• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.3
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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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• v.9 no.4
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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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• v.52 no.12
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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.

• Journal of Communications and Networks
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• v.7 no.4
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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 Korean Society of Manufacturing Technology Engineers
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• v.23 no.2
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• pp.199-205
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• 2014

This research focuses on the development of an interrogator that operates and measures fiber Bragg grating(FBG) multiplexing sensor probes for accurate-measurement of the blade deflection in a wind power generator. We designed and fabricated an optical source and spectrum module for the interrogator. Additionally, we verified the wavelength repeatability within 0.001 nm and the wavelength stability within 1 pm of the optical source, and we experimentally determined that the wavelength scanning range was about 44.4 nm. The FBG sensor with 2 nm resolution can be extended to a performance-efficient system that measures more than 20 sensors. The implemented interrogator has 0.141 nm wavelength variations corresponding to an ambient temperature range of $0^{\circ}C$ to $70^{\circ}C$. The measurement error can be easily reduced by employing a temperature compensation algorithm. In this study, we quantitatively confirmed the accuracy and operating stability of the interrogator.

• Current Optics and Photonics
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• v.3 no.3
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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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• v.18 no.8
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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 Korea Society of Computer and Information
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• v.10 no.6 s.38
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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.

• Proceedings of the Optical Society of Korea Conference
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• 1991.07a
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• pp.77-82
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• 1991

여러개의 레이저 빔을 결합하여 대표적인 방법의 장단점을 비교 분석하였다. incoherent 방법으로는 wavelength multiplexing, spatial multiplexing, polarization multiplexing을 분석하였고 coherent 방법으로는 binary phase grating과 travelng-were amplification을 고려하였다. 특히 고출력 laser diode array를 이용한 대출력 증폭기 시스템을 분석하였다.

• The Journal of the Korea Contents Association
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• v.6 no.10
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• pp.153-162
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• 2006

The WDM/SCM-FTTH is an advanced optical access Network that can efficiently support various kinds of access network requirements using the WDM and SCM technologies in the near future. In this paper, we propose new network structures of the FTTH(Fiber To The Home) in the WDM(Wavelength Division Multiplexing) and WDM/SCM(Sub-Carrier Multiplexing) FTTH, and evaluate its performance with simulation results for the optical characteristics of the network and the dynamic allocation of bandwidth on demand of the users.