We have proposed and demonstrated the optical time-and-polarization interleaving (OTPI) technique, which can effectively extend the transmitter bandwidth for an intensity modulation and direct detection (IM/DD) optical system. The 224-Gbit/s line-rate OTPI-PAM-4 signal is successfully transmitted over a 500-m standard single-mode fiber (SSMF) in the C band, using the transmitter with a bandwidth of 25 GHz and the receiver with a single photodiode. By using a 33%-return-to-zero (RZ) pulse train, a bit-error ratio (BER) below 7% hard-decision forward error correction (HD-FEC) threshold is achieved. BER below 20% soft-decision forward error correction (SD-FEC) threshold is also realized using a carrier suppressed return-to-zero (CSRZ) pulse train. The OTPI technique can also be used for more higher-order pulse amplitude modulation (PAM) formats, making it a promising technique for next-generation high-speed optical interconnects.

中文翻译：

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224 Gbps单光电二极管PAM-4传输，具有基于光学时间和偏振交织的扩展发射器带宽。

我们已经提出并演示了光时极化交织（OTPI）技术，该技术可以有效地扩展强度调制和直接检测（IM / DD）光学系统的发射机带宽。使用带宽为25 GHz的发送器和带宽为25 GHz的接收器，可以在C波段通过500-m标准单模光纤（SSMF）成功发送224 Gbit / s线速OTPI-PAM-4信号。单光电二极管。通过使用33％归零（RZ）脉冲序列，可实现低于7％硬判决前向纠错（HD-FEC）阈值的误码率（BER）。还可以使用载波抑制的归零（CSRZ）脉冲序列来实现低于20％软判决前向纠错（SD-FEC）阈值的BER。OTPI技术还可用于更高级的脉冲幅度调制（PAM）格式，