for different pumping current without the fixation to the exact values only for
understanding of physical processes. Values and the slope of PFC decrease with
the growth of the pumping current. The ratio of the module of the QWLD transfer
function owing to the coherent stimulated emission to the module of the transfer
function owing to spontaneous emission is 10
À2 to 10
À3 for different QWLDs. With
the pumping current growth, the PFC value and the slope due to the luminescence
increase for different frequency values. Designations RFF1 and RFF2 is concerned
to the inverted PFC of RF filters, which are tuned in different frequencies.
7.3.4 Frequency and Amplitude Control in OEO with QWLD
Now we consider structures of OEO with QWLD presented in Fig. 7.16a, which
differential equations had analyzed in Chap. 5. From the differential equation
(Eq. 5.64) or from the solution of equations of amplitude and phase balance with
account of AFC and PFC of QWLD for the structure in Fig. 7.16a presented in
Fig. 7.18, we obtain expressions for the amplitude and the frequency of oscillations
in OEO with QWLD in the steady-state mode:
f OEO ffi
m þ f eF Á T eF
T PD þ T A þ T FOS þ T eF þ argK LD = 2π f eF
ð
Þ
,
ð7:38Þ
where T eF is the effective delay time in the opened OEO, T PD , T NA are time constants
of PD and NA, T FOS is the delay in FOS, argK LD is the argument of the QWLD
transfer function, f eF is the natural frequency of the RF filter.
Fig. 7.18 Calculated AFC (а) and PFC (b) of the mesa-strip QWLD for different pumping
currents. The threshold pumping current is 12 mA. RFF1, RFF2 are modules and “inverted”
arguments of different (used in Figs. 2.1 and 2.2 in Chap. 2) RF filters with various own frequencies,
SE is the module and argument of the transfer function owing to spontaneous emission
402
7 Optoelectronic oscillator (OEO) as the Time and Spatial Correlator of Random. . .
understanding of physical processes. Values and the slope of PFC decrease with
the growth of the pumping current. The ratio of the module of the QWLD transfer
function owing to the coherent stimulated emission to the module of the transfer
function owing to spontaneous emission is 10
À2 to 10
À3 for different QWLDs. With
the pumping current growth, the PFC value and the slope due to the luminescence
increase for different frequency values. Designations RFF1 and RFF2 is concerned
to the inverted PFC of RF filters, which are tuned in different frequencies.
7.3.4 Frequency and Amplitude Control in OEO with QWLD
Now we consider structures of OEO with QWLD presented in Fig. 7.16a, which
differential equations had analyzed in Chap. 5. From the differential equation
(Eq. 5.64) or from the solution of equations of amplitude and phase balance with
account of AFC and PFC of QWLD for the structure in Fig. 7.16a presented in
Fig. 7.18, we obtain expressions for the amplitude and the frequency of oscillations
in OEO with QWLD in the steady-state mode:
f OEO ffi
m þ f eF Á T eF
T PD þ T A þ T FOS þ T eF þ argK LD = 2π f eF
ð
Þ
,
ð7:38Þ
where T eF is the effective delay time in the opened OEO, T PD , T NA are time constants
of PD and NA, T FOS is the delay in FOS, argK LD is the argument of the QWLD
transfer function, f eF is the natural frequency of the RF filter.
Fig. 7.18 Calculated AFC (а) and PFC (b) of the mesa-strip QWLD for different pumping
currents. The threshold pumping current is 12 mA. RFF1, RFF2 are modules and “inverted”
arguments of different (used in Figs. 2.1 and 2.2 in Chap. 2) RF filters with various own frequencies,
SE is the module and argument of the transfer function owing to spontaneous emission
402
7 Optoelectronic oscillator (OEO) as the Time and Spatial Correlator of Random. . .