Handbook for Sound Engineers

(Wang) #1
449

Chapter 15


Transmission Techniques: Fiber


Optics


by Ron Ajemian

15.1 History................................................................................ 451
15.2 Advantages of Using Fiber Optics for Audio.................................................. 452
15.2.1 Applications for Audio................................................................ 452
15.3 Physics of Light......................................................................... 452
15.4 Fiber Optics............................................................................ 456
15.4.1 Types of Fiber....................................................................... 456
15.4.2 Characteristics of Typical Fibers......................................................... 457
15.4.3 Signal Loss......................................................................... 458
15.4.3.1 Fiber Optic Transmission Loss (FOTL)............................................... 458
15.4.3.2 Optical Fiber Loss................................................................ 458
15.4.3.3 Attenuation Measurement.......................................................... 461
15.4.3.4 Advancements in OTDR Testing.................................................... 462
15.5 Sources............................................................................... 463
15.5.1 LEDs.............................................................................. 463
15.5.2 Laser Diodes........................................................................ 465
15.5.3 Superluminescent Diodes (SLDs)........................................................ 466
15.5.4 Vertical Cavity Surface Emitting Laser (VCSEL)........................................... 466
15.5.5 LED and Laser Characteristics.......................................................... 466
15.5.5.1 Output Power.................................................................... 466
15.5.5.2 Output Pattern................................................................... 466
15.5.5.3 Wavelength..................................................................... 466
15.5.5.4 Speed.......................................................................... 467
15.5.5.5 Lifetime........................................................................ 467
15.5.5.6 Safety.......................................................................... 467
15.6 Detectors.............................................................................. 467
15.6.1 Quantum Efficiency (K)............................................................... 468
15.6.2 Noise.............................................................................. 468
15.6.3 Bandwidth.......................................................................... 468
15.7 Transmitter/Receiver Modules............................................................. 469
15.8 Transceivers and Repeaters................................................................ 469
15.8.1 Demand on Gigabit Optical Transceivers.................................................. 469
15.9 The Fiber Optic Link..................................................................... 470
15.9.1 Fiber Optic Link Design Considerations................................................... 470
15.9.2 Passive Optical Interconnections......................................................... 470
15.9.3 Fiber Optic Connectors................................................................ 471
15.9.3.1 Biconic Connector................................................................ 471

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