A Record 1-km MMF NRZ 25.78-Gb/s Error-Free Link Using a 1060-nm DIC VCSEL

We report successful achievement of a record long distance error-free transmission of 1000-m 50-
$\mu \text{m}$
-core multi-mode fiber (MMF) in a non-return-to-zero 25.78-Gb/s modulated vertical cavity surface emitting laser-based optical link using four-channel miniature parallel-optical modules. The optical power is centralized within the core of MMF by an active alignment assembly. The restricted launch condition gives a very high effective modal bandwidth (EMB) of >9 GHz
$\cdot $
km based on the calculations and the required performance data specified in TIA-FOTP-220. An EMB of 11.5 GHz
$\cdot $
km provides a very good agreement between the calculated and measured power penalty characteristics. Such a long distance low-cost MMF link, operating at 1060-nm wavelength is potentially an alternative solution to PSM4.