Multiterabit Transmission Over OM2 Multimode Fiber With Wavelength and Mode Group Multiplexing and Direct Detection

In this paper, 5 Tb/s bidirectional transmission (2.5 Tb/s in each direction) over 2.2 km of OM2 fiber is demonstrated using selective excitation of four mode groups, wavelength division multiplexing, and direct detection. Twenty wavelengths per mode group are used, each wavelength is modulated using discrete multitone scheme with 1024 subcarriers with external lithium niobate Mach–Zehnder modulator (MZM). A minimum bit rate of 68.8 Gb/s per channel is obtained for a bit error rate of 3.8 × 10
⁻²
using a 65 Gs/s digital to analog converter (DAC). Same bit rate is achieved over 4.4 km using 88 Gs/s DAC. Electroabsorption modulated laser (EML) with a 3 dB bandwidth of 18 GHz is also used in the same mode group division transmission. 1 dB power penalty is measured with the EML compared to MZM. A minimum of channel bit rate of 68.5 Gb/s over 2.2 km of OM2 fiber with the EML and 88 Gs/s DAC is reported. Therefore, we demonstrate the transmission of the same throughput over multimode fiber using a low-cost EML instead of an external MZM.