During September 1997, it was demonstrated that technical issues remained to be solved to achieve the targeted Gigabit Ethernet multimode fibre (MMF) operating distances for type 1000BASE-LX (Long Wavelength Laser) and for type 1000BASE-SX (Short Wavelength Laser). The issues were related to the use of laser sources with multimode fibre. At that time, jitter measurements demonstrated eye-closure not accounted for by the link model used to calculate operating distances. The additional jitter contributions not accounted for in the link model were attributed to the affect of a source mode power distribution (MPD) and fibre differential mode delay (DMD). This paper provides an overview of the DMD related jitter contribution and addresses specific areas of analysis related to the development of the Gigabit Ethernet fibre optic specifications.
