NS Series ― Submarine Repeatered Systems

Key benefits

• DWDM technology enables transmission up to 100Gbps x 100 wavelengths with 10Tbps total capacity per fiber pair
• Up to 80Tbps capacity is achieved over a cable of 8 fiber pairs
• Transmission distances in excess of 12,000km for trans‐oceanic networks
• Extremely reliable submarine network over 25 years life
• Highly agile and flexible solution for growing capacity demands

Example solution

NS Series Lineup

Line Terminal Equipment T740SW

To meet the needs of transporting high‐capacity DWDM signals over transoceanic distances, specialized Line Terminal Equipment is required. This equipment provides the function of translation between the terrestrial network and the undersea network.

Key features

• Highly Dense WDM Multiplexing and Demultiplexing
• Transmission capacity of up to 10Tbps (100 wavelengths @ 100Gbps) or 7.04Tbps (176 wavelengths @ 40Gbps) per fiber pair
• Up to 80Tbps (10Tbps x 8 fiber pairs) of cross‐sectional capacity
• Various channel spacing designs (25GHz/33GHz/50GHz)
• Various and flexible tributary interfaces:
  • 100GbE, OTU4 (software switchable)
  • STM‐256, OC‐768, OTU3 (software switchable)
  • STM‐64, OC‐192, OTU2/2e, 10GbE LAN-PHY/WAN PHY (software switchable)
  • STM-16, OC-48
• Advanced soft decision forward error correction function
• Digital Coherent transponders provide automatic dispersion compensation and polarization demultiplexing
• Multiple modulation schemes available to optimize system capacity
• Simplified maintenance by plug and play scheme
• Extremely small footprint: up to 15 x 100G, 16 x 40G or 32 x 10G transponders per rack
• 100G, 40G and 10G transponders can be mixed in the same rack to optimize floor space and use of optical spectrum
• In-service upgrade without traffic interruption

T740SW with 100G Transponders

T740SW with 40G Transponders

Submarine Repeater R640SW

The NEC R640SW Submarine Repeater has been specially designed for fDWDM applications including 980nm pumped Erbium Doped Optical Amplifiers (EDFAs). This technology enables high power amplification for optimized repeater spacing, wide and flat amplification gain to allow for efficient channel packing density, and a lower noise figure which results in more capacity over longer distances with the highest reliability. Each standard repeater is designed to accommodate up to 8 amplifier systems.

Key features

Block Equalizer Q640

The Block Equalizer equalizes gain differences among channels in a long haul Dense Wavelength Division Multiplex (DWDM) system. When the DWDM signals are transmitted over a long distance, gain undulation is accumulated. The Block Equalizer has been developed to obtain flat characteristics across all wavelengths and to maintain high quality transmission in long haul DWDM systems.

• Precise equalization of accumulated gain differences between wavelengths
• Applicable to any repeater gain profile using slanted fiber grating and/or thin film filter
• Ultra pressure‐resistant housing for water depths up to 8,000m

Note:
The Q640 Block Equalizer can perform two types of equalization function: tilting and shaping, achieved using the TEQ (Tilt Equalizer) and SEQ (Shape Equalizer) respectively. Using both types of equalizer, a flat transmission line profile can be maintained, accurately compensating repeater and cable characteristics.

Branching Unit / OADM Branching Unit B640

Branching Unit (BUs) are laid underwater to branch out fiber transmission paths and power feeding paths to landing stations. The BU provides more economical solutions as well as excellent flexibility in networking with its multi‐landing capability. Three types are available: Fiber Branch BUs, Fixed OADM BUs, and Reconfigurable OADM (ROADM) BUs. All feature remote power path switching capability.

Key features

• Reliable Design for up to 8,000m water depth
• BU powering can be controlled through multiple fiber paths
• Power path is controlled by command signals even with major faults such as cable cuts
• 4-port BU available for use in special applications

Main benefits

• Flexible Add‐drop Capacity
• Robust against Cable/Fiber Failure
• ROADM BU option allows flexible in-service changes to branch capacity according to traffic demand
• End‐to‐end OADM fiber path monitoring via management system simplifies operations

Note:
The design of the optional OADM‐BU employs optical couplers and band‐pass / high‐pass / low‐pass optical filters, allowing the add/drop operation of a set of wavelengths (sub‐bands).

Power Feeding Equipment (PFE) NPF Series

PFEs located at the cable stations provide a constant electrical current to the wet plant, and energize the submersible repeaters. High, Medium and Low Voltage types of PFEs are available depending on the voltage requirements of each link.

Key features

Remote Fiber Test Equipment (RFTE) M640SW

This equipment is used to identify and isolate any faults in the wet plant, providing full visibility of both repeaters and span cable while the system is in‐service.

Key features

Management System WebNSV

WebNSV is the submarine management system to monitor and control the LTE, RFTE, PFE and their associated networks, utilizing web‐based technology. It consists of an Element Management System (WebNSV EMS) for individual station management and a Unified Management System (WebNSV UMS) for centralized system management.

WebNSV EMS Functions

• Fault Management
• Performance Monitoring
• Configuration Management
• Security Management

WebNSV UMS Functions

• Integrated Fault Management
• End‐to‐end Optical Path Management
• Power Feeding Path View and BU Control
• Single sign‐on login

Repeatered Systems ― Solution Capacity

Capacity of New Systems

Capacity Upgrades

NEC has vast experience of upgrading existing submarine cable systems to greatly increase their total capacity. The achievable final capacity is dependent on the detailed system configuration and the traffic migration requirements of the customer. Therefore NEC offers the complete range of equipmet, services and benefits, including;

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