PHOTONIC CRYSTAL FIBRES G. Calò, A. D’Orazio, M. De Sario, L. Mescia, V. Petruzzelli Dipartimento di Elettrotecnica ed Elettronica, Politecnico di Bari, Via E. Orabona 4 - 70125 Bari, Italy
F. Prudenzano Dipartimento di Ingegneria dell'Ambiente e per lo Sviluppo Sostenibile Politecnico di Bari, Via Orabona, 4, 70125 Bari, Italy, e-mail:
[email protected]
7th International Conference on Transparent Optical Networks
July 3 - 7, 2005, Barcelona, Spain
Politecnico di Bari
7th International Conference on Transparent Optical Networks July 3 - 7, 2005, Barcelona, Barcelona, Spain
OUTLINE Brief introduction on PCF properties Passive PCFs Active PCFs Conclusion and prospect
Politecnico di Bari
7th International Conference on Transparent Optical Networks July 3 - 7, 2005, Barcelona, Barcelona, Spain
INTRODUCTION
www.photonics.phys.strath.ac.uk www.photonics.phys.strath.ac.uk
PBFs
Microstructured Optical Fibres
PCFs
HFs
The cladding pumping technique and LMA-HFs
Politecnico di Bari
7th International Conference on Transparent Optical Networks July 3 - 7, 2005, Barcelona, Barcelona, Spain
Microstructured fibers PCFs, MSFs, MOFs High Index Core fiber, Index Guiding Core, Holey Fibers
High NA
Large Mode
High NL
(HNA)
Area (LMA)
(HNL)
PBG fiber Bandgap guiding fiber
Low Index Core (LIC)
Air guiding core Hollow core (AG,HC)
Bjarklev, J. Broeng, A. S. Bjarklev, Photonic crystal fibers, Kluwer Acad. Publ. 2003
Bragg Fiber (BF)
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7th International Conference on Transparent Optical Networks July 3 - 7, 2005, Barcelona, Barcelona, Spain
PASSIVE PCFs
Λ=2.3 µm A= 40µm
Single mode over the wavelength range from 337 to 1550 nm V=
2π λ
nco − ncl
Veff =
2π λ
no − neff
2
2
2
2
FSM SEM image of PCF cross section J.C. Knight, T. A. Birks, P. St. J. Russel, D. M. Aktin, “All silica single mode optical fiber with photonic crystal cladding,” Opt. Lett., vol. 21, pp. 1547-1549, 1996. T. A. Birks, J.C. Knight, P. St. J. Russel, “Endlessly single-mode photonic crystal fiber,” Opt. Lett., vol. 22, pp. 961-963, 1997. J. Broeng, D. Mogilevstev, S. E. Barkou, A. Biarklev, “Photonic Crystal Fibers: A New Class of Optical Waveguides,” Optical Fiber technology, vol. 5, pp. 305-330, 1999. Politecnico di Bari
7th International Conference on Transparent Optical Networks July 3 - 7, 2005, Barcelona, Barcelona, Spain
Control of GVD dispersion
APPLICATIONS Single mode propagation Polarization GVD Dispersion Soliton propagation Generation and amplification Sensor Biomedicine
Biomedicine SEM image of PCF cross section core diameter dc = 1 µm
………….
core silica bridges having width wb=120 nm J.C. Knight, J. Arriaga, T. A. Birks, A. Ortigosa-Blanch, W. J. Wadsworth, P. St. J. Russel, “Anomalous Dispersion in Photonic Crystal Fiber,” Photonics Techn. Lett., vol. 12, pp. 807-809, 2000. A. Ferrando, E. Silvestre, P. Andrès, J. Miret, M. V. Andrès, “Designing the properties of dispersion-flattened photonic crystal fibers,” Optics Express, vol. 9, pp. 687-697, 2001.
Politecnico di Bari
7th International Conference on Transparent Optical Networks July 3 - 7, 2005, Barcelona, Barcelona, Spain
ACTIVE PCFs
SEM image of double cladding ytterbium doped core PCF
Output characteristic of the laser made by the double cladding ytterbium doped core PCF
K. Furusawa, A.N. Malinowski, J. H. V. Price, T. M. Monro, J. K. Sahu, J. Nilsson, D. J. Richardson, “A cladding pumped Ytterbium-doped fiber laser with holey inner and outer cladding," Opt. Express, vol. 9, pp. 714-720, 2001.
Politecnico di Bari
7th International Conference on Transparent Optical Networks July 3 - 7, 2005, Barcelona, Barcelona, Spain
DESIGN OF ERBIUM DOPED PCF AMPLIFIER Theory The design of PCF amplifiers/lasers: Electromagnetic investigation: Element Methodthe (FEM) Great effort Finite is needed, because fiber section morphology affects the other device characteristics: The model takes into account : The ground state absorption (GSA) The stimulated emission of the signal (SE) The amplified spontaneous emission (ASE). The effects of cross-relaxation and up-conversion
Politecnico di Bari
7th International Conference on Transparent Optical Networks July 3 - 7, 2005, Barcelona, Barcelona, Spain
PCF amplifier
PCF parameters
Outer-cladding Outer-cladding diameter
Outer-cladding hole diameter Pitch
Dcl-out = 122 µm
D = 6 µm ? = 8 µm (D/ ? =0.75)
§Inner-cladding InnerInner-cladding apothem h = 41.57 µá µ(m (a) di=2.5 µm (i=1÷5); (d/ ?¿ =0.31) ?·=0.31)
α
=
(a)
(a’) di=3.4 µm (i=1÷5); (d/ ?V ?N=0.42)
(a’)
(b) d1=2 µm and di+1 - di=0.8µ =0.8µm;
(b)
(c) d1=2.5 µm and di+1 - di =0.7µ =0.7µm; (d) d1=3 µm and di+1 - di=0.6 µm.
(c)
Ac A ic − A hic α
≅ 0.009
α
≅ 0.0098
α
≅ 0.011
(d)
§Er3+-doped core PUMP SIGNAL Wavelength ?á 980 [nm] 1536 [nm] ?° [nm] Core refractive index 1.45167 1.44519 (SiO2-GeO2) ∆n = ncore - nsilica = 0.001 due only to erbium ions losses 0.41 [dB/Km] 2 [dB/Km] Excited state lifetime 21 = 10 ms
Other simulation parameters Nonradiative relaxation rates A32 = A43 = 109 [s-1];Cup=C3=10-22 [m3s-1], C14=3.5x10-23 [m3s1]; σ -25 [m2] and σ -25 Er21=7.9x10 Er12=7.1x10 [m2] at λs = 1534 nm;σ nm;σEr13=2.55x10-25 [m2] at λp = 980 nm. Politecnico di Bari
7th International Conference on Transparent Optical Networks July 3 - 7, 2005, Barcelona, Barcelona, Spain
Electric field modulus fundamental mode HEX11 ?á s = 1536nm
Politecnico di Bari
7th International Conference on Transparent Optical Networks July 3 - 7, 2005, Barcelona, Barcelona, Spain
Electric field modulus of the inner cladding pump modes HE11x,cl and HE12x,cl at the pump wavelength, λ = 980 nm.
HE11x,cl
HE12cl
Politecnico di Bari
7th International Conference on Transparent Optical Networks July 3 - 7, 2005, Barcelona, Barcelona, Spain
Amplifier Design Optimal gain G(Lopt) [dB]
32
Pp(0)=3W Ps(0)=100µW
fiber (a) fiber (a’)
28
fiber (b) fiber (c) fiber (d) 24
≅ 0.009
(a’)
α
≅ 0.0098
α
≅ 0.011
(c)
(a) G(Lopt)=32.1 dB
0
α
(b) (d)
(b) G(Lopt)=33.4 dB 20
(a)
2 4 6 8 Erbium concentration NEr x1024 [ions/m3]
10
G. Carlone, A. D’Orazio, M. De Sario, L. Mescia, V. Petruzzelli, F. Prudenzano, “ Design of double-clad erbium doped holey fibre amplifier,” Journal of Non Crystalline Solids 2005
Politecnico di Bari
7th International Conference on Transparent Optical Networks July 3 - 7, 2005, Barcelona, Barcelona, Spain
103
Optimal Length Lopt [m]
fiber (a) fiber (a’) Pp(0)=3W
fiber (b) fiber (c) fiber (d)
102
Ps(0)=100µW Lopt ≅ 140 ÷160 m NEr=1x1024[ions/m3] (b) G(Lopt)=33.4 dB (a) G(Lopt)=32.1 dB
101
0
2 4 6 8 Erbium concentration NEr x1024 [ions/m3]
10
(b) (c) (d) G ≅ 32.6 dB, Lopt ≅ 50 m, NEr=3x1024[ions/m3] (a) (a’)
G ≅ 31. dB
Politecnico di Bari
7th International Conference on Transparent Optical Networks July 3 - 7, 2005, Barcelona, Barcelona, Spain
Optimal Noise Figure F(Lopt) [dB]
11
10
fiber (a) fiber (a’)
9
fiber (b) fiber (c) fiber (d)
Pp(0)=3W Ps(0)=100µW Lopt +
1 P (L, s ) F = + ASE G Gh ∆ s
8
7
6
0
2 4 6 8 Erbium concentration NEr x1024 [ions/m3]
10
Politecnico di Bari
s
7th International Conference on Transparent Optical Networks July 3 - 7, 2005, Barcelona, Barcelona, Spain
Output Signal Power Ps(L) [dBm]
30 Pp(0)=3W NEr=3x1024[ions/m3]
20 fiber (a) Lopt =48.94 m fiber (a') Lopt =44.55 m fiber (b) Lopt =53.4 m fiber (c) Lopt =49.46 m fiber (d) Lopt=46.3 m
10
G=32.7 dB Lopt= 53.4 m F = 6.5 dB QCE = 9.50% λ P (L )− P (0 ) p s s QCE = λ P (0 ) s p
NEr= 3×1024 0 -40
-30
-20
-10
0
Input signal power Ps(0) [dBm]
10
20 Inner cladding air holes with a graded diameter.
Politecnico di Bari
7th International Conference on Transparent Optical Networks July 3 - 7, 2005, Barcelona, Barcelona, Spain
Ytterbium doped laser, LMA-HF section LMA-HF parameters Outer-cladding diameter
Dcl-out = 122 µ¢ m
Pitch
?u= 8 µu m
Outer-cladding hole diameter
D = 6 µ“m
(D/?“= 0.75)
Inner-cladding hole diameter d = 2.5 µ5 m (d/?5 =0.31) Inner-cladding sizes
a = 80 µÐ m b = 50 µg m
§Yb3+-doped core Wavelength ?£ Core refractive index (SiO2-GeO2) losses σA σE Excited state lifetime
PUMP 975 1.45167 4.2 2.64 x 10-24 2.64 x 10-24 21 = 0.8 ms
Core diameter
dc = 7.6 µžm
Refractive index change
?ån = 0.001
SIGNAL 1030 1.45106 2 5 x10-26 6.8 x10-25
[nm] [dB/Km] [m2] [m2]
Politecnico di Bari
7th International Conference on Transparent Optical Networks July 3 - 7, 2005, Barcelona, Barcelona, Spain
Laser Design
Optimal Length
L opt [m]
12 10
94
R =0.05 2
Max output power Pmax [W]
Input mirror Reflectivity R1=0.99 Pp(0) = 100 W Inner cladding air filling factor d/?=0.31
R =0.3 2
8
R2=0.05 R2=0.3
92
R2=0.6
90
6
R =0.6 4 2
2
R =0.8 3
R2=0.8
88
4
2
5 25 6 7 3 Yb concentration N x 10 [ions/m ] Yb
86 2
3
4
5 6 7 25 3 x 10 [ions/m ] Yb
Yb concentration N
Ytterbium concentration NYb=6·1025; optimal laser length Lopt ≅ 4.6 m Politecnico di Bari
7th International Conference on Transparent Optical Networks July 3 - 7, 2005, Barcelona, Barcelona, Spain
LASER CHARACTERISTIC Ytterbium concentration NYb=6x1025 ioni/m3 Input mirror reflectivity R1=0.99 Laser length L = 4.6 m, d/?Š d/?•=0.31
Output power
P out [W]
200
R2=0.05
R1=0.99
150
R1=0.95
100 50 0 0
R1=0.9
50 100 Pump power
150 Pin [W]
Slope efficiency S=93.6% Threshold pump power Pth=217 mW
200
D’Orazio, M. De Sario, L. Mescia, V. Petruzzelli, F. Prudenzano, “Design of double-clad ytterbium doped microstructured fibre laser,” Applied Surface Science. 2005
Politecnico di Bari
7th International Conference on Transparent Optical Networks July 3 - 7, 2005, Barcelona, Barcelona, Spain
OPTIMIZATION: INNER CLADDING AIR FILLING FACTOR EFFECT Λ = 8 µm Core single mode for 0
