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74 2 Extremely Short-External-Cavity Laser Diode
(a) Absorption A, Reflectivity R (b) Absorption A, Reflectivity R
1.0 1.0

0.8 Si N 366 nm 0.8 Si N 223 nm
3 4
3 4
0.6 0.6 R
R
0.4 0.4
A A
0.2 0.2 l = 0.83 mm
l = 1.3 mm
26 nm 16 nm
0 0
0 20 40 60 80 100 0 20 40 60 80 100
(1)
(1)
Au thickness (nm) Au thickness (nm)
Fig. 2.52. Total absorption A and reflectivity R of Au/Si 3N 4/Au versus the
Au thickness at the optimum Si 3N 4 thickness for wavelengths of 1.3 µm(a),and
0.83 µm(b)

l

Antireflection films { Metal b
Dielectric
{ Metal
Bimorph films Dielectric
Semiconductor t t t t t
1 2 3 4 5
Fig. 2.53. Schematic drawing of a five-layer MC

M 1 r 1
r
M 2 2 h
r h 2 1
M 3 3
r h 3 P M’
M 4 4 h 4 1 1 d
M 5 r 5 P 2 M’ 2
h 5 P 3 M’
P 4 3
P 5 M’ 4
M’ 5

Fig. 2.54. Deflection of a five-layer MC and internal stress due to temperature
change