Bend Loss in Optical Fibersopti500.cian-erc.org/opti500/pdf/Lecture 24 Bend Loss, Nonlinear...
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• It is common to wrap optical fiber in communication systems OPTI 500 C, Spring 2011, Lecture 24, Bend Loss, Nonlinear Effects 1 Bend Loss in Optical Fibers
Transcript of Bend Loss in Optical Fibersopti500.cian-erc.org/opti500/pdf/Lecture 24 Bend Loss, Nonlinear...
• It is common to wrap optical fiber in communication systems
OPTI 500 C, Spring 2011, Lecture 24, Bend Loss, Nonlinear Effects 1
Bend Loss in Optical Fibers
• Power in the tail of the mode profile is lost.
OPTI 500 C, Spring 2011, Lecture 24, Bend Loss, Nonlinear Effects 2
Bend Loss in Optical Fibers
From Integrated Optics, Robert G. Hunsperger, 4th Edition, pp. 84-87.
• Keeping bend radii greater than 10 cm makes bend loss negligible
OPTI 500 C, Spring 2011, Lecture 24, Bend Loss, Nonlinear Effects 3
Bend Loss in Optical Fibers
From Photonics, Yariv and Yeh, 4th Edition
OPTI 500 C, Spring 2011, Lecture 24, Bend Loss, Nonlinear Effects 4
OPTI 500 C, Spring 2011, Lecture 24, Bend Loss, Nonlinear Effects 5
OPTI 500 C, Spring 2011, Lecture 24, Bend Loss, Nonlinear Effects 6
OPTI 500 C, Spring 2011, Lecture 24, Bend Loss, Nonlinear Effects 7
OPTI 500 C, Spring 2011, Lecture 24, Bend Loss, Nonlinear Effects 8
Draka BendBright-Elite Fiber (G.657.B3)
• Larger core-clad index difference minimizes bend loss, but smaller mode profiles increase splice loss
• Fiber with a trench-index profile minimizes bend loss while maintaining a larger mode profile
OPTI 500 C, Spring 2011, Lecture 24, Bend Loss, Nonlinear Effects 9
Low Bend Loss Optical Fiber
From “Low-Bending-Loss Single-Mode Fibers for Fiber-to-the-Home,” Himeno, Matsuo, and Guan, J. Lightwave Tech. Vol. 23, (11) 2005, p. 3494
• Self-Phase Modulation • Four-Wave Mixing
OPTI 500 C, Spring 2011, Lecture 24, Bend Loss, Nonlinear Effects 10
Nonlinear Impairments in Optical Fiber
• An increasing intensity, and refractive index, has the effect of increasing frequency (decreasing wavelength) and vice versa
OPTI 500 C, Spring 2011, Lecture 24, Bend Loss, Nonlinear Effects 11
Nonlinear Impairments in Optical Fiber
( ) ( )( )
( )
0 2
2 20
0
2 22 02
0
exp /
2 2 exp /
n n n I
I t I t
ttn L I t
τ
ω ω ω
π τλ τ
= +
= −
∆ = −
= −
From Photonics, Yariv and Yeh, 4th Edition
OPTI 500 C, Spring 2011, Lecture 24, Bend Loss, Nonlinear Effects 12
Four-Wave Mixing
Simulations from “Four-Photon Mixing And High-Speed WDM Systems, Tkach et al. J. Lightwave Tech. Vol. 13 (5) 1995, p. 841
Eye Diagram - Output
Eye Diagram - Input WDM Input
WDM Output
