Specialty Optical Fibers Handbook

RDS ¼

D

0

(l

c

)

D(l

c

)

: (5:9)

The RDS should be considered a fundamental parameter and figure of merit

for a telecommunication optical fiber.

With reference to Fig. 5.7, consider that the transmission fiber is characterized

by length L

1

and dispersion D

1

(l), while the DCF is characterized by length L

2

and dispersion D

2

(l). Then the condition for 100% dispersion compensation

across the band of interest is that

L

1

D

1

(l) þ L

2

D

2

(l) ¼ 0(5:10)

must be satisfied for every value of l. Substituting Eq. (5.8) into Eq. (5.10) and

regrouping terms yields the following expression:

[L

1

D

1

(l

c

) þ L

2

D

2

(l

c

)] ¼ (l

c

 l)[L

1

D

0

1

(l

c

) þ L

2

D

0

2

(l

c

)]: (5:11)

In order for this expression