23.4 Lasers
685
(a)
(b)
(c)
laser
ridge
Fig. 23.66 a Horizontal Fabry–Perot cavity InP-based laser with 1310 nm emission length and 10 mW output power
for modulation at 2.5 GB/s. The right facet is formed as DBR, emission is to the left. The trapezoid area in the center
bottom of the image is the bond pad for the top contact. b Horizontal-cavity surface-emitting laser. Compared to a, the
right facet is replaced with a 45 ◦ mirror, leading to surface emission. c Schematic drawing of the tilted facet. Parts a and
b from [2020]
Fig. 23.67 In-plane near field of a VCSEL with 6 µm oxide aperture at various currents, a 3.0 mA, b, 6.2 mA, c 14.7 mA,
d 18 mA
(a)
(b)
Fig. 23.68 a, b VCSEL arrays. Part a reprinted from [2022] with permission, part b reprinted from [2023] with
permission
e.g. for InP-based VCSELs. In Fig. 23.69, the distribution of light intensity along a 3λ/2 cavity is
shown. In the stop band of the mirrors, there is only one optical mode, the cavity mode, that can
propagate along the vertical (z) direction.
The current path through the active layer can be defined with an oxide aperture. This aperture is
fabricated by selective oxidation of an AlAs layer, leaving a circular opening in the center of the
VCSEL pillar as shown in Fig. 23.70. The current can be injected through the mirrors if they are doped.
Alternatively, the current can be directly fed to the active layer by so-called intracavity contacts.
The emission wavelength of a VCSEL can be shifted via a variation of temperature or pump power.
Tuning of the VCSEL emission can also be accomplished by leaving an air gap between the cavity
685
(a)
(b)
(c)
laser
ridge
Fig. 23.66 a Horizontal Fabry–Perot cavity InP-based laser with 1310 nm emission length and 10 mW output power
for modulation at 2.5 GB/s. The right facet is formed as DBR, emission is to the left. The trapezoid area in the center
bottom of the image is the bond pad for the top contact. b Horizontal-cavity surface-emitting laser. Compared to a, the
right facet is replaced with a 45 ◦ mirror, leading to surface emission. c Schematic drawing of the tilted facet. Parts a and
b from [2020]
Fig. 23.67 In-plane near field of a VCSEL with 6 µm oxide aperture at various currents, a 3.0 mA, b, 6.2 mA, c 14.7 mA,
d 18 mA
(a)
(b)
Fig. 23.68 a, b VCSEL arrays. Part a reprinted from [2022] with permission, part b reprinted from [2023] with
permission
e.g. for InP-based VCSELs. In Fig. 23.69, the distribution of light intensity along a 3λ/2 cavity is
shown. In the stop band of the mirrors, there is only one optical mode, the cavity mode, that can
propagate along the vertical (z) direction.
The current path through the active layer can be defined with an oxide aperture. This aperture is
fabricated by selective oxidation of an AlAs layer, leaving a circular opening in the center of the
VCSEL pillar as shown in Fig. 23.70. The current can be injected through the mirrors if they are doped.
Alternatively, the current can be directly fed to the active layer by so-called intracavity contacts.
The emission wavelength of a VCSEL can be shifted via a variation of temperature or pump power.
Tuning of the VCSEL emission can also be accomplished by leaving an air gap between the cavity