• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.238-239
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• 2000

The optical fibers are an interesting medium for effective tunable optical frequency conversion in the spectral range of UV, Visible, and near-IR through the nonlinear processes. A number of papers for developing the wideband and flat-gain amplifier for the WDM system applications through the combination of EDFA or thulium-doped fluoride fiber amplifier and Raman amplifier, are reported$^{(1)}$ . Even though a variety of papers related to Raman amplifications are published, the amplification with the feedback of the residual pump is not investigated yet. Accordingly, in this paper, we report the characteristics of forward Raman amplification by the simple and double-pass fiber Raman configuration through the feedback of residual pump beam. (omitted)

• Korean Journal of Optics and Photonics
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• v.5 no.2
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• pp.291-297
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• 1994

A feedback loop with bandpass filter is introduced in erbium-doped fiber amplifier to clamp the amplifier gain by lasing the amplifier at a selected wavelength. The gain and the ASE (amplified spontaneous emission) output spectra are found to be independent of input signal power and pump power variation so long as the amplifier is lasing. Also they are found to be dependent only on the overall loss of the feedback loop. Even in the case of slowly modulated large signal input, signal distortion due to gain saturation is not observed.served.

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.657-662
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• 2014

We demonstrate a simulation of a parallel hybrid fiber amplifier in the C+L-band with a gain controlling technique. A variable optical coupler is used to control the input signal power for both EDFA and RFA branches. The gain spectra of the C+L-band are flattened by optimizing the coupling ratio of the input signal power. In order to enhance the pump conversion efficiency, the EDFA branch was pumped by the residual Raman pump power. A gain bandwidth of 60 nm from 1530 nm to 1590 nm is obtained with large input signal power less than -5 dBm. The gain variation is about 1.06 dB at a small input signal power of -30 dBm, and it is reduced to 0.77 dB at the large input signal power of -5 dBm. The experimental results show close agreement with the simulation results.

• Korean Journal of Optics and Photonics
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• v.16 no.5
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• pp.411-416
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• 2005

We have designed an extended L-band Erbium-doped fiber amplifier to amplify 1625 nm optical time domain reflectometry signal for a long distance monitoring system. The proposed amplifier has a dual-stage structure without an isolator. Gain improvement of 5.1 dB has been achieved by adding a fiber Bragg grating and a narrow band pass filter. As a result, the 16.3 dB gain and 7.1 dB noise figure has been successfully accomplished.

• Journal of Communications and Networks
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• v.18 no.4
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• pp.551-558
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• 2016

In multifiber all-optical networks, optical amplifiers are used for amplifying multiple optical signals with different wavelengths in fibers. An optical amplifier operates when any of lightpaths passes through it. Therefore, it should simultaneously amplify as many lightpaths as possible for efficiently utilizing its power. This paper proposes a dynamic lightpath establishment scheme considering the use efficiency of the optical amplifiers and the depletion of the wavelength resources in multifiber all-optical networks. The proposed scheme provides a routing and wavelength assignment strategy that reduces both the power consumption of the optical amplifiers and the blocking probability of the lightpath establishment. Through simulation experiments, we demonstrate the effectiveness of the proposed scheme.

• Current Optics and Photonics
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• v.2 no.6
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• pp.563-567
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• 2018

We propose and experimentally demonstrate a simple tunable photonic microwave band-pass filter with high resolution using a reflective semiconductor optical amplifier (RSOA) and an optical time-delay line. The RSOA is used as a gain medium for generating cross-gain modulation (XGM) effect as well as an optical source. The optical source provides narrow spectral width by self-injection locking the RSOA in conjunction with a partial reflection filter with specific center wavelength. Then, when the RSOA is operated in the saturation region and the modulated recursive signal is injected into the RSOA, the recursive signal is inversely copied to the injection locked optical source due to the XGM effect. Also, the tunability of the passband of the proposed microwave filter is shown by controlling an optical time-delay line in a recursive loop.

• Proceedings of the Optical Society of Korea Conference
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• 1998.08a
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• pp.214-215
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• 1998

• Proceedings of the Optical Society of Korea Conference
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• 1999.08a
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• pp.224-225
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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

• Optical Science and Technology
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• v.5 no.2
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• pp.36-45
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• 2001