• Journal of the Optical Society of Korea
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• 제15권1호
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• pp.4-8
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• 2011

We have evaluated the performances of bidirectional optical amplifiers which were suited for the cost-effective implementation of amplified bidirectional passive optical networks (PONs). First, we measured the maximum gains of two simple bidirectional optical amplifiers implemented without using any optical components for the suppression of reflected signals. From the results, the maximum gains of two simple bidirectional amplifiers with a broadband light source (BLS) seeded optical source were limited to be 27 dB due to the reflection-induced in-band crosstalk, when the reflectance coefficients were measured to be -33 dB in both directions. Then, we have also implemented a bidirectional optical amplifier with two band splitters for the amplified bidirectional PON where the two different wavelength bands were allocated to the downstream and upstream signals transmission. In our measurement, we confirmed that the maximum gain of bidirectional optical amplifier with two band splitters could be increased to more than 30 dB owing to the efficient suppression of in-band crosstalk.

• ETRI Journal
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• 제28권1호
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• pp.1-8
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• 2006

A novel all-optical gain-controlled (AOGC) bidirectional amplifier is proposed and demonstrated in a compact structure. The AOGC function using fiber Bragg grating (FBG) pairs controls both directional signals independently, and combinations of optical interleavers and isolators suppress Rayleigh backscattering (RB) noise. The amplifier achieves high and constant gain with a wide dynamic input signal range and low noise figure. The performance does not depend on the input signal conditions, whether static-state or transient signals, or whether there is symmetric or asymmetric data traffic on bidirectional transmission. Transmission comparison experiments between invariable symmetrical and random variable asymmetric bidirectional data traffic verify that the all-optical gain control and bidirectional amplification functions are successfully combined into this proposed amplifier.

• 한국전자파학회논문지
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• 제22권11호
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• pp.1111-1116
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• 2011

본 논문에서는 기존 CMOS 수동 스위치를 사용한 switched - line 타입 위상변화기의 수동 스위치를 공통게이트 증폭기(양방향 증폭기)로 대체한 60 GHz CMOS 양방향 능동 위상변화기를 제안한다. 양방향 능동 위상변화기는 양방향 증폭기 블록과 수동 delay line 네트워크 블록으로 구성된다. 양방향 증폭기 블록은 순방향과 역방향의 특성이 같도록 설계하기 위해 공통 게이트 증폭기(CGA) 구조가 적합하며, 입력단과 출력단의 매칭은 대칭으로 이루어진다. 또한, 통합 바이어스 회로를 이용하여 1개의 바이어스 전압($V_{DS}$)만으로도 증폭의 방향(순방향, 역방향)과 크기를 조절할 수 있도록 구성하였다. 수동 delay line 네트워크 블록은 마이크로스트립 라인으로 구성하였다. 동부 하이텍 1P8M 130-nm CMOS 공정을 이용하여 90도, 180도 1-bit 양방향 능동 위상변화기를 각각 설계하였고, 시뮬레이션 결과 60 GHz에서 평균 -3 dB의 삽입 손실을 얻었으며, 각각 90도 180도의 위상차를 얻었다.

• Journal of the Optical Society of Korea
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• 제15권3호
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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.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권6호
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• pp.817-824
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• 2016

A simultaneous bidirectional transceiver over a single wire has been developed in a 65 nm CMOS technology for a command and control bus. The echo signals of the simultaneous bidirectional link are cancelled by controlling the decision level of receiver comparators without power-hungry operational amplifier (op-amp) based circuits. With the clock information embedded in the rising edges of the signals sent from the source side to the sink side, the data is recovered by an open-loop digital circuit with 20 times blind oversampling. The data rate of the simultaneous bidirectional transceiver in each direction is 75 Mbps and therefore the overall signaling bandwidth is 150 Mbps. The measured energy efficiency of the transceiver is 56.7 pJ/b and the bit-error-rate (BER) is less than $10^{-12}$ with $2^7-1$ pseudo-random binary sequence (PRBS) pattern for both signaling directions.

• 한국통신학회논문지
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• 제32권12B호
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• pp.809-814
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• 2007

본 논문에서는 중앙국(Central of office)에서 반송파가 억제된 광원을 생성하여 파장에 무관한 RSOA기반 양방향 WDM-PON구조를 제안 하였다. 중앙국에 위치한 마흐젠터 모듈레이터 (LiNbO3 Mach Zehnder Modulator)를 이용해서 5 GHz 변조된 반송파가 억제된 광원(Suppressed Optical Carrier)을 만들어 상향 신호 광원으로 전송을 하고 이와 더불어 하향 신호용 광원은 반사형 광증폭기(Reflective Semi-conductor Optical Amplifier)를 이용해서 데이터 변조 후 전송을 하게 된다. 상향 신호는 반송파가 억제된 광원을 광망 전달 장치(Optical Network Unit)보내 다시 데이터 재변조를 하고 증앙국(Central Office)으로 재전송함으로써 파장에 무관한 새로운 양방향 WDM-PON 구조를 실험을 통해 검증하였다.

• 한국항행학회논문지
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• 제21권1호
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• pp.66-71
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• 2017

본 논문은 입자 가속기에 이용되는 165 MHz, 5 kW 고전력 증폭기의 제작에 대한 내용을 서술하였다. 이 고전력 증폭기 구성은 주 증폭기를 구동할 수 있는 드라이브 증폭기 모듈, 16개의 600 W 클래스 AB 푸쉬풀 증폭기 모듈 그리고 이 모듈 출력을 분배 또는 결합하기 위해 집중소자 LC로 구현한 입출력의 윌킨슨 결합기로 구성되어 있다. 그리고 정상적인 출력과 부하에서 반사되는 전력을 감시하여 증폭기를 보호하기 위한 방향성 결합기가 구성되어있으며, 600 W 주 증폭기는 입력전원에 의해서 발생되는 열을 방출시키기 위해서 방열판 밑에 물을 통과시키는 관을 넣어 방열하는 워터 쿨링 방법을 사용하였다. 여기서 구현된 증폭기는 중심주파수 165 MHz에서 포화 전력레벨이 5.0 kW 출력레벨에서 62.5 %의 효율을 얻었다.

• ETRI Journal
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• 제35권2호
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• pp.245-252
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• 2013

In this work, we study the physical layer solutions for 10-gigabit-capable passive optical networks (PONs), particularly for an optical link terminal (OLT) including a 10-Gbit/s electroabsorption modulated laser (EML) and a 2.5-Gbit/s burst mode receiver (BM-Rx) in a novel bidirectional optical subassembly (BOSA). As unique features, a bidirectional mini-flat package and a 9-pin TO package are developed for a 10-gigabit-capable PON OLT BOSA composed of a 1,577-nm EML and a 1,270-nm avalanche photodiode BM-Rx, including a single-chip burst mode integrated circuit that is integrated with a transimpedance and limiting amplifier. In the developed prototype, the 10-Gbit/s transmitter and 2.5-Gbit/s receiver characteristics are evaluated and compared with the physical media dependent (PMD) specifications in ITU-T G.987.2 for XG-PON1. By conducting the 10-Gbit/s downstream and 2.5-Gbit/s upstream transmission experiments, we verify that the developed 10-gigabitcapable PON PMD prototype can operate for extended network coverage of up to a 40-km fiber reach.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권12호
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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.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권4호
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• pp.224-230
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• 2006

The conventional way to implement a bidirectional converter with boost/buck has been to use two general purpose PWM ICs with a single supply voltage. In this case, when one direction mode is in operation, the other is disabled and the output of the error amplifier of the disabled IC may be saturated to a maximum value or zero. Therefore, during mode transition, a circuit which can disable the switching operation for a certain time interval is required making it impossible to get a seamless transition. In this paper, the limitations of the conventional 42V/14V bi-directional DC/DC converter implemented with general current mode PWM ICs with a single supply voltage are reviewed and a new current mode PWM controller circuit with a dual voltage system is proposed. The validity of the proposed circuit is investigated through simulation. and experiments.