II. Polarizations III. Fiber configurations
2008-2009 Min’s Fiber Optics
I. Review
1. History 2. The nature of light
①EM waves: Wavelength & Period, Wavefront &
Example 2.3.1
Energy →
• EPnroebrgleyml:eaveLlDdraiadgiartaems λ=650nm, what is the energEy 4of a single
p–hoBtoonh?r’s model (solar)
E3 E2
Solution:
(1) the enEergy oEf a3 sinEgle2 photoEnp: hf
/
s)
Materials
Air Water Glass Diamond
Refractive index 1.003 1.33 1.52-1.89 2.42
2008-2009 Min’s Fiber Optics
2.2.2. Basic optical laws
• Reflection & refraction
2008-2009 Min’s Fiber Optics
2.2.1 Rays: refractive index
n cv
Example 2.2.1
Problem: what is the Байду номын сангаасight velocity with glass?
Solution:
v
c
n
3108 (m /
s) 1.5
2108 (m
Solution:
n1 sin 1 n2 sin 2 , since, n1 1.6, n2 1.0, while2 90
1c
sin 1 1 1.6
38.68
1 1c
Glass rod:n1=1.6 Air: n2=1.0
2008-2009 Min’s Fiber Optics
2.3 A stream of photons
E1
• A(2pE)hPpoLDto=hn1fmwh, hco/ w m a(n6y.6ph1o0to3n64s5)0iJtra1sd0ia(93tems1p0e8r)sme/csoEn0d?3.04G1r0ou19nJd state
– Ththeeenetorgtaylof eanneprghyot:oEn:(pPp.317s)1103 w1s 1103 J
• In physical optics viewpoint: e-wave →fig. • Concept: Wave front – same phase, i.e., phase front • Concept: Plane wave – wavelength the object
(opening) → ray-geometrical optics
Plane wave
②Geometric optics:
• Refractive index • Basic optical laws and definitions
③A quantum view
2008-2009 Min’s Fiber Optics
1. History
• 17th century: a stream of minute particles emitted by luminous sources
• 1815, Fresnel: diffraction • 1864, Maxwell: light waves must be electromagnetic
wave, polarization → transverse wave
2008-2009 Min’s Fiber Optics
2. The nature of light
90
n2 n1
2008-2009 Min’s Fiber Optics
Totally internal reflection in fiber
Example 2.2.3
Problem: assume you have a glass rod surrounded by air, as shown in fig.2.7. find the critical incident angle.
2.1 EM waves: wavelength & period
• Concepts/definitions: (pp.30 )
• General parameters:
f c
1.550 10 6 (m) 1.55m 1550 (nm)
known cvac 3.0 108 (m / s) f 1.935 1014(Hz)
then,2
n2 n1
cos1
2008-2009 Min’s Fiber Optics
2.2.3 Totally internal reflection
if , n1 n2
@ n1 sin1 n2 sin2 sin2 sin1 then,2 1 when,2 90
sin c
n2 n1
sin
Chapter 2:
A Brief Review of Optics
Chapter 3:
Optic Fibers — Basics
Lecture 2
2006-2007 Min’s Fiber Optics
Contents
I. Review
1. History 2. The nature of light
– traveling in straight line; – penetrate transparent materials; reflected by opaque ones
→ reflection & refraction – failed → interference & diffraction
Fig. 2-1: Spherical a2n0d 0pl8a-n2e0w0a9ve fMroinnts’s Fiber Optics
2.1 EM waves
• Assumption: vacuum, at moment t • Transverse/lognitudinal EM wave
2008-2009 Min’s Fiber Optics