Fiber Optic Fundamentals

Prepared for The Handbook of Fiber Optic Data Communication

Third Edition

Dr. Casimer DeCusatisIBM Corporation

Key Concepts

• Brief History of Optical Fiber Technology

• Multimode and Single-mode Fiber

• Basic Fiber Optic Link Concepts and Applications to the Computer Industry

Optical fiber vs Copper

Challenges: Connectivity and Interoperability

ElectricalConnector Electrical

Connector

Transceiver

Transceiver

Fiber Optic Cable

OpticalConnector

OpticalConnector

OpticalPort

OpticalPort

Newer technologies involving higher datarates, smaller form factors, higher port densities, pluggability, and parallel links are

showing an increased need to focus on connectivity and interoperability issues

A failure anywhere along this link will cause the entire link to fail

Conclusions

• Historically, the fundamental concepts of fiber optics date back to 1927

• Multimode fibers use a core diameter of either 50 or 62.5 microns– Short wavelength lasers– Shorter distances (few hundred meters)

• Single-mode fibers use a core diameter of 9-10 microns– Long wavelength lasers– Longer distances (several kilometers)

• A basic link is composed of optical transceivers, cables, and connectors

• Fiber optics is widely used for both voice and data communication, and is gradually becoming a more fundamental part of future computer architectures