Numerical and experimental study on the impact of chromatic dispersion on O-band direct-detection transmission.
Numerical and experimental study on the impact of chromatic dispersion on O-band direct-detection transmission.
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色散对O波段直接探测传输影响的数值和实验研究。
DOI：
10.1364/ao.424962
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发表时间：
2021
期刊：
影响因子：
1.9
通讯作者：
P. Petropoulos
中科院分区：
文献类型：
--
作者：
Yang Hong;K. Bottrill;N. Taengnoi;N. Thipparapu;Yu Wang;J. Sahu;D. Richardson;P. Petropoulos
最近出现的有效的O波段放大技术，使O波段传输的考虑超出了短距离。尽管O波段是一个低色散（CD）窗口，但当扩展直接检测（DD）系统的范围时，CD的影响将变得越来越重要。在这项工作中，我们首先数值研究了强度调制DD系统中单模光纤（SMF）的3 dB带宽和CD限制传输范围，确认了低色散和高色散O波段波长之间的显着差异。然后，我们在SMF上进行实验传输研究的距离高达70公里，在两个不同的波长，低色散1320 nm和更分散的1360 nm，使通过使用O波段掺铋光纤放大器作为接收器的放大器。我们比较了三种50 Gb/s的光DD格式，即奈奎斯特开关键控（OOK），奈奎斯特4进制脉冲幅度调制（PAM 4）和Kramers-Kronig检测辅助单边带正交相移键控（KK-QPSK）半周期副载波调制。我们的研究结果表明，在这两个波长，OOK和QPSK表现出更好的误码率性能比PAM 4。当在色散较小的1320 nm波长下传输超过70 km的SMF时，与50 Gb/s QPSK相比，50 Gb/s OOK调制在光电二极管（PD）处提供了超过1.5 dB的光功率灵敏度改进。相反，在1360 nm处，通过使用QPSK而不是OOK，可以将PD所需的光功率降低超过3 dB。
The recent emergence of efficient O-band amplification technologies has enabled the consideration of O-band transmission beyond short reach. Despite the O-band being a low chromatic dispersion (CD) window, the impact of CD will become increasingly significant when extending the reach of direct-detection (DD) systems. In this work, we first numerically investigate the 3-dB bandwidth of single-mode fibers (SMF) and the CD-restricted transmission reach in intensity-modulation DD systems, confirming the significant difference between low- and high-dispersion O-band wavelengths. We then carry out experimental transmission studies over SMF for distances of up to 70 km at two different wavelengths, the low-dispersion 1320 nm and the more dispersive 1360 nm, enabled by the use of an O-band bismuth-doped fiber amplifier as a preamplifier at the receiver. We compare three 50-Gb/s optical DD formats, namely, Nyquist on-off keying (OOK), Nyquist 4-ary pulse amplitude modulation (PAM4) and Kramers-Kronig detection-assisted single-sideband quadrature phase shift keying (KK-QPSK) half-cycle subcarrier modulation. Our results show that at both wavelengths, OOK and QPSK exhibit better bit error rate performance than PAM4. When transmitting over 70-km of SMF at the less dispersive wavelength of 1320 nm, 50-Gb/s OOK modulation offers more than 1.5-dB optical power sensitivity improvement at the photodiode (PD) compared to 50-Gb/s QPSK. Conversely, at 1360 nm, the required optical power to the PD can be reduced by more than 3 dB by using QPSK instead of OOK.