• Title/Summary/Keyword: NRZ

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New wavelength converter for optical NRZ data signal using SOA-loop-mirror (반도체 광 증폭기가 삽입된 광섬유 루프 미러를 이용한 NRZ 데이터에 대한 새로운 파장 변환기)

  • Lee, Hyuek-Jae
    • Korean Journal of Optics and Photonics
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    • v.16 no.1
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    • pp.27-33
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    • 2005
  • In this paper, a new wavelength converter using an SOA(Semiconductor Optical Amplifier)-loop-mirror for NRZ(NonReturn to Zero) optical data has been proposed and experimentally demonstrated. Conventional nonlinear fiber-loop-mirror methods can perform RZ-to-RZ, NRZ-to-RZ, and RZ-to-NRZ data format conversion, but NRZ-to-NRZ conversion has not been demonstrated until now. The experiment for the conversion from a 1300 nm NRZ data signal at 1.5 Gbps to a 1550 nm NRZ data one is successfully performed using a fiber-loop-mirror with 1300 nm-SOA.

Sampling Phase Detector for NRZ Random Bit Synchronization (NRZ Random Bit 동기를 위한 표본 위상 검출기)

  • 박세현;박세훈
    • Journal of Korea Multimedia Society
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    • v.3 no.6
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    • pp.652-660
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    • 2000
  • This paper proposes a new type of sampling Phase Detector (SPD) for NRZ random bit synchronization circuit. The proposed SPD calculates the mean value of phase difference between bit interval of input signal and period of local reference. Simulated and experimental results show that the proposed SPD is applicable to the phase detector for NRZ random signal. finally the Random NRZ bit synchronization circuit. is designed and implemented by using SPD.

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Optical Clock Recovery from RZ and NRZ data using a Multi-Section Laser Diode with a DFB Reflector (DFB 반사기가 집적된 다중전극 레이저 다이오드를 이용한 RZ 및 NRZ 데이터 신호의 광클럭 재생)

  • Jeon, Min-Yong;Leem, Young-Ahn;Kim, Dong-Churl;Sim, Eun-Deok;Kim, Sung-Bock;Park, Kyung-Hyun;Yee, Dae-Su
    • Korean Journal of Optics and Photonics
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    • v.17 no.1
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    • pp.68-74
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    • 2006
  • We have extracted an optical clock signal from a return-to-zero(RZ) pseudorandom bit sequence(PRBS) and non-return-to-zero(NRZ) PRBS data in a pulsation multi-section laser diode with DFB reflector. The ms timing jitter achieved less than 1 ps for the input 11.727 Gbit/s RZ PRBS and NRZ PRBS data. The PRE data wasconverted from the NRZ data using an NRZ to pseudo-return to zero(PRZ) converter module. The optical clock was extracted from the PRZ data which contains the clock components. Although the input PRZ data gives a timing jitter of 2 ps, the extracted clock has timing jitter of ${\~}$1 ps.

The Compensation Characteristics of WDM Channel Distortion Dependence on NRZ format and RZ Format (NRZ 형식과 RZ 형식에 따른 WDM채널 왜곡의 보상 특성)

  • 이성렬;조성언
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.11
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    • pp.1184-1190
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    • 2003
  • In this paper, we investigated the characteristics of compensation for distorted NRZ signal and RZ signal in 320 Gbps WDM system as a function of channel input power, fiber dispersion coefficient and transmission length, respectively. The considered WDM transmission system is based on mid-span spectral inversion(MSSI) compensation method having highly nonlinear dispersion shifted fiber(HNL-DSF) optical phase conjugator(OPC) in the mid-way of total transmission line. We confirmed that the signal input power range compensated by MSSI is broadened by using RZ as a signal format in WDM system with small fiber dispersion coefficient, The range of fiber dispersion coefficient compensating overall distorted WDM channels is limited, because degree of compensation for distorted channel with low conjugated-wave power becomes gradually degrade as fiber dispersion coefficient becomes gradually higher. It is showed that RZ format and NRZ format is suited for long-haul transmission in WDM system with small fiber dispersion coefficient and with large fiber dispersion coefficient, respectively.

A Study on Transmission Performance for Optical NRZ Transmitters (광 NRZ 송신기의 전송 특성에 관한 연구)

  • Lee, Dong-Soo
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.15 no.5
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    • pp.119-123
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    • 2015
  • This paper presents a theoretical study of transmission performance for an optical NRZ (nonreturn-to-zero) transmitter employed a Mach-Zehnder modulator. Especially, we have investigated the effects of the ${\alpha}$-parameters that represents the chirps and the driving voltage ratios(=driving voltage/switching voltage) of Mach-Zehnder modulators for transmitting 25Gbps optical NRZ signals at a wavelength of 1550nm without any dispersion compensation methods over single mode fiber. By optimizing the negative values of ${\alpha}$-parameters for the dispersion tolerance with the change of driving voltage ratios, it has been tested whether the transmission performance has improved. We have verified the improvement by the BERs and the optical eye diagrams.

NRZ versus RZ Modulation Format in Lumped Dispersion Managed Systems (집중형 분산 제어 시스템에서 NRZ 변조 형식 대 RZ 변조 형식)

  • Lee, Seong-Real;Cho, Sung-Eon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.2
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    • pp.328-335
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    • 2008
  • The system performance of NRZ format in WDM transmission system with lumped dispersion management(DM) and optical phase conjugator(OPC) is compared with that of RZ format. It is confirmed that eye opening penalty(EOP) of both NRZ and RZ format in WDM transmission system having lumped DM combined with OPC are greatly improved than those in WDM system with only OPC. The optimal net residual dispersion(NRD) in the case of RZ format is decided to so small value that path-averaged dispersion coefficient become almost zero, while that in the case of NRZ format is decided to larger value, for the best improvement of overall WDM channels. It is also confirmed that EOP in the case of RZ format is more improved than that in the case of NRZ format in lumped DM with optimal NRD. This is resulted from that lumped DM combined with OPC suppress the signal distortion due to intrachannel four-wave mixing(IFWM) and intrachannel cross phase modulation(IXPM). Consequently, lumped DM combined with OPC proposed in this paper is effective technique to mitigate intrachannel nonlinearities in WDM transmitting RZ format.

Compensation Characteristics Dependence on Variation of Fiber Dispersion in WDM Systems with Optical Phase Conjugator (광 위상 공액기가 적용된 WDM 시스템에서 광섬유 분산 계수 변동에 따른 보상 특성)

  • 이성렬;박경호;정명래
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.5
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    • pp.517-524
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    • 2004
  • In this paper, we investigated the compensation characteristics of distorted NRZ format and RZ format signal dependence on dispersion variation of each transmission section in 8-channel WDM system. The WDM system have two transmission sections of unequal length with respect to optical phase conjugator(OPC) position. We select highly-nonlinear dispersion shifted fiber(HNL-DSF) as a nonlinear medium of OPC in order to convert wideband signal waves to conjugated waves. First, we confirmed that RZ is better than NRZ as a modulation format for maintenance or stable performance, when total dispersion or both sections in WDM system is different each other. Also, we confirmed that total dispersion of the short length section must be smaller than that of the long length section in order to excellently compensate for NRZ format signal.

Bit Error Rate Dependence on Amplifier Spacing in Long-Haul Optical Transmission System with Mid-Span Spectral Inversion (Mid-Span Spectral Inversion 기법을 채택한 장거리 광 전송 시스템에서의 증폭기 간격에 따른 비트 에러율)

  • Lee, Seong-Real
    • Journal of Advanced Navigation Technology
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    • v.9 no.2
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    • pp.109-120
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    • 2005
  • In this paper, bit error rate (BER) characteristics, sensitivity and minimum allowable launching power are numerically investigated as a function of amplifier spacing that consisted of 1,200 km WDM systems with MSSI method. It is conformed that the sensitivity and minimum allowable launching power are gradually degraded as amplifier spacings are gradually expanded, but those are not largely affected by modulation format. The sensitivity of RZ transmission system is smaller than that of NRZ transmission system, but minimum allowable launching power of NRZ transmission system is smaller than that of RZ transmission system. And, it is confirmed that the best amplifier spacing in NRZ and RZ transmission system is less than 50 km, because the sensitivity and minimum allowable launching power are less affected by fiber dispersion, channel wavelength and pump light power.

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Analysis for the Bit Error Probability in the PCM-NRZ/FM Telemetry System (PCM-NRZ/FM Telemetry 시스템에서 Bit 오차확률에 관한 분석)

  • 강정수
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.8 no.2
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    • pp.76-81
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    • 1983
  • PCM-NRZ/FM Telemetry system is constructed on the basis of RF link with FM modulatedand NRZ-L binary coded PCM data are assumed to transmit through 5th-order Bessel filter. Upon demodulated by the limiter-discriminator at the receiver, the probability of bit error, which is important for performance estimation of digital system, is analyzed against SNR. The analysis based on the following parameters, that is bit rate 140kHz, frequency of pre-modulation filter f-100kHz, maximum frequency deviation of transmitter 2f=300kHz, was performed. As a result, when the telemetry system with the parameters above is designed, the probability of bit error is obtained as 10 along with fT=0.7 and h=2, T=2.

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