Single-core optical cable throughput capacity

A single-core (single-mode) optical fiber can theoretically support hundreds of terabits per second, with practical commercial systems achieving 100–400 Gbps per channel.

Core Characteristics

Single-mode fibers have a core diameter of approximately 9 microns, allowing light to travel in a single path, which minimizes dispersion and signal loss over long distances . They operate at standard wavelengths of 1310 nm and 1550 nm, with low attenuation (0.3–0.4 dB/km), making them ideal for long-haul and high-speed networks . OS1 fibers are typically used for shorter distances (up to 10 km at 10 Gbps), while OS2 fibers support longer spans (up to 40 km at 10 Gbps) without amplification .

Bandwidth and Throughput

The bandwidth of single-mode fiber is extremely high. Theoretical limits exceed 100 THz, and modern commercial systems can achieve up to 800 Gbps per wavelength using advanced transceivers . Experimental setups using wavelength-division multiplexing (WDM) and advanced modulation techniques have reached 402 Tbps over a single fiber . Practical deployments, such as submarine cables, typically operate at 15–20 Tbps per fiber pair, while enterprise networks commonly achieve 100–400 Gbps per channel .

Factors Affecting Throughput

1. Distance and Attenuation: Signal strength decreases over long distances, requiring optical amplifiers or repeaters to maintain high throughput .
2. Terminal Equipment: The maximum data rate is limited by lasers, receivers, and optical transponders rather than the fiber itself .
3. Multiplexing Techniques: WDM allows multiple wavelengths to transmit simultaneously, multiplying the effective throughput of a single fiber strand .
4. Signal Modulation: Advanced modulation formats (e.g., QAM, coherent detection) increase the amount of data per wavelength .

Practical Implications

For consumer-grade connections, single-mode fiber typically delivers up to 10 Gbps per user. In data centers and enterprise networks, throughput ranges from 100 to 400 Gbps per channel, while long-haul and submarine systems can handle tens of terabits per second . The fiber itself has near-limitless potential, but real-world throughput is constrained by equipment, distance, and network design considerations. In summary, single-core optical fibers offer extremely high theoretical and practical throughput, with modern technologies enabling multi-terabit capacities over long distances, making them the backbone of high-speed telecommunications and data networks .