1. Next Generation Optical Amplifier for 10’s of Tera-bps Data Transmission Optical Communication Systems Lab. Seoul National University http://stargate.snu.ac.kr KJIST Fiber Optics Research Lab SNU Optical Communication Systems Lab National Research LaboratoryUltra-Wideband Optical Amplifier

2. National Research LaboratoryUltra-Wideband Optical Amplifier 2 Outline l Background n History of Transmission Capacity Expansion n Why WDM ? n Why Ultra-Wideband Optical Amplifiers ? n Market Aspects / Relation to Other Technologies n Building blocks for Optical Amplifier l Technologies / Team potential n Approach 1 : WEDFAApproach 2 : TDFA n Approach 3 : Raman amplifierApproach 4 : Specialty fiber l Team profile / Approach / Goal KJIST Fiber Optics Research Lab SNU Optical Communication Systems Lab

3. National Research LaboratoryUltra-Wideband Optical Amplifier 3 History of Transmission Capacity Expansion AT&T 10 Year Plans Did Not Give Sufficient Capacity !! Always Beyond Expectation !! Gb/s 0.1 1 10 1 10 2 10 3 19801990200020101970 190019502000 Yr 1850 BL (bps*km) 1 10 12 10 9 10 6 10 3 10 15 Telegraph Telephone Coax MW Lightwave EDFA KJIST Fiber Optics Research Lab SNU Optical Communication Systems Lab

4. National Research LaboratoryUltra-Wideband Optical Amplifier 4 Why WDM ? Fiber Fiber MUX Lasers Detectors Amplifier # of WDM channels Bit rate per channel (Gbps) 1 0.11101001000 10 4 10 3 10 2 10 Yr 96 - 97 WDM 1 Tbps Yr 98 - 99 Yr 99 : 40G x 40ch Raman Amp KJIST Fiber Optics Research Lab SNU Optical Communication Systems Lab

5. National Research LaboratoryUltra-Wideband Optical Amplifier 5 Why Ultra-Wideband Optical Amplifier ? Until the beginning of 1998, less than 10 published papers on Wideband EDFA NTT 35nm1450 - 1485nmThulium1998 NTT 37nm1300nm regionPraseodymiumPCE < 20%1998 NTT 75nm1531 - 1606nmEDFA & Raman1998 NTT 50nm1460 - 1510nmTDFA & Raman1999 NTT 110nmC & L plus ThuliumPCE < 15%1999 SNU 80nm1530 - 1610nmC & LPCE > 27%1999 Tyco100nmformerly AT&TRamanMulti-pump1999 Year 1999, Lucent Technology started to hire optical engineers for Raman Amplifier Development Year 2000, Raman amplifier became a preliminary product : Major effort by Majors Silica-Er C+L band Other Rare Earth Raman Amplifier Raman Pump RE Pump KJIST Fiber Optics Research Lab SNU Optical Communication Systems Lab

6. National Research LaboratoryUltra-Wideband Optical Amplifier 6 Market Aspects / Relation to Other Technologies 실리카 계열 EDFA (WEDFA) 광섬유 Raman 증폭기 다른 희토류 이온을 첨가한 증폭기 A. 세계 시장 규모 ($) < 초광대역 광 증폭기 > 2000 년 :12 억 2005 년 : 32 억 + < 광전송 장비 > 2000 년 :40 억 2005 년 :120 억 B. 추가 광선로 포설 비용 (km 당 3 억원 ) 절감 광전송 장비 / 기술 수출 기간망 구축 비용 절감 통신 수요의 안정적 공급 차세대 반도체 레이저수동광소자 특수광섬유 핵심기술 소자 기술 초광대역 광증폭기 대용량 전송 시스템 KJIST Fiber Optics Research Lab SNU Optical Communication Systems Lab

7. National Research LaboratoryUltra-Wideband Optical Amplifier 7 Building Blocks for Optical Amplifier Pump LD C band L band C + L Sub - optical components Laser diode / photo diode Specialty Fiber Optical Isolator Optical coupler AWG / FBG Spectral filters Also a fundamental module for optical transmission system Market price ~ 30K$ since 1991 while.. Component price dropped to 1/20 since 1991 KJIST Fiber Optics Research Lab SNU Optical Communication Systems Lab

8. National Research LaboratoryUltra-Wideband Optical Amplifier 8 WEDFA IEEE Photonics Technology Letters, vol. 12, May to be printed, 2000, 5 Wideband EDFA Patent (international) OSA Applied Optics, vol. 39, no. 7, pp. 1118-1120 2000, 4 EDFA sensor IEEE Photonics Technology Letters, vol. 12, pp. 329-331, 2000, 3 Wideband EDFA IEE Electronics Letters, vol. 35, pp. 1099-1100 1999, 6 Wideband EDFA OSA Applied Optics, vol. 38, pp. 2749-2751 1999, 5 EDFA sensor IEEE Photonics Technology Letters, vol. 11, pp. 316-318, 1999, 3 EDFA dynamics OSA Optics Letters, vol. 24, pp. 279-281, 1999, 3 Wideband EDFA Patent (international) IEEE Photonics Technology Letters, vol. 11, pp. 42-44, 1999, 1 Wideband EDFA Patent (international) IEEE Photonics Technology Letters, vol. 10, pp. 1721-1723, 1998, 12 WDM EDFA Patent (international) IEEE Photonics Technology Letters, vol. 10, pp. 1168-1170, 1998, 8 WDM EDFA Patent (international) IEEE Photonics Technology Letters, vol. 10, pp. 790-792, 1998, 6 WDM EDFA KJIST Fiber Optics Research Lab SNU Optical Communication Systems Lab

9. National Research LaboratoryUltra-Wideband Optical Amplifier 9 TDFA l 1450-1520nm band can be utilized using TDFA and GS-TDFA Low loss region in optical fiber Not seriously explored until recent years l We developed numerical model for TDFA for the first time (6 months of research) l Pump laser require specialty fiber (double clad, Yb doped fibers) l Amplifier, pump laser, and fiber design require extensive numerical analysis 3H63H6 3F43F4 3H53H5 3H43H4 3F33F3 3F23F2 1G41G4 PumpSignal & ASE 0 1 3 2 4 5 Level  P1  P2  P3 1.47  m Signal band 0.8  m band ASE 1.8  m band ASE KJIST Fiber Optics Research Lab SNU Optical Communication Systems Lab

10. National Research LaboratoryUltra-Wideband Optical Amplifier 10 Raman Outperform the most recent results from Tyco Submarine (Simulation, May 1999) plus Derivation of new equation set for the much faster numerical analysis (IEEE PTL 2000) l Amplifier dynamics based on nonlinearity in optical fiber (specialty fiber required) l Each pump provides approximately 25 - 30nm of gain bandwidth l Gain bandwidth, wavelength selectable with appropriate pumps KJIST Fiber Optics Research Lab SNU Optical Communication Systems Lab

11. National Research LaboratoryUltra-Wideband Optical Amplifier 11 Specialty Fiber : TDFA ESA at 980 nm PIQ at 1.55  m 980 nm 1550 nm 1800 nm 1450 nm Er 3+ Tm 3+ OSA, Advanced Solid State Lasers, paper MB15 1999, 1 EDF laser Optics Lettersin preparation ASE source KJIST Fiber Optics Research Lab SNU Optical Communication Systems Lab

12. National Research LaboratoryUltra-Wideband Optical Amplifier 12 Specialty Fiber : pump Er Sm 1530nm 980nm Power Density core cladding 0 100 200 300 400 500 Sm Absorption (dB/Km) 10001200140016001800 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 *1000 Er Fluorescence wavelength, nm ErSm l IEEE Journal of lightwave technology, accepted 1999 Fiber Stress l Journal of Optics B: Quant. Semiclassic. Optics, accepted 1999 Hollow Fiber l Journal of Non-crystalline Solids, accepted 1999Erbium Fiber l Optics Communications, Vol. 161, 25 1999 Hollow fiber l Optics Communications, Vol. 159/1-3, 139 1999 Dispersion IEE Electronics Letters, Vol. 34, No. 19, pp1852-1853 1998Annular EDF l IEEE Journal of Lightwave Technology, Vol. 16, 285 1998Fiber Coating KJIST Fiber Optics Research Lab SNU Optical Communication Systems Lab

13. National Research LaboratoryUltra-Wideband Optical Amplifier 13 Approach / Goal Amplifier structure Simulation SNU Fiber, pump structure SNU Amplifier Test Transmission penalty Integration Tm, Ho, Yb, Nd doping Spectroscopy KJIST Heavy metal silica fiber KJIST Manufacturability Double clad pump fiber Co-doping WEDFA SNU / Lucent Raman SNU / Southampton RE-DFA KJIST / Brown Who could tell us about the target ? We can’t.. well, modest target will be 150nm bandwidth optical amplifier.. Rather, we promise that we will be keep staying as one of the world leaders ! KJIST Fiber Optics Research Lab SNU Optical Communication Systems Lab

14. National Research LaboratoryUltra-Wideband Optical Amplifier 14 Reminder : How much bandwidth? Current technology cover only 10% of usable bandwidth Nortel working on 100 Tera bps Ethernet router Lucent / JDS / Cronos / Xros working on 1000 x 1000 WDM channel optical switch Lucent / Nortel / Corning / NEC working on Ultra-wideband amplifier wherever the technology goes, we will trace, and will keep staying at the competitive edge KJIST Fiber Optics Research Lab SNU Optical Communication Systems Lab