40 km amplifier-less transmission of single wavelength 90 Gbps four-level pulse amplitude modulation signals enabled by an ultrabroadband directly modulated laser.

Abstract

An ultrabroadband, high linearity directly modulated laser (DML) module operated at the O-band is proposed. The effect of the package network on the DML module is first investigated. In the package network, a wire bonding compensation method is used to improve the resonance at high frequency, which can be equivalent to the channel equalization technique. Without any optical amplification, we experimentally demonstrated 90Gb/s four-level pulse amplitude modulation transmission over 40km standard single mode fiber, which is the longest reach to the best of our knowledge. A bit error rate of 6.74×10-4 is achieved at a received optical power of -2.5 dBm. A receiver sensitivity of -4.5 dBm at 7% overhead forward error correction limit (3.8×10-3) is obtained for back-to-back with a power margin of more than 8.5dB.