Fiber n 2 n 1 CORNING Total Internal

光纖 (Fiber) n 2 n 1 CORNING 全內反射 (Total Internal Reflection)

訊號在光纖中傳播的衰減與色散問題 資料來源：http: //www. corning. com/opticalfiber/discovery_center/fiber 101/attenuation. aspx

光纖損耗(Fiber attenuation) 850 nm (短距離) 1310 nm (中距離) 1550 nm (長距離) 損耗(Attenuation) =吸收(Absorption loss) +散射(Scattering loss ) Example: Pout/Pin=0. 95, d. B~0. 22

光纖的數值孔徑 2 NA~0. 22 n 1 n 0 c 數值孔徑 (Numerical Aperture) CORNING

階變折射率多模光纖 (Step-index multimode fiber) 光纖中的模態數 Example: A 100 µm core fiber with NA=0. 29 would transmit 5744 modes at 850 nm.

多模態對光訊號傳輸的影響 l Modal dispersion ¡ l 與光軸夾角大的光線，其 所行經的路徑長度較長。 Modal noise ¡ 不同模態會相互干涉 資料來源： www. rp-photonics. com/fibers. html http: //grad. physics. sunysb. edu/~xmiao/project 2. html

漸變折射率多模光纖 (Graded-index multimode fiber) l 縮短高階模態傳播時間，降低Modal dispersion

階變折射率單模光纖 (Step-index single-mode fiber) 單模態條件 Example: If NA=0. 14, =1310 nm, then D< 7. 1 µm

色散的種類 Modal dispersion l 發生在單模光纖 ¡ 不同模態有不同的路徑長度 Chromatic dispersion l Material dispersion. ¡ l ¡ 發生在多模光纖 不同波長的光波有不同的傳播速度 Waveguide dispersion. l 光能量在core與cladding的分佈與波長有 關 Polarization mode dispersion l ¡ 雙折效應 Light penetrates slightly into the cladding of a single-mode step-index fiber.

零色散位移單模光纖 (Zero dispersion-shifted single-mode fiber) 1. 31 m 1. 55 m l l 1. 55 µm 處色散總和為零 有 Four-Wave Mixing問題

LED 與 LD 的特性比較 單頻LD(0. 08 nm) LED(30~50 nm wide) Wavelength Different scale for LED and LD LD(1~3 nm wide) LD輸出 LED輸出 Drive Current

材料與波長(光通訊用) LED (wavelength for short glass fibers are 820~850 nm) Material Ga. As (砷化鎵) Ga. Al. As (砷化鋁鎵) In. Ga. As. P (磷砷化銦鎵) Wavelength (nm) 930 750~900 1300 LD Material Ga(1 -x)Alx. As on Ga. AS Wavelength (nm) 780 to 850 In(1 -x)Gax. As(1 -y)Py In(1 -x)Gax. As on In. P on Ga. As 1100 to 1700 980

光偵測器 (Detector) In. Ga. As

各種光偵測器的特性 Device Responsivity Rise Time Dark Current Phototransistor (Si) 18 A/W 2. 5 µs 25 n. A Photodarlington (Si) 500 A/W 40 µs 100 n. A pin photodiode (Ge) 0. 4 A/W 0. 1 -1 ns 100 n. A pin photodiode (Si) 0. 5 A/W 0. 1 -5 ns 1 -10 n. A pin photodiode (In. Ga. As) 0. 8 A/W 0. 005 -5 ns 0. 1 -3 n. A Avalanche Photodiode (Ge) (Voltage dependent) 0. 3 -1 ns 400 n. A (Voltage dependent) Avalanche Photodiode (Si) 10 -125 A/W (Voltage dependent) 0. 1 -2 ns 10 -250 n. A (Voltage dependent) Avalanche Photodiode (In. Ga. As) 7 -9 A/W (Voltage 0. 1 -0. 5 ns 6 -160 n. A (Voltage dependent)

摻鉺光纖放大器 (Erbium-Doped Fiber Amplifier, EDFA)

通訊波段及其對應的光放大器 Band Name Meaning Wavelength (nm) Amplification Technology O band Original 1260 -1360 Praseodymium鐠(? ) E band Extended 1360 -1460 --- S band Short 1460 -1530 Thulium銩-fiber (developmental) C band Conventional 1530 -1565 Erbium鉺-fiber L band Long 1565 -1625 Erbium-fiber U band Utra-long 1625 -1675 ---

波長分波多 系統 (Wavelength-Division Multiplexing System)

ITU DWDM Channel ITU C band, 0. 4 nm or 50 GHz spacing , 81 channels 1528. 77 1534. 64 1540. 56 1546. 52 1552. 52 1558. 58 1529. 16 1535. 04 1540. 95 1546. 92 1552. 93 1558. 98 1529. 55 1535. 43 1541. 35 1547. 32 1553. 33 1559. 39 1529. 94 1535. 82 1541. 75 1547. 72 1553. 73 1559. 79 . . . . Unit: nm • ITU: International Telecommunication Union • DWDM: Dense Wavelength-division Multiplexing • 通道間距等於或小於 200 GHz

陣列波導光柵 (Arrayed Waveguide Grating, AWG) 5 4 1, 2 , 3, … 資料來源：http: //en. wikipedia. org/wiki/Arrayed_waveguide_grating 3 1 2

干涉濾光片(Interference filter) 多腔窄帶濾光片 50 GHz DWDM Filter a Multi-layered thin -film filter 1549. 3 nm 1549. 90 nm 1550. 50 nm

光開關 (Optical Switch) l Opto-Mechanical Switch l MEMS Switch l l Bubble Switch Bubble Lucent micro-mirror optical switch Electro-Optical Switch TIR

幾種不同光碟系統的結構及使用的LD波長 l l l CD (Compact disk): 780 nm DVD (Digital Versatile Disc): 650 nm Blue-ray Disk & HD (High-Definition) DVD: 405 nm http: //www. blu-raydimensions. com/blu-ray. asp

Sony Blu-ray Disk

光儲存技術規格 DVD HD DVD Blu-ray Disc 波長(nm) 650 405 數值孔鏡 (NA) 0. 65 0. 85 軌距( m) 0. 74 0. 32 碟片直徑(cm) 12 12 12 碟片架構 0. 6 mm. X 2 0. 1 mm+1. 1 mm 單面儲存容量 4. 7 GB 15 GB 25 GB 資料傳輸速(Mbps) 11. 08 36. 55 36 Toshiba Sony 領導廠商

日本光儲存用LD技術發展 l. Pioneer, 藍/紅 ( 405/650 nm)LD l. Sony, l. Sony & NICHIA, Dual wavelength laser coupler (405 & 660 nm) 3 wavelength Optical Head (405, 660 m and 785 nm)

資料來源 l l l Jeff Hecht, Understanding fiber optics, 4 th ed. , Prentice Hall, 2002. "Understanding Optical Communications" - An IBM redbook G. Bouwhuis et al. , Principles of optical Disc systems, Adam Hilger, 1985. 羅正忠, 許招墉, 最新圖解半導體製程概論, 普林斯 頓, 民國93年。 2004年我國與全球光電產業及技術動態調查報告, 2005年 3月出版, 光電科技 業協進會。