- Gerd Keiser, Optical Fiber Communications. The standard textbook. Comprehensive, clear, fifth edition is current.
- Govind Agrawal, Fiber-Optic Communication Systems. Mathematical and modern. Especially strong on coherent and nonlinear effects.
- John Senior, Optical Fiber Communications: Principles and Practice. Excellent introductory pacing.
- Saleh and Teich, Photonics. Broader than just communications. Covers lasers, modulators, and quantum optics in a unified way.
- Govind Agrawal, Nonlinear Fiber Optics. Deeper dive into the physics of high-power propagation.
- Cisco's annual Visual Networking Index and TeleGeography's submarine cable map for geography of deployed fiber.
- DSP for Optical Communications Systems (Savory et al., various papers). Open-access primer on coherent DSP architecture.
- Andrew Ellis et al., The Capacity of Fiber-Optic Communications for the open question of how much more we can squeeze out of a single fiber.
The next chapter pivots from communication links to the systems that consume them: networks, protocols, and the digital infrastructure that puts the bits to work.