Page 472 - High Power Laser Handbook

440 Fi b er L a s er s Intr oduction to Optical Fiber Lasers 441

1.0E+02
Second-order mode
1.0E+01
Confinement loss (dB/m) 1.0E+00

1.0E−01

1.0E−02

1.0E−03
Fundamental mode
1.0E−04
0.50 0.55 0.60 0.65 0.70
d/Λ
(a)

d
0.95

2ρ
0.85
∆
d/Λ
0.75

0.65

0.55
25 50 75 100 120 150 175 200
Core diameter (µm)
(b)
Figure 15.22 (a) Confinement losses for the fundamental and second-
order mode in leakage channel fibers (LCFs) with a 50-µm core diameter.
(b) Design space of LCFs constrained by a fundamental mode loss of less
than 0.1 dB/m and second-order mode loss larger than 1 dB/m. (Designs
are illustrated in the insets. n = 1.444, n = 1.4428, and λ = 1 µm.)
B
F