title: Optical filter requirements in an EML-based single-sideband PAM4 intensity-modulation and direct-detection transmission system.
abstract: The feasibility of a single sideband (SSB) PAM4 intensity-modulation and direct-detection (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 feed-forward equalization.
authors.forename: Hsing-Yu
authors.initials: HY
authors.lastname: Chen
authors.forename: Noriaki
authors.initials: N
authors.lastname: Kaneda
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Lee
authors.forename: Jyehong
authors.initials: J
authors.lastname: Chen
authors.forename: Young-Kai
authors.initials: YK
authors.lastname: Chen