802.3ae 10 Gbit/s Ethernet Multimode Optical Fiber Introduction

The increasing requirements on network transmission capacity have promoted the further development of the 10 Gbit/s system. The IEEE Institute of Electrical and Electronics Engineers (IEEE) provides a description of the system configurations in LAN) and WAN in 802.3ae in terms of 10-bit Ethernet technical specifications.

When the transmission speed of a Multimode system driven by an LED is 622 Mbit/s, the 10Git/s system can take full advantage of the cost-effective vertical resonator Surface Emitting Laser VCSEL) diode with an 850nm working window. In order to use this VCSEL, teanchi developed a new 50/125 μm multimode optical fiber, that is, "GigaBand Yibo optical fiber )". When the standard multimode optical fiber with a diameter of 50 μm has the optimal bandwidth in the 1300nm window or in the window between 850 and 1300nm, the new optical fiber has an ideal bandwidth at the 850nm operating wavelength of VCSEL. The designed optical fiber parameters ensure that the system transmission distance is 300 meters.

Bandwidth requirements

The information carrying capacity of a single multimode optical fiber is usually determined by the mode bandwidth. Strictly speaking, the system capacity depends on the interaction between various components, such as lasers, optical fibers, and detectors. In particular, the interaction between the VCSEL signal source and the light injected into multi-mode optical fiber can affect the effective bandwidth of the system.

The latest IEC International Electrotechnical Commission) multimode optical fiber specification IEC60793-2-10 specifies a new optical fiber classification level Ala.2. In addition to bandwidth exceeding 1500 MHZ. km during full injection, this optical fiber also describes the "effective" Laser Injection bandwidth exceeding 2000 MHZ. km.

To facilitate understanding of the definition of this "valid" bandwidth, the requirements in the Specification can be interpreted as requirements for fiber-optic DMD Differential Mode Display.

The Specification defines six DMD templates, each of which consists of an internal mask and an external mask. The fiber-optic mode must meet one of the six templates listed in the following table.

Table 1: DMD template for IEC 60793-2-10 Ala.2 Multimode Optical Fiber 50/125 μm

Template No.	Inner mask (radius 5-18 μm) [Ps/m]	Inner mask (radius 0-23 μm) [Ps/m]
1	≤ 0.23	≤ 0.70
2	≤ 0.24	≤ 0.60
3	≤ 0.25	≤ 0.50
4	≤ 0.26	≤ 0.40
5	≤ 0.27	≤ 0.35
6	≤ 0.33	≤ 0.33

Standardization provision

In addition to IEC 607983 standards for Category 2 Ala.2, TIA has also standardized the optical fiber in Technical Specifications TIA/EIA-492AAAC. This type of optical fiber is also referred to as OM3 optical fiber in IEC/ISO indoor cabling 11801 standard.