Korea Advanced Institute of Science and Technology

Electronics and Telecommunications Research Institute

Eui Seung Son

Yun Chur Chung

Kyung Woo Lim

Kwan Young Han

Byoung Whi Kim

Woo Ram Lee

Jun Haeng Lee

Jang Won Chae

Kwan Hee Han

Provided are an apparatus and method for tracking a wavelength in a passive optical subscriber network in which a central base station and at least one subscriber terminal are connected via a remote node. The apparatus includes a first wavelength aligning unit multiplexing and aligning wavelengths of optical signals from a plurality of single-mode optical sources of the central base station; a second wavelength aligning unit multiplexing and aligning wavelengths of optical signals transmitted to the remote node from a plurality of single-mode optical sources of the subscriber terminal; and a third wavelength aligning unit demultiplexing and aligning wavelengths of optical signals from the second wavelength aligning unit, the third wavelength aligning unit being included in the central base station. Accordingly, when the wavelengths of passbands of a multiplexer/demultiplexer (MUX/DEMUX) of a remote station change due to a change in the ambient temperature, wavelength tracking is performed by making aligned the wavelengths of optical sources of a central base station, a multiplexer/demultiplexer, and subscriber terminals, thereby minimizing optical channel loss and enabling reliable management of WDM-PON.

Wavelength tracking apparatus and method in WDM-PON system

A communication recovering system for a wavelength division multiplexed passive optical network (WDM PON) includes a central office and remote nodes. When there is a fault in an optical fiber connecting a first blue/red band coupler to a blue/red band coupler R, optical signals are inputted/outputted thereto/therefrom through a first 1&#xd7;2 optical switch and a second blue/red band coupler, and when there is a fault in an optical fiber connecting the second blue/red band coupler to a blue/red band coupler R, optical signals are inputted/outputted thereto/therefrom through the second 1&#xd7;2 optical switch and the first blue/red band coupler.

Communication recovering system for wavelength division multiplexed passive optical network

An optical fiber, and an optical access network, a local area network and optical parts for communication, which uses the optical fiber, are disclosed. The optical fiber whose core diameter is 10 &#x3bc;m&#x2dc;40 &#x3bc;m has at least two propagation modes in a wavelength over 1200 nm. The optical fiber according to the present invention can reduce packaging costs for optical components, since cross-sectional area of the core is large, compared with the prior art technique adopting a single mode optical fiber, and can transmit ultra-high speed data a relatively long distance, since the mode number and modal dispersion effect of the optical fiber is relatively small, compared with the prior art multimode optical fiber. Also, when using the optical fiber according to the present invention, the optical subscriber network and the local area network can be cost-effectively implemented. In addition, when adopting the optical fiber according to the present invention, productivity of optical components for communication can be improved, costs for an optical component can be reduced and quality of the optical component can be improved.

Optical fiber, and optical access network, local area network and optical parts for communication, which use the optical fiber

A communication recovering system for a wavelength division multiplexed passive optical network (WDM PON). The communication recovering system can recover fault of optical fibers between the central office and the remote nodes without additional optical fibers by grouping two remote nodes and employing AWGs having periodic transmission characteristics, and can also simply and rapidly recover such a fault with minimal optical loss using 1&#xd7;N structure of the AWGs and On-Off optical switches, although protection optical fibers are additionally installed therein. The communication recovering system has advantages in that it can simplify network structure, be cost-effectively implemented, reduce optical loss, and rapidly perform protection of optical fiber fault.

A fault localization apparatus for an optical line in a wavelength division multiplexed passive optical network is disclosed. The apparatus can detect light loss and fault positions as a channel exhibiting an abnormal receiving state of signals received by each of the upstream receivers is checked, and a monitoring optical signal is used, in which the monitoring optical signal is generated as a pulse is inputted to a light source of the downstream transmitter corresponding to the channel showing such an abnormal receiving state. The apparatus according to the present invention can detect fault positions of optical lines between the central office and the remote nodes and between the remote nodes and the optical network units, since the light source of downstream channel in which faults occur is used as a monitoring light source. The apparatus according to the present invention can be cost-effectively implemented.

Growing community of inventors

Gyeonggi-do, South Korea

Eui Seung Son