Next Generation Optical Amplifier for 10 ’ s of Tera-bps Data Transmission

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

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

3. History of Transmission Capacity Expansion 10 15 10 3 EDFA 10 2 10 12 10 1 Gb/s 10 9 Lightwave BL (bps*km) 1 MW 10 6 Coax 0.1 1970 1980 1990 2000 2010 10 3 Telephone AT&T 10 Year Plans Did Not Give Sufficient Capacity !! Always Beyond Expectation !! Telegraph 1 Yr 1850 1900 1950 2000 SNU Optical Communication Systems Lab KJIST Fiber Optics Research Lab

4. Fiber Fiber Amplifier MUX Lasers Detectors Why WDM ? WDM 10 4 1 Tbps 10 3 Yr 99 : 40G x 40ch Raman Amp # of WDM channels 10 2 Yr 98 - 99 10 Yr 96 - 97 1 0.1 1 10 100 1000 Bit rate per channel (Gbps) SNU Optical Communication Systems Lab KJIST Fiber Optics Research Lab

5. Silica-Er C+L band Other Rare Earth RE Pump Raman Pump Raman Amplifier Why Ultra-Wideband Optical Amplifier ? • Until the beginning of 1998, less than 10 published papers on Wideband EDFA • NTT 35nm 1450 - 1485nm Thulium 1998 • NTT 37nm 1300nm region Praseodymium PCE < 20% 1998 • NTT 75nm 1531 - 1606nm EDFA & Raman 1998 • NTT 50nm 1460 - 1510nm TDFA & Raman 1999 • NTT 110nm C & L plus Thulium PCE < 15% 1999 • SNU 80nm 1530 - 1610nm C & L PCE > 27% 1999 • Tyco 100nm formerly AT&T Raman Multi-pump 1999 • 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 SNU Optical Communication Systems Lab KJIST Fiber Optics Research Lab

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

7. Building Blocks for Optical Amplifier Pump LD Market price ~ 30K$ since 1991 while.. Component price dropped to 1/20 since 1991 C band C + L C + L L band Pump LD Pump LD 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 SNU Optical Communication Systems Lab KJIST Fiber Optics Research Lab

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 SNU Optical Communication Systems Lab KJIST Fiber Optics Research Lab

9. Level 5 1G4 3F2 3F3 3H4 4 3H5 3F4 3 3H6 2 1 0 TDFA P3 P2 1.47m Signal band P1 0.8m band ASE 1.8m band ASE Pump Signal & ASE • 1450-1520nm band can be utilized using TDFA and GS-TDFA Low loss region in optical fiber Not seriously explored until recent years • We developed numerical model for TDFA for the first time (6 months of research) • Pump laser require specialty fiber (double clad, Yb doped fibers) • Amplifier, pump laser, and fiber design require extensive numerical analysis SNU Optical Communication Systems Lab KJIST Fiber Optics Research Lab

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) • Amplifier dynamics based on nonlinearity in optical fiber (specialty fiber required) • Each pump provides approximately 25 - 30nm of gain bandwidth • Gain bandwidth, wavelength selectable with appropriate pumps SNU Optical Communication Systems Lab KJIST Fiber Optics Research Lab

11. Specialty Fiber : TDFA ESA at 980 nm PIQ at 1.55 m m 980 nm 1450 nm 1550 nm 1800 nm 3+ 3+ Er Tm • OSA, Advanced Solid State Lasers, paper MB15 1999 , 1 EDF laser • Optics Letters in preparation ASE source SNU Optical Communication Systems Lab KJIST Fiber Optics Research Lab

12. Specialty Fiber : pump 0.35 core Sm Er 500 0.30 cladding Er 400 0.25 Sm 0.20 300 Er Fluorescence Sm Absorption (dB/Km) 0.15 200 0.10 Power Density *1000 100 0.05 0 0.00 1000 1200 1400 1600 1800 wavelength, nm 980nm 1530nm • IEEE Journal of lightwave technology, accepted 1999 Fiber Stress • Journal of Optics B: Quant. Semiclassic. Optics, accepted 1999 Hollow Fiber • Journal of Non-crystalline Solids, accepted 1999 Erbium Fiber • Journal of Non-crystalline Solids, accepted 1999 Erbium Fiber • Optics Communications, Vol. 161, 25 1999 Hollow fiber • Optics Communications, Vol. 159/1-3, 139 1999 Dispersion • IEE Electronics Letters, Vol. 34, No. 19, pp1852-1853 1998 Annular EDF • IEEE Journal of Lightwave Technology, Vol. 16, 285 1998 Fiber Coating SNU Optical Communication Systems Lab KJIST Fiber Optics Research Lab

13. Approach / Goal 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 ! Amplifier structure Simulation Fiber, pump structure SNU Amplifier Test Transmission penalty Integration Tm, Ho, Yb, Nd doping Spectroscopy Heavy metal silica fiber KJIST Manufacturability Double clad pump fiber Co-doping WEDFA SNU / Lucent RE-DFA KJIST / Brown Raman SNU / Southampton SNU Optical Communication Systems Lab KJIST Fiber Optics Research Lab

14. SMF 0.4 0. 3 dB / km fiber loss 0.3 Loss (dB/km) 0.2 OH-free Fiber C-EDFA L-EDFA WEDFA S + -TDFA GS-TDFA TDFAs 0.1 Raman-Amp 0.0 Wavelength (nm) 1300 1400 1500 1600 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 SNU Optical Communication Systems Lab KJIST Fiber Optics Research Lab