• Journal of the Korea Academia-Industrial cooperation Society
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• 제13권3호
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• pp.1263-1269
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• 2012

This paper is the research on the heated CWDM optical transmitter for the wavelength compensation at the low temperature. In general, the wavelength deviation of DFB laser is around 0.1 nm/C. The wavelength of DFB laser shifts to longer(shorter) wavelength according to the temperature increase(decrease). Typical CWDM optical communication network has 20 nm channel spacing from reference center wavelength per each channel. There is some limitation problem in the range of operating temperature due to the channel interference. For solving the limited temperature range problem, especially at the low temperature, we use the heater on the DFB laser. As a result, we could realize the CWDM optical transmitter to meet +/-6.5 nm from reference center wavelength in the range of temperature at $-40{\sim}+85^{\circ}C$, which is applicable to the industrial field.

• Journal of Communications and Networks
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• 제9권4호
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• pp.368-376
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• 2007

The large potential bandwidth available in wavelength-division multiplexed optical networks makes this technology of crucial importance for satisfying the ever increasing capacity requirements of the next-generation Internet. In this scenario, the routing and wavelength assignment(RWA) problem that concerns determining the optical paths and wavelengths to be used for connection establishment in a wavelength-routed network, is still one of the most important open issues. In this paper we propose a new online dynamic grooming-capable RWA heuristic scheme working on wavelength division multiplexing(WDM) networks as a multistage selection process. The proposed algorithm is transparent with respect to the presence of wavelength converters, achieves very low connection rejection ratios with minimal computational complexity and is appropriate for the modern multilayer optical circuit and wavelength switched networks with sparse wavelength conversion capability.

• Nuclear Engineering and Technology
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• 제52권12호
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• pp.2847-2851
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• 2020

A simple water level measurement method based on wavelength division multiplexing (WDM) is proposed and demonstrated. The measurement principle is based on the change of Fresnel reflection occurring at the end facet of the optical fiber tip (OFT). To increase the spatial resolution of water level sensing, a broadband light source (BLS) and an arrayed waveguide grating (AWG) are employed. The OFTs are multiplexed with the dedicated wavelength channels of AWG. By measuring all of the reflection powers reflected at the OFTs with a proposed on-site reflectometer, the water level can be monitored continuously for a fast emergency response. Moreover, it can be implemented easily with the commercially available optical components and devices with the simple configuration.

• Current Optics and Photonics
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• 제3권3호
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• pp.193-198
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• 2019

We propose a novel method to design a dispersion map for a WDM (Wavelength Division Multiplexing) ring network with the capability of wavelength reconfiguration. The method is simple, but gives us an optimum set of DCMs (Dispersion Compensation Modules) which satisfies a given value of the tolerable residual dispersion. The proposed method does not depend on compensation method, fiber type, or modulation format. We also demonstrate numerically how it works with an example 10-node ring network.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제17권6호
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• pp.1419-1424
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• 2013

Passive optical networks (PONs) are the emerging solution for access networks since PONs provide high bandwidth and the low operation cost. In recent, the new solution in access networks is TWDM PON which is a mixture of WDM (wavelength-division multiplexing) and TDM (time-division multiplexing). This paper proposes a new MAC (media access control) protocol for TWDM PON. In addition, this paper proposes and evaluates a new dynamic bandwidth allocation method for TWDM PON.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.741-742
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• 2013

Passive optical networks (PONs) are the emerging solution for access networks since PONs provide high bandwidth. TDM ((time-division multiplexing) PON cannot support sufficient bandwidth for new broadband services such as UHD (ultra high-definition) IP TV, and VOD (video on demand). The solution is TWDM PON which is a mixture of WDM (wavelength-division multiplexing) and TDM. This paper proposes a new MAC (media access control) protocol for TWDM PON.

• Journal of Communications and Networks
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• 제7권4호
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• pp.499-508
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• 2005

In this paper, we address the problem of efficient routing and wavelength assignment (RWA) in multi-fiber wavelength division multiplexing (WDM) networks without wavelength translation, under dynamic traffic. We couple Dijkstra's shortest path algorithm with a suitable weight function which chooses optical paths based both on wavelength availability and multi-fiber segments. We compare our approach with other RWA schemes both for regular and irregular WDM multi-fiber network topologies in terms of blocking probability and overall link utilization.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제18권8호
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• pp.2037-2042
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• 2014

Three methods for gain saturation tone application were compared for optical wavelength division multiplexing transmission using more than 32 channels. The methods are to use high power distributed feedback laser diodes, to use amplified light sources, and lastly to use one saturation tone and several WDM light sources. 1532.3 nm, 1545.7 nm, and 1558.2 nm for the wavelength dependency of the saturation tone were also compared. As a result, the effect of amplified spontaneous emission noise caused by an amplifier was very slight. long wavelength for a saturation tone caused 1 dB gain reduction and its reason was analyzed.

• Journal of the Institute of Electronics and Information Engineers
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• 제52권7호
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• pp.40-48
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• 2015

An optical network-on-chip(ONoC) architecture is emerging as a new paradigm for solving on-chip communication bottleneck. Recent studies on ONoC have been focusing on supporting the parallel transmission and avoiding path collisions using wavelength division multiplexing(WDM). However, since the maximum number of wavelengths, which a single waveguide can accommodate is limited by crosstalk and insertion loss. Therefore previous WDM studies based on incrementing the number of different wavelengths according to the number of nodes would be infeasible due to the implementation complexity. To solve such problems, we combined time division multiplexing(TDM) and wavelength-routed ONoC, along with an optimized channel allocation algorithm, which can minimize the number of extra wavelength channels and latency caused by combining TDM scheme.

• Journal of the Korea Society of Computer and Information
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• 제10권6호
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• pp.209-218
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• 2005

In this paper, we present an Active Optical Network(AON) . The AON uses the Dense Wavelength Division Multiplexing(DWDM) from optical communication access network of ring type, and will be able to provide the smoothly service in the Bandwidth on Demand by using DWDM. It supports the connection of the multiple wavelength and the Sub-Carrier from the optical gigabit ethernet switch. The Wavelength Add Drop Multiplexer(WADM) extracts a specific wavelength, and composes a node of the ring network. The specific wavelength becomes demultiplexing in the Sub-Carrier and it is distributed in the user The active connection of optical gigabit ethernet switch where the distribution of access network is started and access terminal connection equipment is possible. By the BoD from the AON it compares the buffer size which changes, and it analyzes. Also the Time delay of bit compares with the throughput of server The limit of amount of time is decided. Consequently it will be able to realize the dynamic use protocol and an efficient algorithm of the network.