Very shortly, 2021, HMN Technologies will complete another industry-first: a 16-fiber-pair repeatered submarine cable system connecting Hainan Island to Hong Kong. This is another milestone project that showcases both HMN’s advances in submarine cable technology reinforcing that high fiber count, large capacity Space Division Multiplexing (SDM) systems are no longer a concept, but a fast-evolving reality.


How the subsea industry meets the dramatically increasing demand?

TeleGeography research indicates global bandwidth demand continues to grow at healthy CAGR rates. Addressing this market evolution while retaining optimal system price metrics is an important goal for all system suppliers. Space Division Multiplexing (SDM) is one technology that will realize the next-generation capacity submarine systems. However, SDM systems remain constrained by legacy technology that suppliers need to overcome through further technological innovation.


What SDM system needs to revolve from the current design?

Power is one such constraint. Powering the optical amplifiers and other wet plant components of a submarine system is provided by power feeding equipment located in terminal stations and the copper conductor incorporated into the cable design.

Powering requirements of wet plant components have a correlation with the number of fiber pairs and design capacity of a submarine network. A number of solutions have been proposed to solve the increasing power demands of higher fiber count SDM systems.

SDM technology has improved systems’ power efficiency by splitting the power for one fiber pair into two or more fiber pairs. This solution mitigates the power constraints of a 15kV power feed equipment for some but not all systems. Nevertheless, it doesn’t solve the problems associated with ultra-long systems particularly as design capacity evolves to a half Petabit/s or more.

Increasing a system’s power feed equipment output is a fundamental solution to solve this problem. We believe that such technological improvement will have a profound impact on the industry, and develop an innovative solution that balances all parameters associated with the design complexities and sophistication of submarine networks.

Our R&D team has optimized the system design by reducing voltage drops across wet plant components improves the power feeding ability, but also enhances branching units’ hot switching functionality. As a result, we have pushed beyond the legacy 15kV power feed output to a greater output of 18kV.


How does this power improvement benefit the investors and owners of submarine cable networks?

The 20% improvement of power output translates into over 50% increase in system capacity by substantially increasing the fiber pairs in long-haul transoceanic systems.

For example, 18kV can support a 16 fiber-pair trans-Pacific system resulting in a significant 300Tbit/s capacity increase, lowering the cost per Tbit/s economics. Likewise, 18kV can support a 6,000km trans-Atlantic system of 32 fiber pairs providing system transmission capacity to an eye-watering 700Tbit/s. This corresponding capacity increases lower the cost per Terabyte metrics and enables a significantly greater return on investment potential.

Another notable benefit is the capability to improve reliability by extending single-end system power feeding distance; a key requirement when a system is under fault conditions or during system maintenance operations. In parallel, our cable and optical amplifier designs have been qualified to 20kV facilitating a roadmap for future technological advancements.

The evolution of power feed capability entering this new era is widely recognized by industry experts and investors. At HMN Technologies, we recognize continuous innovation allows our customers greater choice, functionality, and reliability to address the escalating demand for system capacity and global connectivity.