实例分析电力通信系统光传输网络优化

如今,电力能源作为一种通用型能源被广泛的运用在人们日常生活和社会生产活动中,在一定程度上极大的提高了人类生产活动的效率,提升了人们的生活质量。本文以某省电力网络建设为例,对电力通信光传输网出现的问题和面临的困境进行分析,指出了电力通信光传输网络优化的必要性,并详细介绍对电力系统光传输网络的优化的具体方案。

High Speed VCSEL-Based Parallel Optical Transmission Modules

Design and fabrication of a parallel optical transmitter are reported. The optimized 12 channel parallel optical transmitter,with each channel＇s data rate up to 3Gbit/s,is designed, assembled, and measured. A top-emitting 850nm vertical cavity surface emitting laser（VCSEL） array is adopted as the light source,and the VCSEL chip is directly wire bonded to a 12 channel driver IC. The outputs of the VCSEL array are directly butt coupled into a 12 channel fiber array. Small form factor pluggable （SFP） packaging technology is used in the module to support hot pluggable in application. The performance results of the module are demonstrated. At an operating current of 8mA, an eye diagram at 3Gbit/s is achieved with an optical output of more than 1mW.

Quantum Secure Direct Communication by Using Three-Dimensional Hyperentanglement

We propose two schemes for realizing quantum secure direct communication (QSDC)by using a set ofordered two-photon three-dimensional hyperentangled states entangled in two degrees of freedom (DOFs)as quantuminformation channels.In the first scheme,the photons from Bob to Alice are transmitted only once.After insuring thesecurity of the quantum channels,Bob encodes the secret message on his photons.Then Alice performs single-photontwo-DOF Bell bases measurements on her photons.This scheme has better security than former QSDC protocols.In thesecond scheme,Bob transmits photons to Alice twice.After insuring the security of the quantum channels,Bob encodesthe secret message on his photons.Then Alice performs two-photon Bell bases measurements on each DOF.The schemehas more information capacity than former QSDC protocols.

Design of a multi-channel free space optical interconnection component

A multi-channel free space optical interconnection component, fiber optic rotary joint, was designed using a Dove prism. When the Dove prism is rotated an angle of at around the longitudinal axis, the image rotates an angle of 2 at. The optical interconnection component consists of the signal transmission system, Dove prim and driving mechanism. The planetary gears are used to achieve the speed ratio of 2：l between the total optical interconnection component and the Dove prism. The Clenses are employed to couple different optical signals in the signal transmission system. The coupling loss between the receiving fiber of stationary part and the transmitting fiber of rotary part is measured.

Design of Dispersion Compensation and Nonlinear Distortion Self-compensationin Co -network Transmission Systems

Dispersion and nonlinear distortion have an effect on transmission performanc es of optic al fiber transimission systems. The schemes of dispersion compensation and nonli near distortion self-compens ation in telecom-CATV co-network transmission systems are reported, followed by investigation on (1) the impact of dispersion compensation fiber (DCF) on fi ber nonlinear effects with a cascade of erbium-doped fiber amplifiers (EDFAs) an d different dispersion compensation schemes, (2) the impact of the complex on th e total nonlinear distortion induced by EDFA gain tilt and the light source. As a result , dispersion compensation optimal scheme and EDFA negative gain tilt are suggest ed as a solution to dispersion compensation and the nonlinear distortion self-c ompensation.

8×10 Gb/s transmission system over 2015 km with dispersion compensation by fiber Bragg Grating

The cascaded chirp fiber Bragg gratings(CFBGs) with ITU-T standard wavelengths and wavelength grid are applied to compensate the dispersion of 8×10 Gb/s WDM system.The ASE of the EDFA could be reduced,the OSNR of the transmitted signal can be increased and the fluctuation of the EDFA gain can be restrained in a certain scope by the CFBG employed in the system.Experiment of error-free 8×10 Gb/s 2 015 km transmission without FEC and electric regeneration is demonstrated in this paper.In this system,only EDFA is used as amplifier,and no other form of dispersion compensator is adopted except CFBG.The experimental result showed that after 2015 km transmission,the consistency of the dispersion compensating for each channel is perfect.

Separate Dimming Controlling and Data Transmission for an Indoor Visible Light Communication System

Simultaneous dimming controlling and data transmission are usually required in a white LED based indoor visible light communication system.However,the diming controlling of LED normally interferes the data transmission due to the modulation nonlinearity of LED.In order to solve this problem,a scheme by separating the LEDs for the functions of dimming control and data transmission respectively is proposed in this paper.In the scheme,the LEDs used for dimming control function are driven by a dc amplified circuit,and the LEDs for data transmission are driven by a digital modulation circuit respectively.In this way,the modulation distortion to the data signal caused by the modulation nonlinearity can be avoided even if the dimming is at high level dc driven current.The proof-of-concept experiment of a 2.5Mbit/s visible light communication system demonstrates that the dimming controlling and data transmission can be realized simultaneously in a simple way,and the data transmission is not affected by the dimming controlling function.Compared to previous methods,the scheme in this paper is simpler and cost effective,and makes sense when high rate data is transmitted in a visible light communication system.

A method of simulating intensity modulation-direct detection WDM systems

In the simulation of Intensity Modulation-Direct Detection WDM Systems,when the dispersion and nonlinear effects play equally important roles,the intensity fluctuation caused by cross-phase modulation may be overestimated as a result of the improper step size.Therefore,the step size in numerical simulation should be selected to suppress false XPM intensity modulation (keep it much less than signal power).According to this criterion,the step size is variable along the fiber.For a WDM system,the step size depends on the channel separation.Different type of transmission fiber has different step size.In the split-step Fourier method,this criterion can reduce simulation time,and when the step size is bigger than 100 meters,the simulation accuracy can also be improved.

Analysis of Optical Signal Transmission Characteristics in AWG Multi/Demultiplexer with Electromagnetic Field Theory

Based on the electromagnetic field theory, the optical signal transmission characteristics in input/output waveguides, slab waveguides and arrayed waveguides of the arrayed waveguide grating (AWG) multi/demultiplexer are analyzed. The relationship between the physical parameters such as geometry sizes and relative refractive index in AWG multi/demultiplexer and the optical signal transmission characteristics are discussed. This theoretical study can be used for optimizing the design and improving the performance of the AWG multi/demultiplexer.

Optical-fiber distributed temperature sensor:design and realization

Through analyzing theoretically the temperature effect of the optical-fiber Raman backscattering,a distributed temperature sensor is designed based on the single-mode fiber. Demodulation methods of temperature transduction are compared,and then the demodulation method using the ratio of the anti-Stokes and the Stokes Raman backscattering intensity is adopted. Both the hardware composition and the software realization of the system are introduced in detail. The experiment shows that the distinguishing ability of the temperature and that of the space are 1℃ and 2m,respectively,and that the system response time is about 180 s with a sensing range of 5km and with a temperature measurement range of 0-100℃.

A novel fiber audiotransmission systemfor secure communication

A new,simple and efficient fiber audio transmission method for the long distance secure communication is presented, which performs signal modulation by the strain-optic effects and signal demodulation by the all-fiber interferometer. The interferometer is a truly path-matched device, which eliminates much of the undesirable noise by combining the reference and the sensing arms within the same optical fiber. The sinusoidal signals adopted in the experiment are in a frequency range of 300 HZ-3 400 HZ and of the multi-frequency, and the system shows good capabilities, robust security and maintenance of audio integrity. The device may be applicable in the field of point to point secure communication of 40 kilometer long transmission range.

Quantum Information Transfer from a Double Quantum Dot System to a Cavity Field

In this paper, we propose a scheme to realize quantum information transfer from a double quantum dot （DQD） system to a quantized cavity field. The DQD and the cavity field are treated as a two-state charge qubit and a continuous-variable system, respectively. It is shown that quantum information encoded in the two-state DQD system can be transferred to quantum states of the cavity field with a continuous-variable basis through appropriate projective measurements with respect to the DQD.

Investigation of Differently Modulated Optical Signals Transmission in HDWDM Systems

The authors＇ developed combined system model can be considered under the concept of next generation optical network （NGON） as a model for the future design of backbone networks. Such solution can be topical in the result of different telecom operators＇ optical networks convergence. In this case a necessity to transmit differently modulated signals over a single optical fiber even with different bit rates may occur. This research is performed with OptSim 5.2 simulation software that numerically solves nonlinear SchrOdinger equation. The authors have revealed the optimal parameter configuration for developed combined transmission systems and obtained in system＇s channels detected signals bit-error-rate （BER） correlation diagrams. They represent BER as a function from different system＇s parameters such as channel output power level, optical amplifier fixed output power level and system＇s channels allotment in C-band of ITU-T （Telecommunication Standardization Sector of the International Telecommunications Union） recommended spectral grid. As well as these obtained BER values were compared with the results for similar system, where instead of standard single mode fiber （according ITU-T Rec. G.652 D） optical signals are transmitted over non-zero dispersion shifted fiber （ITU-T Rec. G. 655）.

Determination of Transmission Routing of OXC Nodes Based on AWG Multiplexer by Matrix Transformation

The structures of the space switching and the wavelength switching optical cross connect (OXC) nodes which are based on the arrayed waveguide grating (AWG) multiplexer are analyzed.By the matrix transformation relation between the input and output wavelengths of the AWG multiplexer, the wavelength transmission routings of the space switching and wavelength switching OXC nodes are determined.

Differentiating QoS and Un-conflicting Channel-times lot Allocation Algorithm in WDM

A new effective and reliabl e channel-timeslot allocation algorithm has been proposed, which is applied in WD M optical networks using fiber as their media to allocate the operational reques t. This new algorithm can differentiate the priority of all requests and avoid c onflict and collision in the process of distributing channel and timeslot for th e data waiting for transmission. The method in calculating the best wavelength c hannel and the best timeslot number is simply given. The algorithm is carried o ut in a math language. On the basis of the experiment results, the performance a nd feasibility of the algorithm are analyzed, which prove that the allocation me thod can reach the requirements of an algorithm both in space complexity and tim e complexity .

10-Gb/s Transmission in WDM PON Employing Reflective Semiconductor Optical Amplifier and Fibre Bragg Grating Equaliser

We propose a 10-Gb/s Wavelength- Division-Multiplexed Passive Optical Network （WDM-PON） scheme with upstream transmi- ssion employing Reflective Semiconductor Op- tical Amplifier （RSOA） and Fibre Bragg Gra- ting （FBG） optical equaliser. Transmissions of 10-Gb/s non return-to-zero signals using a 1.2- GHz RSOA and FBG optical equaliser with different setups are demonstrated. Significant performance improvement and 40-kin standard single mode fibre transmission are achieved using FBG optical equaliser and Remotely Pum- ped Erbium-Doped Fibre Amplifier （RP-EDFA）, where they are used to equalise the output of the band-limited RSOA and amplify the seed light and upstream signal, respectively.

Remote I/O Unit for Optical Fiber Demmunication

Abstract:Based on optical fiber technology, the main electric circuit of the remote I/O unit controller is studied. And the application of the system is illustrated.

STUDY ON MINE FIRE-RESISTANT OPTICAL FIBER CABLE KL5004

This paper introduces a new-developed mine fire-resistant optical fiber cable (OFC)KL5004,its structural characteristics, main feature, the theory about fire resistance and its application in high output and efficiency mine.

Location-adaptive transmission for indoor visible light communication

A location-adaptive transmission scheme for indoor visible light communication(VLC) system is proposed in this paper.In this scheme,the symbol error rate(SER) of less than 10-3 should be guaranteed.And the scheme is realized by the variable multilevel pulse-position modulation(MPPM),where the transmitters adaptively adjust the number of time slots n in the MPPM symbol according to the position of the receiver.The purpose of our scheme is to achieve the best data rate in the indoor different locations.The results show that the location-adaptive transmission scheme based on the variable MPPM is superior in the indoor VLC system.

Hadamard precoding for PAPR reduction in optical direct detection OFDM systems

The high peak-to-average power ration (PAPR) values of optical orthogond frequency division multiplexing (OFDM) signal limit the system nonlinear tolerance (NLT). In this paper, a novel method based on Hadamard precoding is proposed to reduce the peak-to-average power ratio in optical direct detection OFDM system. The proposed scheme is successfully applied to an experimental system of optical direct-detection OFDM signal transmission through fiber. In this experiment, the 2.5 Gbit/s binary phase shift keying (BPSK) optical OFDM signals with Hadamard precoding are generated and transmitted though a single mode fiber. The experimental results show that the proposed scheme can reduce PAPR by almost 1.5 dB. Meantime the received sensitivity is improved by 2 dB with 100 km fiber transmission compared with that of an ordinary optical direct detection OFDM system.