• Title/Summary/Keyword: optical transmitter

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The Efficiency Design & MAC Function of the Composition Optical Network (광통신망 구축의 효과적인 설계 및 MAC고려 요소)

  • 하창국
    • Journal of the Korean Professional Engineers Association
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    • v.34 no.4
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    • pp.41-47
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    • 2001
  • The paper describes SR3 (Synchronous Round Robin with Reservations), a collision-free medium access control protocol for all-optical slotted packet networks based on WDM multi-channel ring topologies where nodes are equipped with one fixed-wavelength receiver and one wavelength-tunable transmitter SR3 is derived from the SRR and MMR protocols previously proposed by the same authors for the same class of all-optical networks. SRR and MMR already achieve an efficient exploitation of the available bandwidth, while guaranteeing a throughput-fair access to each node. SR3, In addition, allows nodes to reserve slots. thereby achieving a stronger control on access delays; it is thus well suited to meet tight delay requirements, as it is the case for multimedia applications. Simulation results show that SR3 provides very good performance to guaranteed qualify traffic, but also brings signigicant performance improvements for best-effort traffic. Energy effciency is an important issue for optical network since they must rely on their batteries. We present a novel MAC protocol that achieves a good energy efficiency of optical interface of the network and provides support for diverse traffic types and QoS. The scheduler of the base station is responsible to provide the required QoS to connections on the optical link and to minimise the amount of energy spend by the High speed Network. The main principles of the MaC protocol are to avoid unsuccessful actions, minimise the number of transitions , and synchronise the mobile and the base-station. We will show that considerable amounts of energy can be saved using these principles.

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Physical Media Dependent Prototype for 10-Gigabit-Capable PON OLT

  • Kim, Jongdeog;Lee, Jong Jin;Lee, Seihyoung;Kim, Young-Sun
    • ETRI Journal
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    • v.35 no.2
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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.

Characteristics of Compensation for Distorted Optical Pulse with Initial Frequency Chirp in 3 X 40 Gbps WDM Systems Adopted Mid-Span Spectral Inversion

  • Lee, Seong-Real;Lee, Yun-Hyun
    • Journal of electromagnetic engineering and science
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    • v.3 no.2
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    • pp.79-85
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    • 2003
  • In this paper, we investigated the degree of compensation for distorted optical pulse of wavelength division multiplexed(WDM) channel with initial frequency chirp generated in optical transmitter. The WDM channel signal distortion is due to chromatic dispersion, self phase modulation(SPM) and cross phase modulation(XPM) in fiber. The considered system is 3 ${\times}$ 40 Gbps intensity modulation direct detection(IM/DD) WDM transmission systems, which adopted mid-span spectral inversion(MSSI) as compensation method. We confirmed that the effect of initial frequency chirp on compensation for signal distortion due to a SPM is gradually decreased as a dispersion coefficient of fiber becomes gradually small. But, in the aspect of a compensation for signal distortion due to both SPM and XPM, the effect of initial frequency chirp on compensation is gradually decreased as a dispersion coefficient of fiber becomes gradually large.

Comparison with Dispersion Compensation Scheme Using 10 Gbit/s × 40 Channels Wavelength Division Multiplexing Transmission over 323 km of Field Installed Non-Zero Dispersion Shift Fiber

  • Kim, Geun-Young;Park, Soo-Jin;Jeong, Ki-Tae
    • Journal of the Optical Society of Korea
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    • v.10 no.3
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    • pp.112-117
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    • 2006
  • We experimentally investigated the transmission characteristics of 400 Gbit/s (10 Gbit/s ${\times}$ 40 channels) WDM signals with 100 GHz channel spacing over 323 km of installed NZ_DSF. The installed fiber has optical properties of 0.28 dB/km attenuation, 4.3 ps/nm/km dispersion, $0.083ps/nm^2/km$ dispersion slope and less than $0.05ps/km^{1/2}$ PMD coefficient. In this experiment, two cases of dispersion compensation schemes, the lumped type and the distributed type, were compared. The results implied that the distributed type dispersion compensation in which dispersion compensation devices are inserted at the end of the each span showed better transmission performance than the lumped one in which dispersion compensation devices are located at the transmitter and receiver sites. From the analysis of the experimental results, we verified that different transmission performance comes from the power penalty induced by XPM in the distributed scheme is lower than the lumped scheme case.

Performance Analysis of Optical Transmitters with the Non-ideal Mach-Zehnder Modulator

  • Lee, Dong-Soo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.11
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    • pp.9-14
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    • 2008
  • This paper presents the performance analysis of 10[Gb/s] optical duobinary transmitters with the non-ideal Mach-Zehnder modulator which does not have exactly 50/50 splitting/combining ratios by computer simulations. For driving voltage ratios(=driving voltage/switching voltage) with smaller than 100[%], the transmission performance has been greatly affected by extension of LPF bandwidths. Nevertheless, the performance has been degraded when the driving voltage ratio is 100[%]. The smaller driving voltage ratios has, the more sensitivity improves by extension of LPF bandwidths under the asymmetry condition. But the driving voltage ratio with 80[%] has better bit error rate(BER) than those with 50[%] and 25[%].

Performance analysis of a MAC Protocol on WDM Non-Slotted Ring (Fixed Length Packet) Network (Non-Slotted Ring (Fixed Length Packet) 구조를 가지는 WDM 광 네트워크의 성능 분석)

  • 정지훈;김종훈
    • Proceedings of the IEEK Conference
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    • 2000.06a
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    • pp.229-231
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    • 2000
  • Nowadays, the telecommunication service provider has witnessed an unprecedented growth in data traffic and the need for networking. optical fiber can provide some THz of huge bandwidth WDM technology has been an emerging issue for the efficient use of optical links. WDM uses a number of different wavelength that are assigned to each channel. The minimal number of optical transceivers and receivers should be used in a node to build an economic WDM transmission system without degrading system performance. Hence, the analysis of performance parameters such as throughput and delay is important to guarantee the WDM system performance. in this paper, the performance of a MAC protocol on a slotted WDM system that has a tunable transmitter(Txt), a tunable receiver(Rxt), and a fixed receiver(Rxf), respectively, on each node, was statistically analyzed The computer simulation validates the performance analysis.

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Optical Camera Communication Based Lateral Vehicle Position Estimation Scheme Using Angle of LED Street Lights (LED 가로등의 각도를 이용한 광카메라통신기반 횡방향 차량 위치추정 기법)

  • Jeon, Hui-Jin;Yun, Soo-Keun;Kim, Byung Wook;Jung, Sung-Yoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.9
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    • pp.1416-1423
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    • 2017
  • Lane detection technology is one of the most important issues on car safety and self-driving capability of autonomous vehicle. This paper introduces an accurate lane detection scheme based on OCC(Optical Camera Communication) for moving vehicles. For lane detection of moving vehicles, the streetlights and the front camera of the vehicle were used for a transmitter and a receiver, respectively. Based on the angle information of multiple streetlights in a captured image, the distance from sidewalk can be calculated using non-linear regression analysis. Simulation results show that the proposed scheme shows robust performance of accurate lane detection.

Asymmetry Effects on Optical Duobinary Transmitters

  • Lee, Dong-Soo;Huh, Hyun-Gue
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.3
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    • pp.1-7
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    • 2008
  • We have theoretically investigated the asymmetry effects on 10[Gb/s] optical duobinary transmitters from the viewpoint of the driving voltage ratios by computer simulations. For driving voltage ratios(=driving voltage/switching voltage) with smaller than 100[%], the transmission performance has been greatly affected by the asymmetry of the bandwidth of LPFs than that of the Mach-Zehnder Modulator driving voltage. On the other hand, for driving voltage ratios with 100[%], the transmission performance has been degraded by the asymmetry of the driving voltage and is not sensitive to that of the bandwidth of LPFs. For the transmission performance within 1[dB] power penalty under the asymmetry condition, the driving voltage ratio with 100[%] has performed better than the low driving voltage ratios.

Channel Characteristics of Indoor Wireless Infrared Communication System Due to Different Transceiver Conditions

  • Peng, Chuan;Wang, Zan;Kim, Ji-Do;Pan, Jae-Kyung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.2A
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    • pp.198-203
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    • 2008
  • In this paper, we consider the diffuse type of indoor wireless optical communication (WOC) system. To find the channel characteristics of indoor wireless infrared communication system, we investigate the simulation process to get the impulse response of diffuse type and analyze the scenario of the indoor structure which we have built. The simulation results of the impulse response include power ratio and time delay due to bounce times. We get and discuss the receiving power distribution according to six configurations which have different transmitter and receiver positions and reflection coefficients of the indoor structure assumed. The results of this paper are useful to design the indoor wireless optical communication systems.

Illumination Control in Visible Light Communication Using Transition Frequency Modulation (천이주파수 변조를 이용한 가시광통신의 조명제어)

  • Lee, Seong-Ho
    • Journal of Sensor Science and Technology
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    • v.30 no.2
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    • pp.99-104
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    • 2021
  • In this study, we utilized the duty factor of the transition frequency modulation (TFM) for the illumination control of the light emitting diode (LED) light in visible light communication (VLC). The average optical power is linearly proportional to the duty factor in TFM waveforms. We used the transition frequencies of Na=5 and Nb=1 for the high and the low bits, respectively, of the non-return-to-zero (NRZ) data in the VLC transmitter. A resistor and capacitor high-pass filter (HPF) was used in the VLC receiver to eliminate the 120 Hz optical noise from adjacent lighting lamps and the spikes at the HPF output were used to recover NRZ data from the TFM waveform. In experiments, the illumination of the LED light was controlled in the range of 25-90% of the constant-wave optical power by changing the duty factor of the TFM waveforms.