Improvement of normalized throughput in WDM ＋ OCDMA system using optical hard-limiters

Recently,because of advantages of high-speed opticalprocessing and si mple network control ,the optical codedivision multiple access (OCDMA) has become a hotscheme in LAN and access network[1-5]. According tothe spreading mode, OCDMAcan be mainly dividedi…     

New scheme of optical switch technology of time division

Intheopticalnetwork,opticalswitchcanrealizethe signaltransformandswitchinopticalfield.Thetechnol ogyincludeswavelengthdivisionandtimedivision.Thetimedivisionswitchisthebestsolution,whileitisdiffi culttoberealized,especiallyforthelargescaleandlittle timesl…     

Research on fault location technology based on BP neural network in DWDM optical network

BP neural network is introduced to the fault location field of DWDM optical network in this paper. The alarm characteristics of the optical network equipments are discussed, and alarm vector and fault vector diagrams are generated by analyzing some typical instances. A 17 × 14 × 18 BP neural network structure is constructed and trained by using MATLAB. By comparing the training performances, the best training algorithm of fault location among the three training algorithms is chosen. Numerical simulation results indicate that the sum squared error （SSE） of fault location is less than 0.01, and the processing time is less than 100 ms. This method not only well deals with the missing alarms or false alarms, but also improves the fault location accuracy and real-time ability.     

Pulse-width compression based on photonic crystal fiber

Since the first PCF was fabricated in 1996 ,PCF hasattractedthe significant attention due toits unique char-acteristics . One of the highlights is that ,according tothe flexibility of conveniently changing the core area ofPCF,a smaller mode-field area can…     

Design of buffer structure at core nodes in optical burst switching

DrivenbybothpromptincreaseofIPserviceandvast bandwidthofWDM,conventionalopticalnetworksareevolvingintothenextgenerationopticalInternet(NGOI).Somefunctionsofconfiguration,performance andfaultmanagement,executedinelectronicdomainatpresent,willbeshiftedintoo…     

PCCC for the performance improvement of the wireless optical communication system

Opticalwireless,alsoknownasfree spaceoptics,isa cost effectiveandwidebandwidthaccesstechniqueandreceivesgrowingattentionwithrecentcommercialization success.Buttheperformanceofwirelessopticalcommu nicationwouldbeimpairedintheatmosphericchannelbyattenuation…     

Pairwise codeword error probability for coded atmospheric optical communication systems

In atmospheric optical channels ,turbulence affects theperformance of I M/DDatmospheric optical communica-tion systems seriously,especiallyinthe range of 1kmormore.Using error-control code (error-correcting code orchannel code) it can be i mproved remarka…     

Statistical characteristics and effects of polarization mode dispersion in dispersion managed soliton systems

Recently,the dispersion-managed solitons(DMS) areof great interest in soliton communication systems .Be-cause of some prior advantages compared with conven-tional solitons ,such as higher pulse energy and signalnoise ratio,lower averaged dispersionline an…     

Channel Arrangement for optical communication subsystems with 12 parallel channels

This paper devoted to report the design and the achievement of an optical communication subsystem with 12 parallel channels in one chip. The system is capable of,transmitting 10 Gbps bidirectional date over hundreds of meters. It can provide error detection and correction by using 8B/10B encoding and Cyclical Redundancy Checking （CRC） encoding when only single-channel fails. The design scheme has already passed the simulation in FPGA. This technique is useful to enhance the capability and the reliability of the very short reach （VSR） transmission systems.     

Novel algorithm of finding good candidate pre-configuration cycles in survivable WDM mesh network

Pre-configuration Cycle (p-cycle) is a promising ap-proach for protecting working capacities in WDMnet-works because of its ability to achieve ring-like recoveryspeed while maintaining the capacity efficiency of amesh-restorable network[1].The first and t…     

Multilength two-dimensional codes for optical CDMA system

A new class of multilength, constant-weight and two-dimensional multiwavelength optical orthogonal code （2D MWOOCs） with large capacity and good correlation properties is constructed based on multilength one-dimensional （1D） OOCs. The performance of these new MWOOCs in an OCDMA network with double-services is analyzed. The result shows that media with the shorter codeword performs much better than the media with longer codeword, and OCDMA system with these new multilength MWOOCs performs well. These features allow multimedia transmission of large capacity in OCDMA system.     

Threshold level and gain of forward stimulated Brillouin scattering in a forward pumped s-band discrete DCF fibers Raman amplifier

Recently,with fast developing of extra-capacity of fi-ber communication experi mental systems ,dense wave-length division multiplexing (DWDM) technology hasbeen adopted widely[1-3].Now,1300 nmband and 1550nmband have been connected with each other to be a…     

Narrow-channel-spacing 32-channel AWG multiplexer with an innovative alignment method

A 32-channel 50 GHz spaced arrayed-waveguide grating（AWG） with our innovative configuration has been designed and fabricated. The performance of the device has been fully tested by using a system that consists of a tunable laser light source （TLS）, an optical power meter and a polarization controller. The insertion loss （IS） of the device is 4.2-7.4 dB. The crosstalk is about - 28 dB. The IS uniformity is less than 3.3 dB. With our configuration,the performance of the device has been enhanced effectively and the difficulty in alignment process has been decreased obviously.     

Box-like spectral response of a series-coupled microring resonant filter in a parallel channel

Inthelast decades ,microring resonator( MRR) wave-lengthfilters are developed rapidly because of their po-tential applications in wavelength division multiplexing( WDM) communicationsystems andtheir excellent fea-tures includingfunctionality,compactness a…     

A novel fiber audio transmission system for 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.     

Fabrication and characterization of 1 550 nm polarization-insensitive semiconductor optical amplifiers

Semiconductor Optical Amplifiers (SOAs) can beused asin-line amplifier ,preamplifier ,optical switch,andwavelength converter in future optical systems[1-3].Po-larization-independent gain,high output power and lowgain ripple are desirable features for most…     

Quality improvement of the dual-wavelength signals in DLOB via power equalization

The data packet buffeting can be implemented in dual loop optical buffer （DLOB） through cross-phase modulation （XPM） between the control signal and the data packets. However, the output equality of dual wavelength signals will degrade due to the unbalanced gain and phase shift. This problem can be resolved by power oqualizafion using the saturation characteristics of SOA. The data packets with 2.5 Gb/s can be buffered in DLOB for 16 cycles corresponding to 16.5 μs.The extinction ratio of the output packet is 8 dB while the S/N is 8.1 dB.     

Applying Hopfield neural network to QoS routing in communication network

The main goal of routing solutions is to satisfy the requirements of the Quality of Service （QoS） for every admitted connection as well as to achieve a global efficiency in resource utilization. In this paper proposes a solution based on Hopfield neural network （HNN） to deal with one of representative routing problems in uni-cast routing, i. e. the multi-constrained（MC） routing problem. Computer simulation shows that we can obtain the optimal path very rapidly with our new Lyapunov energy functions.     

Demodulated method of optical fiber stokes temperature sensors

The optical fiber temperature sensoris one of the dis-tributed measurement apparatus applied to the smartstructures of civil and military engineering.In the dis-tributedfiber Ramantemperature sensor ,the anti-Stokesand Stokes scattering radiation is sensi…