multifrequency laser, or the laser with passive or active synchronization of longitudinal modes. We may also notice circuits for RF oscillation formation with the
frequency of 40 GHz using the nonlinear Brillouin effect in the specific perforated
optical fiber. The cross-section of such an optical fiber is shown in Fig. 2.13a, b [79].
Table 2.4 Methods of oscillation formation in RF oscillators, lasers (OQG), and in the optoelectronic oscillator
Traditionally RF
oscillators
OEO as the laser with the positive
feedback loop
The laser or the
optical quantum
generator
Oscillation
frequency f 0
and ν 0
f 0 ¼ 0.001–100 GHz f 0 ¼ 0.001–100 GHz
ν 0 ¼ 100–280 THz
ν 0 ¼ 100–280 THz
The main
construction
circuit
The RF van-der Pol
oscillator
The RF van-der Pol oscillator + RF FODL
OQG—the van-der
Pol oscillator
Resonator or
delay lines,
their Q-factor
and time
constants
Electronic: QR,
SAW, DCR, YIG,
DDRLS.
Q ¼ 10
6
,
T ep ¼ 10
À4 s
Electronic: QR, SAW, DCR,
YIG, DDRLs
Optical: {Fabry–Perot, DOptR,
BraggR, FtCr} + RF FODL + Cz
cell
Q REFODL ¼ 10
6
Q e ¼ 10
6
, T ep ¼ 10
À4 s
Optical: {Fabry–
Perot, DOptR,
FtCr, FOS,
BraggR}
Q O ¼ (2 Â 10
3
)/
10
10
T op ¼ 10
À11 s
Natural width
of the RF
spectral line
and laser
generation
Δf G ¼
f 0
Q e
2 kTB
2Pe
Defined by laser noises, which
have the quantum nature, and by
noises of the electronic amplifier
Δν ¼
ν
2
0 hν0
Q
2
O 2POL
Active elements and
their noises
RF amplifier {Thermal noise and shot
noise, flicker noise
(1/f ) etc.}
RF amplifier + laser + photodetector {Spontaneous quantum
noise} + {noise of photodetector} + {thermal noise and shot
noise, flicker-noise (1/f )}
Active optical
medium with
inverse population.
Spontaneous quantum noise. Noises
of carriers, the
pumping current
Restrictions
on Q-factor
improvement
of the oscillating system
Sound-wave dispersion and losses in the
resonator
RF FODL light dispersion,
nonlinear effects in the optical
resonator, thermal effects
Dispersion of the
optical amplifier,
laser and optical
fiber system
S ¼
f
2
0 kTB
Q
2
e Pe
DY
4F
2
PSD of phase noise
is determined by
phase noises of a
laser, the electronic
amplifier, and the
photodetector.
S F
ð Þ ¼
ν
2
0 hν0D0Y
4Q
2
O F
2 POL
2.9 Modern Optoelectronic Methods for Precision RF Oscillation Formation
63
frequency of 40 GHz using the nonlinear Brillouin effect in the specific perforated
optical fiber. The cross-section of such an optical fiber is shown in Fig. 2.13a, b [79].
Table 2.4 Methods of oscillation formation in RF oscillators, lasers (OQG), and in the optoelectronic oscillator
Traditionally RF
oscillators
OEO as the laser with the positive
feedback loop
The laser or the
optical quantum
generator
Oscillation
frequency f 0
and ν 0
f 0 ¼ 0.001–100 GHz f 0 ¼ 0.001–100 GHz
ν 0 ¼ 100–280 THz
ν 0 ¼ 100–280 THz
The main
construction
circuit
The RF van-der Pol
oscillator
The RF van-der Pol oscillator + RF FODL
OQG—the van-der
Pol oscillator
Resonator or
delay lines,
their Q-factor
and time
constants
Electronic: QR,
SAW, DCR, YIG,
DDRLS.
Q ¼ 10
6
,
T ep ¼ 10
À4 s
Electronic: QR, SAW, DCR,
YIG, DDRLs
Optical: {Fabry–Perot, DOptR,
BraggR, FtCr} + RF FODL + Cz
cell
Q REFODL ¼ 10
6
Q e ¼ 10
6
, T ep ¼ 10
À4 s
Optical: {Fabry–
Perot, DOptR,
FtCr, FOS,
BraggR}
Q O ¼ (2 Â 10
3
)/
10
10
T op ¼ 10
À11 s
Natural width
of the RF
spectral line
and laser
generation
Δf G ¼
f 0
Q e
2 kTB
2Pe
Defined by laser noises, which
have the quantum nature, and by
noises of the electronic amplifier
Δν ¼
ν
2
0 hν0
Q
2
O 2POL
Active elements and
their noises
RF amplifier {Thermal noise and shot
noise, flicker noise
(1/f ) etc.}
RF amplifier + laser + photodetector {Spontaneous quantum
noise} + {noise of photodetector} + {thermal noise and shot
noise, flicker-noise (1/f )}
Active optical
medium with
inverse population.
Spontaneous quantum noise. Noises
of carriers, the
pumping current
Restrictions
on Q-factor
improvement
of the oscillating system
Sound-wave dispersion and losses in the
resonator
RF FODL light dispersion,
nonlinear effects in the optical
resonator, thermal effects
Dispersion of the
optical amplifier,
laser and optical
fiber system
S ¼
f
2
0 kTB
Q
2
e Pe
DY
4F
2
PSD of phase noise
is determined by
phase noises of a
laser, the electronic
amplifier, and the
photodetector.
S F
ð Þ ¼
ν
2
0 hν0D0Y
4Q
2
O F
2 POL
2.9 Modern Optoelectronic Methods for Precision RF Oscillation Formation
63