• Proceedings of the Optical Society of Korea Conference
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• 1999.08a
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• pp.104-105
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• 1999

• Proceedings of the Optical Society of Korea Conference
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• 2004.02a
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• pp.94-95
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• 2004

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.103-104
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• 2006

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.7
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• pp.1249-1255
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• 2008

1530nm band has been studied as pump wavelength for long-wavelength-band erbium-doped fiber amplifier (L-band EDFA). The pump source is built using a tunable light source and cascaded conventional-band (C-band) EDFA. The L-band EDFA uses a forward pumping scheme. Within the 1530nm band, 1545nm pump demonstrates 0.45dB/mW gain coefficient, which is twice better than that of conventional 1480nm pumped EDFA. The noise figure of 1530nm pump is at worst 6.36dB, which is 0.75dB higher than that of 1480nm pumped EDFA. Such high gain coefficient indicates that the L-band EDFA consumes low power.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.7
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• pp.1393-1397
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• 2009

A high-speed wavelength swept laser, which is based on oscillation characteristics of a fiber Fabry-Perot tunable filter, is described. The laser is constructed by using a semiconductor optical amplifier, a fiber Fabry-Perot tunable filter, and 3.348 km fiber ring cavity. The wavelength sweeps are repeatatively generated with the repetition period of 61 kHz which is the first parallel oscillation frequency of the Fabry-Perot tunable filter for the low power consumption. Mode-locking is implemented by 3.348 km fiber ring cavity for matching the fundamental of cavity roundtrip time to the sweep period. The wavelength tuning range of the laser is 87 nm(FWHM) and the average output power is 1.284 mW.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.203-206
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• 2003

Thermo-optic tunable filter, with 4-pairs of H/L layers for DBR, was designed and fabricated. The transmittance characteristics of the filter were measured. Additionally, heating system and temperature sensor system were used in order to observe property of the filter by thermo-optic effect. The tuning efficiency of the filter was measured to be 0.144nm/K$^{-1}$ showing the tuning range of 9.4nm for the temperature variation of 64.7$^{\circ}C$. Filter, lens and fiber were aligned by micro-optical bench.

• Korean Journal of Optics and Photonics
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• v.14 no.1
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• pp.8-11
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• 2003

For the first time to our knowledge we have developed compact mechanically-induced long-period fiber grating devices which have an excellent tunability in the center wavelength and the depth of the notch. The compactness and ease to tune allow us to include them in other optical devices or systems. The devices were characterized by measuring their transmission spectra with different grating periods and applied pressures. We have also demonstrated the EDFA gain flattening using the mechanically-induced long-period fiber grating devices.

• Korean Journal of Optics and Photonics
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• v.11 no.3
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• pp.166-170
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• 2000

A wavelength tunable all-optical clock recovery using a semiconductor optical amplifier in a fiber ring cavity is proposed and demonstrated at the wavelength of 1530 nm to 1570 nm. A synchronized optical pulse train is recovered from 10 Gbps and 30 Gbps randomly generated optical pulse streams with injection locking technique. Also, the system responses to the perturbation and the input average power variation are analyzed by a large-signal model based on time-domain travelling wave equation. ation.

• Electronics and Telecommunications Trends
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• v.39 no.1
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• pp.48-61
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• 2024

The integration of high-capacity terrestrial networks with non-terrestrial communication using satellites has become essential to support seamless low-latency services based on artificial intelligence and big data. Tunable light sources have been instrumental in resolving the complexity of channel management in wavelength division multiplexing (WDM) systems, contributing to increased network flexibility and serving as optical sources for long-distance coherent systems. Recently, these light sources have been applied to beam-steering devices in laser communication and sensing applications across ground, aerial, and satellite transport. We examine the utilization and requirements of tunable lasers in WDM networks and describe the relevant development status. In addition, performance requirements and development directions for tunable lasers used in optical interference systems and beam-steering devices are reviewed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11C
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• pp.85-93
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• 2001

In this paper, a path restoration method independent of failure location in all-optical networks is proposed and its wavelength requirements are calculated. In the proposed method, since a single backup wavelength is used for any link failure, a node can consist of only fixed wavelength transmitters, resulting in the levels node cost. Hence, restoration process can be triggered just after the failure detection, if combined with edge-disjoint path restoration method. This feature and the parallel cross-connection message transfer technique proposed in this paper make the restoration process faster. Also, it is shown the wavelength requirements in the proposed method are similar to the ones in the method using tunable backup wavelength, resulting in little increment for transmission cost.