用的色散补偿技术

阐述超高速单信道、多信道传输系统克服光纤波长色散、偏振模色散（PMD）以及色散斜率影响的技术措施。     

Dispersion compensation by optical phase conjugation in silicon waveguide

The use of a silicon-waveguide-based optical phase conjugator at the mid-span of a fibre link for dispersion compensation is experimentally demonstrated, enabling transmission of optical data at up to 40 Gbit/s over 320 km of standard fibre with clear open eye diagrams at the receiver. In addition, the feasibility of dispersion compensation for multiple DWDM channels simultaneously is demostrated. A signal conversion efficiency of -10 dB is obtained with a pump intensity of 37.5 MW/cm² in the waveguide.     

Dispersion compensation for Huygens' sources and far-zonetransformation in FDTD

The equivalence principle is utilized for generation of both incident plane waves and for near- to far-zone transformation in the finite-difference time-domain (FDTD) method. Small errors will appear due to numerical dispersion when a plane wave is generated by Huygens' sources using an analytical expression for the incident field. These errors can be derived from the numerical dispersion relation in the frequency domain. By using a second-order approximation of the numerical wavenumber it is shown that a simple approximative time-domain compensation procedure for the dispersion can be derived. This has been implemented in a Huygens' source routine and in a time-domain near- to far-zone transformation routine. It is shown that this compensation significantly reduces the errors produced when calculating far-zone scattered fields of low amplitude. It is also shown that it is sufficient to compensate either the Huygens' sources or the time-domain near- to far-zone transformation with respect to dispersion. For validation, plane wave propagation through empty space and scattering of a dipole have been studied     

Dispersion compensation optical fiber modules for 40 Gbps WDM communication systems

Dispersion compensation was originally proposed to equalize pulse distortion.With the development of wavelength division multiplexing (WDM) techniques for large capacity optical communication systems,dispersion compensation technologies have been applied into the field.Fiber-based dispersion compensation is an attractive technology for upgrading WDM communication systems because of its dispersion characteristics and good compatibility with transmission optical fibers.Dispersion compensation fibers and the modules are promising technologies,so they have been receiving more and more attention in recent years.In this work,high performance dispersion compensation fiber modules (DCFMs) were developed and applied for the 40 Giga bit-rate systems.First,the design optimization of the dispersion optical fibers was carried out.In theory,the better the refractive index profile is,the larger the negative dispersion we could obtain and the higher the figure of merit (FOM) for the dispersion optical fiber is.Then we manufactured the fiber by using the plasma chemical vapor deposition (PCVD) process of independent intellectual property rights,and a high performance dispersion optical fiber was fabricated.Dispersion compensation fiber modules are made with the dispersion compensating fibers (DCFs) and pigtail fibers at both ends of the DCFs to connect with the transmission fibers.The DCFMs present the following superior characteristics:low insertion loss (IL),low polarization mode dispersion,good matched dispersion for transmission fibers,low nonlinearity,and good stability for environmental variation.The DCFMs have the functions of dispersion compensation and slope compensation in the wavelength range of 1525 to 1625nm.The experiments showed that the dispersion compensation modules (DCMs) met the requirements of the GR-1221-CORE,GR-2854-CORE,and GR-63-CORE standards.The residual dispersions of the G.652 transmission lines compensated for by the DCM in the C-band are less than 3.0ps/nm,and the dispersion slopes are also compensated for by 100%.With the DCFMs,the 8×80km unidirectional transmission experiments in the 48-channel 40Gbps WDM communication system was successfully made,and the results showed that the channel cost was smaller than 1.20dB,without any bit error.