• Journal of the Optical Society of Korea
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• v.12 no.4
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• pp.351-354
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• 2008

We demonstrate an ultra-dense wavelength-division- multiplexed (UD-WDM) passive optical network (PON) where 12.5-GHz spaced 1 GbE ${\times}$ 256 optical channels are distributed using 12.5- and 200-GHz arrayed waveguide gratings in series. For the generation of upstream signals, we use reflective semiconductor optical amplifiers. We use two optical fiber amplifiers at the optical line terminal to amplify downstream and upstream channels.

• Current Optics and Photonics
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• v.1 no.6
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• pp.579-586
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• 2017

In this paper, we theoretically demonstrate that semiconductor optical amplifiers (SOAs) with strong wavelength dependence of gain and phase are capable of all-optical inverted and non-inverted wavelength conversion (WC) over a wide range, with the assistance of an optical filter. First, the gain dynamics and phase dynamics in a common quantum well (QW) SOA with the $In_{0.53}Ga_{0.47}As/In_{0.7322}Ga_{0.2678}As_{0.5810}P_{0.4190}$ material system are found to be strongly dependent on wavelength, which is mainly related to the wavelength dependence of the differential gain and the differential refractive-index change. Second, the wavelength dependence in an all-optical wavelength converter based on the QW SOA cascaded with a detuning band pass filter is studied. Simulations show that the quality of the converted signal has little dependence on the operation wavelength. Both inverted and non-inverted WC can be achieved, over a large wavelength range. Therefore, although the gain and phase change are strongly wavelength-dependent, the effects of this dependence can be erased by appropriate optical filtering.

• Korean Journal of Optics and Photonics
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• v.13 no.2
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• pp.151-154
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• 2002

All-optical OR logic gate is realized by use of gain saturation and wavelength conversion in the semiconductor optical amplifiers (SOA). It is operated by the nonlinearity of the SOA gain and hence to obtain the sufficient gain saturation of the SOA, pump signals are amplified by an Er-doped fiber amplifier (EDFA) at the input of the SOA. The operation characteristics of all-optical OR logic gate are successfully measured at 2.5 Gbit/s.

• ETRI Journal
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• v.26 no.4
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• pp.344-350
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• 2004

We propose a filter-free wavelength conversion using a Mach-Zehnder interferometer with monolithically integrated $2{\times}2$ multimode interference semiconductor optical amplifiers (MMI-SOAs). The device has been optimized by considering a non-homogeneous carrier distribution due to the self-imaging properties of the MMI-SOA. Static measurements show an extinction ratio of up to 18 dB and an input signal rejection ratio of up to 20 dB.

• Proceedings of the Optical Society of Korea Conference
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• 2006.02a
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• pp.375-376
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• 2006

• Korean Journal of Optics and Photonics
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• v.14 no.2
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• pp.166-168
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• 2003

By using gain saturation of semiconductor optical amplifiers (SOAs), an all-optical AND gate at 10 Gb/s has been successfully demonstrated. Firstly, Boolean (equation omitted) has been obtained using the first SOA with signal B and clock injection. Then, the all-optical AND gate is achieved using the second SOA with signals A and (equation omitted) injection.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.222-223
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• 2003

The optical gain characteristics of 1550nm traveling-wave semiconductor optical amplifiers are analyzed experimentally and theoretically. The result shows that there is an optimum active layer thickness for high saturation output power.

• Korean Journal of Optics and Photonics
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• v.17 no.6
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• pp.564-568
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• 2006

Using the cross-gain modulation (XGM) characteristics of semiconductor optical amplifiers (SOAs), multi-functional all-optical logic gates, including XOR, AND, and OR gates are successfully simulated and demonstrated at 10Gbit/s. A VPI component maker^TM simulation tool is used for the simulation of multi-functional all-optical logic gates and the10 Cbit/s input signal is made by a mode-locked fiber ring laser. A multi-quantum well (MQW) SOA is used for the simulation and demonstration of the all-optical logic system. Our suggested system is composed of three MQW SOAs, SOA-1 and SOA-2 for XOR logic operation and SOA-2 and SOA-3 for AND logic operation. By the addition of two output signals XOR and AND, all-optical OR logic can be obtained.

• Korean Journal of Optics and Photonics
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• v.29 no.1
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• pp.32-39
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• 2018

The impact of the amplified spontaneous emission (ASE) on the gain recovery time of a bulk semiconductor optical amplifier (SOA) is investigated. The gain-recovery time is obtained by determining the time evolution of the gain, carrier density, and ASE in an SOA, after the propagation of a short pump pulse and continuous-wave (CW) probe of gain dynamics. In the simulation, a wide-band-semiconductor model, which can be characterized by the material gain coefficient over a wide wavelength range, is used, because the gain bandwidth of a practical SOA is very wide. The pump pulse and counterpropagating CW probe field are considered in the simulation, with the ASE noise spectrum equally divided.

• Journal of the Optical Society of Korea
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• v.12 no.4
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• pp.359-363
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• 2008

A novel WDM-PON system delivering bidirectional 1.25-Gbps data and broadcasting data is proposed. A subcarrier signal modulates optical carriers of a Fabry-Perot-laser-diode based broadband light source to broadcast to all users. Reflective semiconductor optical amplifiers are used as modulators for the baseband data at both the optical line terminal and the remote optical network unit for a channel. Bit error rate and error vector magnitude were measured to demonstrate the proposed scheme.