High Gain Fiber Amplifiers for DWDM and Metro Networks N. Peyghambarian Optical Sciences Center, University of Arizona
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OUTLINE Motivation Glass and Fiber Fabrication Spectroscopic Characterization Gain Performance Conclusion
Amplifier Performance Signal: 1534.9 nm at -31 dbm 20 26 Net gain (db) 15 10 5 0-5 -10-15 -20 Net Gain Noise Figure 24 22 20 18 16 14 12 10 8 6 Noise Figure (db) -25 4 0 50 100 150 200 250 Pump power (mw) 15.5 db net gain for 5.1 cm fiber
Motivation Lossless Splitter Ultra Compact 1.54 µm Fiber Amplifier EDF in V-Groove High Er 3+ Doping Concentration Low Cooperative Upconversion Co. 1x16 splitter: 15dB loss Commercial EDFA gain : 0.02dB/cm Phosphate Glasses Phosphate Glass Fiber Amplifier
Amplifying Splitter NP Integrated Power Splitter Concept Splitter Y- junction Fiber Amplifier Array
NP Amplifying Arrayed Waveguide Multiplexer NP Arrayed Waveguide Multiplexer Arrayed Waveguide DWDM Fiber Amplifier Array
Glass Fabrication P 2 O 5 Al 2 O 3 R 2 O, et al Batch Mixing Melt Cast Annealing Inspection Fabrication
Influence of Glass Composition on Refractive Index Glass type Glass composition ( Mole % ) P 2 O 5 Al 2 O 3 La 2 O 3 MgO CaO BaO P1 64 12 3.5 20.5 P2 64 12 3.5 20.5 P3 64 12 3.5 20.5 P4 64 15.5 3.5 17 P5 64 18.5 3.5 14 P6 64 21.5 3.5 11 Refractive index Refractive index 1.58 1.56 1.54 1.52 632.8nm 1550nm 1.5 MgO CaO BaO 1 2 3 20.5 Mol % 1.56 1.55 1.54 1.53 1.52 632.8nm 1550nm 10 15 20 25 BaO mol% 22.5 17.5 12.5 7.5Al 2 O 3 mol%
Influence of Glass Composition on Effective Linewidth of Er 3+ 4 I 13/2-4 I 15/2 Transition Effective linewidth [nm Effective linewidth [nm] 44 43 42 41 MgO 1 CaO 2 BaO 3 20.5 Mol % 44 43 42 41 10 15 20 25 BaO 22.5 17.5 12.5 7.5 Al 2 O 3 Mol % Effective Line width of the 1.54 µm transition λ eff = α ( γ ) dγ α peak
Measured 1/e Lifetime of Er 3+ Ions Samples Er 3+ concentration (ions/cm 3 ) Yb 3+ concentration (ions/cm 3 ) E1 2.0 10 20 0 E2 3.0 10 20 0 E3 3.5 10 20 0 E4 4.0 10 20 0 YE1 2.0 10 20 2.0 10 20 YE2 2.0 10 20 4.0 10 20 YE3 2.0 10 20 6.0 10 20 Measured 1/e Lifetime (msec) 9 8 7 6 5 4 3 E4 E1 0 20 40 60 80 100 Pump Power (mw)
Cooperative Upconversion Coefficient and Spontaneous Lifetime Cooperative upconversion coefficient (10-18 cm 3 /s) 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 Lifetime Cooperative upconversion coefficient 2.0 2.5 3.0 3.5 4.0 Er 3+ concentration (10 20 ions/cm 3 ) 10 9 8 7 6 Lifetime (msec) ( ) 1 N E2 1 (t) = C N 0 N E2 (0) = R t + exp( ) C o o o τ τ τ E o E13τ E o 2Cτ E E + 1 E 2 ( ) 4CN ERE τ o 13 E 1+ 1 o o RE τe + τ 13 E E 1
Cladding Glasses Glass type Refractive index 632.8 nm 830 nm 1300 nm 1550 nm Core P25 1.5431 1.5389 1.5318 1.5290 Cladding1-1 1.5365 1.5309 1.5249 1.5217 Cladding2-1 1.5298 1.5250 1.5187 1.5158 Cladding3-1 1.5257 1.5206 1.5150 1.5116 Thermal Exp Co. [ x10-7 /oc] 160 130 100 70 corep25 clad1-1 clad2-1 clad3-1 100 200 300 400 500 Temperature [oc] n/n 1 =0.48% ~1.14%, NA=0.149 ~ 0.230 α/α 1 < 3% T g /T g1 < 1% T f /T f1 < 3%
Fiber Drawing Rod-in-tube technique Φ3mm Er 3+ 3+ φ 4mm Er Glass Rod Glass Rod Cladding Tube Cladding Tube ID 4mm, OD 12mm Rod Drawing ID 3mm, OD 12mm + Another Tube Twice Fiber Drawing Fiber Fiber Core 4?m Core 4, 5, 6 µm Core Diameter: 4-6 µm
Experimental Setup for Gain Measurement Pump Laser Pump Monitor Tunable Laser Attenuator Er-doped fiber OSA
Gain Characteristics 16 25 Net Gain [db] 12 8 4 0-4 -8-12 1535 nm 1550nm NF 1535nm NF 1550nm 20 15 10 5 Noise Figure [db] Fiber Length: 5.1cm -16 0 50 100 150 200 250 0 Pump Power [mw]
Gain Spectrum Net Gain [db] 16 12 8 4-31dBm -6dBm 0dBm NF (-31dBm) 16 12 8 4 Noise Figure [db] Net Gain [db] 15 12 9 6 3 225mW 198mW 176mW 154mW 131mW 0 1525 1540 1555 1570 Wavelength [nm] 0 0 1525 1535 1545 1555 1565 1575 Signal Wavelength [nm]
Gain Saturation 16 Net Gain [db] 13 10 7 1535nm 1550nm 4-25 -15-5 5 15 Output Power [dbm]
Gain Performance Internal Gain [db] 12 9 6 3 0-3 14 11 8 5 Noise Figure [db] Internal Gain [db] 6 4 2 0 6 4 2 Noise Figure [db] -6 0 100 200 Pump Power [mw] 2-2 0 100 200 Pump Power [mw] 0 1535nm, -31.6dBm 3.2cm-long fiber 1550nm, -31.6dBm 3.2cm-long fiber
Spectral Properties 4 I 9/2 A E43 NR C 2 F 5/2 A E32 NR 4 I 11/2 4 I 13/2 R Y12 R Y21 A Y21 R K K R E13 W E12 W E21 A E21 R C 2 F 7/2 4 I 15/2 Yb 3+ ions Er 3+ ions Energy Levels of Er 3+ and Yb 3+ Ions
Energy Transfer Efficiency 200 91 Efficiency Measured Lifetime τ yb (µ sec) 180 160 140 120 100 80 60 40 YE3 YE2 YE1 o η = 1 - τ yb /τ yb 0 20 40 60 80 100 92 93 94 95 96 97 98 Transfer Efficiency η (%) η = 1- τ τ Yb o Yb τ Yb o Lifetime without Er 3+ ions τ Yb Measured lifetime Pump Power (mw)
Amplifying Splitter (and Combiner) One Input Port and Multiple Ourput Ports (n) for Amplifying and Dividing Optical Signals Near 1.54 µm Technical Drawing Erbium Doped Fiber in V-groove Passive Power Splitter Pump Laser WDM Adhesive Fiber Pigtailing Packaged Product: Rubber Strain Relief NP Photonic Technologies, Inc. NP-Amplifying Splitter -1x16-XX-XX Serial # Aluminum Case Size (1 x n: L x W x H mm 3 ) 1x04: 95 x 11 x 6.5 1x08: 95 x 11 x 6.5 1x16: 115 x 11 x 7 1x32: 150 x 16 x 7
Ion-Exchanged Waveguide Fabrication Ti Mask Deposition Mask Patterning Ion Exchange Ag + Na + Mask Removal Field- Assisted Burial
Photoimagable Hybrid Materials
1-N Sol-Gel MMI Splitter L MMI L OS L OP N 5 µm W total W/2 W/2 W/N 50 µm 50 µm 50 µm 18 17 16 15 n f n s W/2N L total 1 1x32 MMI output
Conclusions Er Er 3+ 3+ -doped phosphate glasses Single mode phosphate glass fiber Phosphate glass fiber amplifier 15.5dB net net gain from a 5.1cm fiber Modify glass composition to improve gain spectrum Dope Yb to improve gain efficiency Optimize fiber design to increase the gain Improve coupling loss to reduce the NF
Acknowledgment Assistant Research Professor: Shibin Jiang Ph.D. Students: Bor-chyuan Hwang Yongdan Hu Karine Seneschal Post-doctor: Dr. Jerome Porque Research Scientist: Dr. Yong Ding Visiting Scholar: Dr. Gino Sorbello (Politecnico di Milano, Italy) Collaborator : Dr. Tao Luo ( NP Photonics Technologies LLC ) Dr. Seppo Honkanen ( NP Photonics Technologies LLC ) Prof. Fred Smektala (Universite de Rennes 1) Prof. Jacques Lucas (Universite de Rennes 1)
Acknowledgment BMDO through the SBIR Phase II program NP Photonic Technologies, LLC UA Science and Technology Park 9030 South Rita Road, Suite 120, Tucson, Arizona 85747
Parameters of Single Mode Fiber Core Core diameter 5 µm µm Refractive index of of cladding glass glass at at 1.535 µm µm 1.5170 Refractive index of of core core glass glass at at 1.535 µm µm 1.5327 Numerical aperture 0.219 Cut-off wavelength 1.43 1.43 µm µm Attenuation <0.3dB/cm Er Er 3+ 3+ concentration 35000ppm