mechanics equations is rather complicate, and the theoretical investigation practice
shows that for accurate description of processes in the optical quantum generators is
sufficient to use the semiclassical model in the dipole approximation. As we already
mentioned, in this book, we use exactly such a semiclassical laser model in the
dipole approximation for an analysis of the OEO PSD phase noise (Chaps. 4, 6, and
7). If to perform the investigation of OEO phase noise within the limits of this
semiclassical laser model, we must add the traditional model built for electric field
strength of the laser stimulated emission by the noise source also in the dimension of
the electric field strength, which is proportional to the spontaneous emission level in
the quasi-steady-state condition.
2.4 Hybrid Utilization of Up-to-Date Electro-Optical
Elements and Microwave Elements in OEO
OEO as the oscillation source of new type has advantages caused by the combined
use of up-to-date solid-state components and elements of optoelectronics and
acoustic-optics, the optical fibers and the traditional element base of microwave
and mm-wave engineering.
Application in OEO of the single optical fiber (together with the low-noise laser
and the photodiodes) allows development of the compact (10 mm  100 mm Â
100 mm) low-noise RF FODL of high-Q (more than 1,000,000) with the delay more
than 50 μs (at the fiber length of 10 km). Electric power losses of the transmitted
signal in the frequency range from 0.1 Hz to 50 GHz are from À10 to À18 dB at the
fiber length not more than several kilometers.
This low level of microwave losses occurs at the expense of the relatively high
slope of laser and photodiode transformation, low optical attenuation in optical fibers
and in directional couplers. Such a RF FODL is stable to high percussion and longterm dynamic overloads and acceleration (2–10 g), to long-term acoustic impacts.
The nearest alternative solution of the microwave oscillator on the sapphire monocrystals [25] cannot endure of high percussive and dynamic loads more than
100–200 N/sm
2 . On the other hand, the creation of oscillation delay more than
50 μs (at optical fiber length of 10 km) is possible in RF FODL. At that, due to
raising of the geometric fiber length, the laser power growth, application of the
low-noise lasers in RF FODL, we can achieve the OEO phase noise less than
À120 dB/Hz at frequency offset 1 kHz from 10 GHz carrier.
Obtaining of the microwave phase modulation of the optical emission became
possible at appearance of electro-optical phase modulators of the microwave oscillations. Effective reduction of the phase noise in OEO takes place at the expense of
the RF FODL use with large delay time (10–50 μs for oscillations with frequencies
8–12 GHz), as well as at the expense of coherent photodetection use and the
heterodyne mixing of two delayed optical oscillations. An opportunity to obtain
the phase noise compensation at self-heterodyne mixing is caused by the high ratio
30
2 Nanostructural Optoelectronic Oscillators with the Fiber-Optical Delay Line
shows that for accurate description of processes in the optical quantum generators is
sufficient to use the semiclassical model in the dipole approximation. As we already
mentioned, in this book, we use exactly such a semiclassical laser model in the
dipole approximation for an analysis of the OEO PSD phase noise (Chaps. 4, 6, and
7). If to perform the investigation of OEO phase noise within the limits of this
semiclassical laser model, we must add the traditional model built for electric field
strength of the laser stimulated emission by the noise source also in the dimension of
the electric field strength, which is proportional to the spontaneous emission level in
the quasi-steady-state condition.
2.4 Hybrid Utilization of Up-to-Date Electro-Optical
Elements and Microwave Elements in OEO
OEO as the oscillation source of new type has advantages caused by the combined
use of up-to-date solid-state components and elements of optoelectronics and
acoustic-optics, the optical fibers and the traditional element base of microwave
and mm-wave engineering.
Application in OEO of the single optical fiber (together with the low-noise laser
and the photodiodes) allows development of the compact (10 mm  100 mm Â
100 mm) low-noise RF FODL of high-Q (more than 1,000,000) with the delay more
than 50 μs (at the fiber length of 10 km). Electric power losses of the transmitted
signal in the frequency range from 0.1 Hz to 50 GHz are from À10 to À18 dB at the
fiber length not more than several kilometers.
This low level of microwave losses occurs at the expense of the relatively high
slope of laser and photodiode transformation, low optical attenuation in optical fibers
and in directional couplers. Such a RF FODL is stable to high percussion and longterm dynamic overloads and acceleration (2–10 g), to long-term acoustic impacts.
The nearest alternative solution of the microwave oscillator on the sapphire monocrystals [25] cannot endure of high percussive and dynamic loads more than
100–200 N/sm
2 . On the other hand, the creation of oscillation delay more than
50 μs (at optical fiber length of 10 km) is possible in RF FODL. At that, due to
raising of the geometric fiber length, the laser power growth, application of the
low-noise lasers in RF FODL, we can achieve the OEO phase noise less than
À120 dB/Hz at frequency offset 1 kHz from 10 GHz carrier.
Obtaining of the microwave phase modulation of the optical emission became
possible at appearance of electro-optical phase modulators of the microwave oscillations. Effective reduction of the phase noise in OEO takes place at the expense of
the RF FODL use with large delay time (10–50 μs for oscillations with frequencies
8–12 GHz), as well as at the expense of coherent photodetection use and the
heterodyne mixing of two delayed optical oscillations. An opportunity to obtain
the phase noise compensation at self-heterodyne mixing is caused by the high ratio
30
2 Nanostructural Optoelectronic Oscillators with the Fiber-Optical Delay Line