Yiguang Wang

Transmission of a 120-GBd PM-NRZ Signal Using a Monolithic Double-Side EML

A 120-GBd polarization multiplexed NRZ (PMNRZ) signal is generated using a monolithic double side electroabsorption modulated distributed feedback (DFB) laser. Using a pre-amplified direct detection receiver and direct detection faster than Nyquist technique, the optical receiver sensitivities of -18.3 and -13.5 dBm are obtained for a 240-Gb/s (a net data rate of 200 Gb/s with 20% soft-decision forward error correction) PM-NRZ signal at back-to-back and after 2-km transmission, respectively. To the best of our knowledge, this is the highest baud rate transmission reported to date for single channel polarization multiplexed signal generated by a single device for short reach applications and the longest transmission distance (2 km) at baud-rate >100 GBd IM/DD system without CD compensation at 1.55 μm.

Experimental demonstration of 608Gbit/s short reach transmission employing half-cycle 16QAM Nyquist-SCM signal and direct detection with 25Gbps EML.

In this paper, we experimentally demonstrated an IM/DD short reach transmission system with a total capacity of 608Gbit/s (net capacity of 565.4Gbit/s exclude 7% FEC overhead) employing half-cycle 16QAM Nyquist-SCM signal and 25Gbps EML at O band. Direct detection-faster than Nyquist (DD-FTN) technique was employed to compensate channel impairments. Number of taps of DD-LMS and tap coefficient of post filter in DD-FTN were experimentally studied for different baud rates. Single-lane 152Gbit/s transmission over 10km of SSMF was experimentally demonstrated. Employing a 4-lanes LAN-WDM architecture, a total capacity of 608Gbit/s transmission over 2km was successfully achieved with a receiver sensitivity lower than -4dBm. To the best of authors knowledge, this is the highest reported baud rate of half-cycle 16QAM Nyquist-SCM signal and the highest bit rate employing IM/DD and 25Gbps EML in a four lanes LAN-WDM architecture for short reach systems in the O band.

112-Gbit/s PDM-PAM4 transmission over 80-km SMF using digital coherent detection without optical amplifier

In this work, we experimentally demonstrated a 112 Gbit/s polarization-division-multiplexed (PDM) four-level pulse amplitude modulation (PAM4) transmission over 80-km single mode fiber (SMF) using digital coherent detection without optical amplifier and CD compensation for the short reach applications. Here, a signal-phase aided least-mean-square (SP-LMS) equalization algorithm is proposed to avoid the effects of carrier frequency offset and phase noise. Without additional carrier recovery algorithms, the PDM-PAM4 system shows good transmission performance. The received optical power (ROP) penalty is only about 0.2 dB after 80 km transmission comparing to back-to-back (BTB) transmission. A receiver sensitivity of -20dBm (at 7% FEC limit) can be reached after 80-km transmission.

112 Gb/s transmission over 80 km SSMF using PDM-PAM4 and coherent detection without optical amplifier.

Polarization-division-multiplexed (PDM) four-level pulse amplitude modulation (PAM4) with coherent detection is a promising low cost solution for 80 km inter-datacenter transmissions at 100 Gb/s and beyond. In this paper, three modified adaptive equalization algorithms for the PDM-PAM4 optical coherent systems, i.e. signal-phase aid least-mean-square (SP-LMS) algorithm, training multi-modulus algorithm (TMMA) and cascaded four-modulus algorithm (CMMA-4), are proposed and compared. Based on the proposed algorithms, 112 Gb/s PDM-PAM4 transmission over 80 km standard single mode fiber (SSMF) in C-band for a bit error rate (BER) below 3.8e-3 is successfully demonstrated without optical amplifier, chromatic dispersion (CD) pre-compensation and extra carrier recovery operations.

Recent Advances for High Speed Data Center Inter-connects

In this paper, we review recent advances on optical short reach transmission systems for data center inter-connects. Recent progress from our group on high-speed short reach transmission systems is summarized.