D. Dahan, A. Bilenca, R. Alizon and G. Eisenstein Noise Reduction Capabilities of a Raman - Mediated Wavelength Converter   D. Dahan, A. Bilenca, R. Alizon and G. Eisenstein Technion- Israel Institute of Technology Department of Electrical Engineering

Outline Motivation Raman wavelength converter : Principle of operation Experimental set up and results Wavelength conversion Reshaping capabilities Numerical Simulations Conclusion

Motivations How can we cope with the increasing demand in information capacity? Fiber Type Standard AllWave S+ S C L U 0.35 Raman GS-EDFA Fiber Loss (dB/km) 0.25 EDFA GS-TDFA TDFA 0.15 1300 1400 1500 1600 Optical Wavelength (nm)

Raman wavelength converter : Principle of operation Signal at wavelength λs Optical fiber (L km) P1s P0s t t Ppr t t Probe : λpr~ λs-100 nm, Ppr<<P1s Large detuning may degrade the conversion because of large walk off Need to operate almost symmetrically around the zero dispersion wavelength

Raman wavelength converter : Principle of operation Fast Raman response - few fs Strong depletion regime (Ps>>Ppr) *

Experimental set up: wavelength conversion Signal HNLF 4 km L band EDFA OTF 1584nm WDM couplers 1480/1550 100 MHz PC Mod 10 Gbit/s Data Probe TL RX 1470-1500 nm λ D λ 0~1536.3 nm λs λpr Highly Nonlinear Fiber :  ~ 10.6 W-1/km, 0~1536.3 nm ,S0~ 0.018 ps/(nm2-km)

Experimental result : wavelength conversion Raman induced depletion at 1483 nm in CW regime [dB] -5 10 15 20 25 -16 5 -14 -12 -10 -8 -6 -4 -2 2 4 6 8 12 14 16 Theory Measurements Input Power at 1584 nm [dBm] for probe signal at 1491 nm [dB] Extinction ratio at 10 Gb/s ER Measurements + CR~3.7 W-1/Km extracted from CW measurement

Experimental set up : wavelength conversion with reshaping capabilities Receiver HNLF 4 km L band EDFA OTF WDM couplers 1480 / 1550 PC Probe Tunable Laser 100 MHz Mod 10 Gbit s data Signal % 90 SMF 2 Att 1581 nm 1470 - 1500

Reshaping results @ 10 Gbit/s Converted Signal, p=1500 nm Original Signal, s=1581 nm Converted Signal, p=1495 nm Converted Signal, s=1490 nm

Reshaping results @ 10 Gbit/s Converted Signal, p=1485 nm Converted Signal, p=1480 nm Converted Signal, p=1470 nm Converted Signal, p=1475 nm

BER measurement at 10 Gbit/s : Large crosstalk : -13 dB -28 -26 -24 -22 -20 -18 -16 -14 -12 -10 -8 -6 -4 -2 Received optical power [dBm] Signal @1581 nm Converted signal @1495 nm Converted signal @1485 nm Converted signal @1480 nm Converted signal, p =1495 nm, Q=8 Original Signal, s =1581 nm, Q=3.5 Log10(BER)

BER measurement at 10 Gbit/s : Moderate crosstalk : -18 dB Converted signal @1495 nm Converted signal @1485 nm -28 -26 -24 -22 -20 -18 -16 -14 -12 -10 -8 -6 -4 -2 Received optical power [dBm] Converted Signal, p=1495 nm Q=10 Signal @1581 nm Original Signal, s=1581 nm Q=5.5 p =1485 nm, Q=9.6 Log10(BER)

Numerical simulations : formalism Coupled Nonlinear schrodinger equation : Solved using the split step Fourier method

Numerical simulations : noise transfer CW regime, without walk off and modulation instability : 200 300 Input signal power (GPsin) [mW] walk off=0 ps walk off=10 ps 100 0.05 0.1 0.15 0.3 0.35 Noise Transfer ratio pr/s walk off=40 ps walk off =80ps Simulations results 0.25 0.2

Numerical simulations : operational bandwidth Converted Wavelength [nm] Output Q factor [dB] 1470 1480 1490 1500 1510 1520 7 8 9 10 11 12 13 14 15 Extinction Ratio Q factor Output Extinction Ratio [dB] Original signal @1584 nm, Ps(0)=21 dBm, Q=7.8

Conclusions Raman mediated crosstalk : Novel technique for inter-band wavelength conversion and reshaping Demonstration of conversion and reshaping capabilities from L to S bands at 10 Gbit/s Fast Raman response allows operations to higher bit rates Walk off is the main limiting factor but can be reduce by increasing the power or the fiber Raman gain.