• Journal of the Optical Society of Korea
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• v.15 no.3
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• pp.222-226
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• 2011

We demonstrated the feasibility of an amplified wavelength-division multiplexed passive optical network (WDM-PON) architecture based on broadband light source (BLS) seeded optical sources and a novel bidirectional reach extender. Our bidirectional reach extender could provide an amplification of both downstream and upstream signals as well as a BLS output for the upstream WDM signal generation. An error-free 1.25 Gb/s signal transmission over a 100-km long single-mode fiber was achieved in a bidirectional WDM-PON using BLS seeded reflective semiconductor optical amplifier (RSOA) sources.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.12B
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• pp.809-814
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• 2007

In this paper, we proposed new method of a bidirectional WDM-PON transmission using suppressed optical carreir(SOC) and reflective semi-conductor optical amplifier(RSOA) based on WDM-PON. while LiNbO3 mach zehnder modulator(LN-MZM) generates 5GHz modulated SOC for uplink at central office(CO), RSOA at CO modulates the downstream data. At optical network units(ONUs), Another RSOA modulates the SOC light source for uplink at ONU and uplink data are up-converted to the 5 GHz already modulated SOC using LN-MZM.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.12
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• pp.3310-3329
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• 2023

This work designs an eighteen-channel bidirectional Intensity Modulation with Direct Detection (IM/DD) Wavelength Division Multiplexing-Passive Optical Network (WDM-PON) system. The proposed system meets the requirement of the ITU-T 5G fronthaul link suggested design in G-series Recommendations-Supplement 66. The newly designed system, with a 25Gb/s/λ data rate (450Gbps as a system capacity), has been tested and simulated using OptiSystem V.19 software. The system has been evaluated by the BER with respect to variable the optical span and CW laser power. Based on the ITU-T recommendations, the simulation results demonstrate that this system might be used as an F1 and as an Fx 5G fronthaul link for functional split choices starting from options 1 to 7a. These options are required under 25Gbps/λ for each upstream and downstream link direction. Furthermore, the proposed system utilized a bidirectional single-mode optical fiber within short optical spans of up to 10 km. The proposed system is characterized by a low-cost, simple, DSP-free and amplifier-free system with a reasonable system capacity.

• Journal of the Optical Society of Korea
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• v.12 no.4
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• pp.337-345
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• 2008

This article presents the RSOA-based re-modulation schemes for practical application to the WDM-PON link. Emphasis is put on the three methods for reducing the residual downstream signal in the upstream transmission; the simplest one is to use the RSOA gain-saturation property, the second uses selective filtering of the adiabatic-chirped DFB-LD output spectrum, and the last uses a dynamic RSOA gain control by varying its driving current according to the incident binary signal. The reflection sensitivity in the proposed re-modulation link is also qualitatively presented in the cases of using two different types of seed light: coherent light from DFB-LD array and spectrum-sliced incoherent ASE light. We show experimental results of an error-free bidirectional gigabit transmission over 20 km at -30 dB reflection with the spectrum-sliced ASE seed light.

• Korean Journal of Optics and Photonics
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• v.22 no.3
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• pp.122-128
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• 2011

The AWG-filtering effect was investigated on a bidirectional 100-GHz-channel-spacing WDM-PON link using spectrum-sliced and RSOA-amplified light sources for downstream signals and a wavelength reuse technique for upstream signals. Signal performances of three different filtering AWGs, including Gaussian, trapezoidal, and rectangular types, were compared on link transmission with fiber nonlinear effects. As an extinction ratio of a downstream signal varied, the effect for both directional signals was analyzed and optimized. It was found that there was an optimal pass bandwidth of an AWG for the balance between relative intensity noise decrement and cross phase modulation noise increment as the bandwidth got wider.

• 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.

• Proceedings of the Optical Society of Korea Conference
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• 2004.07a
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• pp.10-11
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• 2004

• Journal of the Optical Society of Korea
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• v.18 no.5
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• pp.436-441
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• 2014

We have demonstrated an amplified wavelength-division multiplexed (WDM) passive optical network (PON) by using broadband light source (BLS) seeded optical sources and chirped fiber Bragg gratings (FBGs) based dispersion compensators. Chirped FBGs located at central office (CO) were fabricated and used as channel-by-channel dispersion compensators in order to mitigate the dispersion-induced distortion of both downstream and upstream signals. Owing to a low insertion loss of chirped FBG based dispersion compensator, the optical signal-to-noise ratio (OSNR) of the downstream signal could be improved to be ~28 dB. Thus, we re-confirmed that an error-free transmission of 1.25 Gb/s signals over a 100 km single-mode fiber (SMF) link could be achieved with a proposed amplified WDM-PON architecture. We have also evaluated the impact of various noises on the system's performance, and found that the low OSNR of the downstream signal would be a main limiting factor on the maximum reach of the proposed amplified WDM-PON architecture. From the measured ~13 dB improvement in OSNR of the downstream signal compared to our previously-proposed dispersion compensating module based scheme, we believe that the proposed architecture can accommodate a reach of longer than 100 km SMF link easily.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.312-313
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• 2003

최근 인터넷 트래픽의 증가와 음성, 데이터, 동영상과 같은 다양한 멀티미디어 서비스의 영향으로 가입자망의 고속화가 요구되고 있다. 인터넷 트래픽을 효율적으로 가입자에게 제공하기 위해서는 광을 이용한 통신이 이루어져야 한다. 이를 위하여 다양한 기술들이 제시되고 있으며, 경제적인 측면과 구성의 용이성을 고려한 광 가입자망인 PON(Passive Optical Network)에 대한 관심이 고조되고 있다. 본 논문에서는 파장 분할 다중화 방식으로 단심 상하향 동일파장을 사용하여 소요되는 광섬유의 비용을 반으로 줄이고, 채널당 전송용량을 두 배로 높일 수 있는 매트로 이더넷용 단심 양방향 버스형 WDM-EPON 시스템에 대한 연구를 하고자 한다. (중략)

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.2
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• pp.90-99
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• 2007

We demonstrate an 80km-reach 64-channel DWDM-PON based on wavelength-locked F-P LDs by changing the position of the C-band BLS for upstream channels from the CO to the RN. It mitigates the necessity of the high power C-band BLS and its handling problems. It also reduces back scattering induced penalty. We obtained less than $10^{-6}$ PLRs in all 128channels through 80km SMF. We also demonstrate a 240km-reach DWDM-PON based on wavelength-locked F-P LDs by adding a bidirectional erbium-doped fiber amplifier(EDFA). We show packet-loss-free transmission in all 128channels at 125 Mb/s per channel over 240km SMF We report the detuning effect of arrayed waveguide gratings(AWGs) and crosstalk effect in the implemented system. We Propose an architecture of a next generation defense wire communication system with the demonstrated long-reach DWDM-PON.