Optical modules do not have storage in gigabytes; they are high-speed transceivers that transmit data at rates like 400G, 800G, or 1.6T per second.

Understanding Optical Modules

An optical module is a hot-pluggable device used in fiber-optic communication to convert electrical signals into optical signals and vice versa, enabling high-bandwidth data transmission between devices such as servers, switches, and GPUs . Unlike storage devices, optical modules do not store data; they transmit it in real time over fiber optic cables.

Data Transmission Rates

Optical modules are classified by their bandwidth, not storage capacity:

• 400G modules: Common in enterprise and hyperscale networks, providing 400 gigabits per second (Gb/s) of throughput .
• 800G modules: Emerging standard for AI clusters and high-density data centers, offering 800 Gb/s and improved power efficiency .
• 1.6T modules: Early deployment in AI-scale data centers, capable of 1.6 terabits per second (Tb/s) transmission . For example, in NVIDIA GPU clusters, each H100 GPU may require multiple optical modules to achieve full interconnect bandwidth, with 400G or 800G modules used depending on the network architecture .

Key Performance Metrics

Optical modules are measured by:

• Transmit and receive power (in mW or dBm)
• Bit error rate (BER)
• Supported wavelengths (850 nm, 1310 nm, 1550 nm)
• Electrical and optical interface standards (e.g., QSFP-DD, OSFP, 100GBASE-LR4), These metrics determine the speed, reliability, and reach of data transmission rather than storage capacity.

Summary

Optical modules do not have gigabytes of storage. Their "capacity" is expressed in data rate per second, such as 400G, 800G, or 1.6T, which defines how much data they can transmit over a network in real time. For high-performance computing or AI clusters, multiple modules are used to scale bandwidth across GPUs and servers .