Fortress Group has entered the in-line amplifier (ILA) market with the NextGen Smart ILA, a modular platform the company says will let network operators deploy amplifier sites faster along long-haul fiber routes.

The Boston-based digital infrastructure company announced the offering recently. ILA sites function as small network points of presence along long-haul routes. Prefabricated modules provide space, power, and cooling for the inline amplifier hardware used in DWDM systems, repeating signals every 80–100 km (50–62 miles) of fiber.

Long-haul fiber operators each run hundreds or even thousands of these modules across their networks. With many operators building new fiber to serve AI data center demand, the number of ILAs is growing considerably.

First model: low-density

The first product is the low-density (LD) module, designed to support optical transport equipment such as the Ciena 6500 RLS. The LD configuration supports 144–288 fibers. Each module delivers ten relay racks within an 8ft × 40ft (2m × 12m) ISO container footprint with independent N+1 cooling. An LD-only cluster can offer approximately 83.5kW of facility load.

Fortress is also developing a high-density (HD) module designed to support up to 864 fibers, alongside six standard configurations that combine HD and LD modules according to site requirements. The HD module will offer rear-door heat-exchanger cooling and a dedicated high-density fiber-management frame, which the company says will host "dramatically more" fiber in the same on-site footprint.

Across the platform, configurations scale from approximately 83.5kW to 406kW of facility load, with two standard utility packages covering the full range.

Rising rack densities

Rack densities at ILAs remain far below those of regular data centers, with networking gear often in the single-digit kilowatt range. Early designs supported around 600–800W per rack. Today's racks typically draw 2–4kW.

That is changing. As operators approach the upper limit of how much data a single fiber can carry, companies are pushing more fiber pairs, which drives rack densities into the low double-digit kilowatts. Future designs are expected to reach 5–6kW, and up to 12kW per cabinet for high-density hyperscaler deployments.

These figures remain lower than many compute racks. But traditional ILA designs have stayed largely unchanged for decades and were never intended to host such densities. Many companies are now reworking their approach to ILAs to fit more fiber into the same footprint.

Fortress also develops Edge data center modules and satellite ground station sites.