Issue link: https://www.epageflip.net/i/1043933
24 I ICT TODAY OM5 multimode fiber and cable standards are fully mature and complete. TIA completed fiber standard TIA-492AAAE in June 2016, and IEC published IEC 60793-2-10 in August 2017. TIA published its structured cabling standard, ANSI/TIA-568.3-D, in October 2016, and ISO/IEC published ISO/IEC 11801-1 in October 2017. The 11801 standard defines the OM5 designation for multimode wideband fiber. That designation will also be included, with reference to 11801, in future TIA and IEC fiber standards. Equipment Trends Follow Suit What equipment can be used with OM5 multimode fiber? Table 3 shows currently available short wavelength division multiplexing (SWDM) transceivers, along with one announced solution. It is clear that, while OM3 and OM4 still support short-reach applications, OM5 gives added reach to the full range of applications. The first widely deployed application for OM5 fiber was 40 Gb/s bidirectional (BiDi) transceivers. Duplex (BiDi and SWDM4) 40 Gb/s links are widely deployed; as 100 Gb/s solutions become more commonplace, similar trends can be expected in that space. The introduction of an extended-reach SWDM (eSWDM4) solution will further expand the market for multimode fiber with its ability to support 400-m duplex 100 Gb/s links. To encourage these developments, an SWDM alliance was formed in 2015. This industry-based organization, which includes OFS and other optical fiber and cable suppliers as well as transceiver and switching equipment suppliers, was created to promote the use of SWDM technology for short-reach applications. An SWDM multi-source agreement (MSA) has also been created to develop interoperable SWDM devices. Specifications for both 40 Gb/s and 100 Gb/s transceivers were released and are available on the swdm.org website. Recently, a 400 Gb/s BiDi MSA was announced. This MSA will continue to build on the advantages of multi-wavelength solutions with a four-pair 400 Gb/s link. The goals of this MSA include the development of a specification that will support up links up to 150 m over OM5 fiber. It should be pointed out that these are not standards-based solutions; they are either MSA-based or proprietary offerings from switch and/or transceiver suppliers. However, the transceivers do fit into the standard quad small form-factor pluggable (QSFP+ or QSFP28) footprint, and as long as they are paired with a like transceiver, no problems should be encountered. While these applications can operate over legacy OM3 and OM4 fiber, OM5 fiber offers a significant reach advantage over the older fiber types. New Developments in Multimode Signal Transmission Another technical achievement not tied specifically to wideband transmission is the use of four-level pulse amplitude modulation (PAM-4) signaling, which is a more complex signaling method than the simple TABLE 3: LC Duplex SWDM transceivers (non-standards based). Link Distance (m) Speed (Gb/s) Transceiver Form Factor λ OM3 OM4 OM5 40 BiDi QSFP+ 2 100 150 200 40 SWDM4 QSFP+ 4 240 350 440 100 BiDi QSFP28 2 70 100 150 100 SWDM4 QSFP28 4 75 100 150 100 eSWDM4 QSFP28 4 200 300 400