2346-2347 / 3107
Equivalent path length (EPL)
03/01/13
d
4
d
1
d
3
d
2
Calculation point
r
4
r
3
r
2
r
1
44
33
22
11
d d d d
EPL
ρ
ρ
ρ
ρ
+ + + =
(
) (
)
(
)
(
)
...
exp
.....
exp
exp
2 2
11
2 2
11
+ + − =
−
−
d d
d
d
µ
µ
µ
µ
d
i
=thickness each layer
ρ
i
=relative density
Based on