Temperature and Noise Dependence of Tri-Mode VCSEL Carried 120-Gbit/s QAM-OFDM Data in Back-to-Back and OM5-MMF Links

The transmission performances of the tri-mode vertical cavity surface-emitting laser (VCSEL) carrying 16-quadrature amplitude modulation orthogonal frequency division multiplexing (16-QAM OFDM) data streams at a data rate beyond 100 Gbit/s are demonstrated in OM5 and OM4 multi-mode fibers (MMFs) over 100 m. By using the double oxide-confined aperture with a diameter of 5 μm, the tri-mode VCSEL provides three main transverse modes at a power of 2 mW and a quantum efficiency of 0.4 mW/mA, in which these main transverse modes individually contribute to 53.1%, 37.6%, and 9.3% of the output power from the tri-mode VCSEL for delivering the QAM-OFDM data. With optimizing the bias current of the tri-mode VCSEL to 8 mA (32 Ith) and pre-leveling the QAM-OFDM subcarrier amplitudes at a slope of 0.5 dB/GHz in the back-to-back (BtB) transmission case, the raw data rate up to 120 Gbit/s can be achieved under the FEC receiving criterion. In particular, the performance of the tri-mode VCSEL operating at the temperature of up to 85°C in BtB case is also demonstrated, while its lasing spectrum translates from tri-mode to quasi-single-mode because of the heating induced carrier dissipation and index reprofiling process. After propagating through the 100-m OM5-MMF, the pre-leveled 16-QAM OFDM data carried by the tri-mode VCSEL guarantees the 104-Gbit/s FEC-certified transmission with a receiving power penalty of 3.8 dB.