connectix
OM4 Standardisation Gathers Pace
News : November 21, 2008
Since the turn of the century OM3 fibre has been specified as the optical multimode fibre optimised for use with VCSEL laser transmission as seen in gigabit and ten gigabit Ethernet along with some other high speed LANs/SANs such as Fibre Channel.
Almost as soon as it was standardised (in ISO 11801:2002) fibre manufacturers realised they could do even better. OM3 fibre offers a huge bandwidth, 2000 MHz.km, when used with 850 nm VCSEL lasers and does not suffer from the so-called modal dispersion problems of older multimode fibres now known as OM1 and OM2.
These older fibres have a poor and sometimes unpredictable performance when used with laser transmission devices, principally because they were designed in the days of Light Emitting Diodes powering LANs at 10 or 100 Mb/s.
It became clear by field experience that the older fibres were reacting in a different way when either LED or laser derived light was being injected into them.
Hence the need for OM3, a fibre that is guaranteed to work with laser transmission, and this fibre guarantees 300 metres transmission distance when coupled with the 10GBASE-SR ten gigabit driver card. This is now the most popular high speed LAN protocol used in the data centre environment.
Even with the large bandwidth on offer with OM3 the 300 m limitation is still down to the restrictions of bandwidth; a larger bandwidth could allow transmission even further. A range of improved optical fibres has come about offering a performance of 4700 MHz.km. This should allow ten gigabit Ethernet transmission up to 550 m. It also opens the door to other high speed protocols of the future such as 40 and 100 Gb/s Ethernet.
In November 2008 the TR42 committee of the TIA reported to the IEEE that a draft ballot had been put out to members to formalise the OM4 standard around 4700 MHz.km bandwidth and work now continues between the TIA, IEEE, ISO and IEC to complete the specification in 2009.
Premium grade OM3 optical fibre meeting the proposed OM4 specification is now available in Connectix fibre optic cables.
These older fibres have a poor and sometimes unpredictable performance when used with laser transmission devices, principally because they were designed in the days of Light Emitting Diodes powering LANs at 10 or 100 Mb/s.
It became clear by field experience that the older fibres were reacting in a different way when either LED or laser derived light was being injected into them.
Hence the need for OM3, a fibre that is guaranteed to work with laser transmission, and this fibre guarantees 300 metres transmission distance when coupled with the 10GBASE-SR ten gigabit driver card. This is now the most popular high speed LAN protocol used in the data centre environment.
Even with the large bandwidth on offer with OM3 the 300 m limitation is still down to the restrictions of bandwidth; a larger bandwidth could allow transmission even further. A range of improved optical fibres has come about offering a performance of 4700 MHz.km. This should allow ten gigabit Ethernet transmission up to 550 m. It also opens the door to other high speed protocols of the future such as 40 and 100 Gb/s Ethernet.
In November 2008 the TR42 committee of the TIA reported to the IEEE that a draft ballot had been put out to members to formalise the OM4 standard around 4700 MHz.km bandwidth and work now continues between the TIA, IEEE, ISO and IEC to complete the specification in 2009.
Premium grade OM3 optical fibre meeting the proposed OM4 specification is now available in Connectix fibre optic cables.
