more than 5–10 times. The extreme suppression of the phase noises is achieved at
small values of σ U and for P 0L /Y 00 values closed to the stability boundary in the
steady-state mode, for example, σ U ¼ 1.02 and P 0L /Y 00 ¼ 1.01, or closed the
generation mode with small excess over the threshold value. The increase of the
laser power and the ratio P 0L /Y 00 does not improve the picture of phase noise
suppression in OEO MZ, but at that, the threshold level of OEO generation undoubtedly decreases.
PSD of the phase noise is much more than PSD of the amplitude noise or
S aμRe Á (Y aRe À 1)
2
( S aμIm Á [Y aIm ]
2 .
Further, we examine the mode when the in-phase component S aμRe is much more
than the quadrature S aμIm . In other words, the level of detected laser noises in the PD
load (PSD of the phase noise) is much more than PSD of the amplitude noise. In this
case, we can simplify Eqs. (6.49) and (6.50): S aμRe Á (Y aRe À 1)
2
( S aμIm Á [Y aIm ]
2 .
10
1
0.10
100
0.01
0.05
s U =1.2
=1.1
P 0L
Y 00
0.10
0.50
Offset frequency
Offset frequency
K 2
ΓPN
K 2
ΓPN
K 2
ΓAN
K 2
ΓAN
K 2
ΓAN (F) , K 2
ΓPN (F)
10
1
0.10
100
K 2
ΓAN (F) , K 2
ΓPN (F)
(a)
(b)
1
5 10
5
10
15
Fig. 6.13 Suppression coefficients for the amplitude K
2
ΓAN F
ð Þ and the phase K
2
ΓPN F
ð Þ noise in
OEO MZ at P 0L /Y 00 ¼ 1.1 for σ U ¼ 1.2 depicted on expressions (6.54) and (6.55). On the abscissa
axis the logarithmic scale (a); on the abscissa axis the linear scale (b)
1000
1
0.001
0.05
s U =1.02
=1.01
P 0L
Y 00
0.10
0.50
Offset frequency
K 2
ΓPN
K 2
ΓAN
K 2
ΓAN (F) , K 2
ΓPN (F)
(a)
1
5 1 0
100
10
1
1000
0.10
0.01
0.05
s U =1.02
=1.1
P 0L
Y 00
0.10
0.50
Offset frequency
K 2
ΓPN
K 2
ΓAN
K 2
ΓAN (F) , K 2
ΓPN (F)
(b)
1
5 1 0
Fig. 6.14 Suppression coefficients of the amplitude K
2
ΓAN F
ð Þand the phase K
2
ΓPN F
ð Þnoise in OEO
MZ at σ U ¼ 1.02 and P 0L /Y 00 ¼ 1.01 (a); σ U ¼ 1.02 and P 0L /Y 00 ¼ 1.1 for (b) depicted on
expressions (6.54) and (6.55). The abscissa axis has the logarithmic scale (a). The abscissa axis has
the linear scale (b)
6.5 Differential Fluctuation Equations of OEO MZ
321
small values of σ U and for P 0L /Y 00 values closed to the stability boundary in the
steady-state mode, for example, σ U ¼ 1.02 and P 0L /Y 00 ¼ 1.01, or closed the
generation mode with small excess over the threshold value. The increase of the
laser power and the ratio P 0L /Y 00 does not improve the picture of phase noise
suppression in OEO MZ, but at that, the threshold level of OEO generation undoubtedly decreases.
PSD of the phase noise is much more than PSD of the amplitude noise or
S aμRe Á (Y aRe À 1)
2
( S aμIm Á [Y aIm ]
2 .
Further, we examine the mode when the in-phase component S aμRe is much more
than the quadrature S aμIm . In other words, the level of detected laser noises in the PD
load (PSD of the phase noise) is much more than PSD of the amplitude noise. In this
case, we can simplify Eqs. (6.49) and (6.50): S aμRe Á (Y aRe À 1)
2
( S aμIm Á [Y aIm ]
2 .
10
1
0.10
100
0.01
0.05
s U =1.2
=1.1
P 0L
Y 00
0.10
0.50
Offset frequency
Offset frequency
K 2
ΓPN
K 2
ΓPN
K 2
ΓAN
K 2
ΓAN
K 2
ΓAN (F) , K 2
ΓPN (F)
10
1
0.10
100
K 2
ΓAN (F) , K 2
ΓPN (F)
(a)
(b)
1
5 10
5
10
15
Fig. 6.13 Suppression coefficients for the amplitude K
2
ΓAN F
ð Þ and the phase K
2
ΓPN F
ð Þ noise in
OEO MZ at P 0L /Y 00 ¼ 1.1 for σ U ¼ 1.2 depicted on expressions (6.54) and (6.55). On the abscissa
axis the logarithmic scale (a); on the abscissa axis the linear scale (b)
1000
1
0.001
0.05
s U =1.02
=1.01
P 0L
Y 00
0.10
0.50
Offset frequency
K 2
ΓPN
K 2
ΓAN
K 2
ΓAN (F) , K 2
ΓPN (F)
(a)
1
5 1 0
100
10
1
1000
0.10
0.01
0.05
s U =1.02
=1.1
P 0L
Y 00
0.10
0.50
Offset frequency
K 2
ΓPN
K 2
ΓAN
K 2
ΓAN (F) , K 2
ΓPN (F)
(b)
1
5 1 0
Fig. 6.14 Suppression coefficients of the amplitude K
2
ΓAN F
ð Þand the phase K
2
ΓPN F
ð Þnoise in OEO
MZ at σ U ¼ 1.02 and P 0L /Y 00 ¼ 1.01 (a); σ U ¼ 1.02 and P 0L /Y 00 ¼ 1.1 for (b) depicted on
expressions (6.54) and (6.55). The abscissa axis has the logarithmic scale (a). The abscissa axis has
the linear scale (b)
6.5 Differential Fluctuation Equations of OEO MZ
321