obtaining S(F) ¼ À 120 dB/Hz, the value B must be B ¼ 10
À10 , which takes place
in the fiber lasers and the semiconductor lasers with the specific resonators.
The calculated functions of the relative power spectral density of the phase noise
of RF oscillations of OEO MZ S(F) versus the frequency offset by F from the mean
generation frequency 10 GHz are presented in Fig. 6.27.
In Fig. 6.27, the presented plots correspond to PSD of the phase noise of OEO
MZ S(F): curve 1—of PD K
2
2ΓPN S PD F
ð Þ, curve 2—of NA K
2
2ΓPN S NA F
ð Þ, curve 3—of
QWLD K
2
2ΓPN S L F
ð Þ, curve 4—of OEO MZ calculated by Eqs. (6.89) and (6.90) for
the following OEO parameters: Δv ¼ 10.0 kHz; P OL ¼ 20 mW; D NA ¼ 100;
D OA ¼ 40; η 1 ¼ 1; K OMZ ¼ 0.5; K FODL ¼ 1; T FOS ¼ 1 μs (the FOS length is
200 m); K FODL ¼ 1.1, the optical frequency of QWLD v 0 ¼ 1.29 Á 10
14 Hz.
On the base of formulas (6.77) and (6.90) obtained in the present section, we
calculated the power spectral density of the phase noise of OEO MZ RF oscillations
S(F) as a function of the ratio of the laser optical power to its threshold value and the
dependences of the normalized first harmonic amplitude in OEO MZ and the RF
FODL transfer function versus this ratio. The module of the slope of S(σ U ) increases
at offset decrease and is ΔS/Δσ U ¼ 2 dB/Hz. The function of the power spectral
density S of the phase noise in OEO MZ S(σ U ) versus the nonlinearity coefficient
σ U ¼ σ was calculated by Eqs. (6.77) and (6.90). At that, the generation frequency is
10 GHz, the mean width of the laser emission spectral line Δv ¼ 10 kHz.
Figure 6.28a shows the function of the SSB power spectral density of the phase
noise in OEO MZ S(T FOS ) versus the delay time T FOS in the optical fiber for different
values of offsets F from the generation frequency of 10 GHz. At that, the generation
frequency of OEO MZ is equal to 10 GHz, the width of the laser emission spectral
line is Δv ¼ 10 kHz.
Fig. 6.27 Calculated
functions of the power
spectral density of the phase
noise S(F) of RF oscillations
in OEO MZ with the
nondispersive RF FODL
and the high-coherent laser
as functions of frequency
offset F from the nominal
frequency of the subcarrier
10.0 GHz at spectral line
width of the laser optical
emission Δv ¼ 100 kHz.
The plots of PSD of the
phase noise of: 1—PD, 2—
NA, 3—the laser, 4—OEO
MZ are presented
346
6 Operation Analysis of Optoelectronic oscillator (OEO) with External. . .
À10 , which takes place
in the fiber lasers and the semiconductor lasers with the specific resonators.
The calculated functions of the relative power spectral density of the phase noise
of RF oscillations of OEO MZ S(F) versus the frequency offset by F from the mean
generation frequency 10 GHz are presented in Fig. 6.27.
In Fig. 6.27, the presented plots correspond to PSD of the phase noise of OEO
MZ S(F): curve 1—of PD K
2
2ΓPN S PD F
ð Þ, curve 2—of NA K
2
2ΓPN S NA F
ð Þ, curve 3—of
QWLD K
2
2ΓPN S L F
ð Þ, curve 4—of OEO MZ calculated by Eqs. (6.89) and (6.90) for
the following OEO parameters: Δv ¼ 10.0 kHz; P OL ¼ 20 mW; D NA ¼ 100;
D OA ¼ 40; η 1 ¼ 1; K OMZ ¼ 0.5; K FODL ¼ 1; T FOS ¼ 1 μs (the FOS length is
200 m); K FODL ¼ 1.1, the optical frequency of QWLD v 0 ¼ 1.29 Á 10
14 Hz.
On the base of formulas (6.77) and (6.90) obtained in the present section, we
calculated the power spectral density of the phase noise of OEO MZ RF oscillations
S(F) as a function of the ratio of the laser optical power to its threshold value and the
dependences of the normalized first harmonic amplitude in OEO MZ and the RF
FODL transfer function versus this ratio. The module of the slope of S(σ U ) increases
at offset decrease and is ΔS/Δσ U ¼ 2 dB/Hz. The function of the power spectral
density S of the phase noise in OEO MZ S(σ U ) versus the nonlinearity coefficient
σ U ¼ σ was calculated by Eqs. (6.77) and (6.90). At that, the generation frequency is
10 GHz, the mean width of the laser emission spectral line Δv ¼ 10 kHz.
Figure 6.28a shows the function of the SSB power spectral density of the phase
noise in OEO MZ S(T FOS ) versus the delay time T FOS in the optical fiber for different
values of offsets F from the generation frequency of 10 GHz. At that, the generation
frequency of OEO MZ is equal to 10 GHz, the width of the laser emission spectral
line is Δv ¼ 10 kHz.
Fig. 6.27 Calculated
functions of the power
spectral density of the phase
noise S(F) of RF oscillations
in OEO MZ with the
nondispersive RF FODL
and the high-coherent laser
as functions of frequency
offset F from the nominal
frequency of the subcarrier
10.0 GHz at spectral line
width of the laser optical
emission Δv ¼ 100 kHz.
The plots of PSD of the
phase noise of: 1—PD, 2—
NA, 3—the laser, 4—OEO
MZ are presented
346
6 Operation Analysis of Optoelectronic oscillator (OEO) with External. . .