ANSWERS TO QUESTIONS Q1. THROUGH Q35.

A1. Refractive index profile describes the value of refractive index as a function of radial distance at any fiber diameter.
A2. Step-index.
A3. Multimode graded-index fiber.
A4. Multimode step-index fibers: 50 μm and 100 μm. Multimode graded-index fibers: 50 μm, 62.5 μm, 85 μm, and 100 μm. Single mode fibers: between 8 μm and 10 μm.
A5. Cladding.
A6. Most modes in multimode step-index fibers propagate far from cutoff.
A7. Make it easier to couple light from a light-emitting diode (LED) into the fiber.
A8. From a triangular shape to step.
A9. When the angle of incidence becomes larger than the critical angle of incidence.
A10. Numerical aperture (NA), relative refractive index difference (Δ), profile parameter (α), and normalized frequency (V).
A11. Decreases the time difference between light rays, which reduces modal dispersion and increases fiber bandwidth.
A12. 62.5/125 μm multimode graded-index fiber.
A13. Source-to-fiber coupling efficiency and insensitivity to microbending and macrobending losses.
A14. Coupling efficiency increases with both core diameter and Δ, while bending losses increase directly with core diameter and inversely with Δ.
A15. Smaller.
A16. Matched-clad and depressed-clad.
A17. Depressed.
A18. Cladding material.

A19. The fundamental mode becomes increasingly lossy.
A20. To increase performance and reduce losses caused by bending and splicing.
A21. To increase performance and reduce cost.
A22. High NA, low bandwidth, tight bend radius, short length, and low cost.
A23. Heavy-metal fluorides, chalcogenide glasses, and crystalline materials.
A24. Vapor phase oxidation and direct-melt process.
A25. Vapor phase oxidation.
A26.

• Protect optical fibers from damage or breakage during installation and over the fiber's lifetime.
• Provide stable fiber transmission characteristics compared with uncabled fibers.
• Maintain the physical integrity of the optical fiber.

A27. To provide additional mechanical protection and preserve the fiber's inherent strength.
A28. Tight-buffered, loose-tube, and gel-filled loose-tube.
A29. Low smoke generation, low toxicity, low halogen content, flame retardance, fluid resistance, high abrasion resistance, and stable performance over temperature.
A30. Optical fiber cable component (OFCC), stranded, and ribbon cables designs.
A31. OFCCs are tight-buffer fiber surrounded by arimid yarn and a low-halogen outer jacket.
A32. To minimize microbending of the fibers.
A33. To minimize fiber stress when the cable is bent.
A34. OFCC (12 fibers), stranded (48 fibers), ribbon (204 fibers).
A35. Ribbon.