Yaojun Qiao

Resource co-scheduling algorithms on optical grid for distributed computing

A service provisioning model in optical grid for distributed computing is proposed, in which grid application resource and optical network resource are regarded as peer entities, and they are abstracted and encapsulated to provide the controllable and sharable service. The resource scheduling in optical grid is investigated, and a minimum cost algorithm to co-schedule the resources is presented. The algorithm co-schedules grid application resource and optical network resource to minimize the cost to perform the job. The simulation results show that the minimum cost algorithm can co-optimize usages of grid application resource and optical network resource and decrease the blocking probability of grid system.

Experimental demonstration of QoS-aware lightpath provisioning mechanism in lambda grid networks

A QoS-aware lightpath provisioning mechanism is experimentally demonstrated on GMPLS-enabled lambda grid testbed. Experimental results show end-to-end lightpath could be either exclusively occupied by one job or shared among multi-jobs according to users dynamic requests.

Channel pre-emphasis equalization for 40×40Gbit/s WDM system

The optical channel pre-emphasis equalization for a 40×40Gbit/s WDM transmission system is experimentally researched in this paper. In our experimental system, three EDFAs are concatenated as booster amplifier. The output spectrum imbalance is 5.0dB, 12.2dB and 7.6dB respectively with input transmitter signal power of 4.5dBm, 0.0dBm and -5.0dBm to EDFA1. For EDFA2 the output spectrum imbalance is 2.3dB, 4.4dB and 7.7dB respectively when input power is 4.5dBm, 0.0dBm and -6.7dBm, and the imbalance is 3.6dB, 5.6dB and 8.6dB for EDFA3 with the same set of input power. The power imbalance of the output spectrum after three spans of 270km changes with the different input power to each EDFA in the system. With the input power to three EDFAs is 5.7dBm, 7.4dBm and 8.0dBm respectively, the output signal spectrum imbalance is about 9.8dB. But with the appropriate input power of 5.2dBm, 3.4dBm and 3.3dBm to three EDFAs respectively, the spectrum imbalance is reduced to 4.3dB. When the input power to three EDFAs are 4.5dBm, 2.2dBm and -3.7dBm, the power imbalance is 9.4dB. The results indicate that, an appropriate choice of input power to three EDFAs, the output signal spectrum after propagation 270km can be equalized to the most extent. With this pre-emphasis equalization, the merit of benefit can be around 5.5dB. Although the equalizer is still necessary, but the requirement for the equalizer is greatly released. The OSNR degradation for the pre-emphasis equalization case is also examined, and about 1.0dB additional degradation is sacrificed. To take into the transmitter signal spectrum imbalance into account, the imbalance of the gain spectrum among 40 channels almost matches that of output signal power spectrum, but the difference is also evident at some channels. Finally, RA pump power is also optimized, and another 1.3dB improvement of channel balance can be achieved.

Multicast routing algorithms in hierarchical intelligent optical networks

The hierarchical multicast routing architecture in intelligent optical networks is investigated in this paper, the two methods of inter-domain information aggregation are given, and two hierarchical multicast routing algorithms are proposed. Their impacts on network performance in terms of blocking probability are evaluated by the simulations in different network models.

Nonlinear limitation of 10Gbit/s NRZ electrical pre-distortion system

In this paper, we study the nonlinear limitation of 10Gbit/s NRZ electronic pre-distortion (EPD) system by simulating. We constructed an ideal EPD simulation system with all chromatic dispersion compensation in electrical domain in transmitter; the fiber link includes Erbium-doped Optical Fiber Amplifier (EDFA) and 50km single mode fiber (SMF) in each span. And a dispersion compensation fiber (DCF) compensation system as a comparing object, with the fiber link includes EDFA, 50km SMF and DCF in each span. In single channel case, we find the EPD system is more sensitive with (self-phase modulation) SPM effect than DCF compensation system; in wavelength division multiplexing (WDM) system with 100GHz channel space, the cross-phase modulation (XPM) effects in EPD system induces more penalty fluctuating than DCF system. This is due to the large power variations in the waveform after large dispersion precompensation necessary for EPD. By compensating SPM effect and chromatic dispersion simultaneous in electrical domain in transmitter ideally, we can suppress SPM effect successfully in single channel system; but for WDM system, XPM effect still induces larger penalty fluctuating than DCF system. Because we can not predict signal patterns of neighbor channel, that means we can not compensate XPM effect. So, the XPM effect is the final nonlinear limitation of 10Gbit/s NRZ EPD WDM system.

Improvement of four wave mixing efficiency in DSF by clock pumping

In this paper, we investigate utilizing clock modulated signal as a pump to improve the efficiency of FWM in 26.5km dispersion shifted fiber. The experimental results show that, with the clock pumping, the conjugated FWM component has higher intensity than that with the CW pumping. The reason behind it is that SBS process is greatly quenched with the clock pumping, so most power of the pumping light contributes to nonlinear interaction with the probe signal during the propagation through DSF. But for CW pumping greater than Brillouin threshold, most power is depleted by SBS process and converted to backward Stokes light, so less power is left for other nonlinear process such as SPM, XPM and FWM to take place. As a result, the FWM components have lower intensity, and the pump and probe signal spectrum is also much less broadened. The measurement shows that, the improvement of FWM efficiency is negligible when the pump power is less than 10dBm. But when the pump power is greater than about 11dBm, the improvement becomes significant and increases with the increased pump power. When pump power reaches 17dBm, the improvement is increased to about 9dB.

Grid optical user network interface (GOUNI): integrating optical networks with grid services

Gird Optical Network Service (GONS) integrates optical networks with Gird services to utilize their numerous benefits. A flexible and simple user network interface between GONS and GMPLS control plane is proposed and its effectivity is verified on the Parallel Lightpath-on-Demand Grid testbed.

A novel signaling method to decrease the connection setup time in optical grid networks

Geographically-distributed computing application for science and enterprise are emerging services for providers, and the optical network is expected to be involved in such the grid computing application by using GMPLS protocols for its high performance. In the optical grid network, network delay and fault recovery time are very important for some special distributed application. However, bandwidth guarantee and dynamic bandwidth provisioning are achieved by the cost of LSP setup delay. In this paper, a parallel GMPLS-based signaling method is proposed to decrease the connection setup time effectively so as to provide fast dynamic bandwidth for grid applications. We implement this novel method on our optical grid network test-bed (GOGrid) and draw the conclusions.

A flexible solution for the next generation EPON with hybrid bidirectional 1Gbps and 10Gbps

Ethernet PON (EPON) has been proved to be a successful technology among all the standardized PON systems [1, 2], in terms of its cost-effective and large bandwidth virtue. And EPON has become a network of a choice for subscriber oriented digital service delivery, taking over the market previously dominated by DSL. However, with the development of advanced video services, the bandwidth capacity of current EPON seems to be not well suited for the future large deployment of triple-play services. Many researches are now taken about the Next Generation EPON; and the recent 10G EPON system standardization effort in the IEEE [3] results a lot of interest in the evolution of current PON systems towards high data rate system capable of providing a future-proof platform for delivery of personalized triple-play services. In this paper, a novel architecture of TDM-based 10GE-PON system is proposed. It combines the GE-PON and 10GE-PON systems, and provides symmetric 1Gbps/10Gbps or asymmetric access simultaneously. According to the results of the simulation on the system throughput and latency performance, the system is verified to be one solution and an important step from 1Gbit/s to 10Gbit/s for the Next Generation EPON.

Study of a novel fast restoration mechanism for data-intensive applications in grid-enabled optical networks

During the past few years, gird technology has gained a rapid progress in E-Science, E-education, etc. All these typical grid applications are involved with huge data transacting and collaborating that need a more capable network infrastructure with sufficient bandwidth provisioning and high QOS guarantee other then the traditional Internet. Thus gives birth to the concept of Grid-enabled Optical Network (Optical Grid), which mainly orients to the data-intensive applications. In this paper, we give a vivid definition to Optical Grid, expound the most distinguished characteristics of it, propose a novel SOA-based architecture for it, and then introduce a fast and flexible restoration mechanism, named DIR, based on mature RSVP-TE for its control plane to support data-intensive grid applications, then make a deep analysis and illustration on the proposed mechanism, finally draw a conclusion that the DIR mechanism can achieve much rapid service recovery speed thus be very applicable for the distributed grid environment.