This PDF file contains the front matter associated with SPIE Proceedings Volume 8331, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

Optical performance monitoring (OPM) becomes an attractive topic as the rapid growth of data rate in optical communication networks. It provides improved operation of the high capacity optical transmission systems. Among the various impairments, chromatic dispersion (CD) is one of major factors limiting the transmission distance in high-speed communication systems. Polarization-mode dispersion (PMD) also becomes a degrading effect in the system with data rate larger than 40 Gbit/s. In this paper, we summarize several CD and PMD monitoring methods based on RF spectrum analysis and delay-tap sampling. By using a narrow band fiber Bragg grating (FBG) notch filter, centered at 10 GHz away from the optical carrier, 10-GHz RF power can be used as a CD-insensitive PMD monitoring signal. By taking the 10-GHz RF power ratio of non-filtered and filtered signal, PMD-insensitive CD monitoring can be achieved. If the FBG notch filter is placed at optical carrier, the RF clock power ratio between non-filtered and filtered signal is also a PMDinsensitive CD monitoring parameter, which has larger RF power dynamic range and better measurement resolution. Both simulation and experiment results show that the proposed methods are efficient on measuring CD and PMD values in 57-Gbit/s D8PSK systems. Delay-tap sampling is another efficient method of measuring residual CD. Amplitude ratio of asynchronous delay-tap sampling plot decreases with CD monotonously, and the amplitude ratio can be obtained by using low bandwidth balanced receiver. The simulated results show that our method is efficient on residual CD measurement in 50-Gbit/s 50% RZ DQPSK systems with a 12-GHz balanced receiver. Since no modification on the transmitter or receiver is required, the proposed scheme is simple and cost effective.

Driven by the need for high-capacity data traffic, various approaches have been deployed to enable the network spectral efficiency and overall capacity. Among them, polarization-division-multiplexing (PDM) has been extensively investigated during last few years due to the fact that it can double the spectral efficiency and system capacity directly. Since two data channels carry the same wavelength while with orthogonal polarization states, most all-optical signal processing schemes that are used for single-polarization channels, we need find cost-effective approaches for PDM systems. We review different schemes for signal processing in PDM systems using different nonlinear elements. Recent experimental demonstration results at 10-Gb/s are discussed with various functionalities such as all-optical signal regeneration, wavelength conversion, mitigating channel degrading effects and so on.

Based on the background of data relay satellite (GEO) to ground laser communication system, we analyze influence of slant atmosphere channel on the coupling efficiency of space light to multimode fiber, and we present a solution with adaptive optics technology to overcome the difficulty of low coupling efficiency when collecting with large aperture in receiver terminal. The feasibility analysis of satellite to ground laser communication based on adaptive optics technology is made. In order to verify the effectiveness of the proposed scheme, laboratory experiments of 2.5Gbps laser communication based AO are carried out. The results shows: average received power increases 4.52dB, severe signal fading is controlled effectively, average bit error rate (BER) reduces and the scheme of satellite to ground laser communication with adaptive optics is correct.

100-Gb/s per channel optical transport technology development has experienced a long journey from purely academic interests to commercially viable solutions. In near future, 100-Gb/s channel will be one of the major building blocks for the next generation transport network. Beyond 100 Gb/s optical channel designs may, however, experience a paradigm change. So far, almost all commercially available optical channels, with capacity up to 100 Gb/s, are single-optical-carrier ETDM (electrical time domain multiplexing) channels. Optical channels with capacities beyond 100 Gb/s, however, will most likely be a superchannel with multiple optical carriers based on our analysis.

With the rapid development of telecommunication service, the broadband amalgamation of full service is becoming the main theme in the development of communication industry. The Packet Transmission Network adopts the technique of T-MPLS to meet next generation's demand on high speed, various services and high quality. Firstly, Requirements of PTN (Packet Transmission Network)are analyzed. Then, by deep analysis the key technology of PTN on MAN. At the same time, PTN technologies have been applied in multi-service's adaptation and transmission which are carried out by communication each other of MSTP and PTN, T-MPLS and IP/MPLS, PBT and IP/MPLS. At last, test of PTN are analyzed in detail. Test results of PTN show that PTN can replace core router to provide highly-efficient packet forward service in core network.

We proposed a novel coherent delayed self-heterodyne technique for laser phase noise measurement. Measurements have been performed for DFB and ECL lasers and compared to self-homodyne using optical coherent receiver to demonstrate the validity of the technique.

Two kinds of routing and signaling schemes for bandwidth-variable (BV) optical networks are compared in the paper. One is the fix routing (FR) together with an extension to the traditional RSVP-TE (RSVP-bBV) , another is adaptive routing (AR) together with an extension to the traditional RSVP-TE (RSVP-fBV). Both are implemented on Tsinghua large-scale ASON test-bed. Experiment results show that the both schemes have different characteristics of blocking probability, and FR+ RSVP-bBV is more suitable to high dynamic BV optical networks than AR+ RSVP-fBV.

In the wavelength-routed optical transport networks, fixed shortest path routing is one of major lightpath service provisioning strategies, which shows simplicity in network control and operation. Specifically, once a shortest route is found for a node pair, the route is always used for any future lightpath service provisioning, which therefore does not require network control and management system to maintain any active network-wide link state database. On the other hand, the fixed shortest path routing strategy suffers from the disadvantage of unbalanced network traffic load distribution and network congestion because it keeps on employing the same fixed shortest route between each pair of nodes. To avoid the network congestion and meanwhile retain the operational simplicity, in this study we develop a Load-Balanced Fixed Routing (LBFR) algorithm. Through a training process based on a forecasted network traffic load matrix, the proposed algorithm finds a fixed (or few) route(s) for each node pair and employs the fixed route(s) for lightpath service provisioning. Different from the fixed shortest path routes between node pairs, these routes can well balance traffic load within the network when they are used for lightpath service provisioning. Compared to the traditional fixed shortest path routing algorithm, the LBFR algorithm can achieve much better lightpath blocking performance according to our simulation and analytical studies. Moreover, the performance improvement is more significant with the increase of network nodal degree.

High power consumption due to O/E/O processing in many conventional electronic datacenter networks can be greatly decreased by a suitable use of all-optical switching technologies. OBS is specially suited to perform this task given its bursty-data traffic friendly mode of operation. In this paper, we evaluate through analysis and simulation the performance of both OBS and electronic networks when used to carry TCP flows inside a 6D-hypercube, a highly symmetrical topology representative of datacenter networks.

Extending the researches on wavelength switched optical networks (WSON), efficient integration of the novel optical packet switching network and wavelength switching-based optical circuit switching network technologies which offers both best-effort packet delivery and QoS guaranteed lightpath services has been being studied. In addition, researches on the optical-layer transparent data processing, such as all-optical wavelength multicasting, all-optical 3R regeneration, etc, are conducted simultaneously. It is believed that future innovative optical network services (INSes) would be built on these novel future-proof technologies, and foster colorful applications in the new generation networks. Before the wide applications of INS in different fields, there would be a foreseeable strong requirement for INS firstly posed by pioneer grid applications, e.g., e-science, e-government, and e-banking, etc, which would require the high-performance underlying networks. Our research here is motivated to glue the optical networks and grid applications by integrating lightpath, geographically distributed INS systems and grid resources (e.g., computers, storages, instruments, etc.), and finally offering an easy-to-use high performance networked grid computing environment-optical grid network (OGN) to user applications. In this paper, we introduce our research activities of a distributed optical grid network infrastructure (OGNI), and the creation of the future easy-to-use INS based on OGNI. The proposals have been validated through fieldtrial experiments over a developed WSON testbed.

A novel approach for the generation of optical minimum shift keying (MSK) signals is presented. The transmitter is based on merely one phase modulator (PM), which is driven by a phase controller. The receiver uses direct detection based on the Mach-Zehnder delay interferometer (MZI) and optical balanced receiver. In this paper, firstly the detailed principle on optical MSK generation and detection is derived and analyzed. Then, 40Gb/s optical MSK signal based on this scheme is successfully generated and transmitted over several fiber links (SMF+DCF) with only the first order dispersion compensation. Finally, the performance of the MSK based on PM is compared with that of the MSK based on other two known schemes, in terms of waveform, phase and spectrum. Simulation results show that not only this approach has a simpler architecture for the optical MSK transmitter, and but also the optical MSK generated has better performance.

Coherent optical OFDM (CO-OFDM) has recently received much attention as a candidate for long haul transmissions. In this paper, we review historical progress on CO-OFDM. Following that, we show some recent experimental demonstrations on both transmission and networks.

Optical frequency-division multiplexing (OFDM) is a promising method to exploit the vast bandwidth of singlemode optical fiber. A key issue in OFDM implementation is the absolute frequency accuracy of each individual channel. The generation of high-quality and free-controllable multi-carrier lightwave source based on frequency shift property of discrete Fourier transform (DFT) is proposed. A 4x100Gb/s all-optical OFDM system by employing polarization division multiplexed (PDM) non return-to-zero (NRZ) quadrature phase shift keying(QPSK) modulation format is designed based on our proposed source. The required optical signal-to-noise ratio (OSNR) at bit error rate (BER) of 1x10^-3 for the 400Gb/s all-optical OFDM signal is simulated to be ~23.25dB.

In this paper, we review the advances of using bit-by-bit optical code scrambling and rapid reconfigurable/codelength variable technologies for security improvement in optical communication systems.

As the demand for higher capacity and longer reach of optical access networks is garnering momentum in recent years, coherent access technology attracts renewed interests in high-capacity optical networking. In this paper, designs of various coherent access networks are investigated and compared. From our results, it may be the most promising solution with high capacity at optimized cost. When coherent detection is employed in access network, the laser linewidth is a key design issue for optimized performance and cost as laser phase noise is larger with lower bit rate. One of our objectives is to examine the feasibility of employing a conventional DFB as carrier sources. We evaluated the performance of ultra-dense WDM access networking system. Experimental results show that 2.5GB/s QPSK data can be transmitted over 35-km SMF-28 with 6.5GHz channel spacing using DFB lasers.

A gain-flattened S-band erbium-doped fiber amplifier (EDFA) using standard erbium-doped fiber (EDF) is proposed and experimentally demonstrated. The proposed amplifier with two-stage double-pass configuration employs two C-band suppressing filters to obtain the optical gain in S-band. The amplifier provides a maximum signal gain of 41.6 dB at 1524 nm with the corresponding noise figure of 3.8 dB. Furthermore, with a well-designed short-pass filter as a gain flattening filter (GFF), we are able to develop the S-band EDFA with a flattened gain of more than 20 dB in 1504-1524 nm. In the experiment, the two-stage double-pass amplifier configuration improves performance of gain and noise figure compared with the configuration of single-stage double-pass S-band EDFA.

We shown that it is possible to produce a entangled one-atom dressed-state laser via atomic coherence effcets. For a V-type three-level atom embedded in a two-mode cavity, two applied fields induce a quantum-beat and the collective field comes into interaction. The stastics of the collective field is sub-Poissonian in the good cavity condition. The collective field intensity quantum noise reducetion produces the entanglement between two cavity fields.

This paper uses a composite exponential function to fit the curve of the spatial frequency spectrum of TE1 mode in planar optical waveguide versus the spatial frequency when the normalized frequency is determined. The relationship among the spatial frequency spectrum, the normalized frequency and the spatial frequency is presented too, and it can reveal the relationship of the spatial frequency spectrum and waveguide structure parameters. Another, relation between the spatial frequency at the maximum value of the spatial frequency spectrum and normalized frequency is researched. These conclusions have some significance for analyzing and calculating the far-field diffraction distribution from end surface of TE1 mode in planar optical waveguide.

Remote Procedure Call (RPC) is widely used for constructing distributed, client-server based applications. Many distributed file systems, such as Lustre, pNFS, Panasas File System, Google File System use the RPC to exchange data and metadata between client nodes and server nodes. We have built a distribute file system called Cappella to meet the next generation high performance computing requirement, which uses the RPC as the communication protocol. But as we deployed the user-space open source RPC on our system, we found that it can't take full advantage of our 40 Gb/s InfiniBand network. This paper shared the problem that we observed during our RPC deployment and proposed a multithread method to enhance the performance of user-space RPC. And we also implemented a Socket Direct Protocol (SDP) based RPC protocol to use the RDMA capability of InfiniBand to transport data. And the experiments showed that our multi-thread user-space RPC had improved the performance over 60%.

This paper proposes an optical continuous-phase frequency shift keying (CPFSK) modulation scheme with an arbitrary modulation index. Simulations on the performances of CPFSK and differential phase shift keying (DPSK) show that CPFSK of modulation index is 2/3 performs best on receiver sensitivity, dispersion penalty and nonlinearity in the balanced receiving system of 40G.

In this article a numerical simulation is carried out on a single channel optical transmission system with channel bit rate greater than 40 Gb/s to investigate optical signal degradation due to the impact of dispersion and dispersion slope of both transmitting and dispersion compensating fibers. By independently varying the input signal power and the dispersion slope of both transmitting and dispersion compensating fibers of an optical link utilizing a channel bit rate of 86 Gb/s, a good quality factor (Q factor) is obtained with a dispersion slope compensation ratio change of ±10% for a faithful transmission. With this ratio change a minimum Q factor of 16 dB is obtained in the presence of amplifier noise figure of 5 dB and fiber nonlinearities effects at input signal power of 5 dBm and 3 spans of 100 km standard single mode fiber with a dispersion (D) value of 17 ps/nm.km.

Compared with other communication methods, optical wireless communication (OWC) holds the merits of higher transmitting rate and sufficient secrecy. So it is an efficacious communicating measure for data transmitting between underwater carriers. However, due to the water attenuation and the transmitter & the receiver (TX/RX) collimation, this application is restrained in underwater mobile carriers. A prototype for underwater OWC was developed, in which a high-powered green LED array was used as the light source which partly raveled the TX/RX collimation out. A small pumped-multiple-tube (PMT) was used as the detector to increase the communicating range, and FPGA chips were employed to code and decode the communicating data. The data rate of the prototype approached to 4 Mb/s at 8.4m and 1 Mb/s at 22m where voice and Morse communications were achieved in a scope of 30 degree TX/RX angle.

The effect of initial frequency chirp of input pulses on pulse dynamics and spectral broadening in all-normal dispersion photonic crystal fibers are investigated numerically. When the input peak power is low, for small initial frequency chirp the positive chirps can enhance the bandwidth of supercontinuum while the negative chirps can compress the spectrum. When the initial frequency chirp increases the bandwidth of supercontinuum can be further increased and the spectral broadening is similar for both signs of the initial frequency chirp. Especially, the simulations show that there exists an optimal chirp value that makes the supercontinuum flattest almost without the fine spectral structures. For high input peak power the initial frequency chirps have a little effect on the supercontinuum generation and the significant fine spectral structures appear which makes the coherence of supercontinuum become worse. In addition, the effects of input pulse parameters such as peak power, pulse duration and central wavelength on the supercontinuum generation have also been investigated. It is found that the broadest spectra can be obtained when central wavelength of pump pulse located near the maximum of the fiber dispersion curve.

In this paper, the performance of four modulation schemes (OOK, PPM, DPPM and DPIM) popular in indoor wireless optical communication systems are analyzed based on average transmitted power, bandwidth requirement and packet error rate. The results show that each modulation scheme has its unique attractive features as well as its challenges. In terms of average transmitted power, PPM achieves the smallest followed by DPIM and DPPM, OOK achieves the biggest. With regard to bandwidth requirement, OOK achieves the smallest followed by DPPM and DPIM, PPM achieves the biggest. Under the condition of the same number of bits per symbol, PPM achieves the smallest followed by DPIM and DPPM, OOK achieves the biggest on the part of packet error rate. Furthermore, PPM requires both slot and symbol synchronizations, while OOK, DPPM and DPIM require no symbol synchronization.

This paper presents the generation and the performance evaluation of an optical quadrature minimum shift keying (QMSK). The performance of our optical QMSK modulated system is evaluated and compared with those of traditional phase shift keying (PSK) and minimum shift keying (MSK) modulated systems, via simulation, in terms of receiver sensitivity, dispersion tolerance and self-phase modulation (SPM) penalty. The proposed scheme shows that the QMSK format offers a few transmission advantages comparing with than that of the other traditional modulation formats under SPM penalty.

The impact of phase noise induced by amplified spontaneous emission and nonlinear Kerr effect is analyzed in investigating the performance of BPSK homodyne systems based OPLL in long-haul optical fiber communications. Under the Gaussian probability density function assumption the equivalent power spectral density of linear and nonlinear phase noise are determined, respectively. Using the power spectral density function the expressions of phase error variance taking into account linear phase noise, nonlinear phase noise and shot noise of corresponding photodiodes are determined. The impact of the number of amplifiers, bit rate and signal power on the phase error variance is analyzed. Using the minimum phase error variance and corresponding BER expression the receiver sensitivity and BER curves are given, respectively. Under the required BER, it is shown that there is a limitation on the maximum transmission distance of the BPSK homodyne system based OPLL. The theory expressions and numerical results obtained in this paper are helpful for designing OPLL and evaluating the impact of phase noise on the receivers based OPLL in long-haul optical fiber communications.

Here optical ray locus method has been employed to analyze the transmission of optical pulse in multi-mode fibre. Combined with training bits, we suggest a new method for MGDM (Mode Group Division Multiplexing), which calculates the energy focus for each mode on its transmitting direction from the optical ray locus. In addition, photodetectors will be placed in various places to measure the signals, contributing to avoid the energy coupling among different modes. After this, we transmit different training bits of each mode and eliminate the energy coupling on the receiver, which consequently generates a new method enabling us to independently modulate signals in each particular mode for the multi-mode fibre. Our simulations present the possibility of this method for two mode group transmitted in 850nm wavelength for the length of 100m at the bit rate of 10Gb/s.