Inside the optical networks…A closer look to the amplifiers Part II Hop Ton That
Optical amplifier type • 2 major classes: • Semiconductor Optical Amplifiers (SOA) conventional SOA GC-SOA (Gain-Clamped SOA) LOA (Linear Optical Amplifier) • Fiber Optical amplifiers (FOA)Rare earth-Doped Fiber Amplifiers Erbium-Doped Fiber Amplifiers (EDFA) : C, L-Band Thulium-Doped Fiber Amplifiers (TDFA) : S-Band Praseodymium-Doped Fiber Amplifiers (PDFA) : O-Band
Other optical amplifier type • Not based on stimulated emission but on nonlinear effects • Fiber Raman Amplifiers Discrete Raman Amplifiers Distributed Raman Amplifiers (DRA) • Hybrid EDFA/Raman Amplifier
EDFA Configuration Co-propagating pump= lower noise butlower output power Counter-propagating pump= higher outputpower but higher noise
Output vs wavelength Amplification between 1.53 and 1.56 um.
Rare earth (Er, Tm, Pr) -Doped Fiber Amplifiers • Gain band: Er (C, L-Band), Tm (S-Band), Pr (O-Band) 76 nm (1532-1608 nm) record gain bandwidth in single band configuration [M. Yamada et al.,OFC’98PD]. - Flat gain: 21 dB, Noise figure: 7 dB - Gain equalizer: two MZ filters with FSR of 32 and 120 nm
Stimulated Scattering • is transferring energy from the incident wave to another, scattered wave at lower frequency (longer wavelength) with the small energy difference being release as phonons. • The incident wave can be seen as a pump wave. • (Scattered waves are called Stokes waves)
Stimulated Scattering • 2 types:- Stimulated Raman Scattering (SRS) - Stimulated Brillouin Scattering (SBS) • In WDM systems, SBS has almost no effect
Distributed Raman Amplifier (DRA) • DRA is based on Raman Scattering. • A large pump is co-launched at a lower wavelength than the signal to be amplified
Fiber Raman Amplifiers • Gain band: 1.3~1.7 um (tunable by pump wavelength) • 132 nm record gain bandwidthin double band configuration has been achieved [H. Masuda et al., ECOC’99]. - Combination of Distributed Raman amplifiers (DRA) and discrete Raman - Two-gain-band Raman amplifier
Companies working in the optical transport network technology field. • Europe Nokia, Ericsson Telecom, Ericsson Comp., Telia, Sonera, Teledanmark, Lucent Nederlands, BT, Marconi, Nortel Networks(Euro), Siemens, Swisscom, France Telecom, ……Italtel, Telecom Italia, Alcatel SEL, Alcatel Italy, Pirelli, Telecom Italia, CSELT, Ukraine, Marconi • North America AT&T, Corning, Ciena, EXFO, Elisa, Fujitsu Networks(US), JDS, Lucent(US), Hitachi Telecom(US), Motorola, NEC(US), Nortel, Networks(US, Canada), MCI Worldcom, Sprint, Telcordia, Tycom, Ciena, Cisco • AsiaChina Telecom, China Unicom, CLPAJ, Corning Int. DDI, ETRI, Fujitsu, Hitachi, Huawei Technol., Japan Telecom, Korea Telecom, KDDI, Mitsubishi, NEC, NTT, Oki, Shanghai Bell, Sumitomo, Sumsung, Toshiba
Bibliography • www.google.com • Télécommunications par fibres optiques: Historical part • www.unice.fr/dess_ntic: flash animations • Raman Amplification Design in WDM Systems (IEC Tutorial) www.iec.org/online/tutorials/raman • Book: Fiber-Optic Communications Technology, course book.
The end! • Thank you for your patience!