Optical Transport Network

About: Optical Transport Network is a research topic. Over the lifetime, 6055 publications have been published within this topic receiving 85783 citations.

Demonstration of RSOA-Based 20 Gb/s Linear Bus WDM-PON with Simple Optical Add-Drop Node Structure

Abstract: We demonstrate a linear bus wavelength-reused gigabit wavelength-division multiplexing passive optical network (WDM-PON) with multiple optical add-drop nodes. A commercially available reflective semiconductor optical amplifier-based WDM-PON has a sufficient power budget to provide multiple optical add/drop nodes in 16 WDM channels. Sixteen 1.25 Gb/s WDM channels are successfully transmitted over 20 km of single-mode fiber with four optical add/drop multiplexers, even with 32 dB reflection and chromatic dispersion in the link.

Optical line switching system

Abstract: An approach for performing fault recovery in an optical communications network is disclosed. An optical switch is connected to working optical fibers and protection optical fibers, which carry WDM (wave division multiplexing) optical signals. The optical switches possess functionality to switch over the optical signals among the working optical fibers and the protection optical fibers. The optical switch includes dual unit optical switches that have a common driving mechanism. The common driving mechanism is configured to perform simultaneously switching operation of the unit optical switches to alter a switching state of the optical switch. Monitoring devices are distributed throughout the node to monitor the transmitted optical signals over the optical fibers, and to output monitoring signals that indicate one or more faults in these optical fibers. In response to the monitoring signals, a control device outputs control signals to the optical switches to effect an optical protection scheme.

Experimental performance evaluation of software defined networking (SDN) based data communication networks for large scale flexi-grid optical networks.

Abstract: Software defined networking (SDN) has become the focus in the current information and communication technology area because of its flexibility and programmability. It has been introduced into various network scenarios, such as datacenter networks, carrier networks, and wireless networks. Optical transport network is also regarded as an important application scenario for SDN, which is adopted as the enabling technology of data communication networks (DCN) instead of general multi-protocol label switching (GMPLS). However, the practical performance of SDN based DCN for large scale optical networks, which is very important for the technology selection in the future optical network deployment, has not been evaluated up to now. In this paper we have built a large scale flexi-grid optical network testbed with 1000 virtual optical transport nodes to evaluate the performance of SDN based DCN, including network scalability, DCN bandwidth limitation, and restoration time. A series of network performance parameters including blocking probability, bandwidth utilization, average lightpath provisioning time, and failure restoration time have been demonstrated under various network environments, such as with different traffic loads and different DCN bandwidths. The demonstration in this work can be taken as a proof for the future network deployment.

Multidimensional Signaling and Coding Enabling Multi-Tb\/s Optical Transport and Networking: Multidimensional aspects of coded modulation

Abstract: The design of next-generation optical transmission systems and networks should address the concerns with respect to a limited bandwidth of information infrastructure, high energy consumption, as well as the need to support the network heterogeneity and demand for an elastic and dynamic bandwidth allocation. To address these concerns simultaneously, we propose an adaptive, software-defined, low-density parity check (LDPC)-coded multiband approach that involves spatial-multiple-input, multiple-output (MIMO) and an all-optical orthogonal frequency-division multiplexing (OFDM) scheme since it can enable energy efficient high-bandwidth delivery with fine granularity and elastic model of bandwidth utilization. The modulation is based on multidimensional signaling to improve the tolerance to fiber nonlinearities and imperfect compensation of channel impairments and has a hybrid nature with both electrical and optical degrees of freedom employed. Optical degrees of freedom include spatial and polarization modes in optical fibers supporting spatial-division multiplexing (SDM), while electrical degrees of freedom are based on 2M orthogonal basis functions. The adaptive coding has been performed by partial reconfiguration of the corresponding parity-check matrix. The proposed scheme is suitable for the conveyance of the information over optical fibers with bit rates exceeding 10 Tb/s. At the same time, the multitude of degrees of freedom will enable finer granularity and elasticity of the bandwidth, the features essential for next generation networking.

Optical add-drop multiplexer, and optical network equipment using the same

Abstract: Heretofore, it was necessary to individually locate an optical switch, an optical switch control circuit, and the like, before and after an optical transceiver that performs optical protection. As a result, costs and the space for implementation increase, and a delay in services is also caused, which were the problems. For the purpose of solving the above problems, the present invention provides a simple optical protection method used in an optical add-drop multiplexer. Add switches 105 - 1 through 105 -N and drop switches 103 - 1 through 103 -N for optical signals corresponding to each wavelength in an optical add-drop multiplexer 100 are made controllable independently of one another. Add switches and drop switches of the active-side and backup-side optical add-drop multiplexers are switched by optical switch control circuits 106 - 1 through 106 -N respectively to make a detour around a failure so that the optical protection is achieved.