EXCLUSIVELY TO REDFERN,
FULLY ELECTRONIC FBG
WRITING SYSTEMS ALLOW US
TO OFFER HIGH DEFINITION (HD) DISPERSION COMPENSATION
MAPS THAT ARE COST EFFECTIVE AND JUST-IN-TIME DELIVERY FOR FINAL SYSTEM TRIM UP.

DISPERSION COMPENSATING FBGs

As system builders transition from 10G to 40G products, compensation of chromatic dispersion becomes a critical design consideration. As 40G deployments have accelerated through 2008 and 2009 FBG based dispersion compensation has emerged as the leading compensation technology for four key reasons;
1. Negligible system penalty
2. Very low insertion loss
3. Small footprint and
4. Very importantly today - a cost effective total compensation solution.

Redfern’s dispersion compensation products are based on a proprietary FBG writing system that is able to produce high fidelity multi channel FBGs. The system is fully electronic and free of phase mask limitations. This enables Redfern to rapidly converge to new compensation product requirements and to cost effectively produce short production runs containing a number of different product types.
In-line compensation was once only possible with DCF owing to the tough concatenation requirements involved. Redfern’s generation II dispersion compensating FBGs have the optical fidelity to meet up to eight amplifier spans whilst passing the system penalty requirements of today’s 40G formats.
The small footprint of FBG based compensation is also well suited to pre and post compensation at the line card ends. Exclusively to Redfern, fully electronic FBG writing systems allow us to offer high definition (HD) dispersion compensation maps that are cost effective and just-in-time delivery for final system trim up. Conventional fixed dispersion compensation products are offered in 20km steps, Redfern is able to offer much higher resolution steps at 2.5 and 5km. As the focus on total system cost increases, Redfern’s lower cost HD fixed compensation maps are an attractive alternative to the conventional tunable dispersion compensation approaches. When combined with the 1.5 to 2.0dB saving in insertion loss, choosing Redfern’s HD fixed compensation also adds a step improvement to the system penalty over TDCs.