Lesson Plan

• Explain the principle of total internal reflection and its role in guiding light within an optical fibre.
• Distinguish between single‑mode and multi‑mode fibres and identify appropriate applications.
• Compare optical fibres with copper cables regarding attenuation, bandwidth, distance, and EMI immunity.
• Interpret a cross‑section diagram of an optical fibre and label its core, cladding, and jacket.
• Evaluate why optical fibres are the preferred medium for modern telecommunications networks.

• Projector or interactive whiteboard
• Slides with diagrams of fibre structure and Snell’s law
• Handout summarising fibre types and comparison table
• Sample optical fibre (or video demonstration)
• Worksheet with critical‑angle calculations and short‑answer questions
• Clickers or online quiz platform for quick checks

Begin with a striking image of a global data network and ask students how such massive amounts of information travel so quickly. Recall their prior knowledge of refraction and ask them to predict how light could be “trapped” inside a thin strand. State that by the end of the lesson they will be able to describe why optical fibres dominate modern telecommunications.

1. Do‑now (5’) – Students calculate the critical angle for a given pair of refractive indices (n₁ = 1.48, n₂ = 1.46) on a worksheet.
2. Mini‑lecture (10’) – Explain total internal reflection, present Snell’s law, and show a cross‑section diagram of an optical fibre.
3. Guided inquiry (10’) – Using a provided comparison table, students discuss the differences between single‑mode and multi‑mode fibres and their typical telecom uses.
4. Demonstration/video (5’) – Show a short video of light traveling through a fibre cable, highlighting low attenuation.
5. Group activity (10’) – Teams create a quick infographic comparing optical fibre with copper cable (bandwidth, loss, EMI, cost) and present one key advantage.
6. Formative check (5’) – Clicker quiz on the benefits and applications of optical fibres.
7. Summary & exit ticket (5’) – Students write one benefit of fibre optics and one real‑world scenario where it is essential; collect for assessment.

Review the core concepts: total internal reflection, fibre structure, and why fibres outperform copper in bandwidth and distance. Collect the exit tickets as a quick retrieval check. For homework, assign a short research task: students find a recent news article describing a new fibre‑optic deployment and summarise its impact.