Browsing by Author "Lee, Jeffrey"

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Comparison of VSB PAM4 and OOK Signal in an EML-Based 80-km Transmission System
(2017-12-01)
Chen, Hsing-Yu
;
Lee, Jeffrey
;
Kaneda, Noriaki
;
Chen, Jyehong
;
Chen, Young-Kai
A comparison between 51.84-Gb/s vestigial sideband 4-level pulse amplitude modulation (PAM4) and ON-OFF keying (OOK) signals at a transmission distance of 80 km is experimentally demonstrated for the first time. An electro-absorption modulated laser-based intensity-modulation and direct-detection 80-km transmission is achieved using both modulation formats without dispersion compensating fiber. The relative frequency between single sideband filter and signal is adjusted to find an optimized condition for both carrier to signal power ratio and sideband suppression ratio. The experimental results show that with linear equalization and without bandwidth limitation, the OOK signal has a 4-dB better sensitivity compared with PAM4 after 80-km standard single-mode fiber transmission.
Optical filter requirements in an EML-based single-sideband PAM4 intensity-modulation and direct-detection transmission system
(2017-03-20)
Chen, Hsing-Yu
;
Kaneda, Noriaki
;
Lee, Jeffrey
;
Chen, Jyehong
;
Chen, Young-Kai
The feasibility of a single sideband (SSB) PAM4 intensity-modulation and directdetection (IM/DD) transmission based on a CMOS ADC and DAC is experimentally demonstrated in this work. To cost effectively build a >50 Gb/s system as well as to extend the transmission distance, a low cost EML and a passive optical filter are utilized to generate the SSB signal. However, the EML-induced chirp and dispersion-induced power fading limit the requirements of the SSB filter. To separate the effect of signal-signal beating interference, filters with different roll-off factors are employed to demonstrate the performance tolerance at different transmission distance. Moreover, a high resolution spectrum analysis is proposed to depict the system limitation. Experimental results show that a minimum roll-off factor of 7 dB/10GHz is required to achieve a 51.84Gb/s 40-km transmission with only linear feedforward equalization. (C) 2017 Optical Society of America