The nonlinear functions of the emission power obtained by authors and presented
in Fig. 8.4 versus the DC pumping current of the LED, the usual LD, and the
quantum-well laser diode QWLD have the following qualitative differences. The
LED nonlinear characteristics can be approximated by the quadratic function
P 0 ¼ γ(I 0 )
2 .
The nonlinear characteristic of the usual (non-quantum-well) is approximated by
the cubic function P 0 ¼ γ(I 0 À I thr )
2 , while the nonlinear characteristics of QWLD
(on the some segments) can be approximated by the linear function P 0 ¼ γ(I 0 À I thr ),
or by the square root function: P 0 ¼
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ffi
γ I 0 À I thr
ð
Þ
p
. Here I thr is the threshold current.
The QWLD (the laser diode Dilas with the emission power 10–15 mW, the
wavelength 1.3 μm, RF modulation is 12 GHz (Fig. 8.3e)) spectra presented in
Fig. 8.4 and measured by authors allows the conclusion that the function of the
generation wavelength of the QWLD central mode increases monotonically at the
pumping DC current growth.
Fig. 8.3 General views of laser diodes ILPN-204 (а), 32DL-103 (b), and an external view of the
laser diode board with an electronic modulator (c), laser diode SL T5412 (15 GHz) (d), laser diode
Dilas (12 GHz) (e), photodiode Dilas (12 GHz) (f), photodiode FRM5N1 (15 GHz) (g)
8.1 Characteristics of Modulated Emission Sources: The Laser Diode and the. . .
469
in Fig. 8.4 versus the DC pumping current of the LED, the usual LD, and the
quantum-well laser diode QWLD have the following qualitative differences. The
LED nonlinear characteristics can be approximated by the quadratic function
P 0 ¼ γ(I 0 )
2 .
The nonlinear characteristic of the usual (non-quantum-well) is approximated by
the cubic function P 0 ¼ γ(I 0 À I thr )
2 , while the nonlinear characteristics of QWLD
(on the some segments) can be approximated by the linear function P 0 ¼ γ(I 0 À I thr ),
or by the square root function: P 0 ¼
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ffi
γ I 0 À I thr
ð
Þ
p
. Here I thr is the threshold current.
The QWLD (the laser diode Dilas with the emission power 10–15 mW, the
wavelength 1.3 μm, RF modulation is 12 GHz (Fig. 8.3e)) spectra presented in
Fig. 8.4 and measured by authors allows the conclusion that the function of the
generation wavelength of the QWLD central mode increases monotonically at the
pumping DC current growth.
Fig. 8.3 General views of laser diodes ILPN-204 (а), 32DL-103 (b), and an external view of the
laser diode board with an electronic modulator (c), laser diode SL T5412 (15 GHz) (d), laser diode
Dilas (12 GHz) (e), photodiode Dilas (12 GHz) (f), photodiode FRM5N1 (15 GHz) (g)
8.1 Characteristics of Modulated Emission Sources: The Laser Diode and the. . .
469