OM2 / OM3 / OM4

With each passing year demand for higher data rates in data center environments grow. More and more sophisticated equipment is introduced into the marketplace and more users need access to data center services. Today, we are able to transmit data within the data center at 10 Gig / second using multimode fiber.

While this seems like an enormous transmission rate, user demand will catch up with it fairly quickly. Thankfully technologies are emerging that will allow transfer rates of up to 100 Gig / second in the data center. Also on the horizon are 10 Gig / second data rates to the desktop. As demand for service grows so must the transmission standard. These new increased data rates will require cleaner signals for transmission of laser pulses on multimode fiber.

Introduction of Laser Optimized Fiber

Standard, Non-Laser Optimized Multimode fiber, typically is manufactured with an optical defect in the center of the core. While this defect is not detrimental to the transmission of light emitted by LED's, coherent light emitted by lasers is greatly affected. In order to efficiently transmit laser light through multimode cable one must use a mode conditioning cable. These costly patch cables offset the launch of the laser to avoid the center defect. In the early 2000's optical fiber manufactures began producing fiber without the center defect… Laser Optimized Multimode Fiber was born. OM3 was the first standard to emerge, codifying laser optimization of multimode fiber. This technology was the first to allow designs of laser transmission systems utilizing multimode optical fiber without the use of mode conditioning cables. This new fiber when paired with new low cost Vertical-cavity surface-emitting laser technology allowed for 10 Gig transmission.

OM3 vs OM4

OM4 fiber has been on the market since 2005, sold as premium OM3 or OM3+ fiber. The OM4 designation standardizes the nomenclature across all manufacturers so that the customer has a clearer idea of the product that they are buying. OM4 is completely backwards compatible with OM3 fiber and shares the same distinctive aqua jacket. OM4 was developed specifically for VSCEL laser transmission and allows 10 Gig / second link distances of up to 550 Meters (compared to 300M with OM3).

The effective modal bandwidth for OM4 is more than double that of OM3 (4700 MHz.km for OM4 v/s 2000 MHz.km for OM3).

While OM3 fiber will still be future proof in most applications, allowing speeds of 10GB/s up to 100GB/s, OM4 fiber offers users longer length distances and more wiggle room in optical budgets