All-Optical Wavelength-Shift-Free NRZ-DPSK to RZ-DPSK Format Conversion with Pulsewidth Tunability by an SOA-Based Switch
All-Optical Wavelength-Shift-Free NRZ-DPSK to RZ-DPSK Format Conversion with Pulsewidth Tunability by an SOA-Based Switch
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DOI：
10.1587/transele.e97.c.755
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发表时间：
2014-07
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影响因子：
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通讯作者：
G. M. Sharif;Q. Nguyen-The;M. Matsuura;N. Kishi
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文献类型：
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作者：
G. M. Sharif;Q. Nguyen-The;M. Matsuura;N. Kishi
利用基于半导体光放大器（SOA）的开关实现了非归零差分相移键控（NRZ-DPSK）到归零差分相移键控（RZ-DPSK）的全光格式转换，该转换具有无波长偏移和脉宽可调的特点。利用RZ时钟将NRZ-DPSK信号注入SOA开关，利用SOA内部的非线性效应将NRZ-DPSK信号转换为RZ-DPSK信号。在该方案中，在格式转换期间，转换后的RZ-DPSK信号的波长保持为输入NRZ-DPSK信号的原始波长。此外，转换信号的脉宽在30至60 ps的较宽工作范围内可调。具有脉宽可调谐性的格式转换基于SOA中的交叉相位调制（XPM）和交叉增益调制（XGM）效应。清晰的眼图、光谱和误码率（BER）特性显示了高的转换性能和宽的脉宽调谐范围。对于具有不同脉冲宽度的转换的RZ-DPSK信号的所有情况，转换的RZ-DPSK信号在BER为10 - 9时的接收器灵敏度比输入的NRZ-DPSK信号的接收器灵敏度高0.7至1.5dB。关键词：差分相移键控（DPSK），格式转换，无波长偏移，脉宽可调操作，交叉相位调制（XPM），交叉增益调制（XGM）
We demonstrate an all-optical non-return-to-zero differential phase shift keying (NRZ-DPSK) to return-to-zero differential phase shift keying (RZ-DPSK) format conversion with wavelength-shift-free and pulsewidth tunable operations by using a semiconductor optical amplifier (SOA)-based switch. An NRZ-DPSK signal is injected into the SOA-based switch with an RZ clock, and is converted to RZ-DPSK signal owing to the nonlinear effects inside the SOA. In this scheme, the wavelength of the converted RZ-DPSK signal is maintained as the original wavelength of the input NRZ-DPSK signal during the format conversion. Moreover, the pulsewidth of the converted signal is tunable in a wider operating range from 30 to 60 ps. The format conversion with pulsewidth tunability is based on cross-phase modulation (XPM) and cross-gain modulation (XGM) effects in the SOA. The clear eye diagrams, optical spectra and the bit-errorrate (BER) characteristics show high conversion performance with the wide pulsewidth tuning range. For all cases of the converted RZ-DPSK signal with different pulsewidths, the receiver sensitivities at a BER of 10−9 for the converted RZ-DPSK signal were 0.7 to 1.5 dB higher than the receiver sensitivity of the input NRZ-DPSK signal. key words: Differential phase shift keying (DPSK), format conversion, wavelength-shift-free, pulsewidth tunable operation, cross-phase modulation (XPM), cross-gain modulation (XGM)