external modulation in the MZ modulator is from 0.1 to 40 GHz and exceeds tuning
ranges of other types of oscillators.
The primary cesium frequency standard (Agilent 5071A from Hewlett-Packard
Company) is the oscillator having the best long-term frequency stability. We should
note that the cost of such commercial oscillators approaches to several ten thousand
dollar depending on complete set.
Power spectral density of the oscillator phase noise is the most suitable characteristics, which reflects of its noisy properties. Noises in oscillators participate in
formation of its spectral liney. The most of known methods for noise measurement
are useless concerning the reference oscillator due to their inability to analyze extranarrowband signals. The oscillator noise can be described more convenient with the
help of such concepts as power spectral densities of amplitude S a ( f ), W/Hz, and
phase S φ (f), rad
2 /Hz, noises, which are functions of the analysis frequency f. The
power spectral density of the oscillator phase noise defines the short-term frequency
instability. So, the low-noise oscillator with the disk dielectric resonator from the
leuco-sapphire, which has a generation frequency about 10–12 GHz, has the best
short-term frequency instability [25, 29, 30, 65] (Table 2.3).
YIG oscillators and oscillators on Gunn diodes, which are electrically tuned in the
wide ranges, have the high output power of 40–400 mW [66], small dimensions
(20 Â 40 Â 40 mm
3 ) and the low cost ($300–$3000) and have advantages in this
regard over low-noise oscillators on the leuco-sapphire dielectric resonators. But
these oscillators have the low short-term and long-term frequency stability and have
low quality of spectrum purity. Their PSD of the phase noise is À50 to 70 dB/Hz at
standard offset 10 kHz from the carrier in the range 2–8 GHz. The utilization of
modern CAD tools allows optimization for the accurate YIG oscillator, which results
in a phase noise performance below À133 dBc/Hz at the frequency offset of 100 kHz
over the entire range of 6–12 GHz [66].
Oscillators on dielectric resonators from ceramics can be attributed to more
efficient models. Their PSD of the phase noise of frequency offset 10 kHz from
the carrier in the range 2–22 GHz is À100 to À90 dBc/Hz [67, 68]. Their cost is from
$2000 to $15,000. SAW oscillators with frequency multiplication take the intermediate place between quartz oscillators and oscillators with dielectric resonators in
their technical specifications. Their cost is from $100 to $7000.
PSD of phase noises in traditional electronic oscillators is determined by the
resonator or the delay line Q-factor. Overall dimensions of oscillators depend on
resonator sizes, because active element (transistors) used in such oscillators have the
overall dimensions by 100 and 1000 times less than the resonator dimensions.
2.8.2 Q-factors of Oscillator Resonance Systems
For comparison, Fig. 2.14a shows the loaded Q-factors of resonators of traditional
oscillators and OEO with RF FODL, and Fig. 2.14b shows the normalized (to delay
time) power losses at oscillation propagation. From analysis of resonator (and delay
50
2 Nanostructural Optoelectronic Oscillators with the Fiber-Optical Delay Line
ranges of other types of oscillators.
The primary cesium frequency standard (Agilent 5071A from Hewlett-Packard
Company) is the oscillator having the best long-term frequency stability. We should
note that the cost of such commercial oscillators approaches to several ten thousand
dollar depending on complete set.
Power spectral density of the oscillator phase noise is the most suitable characteristics, which reflects of its noisy properties. Noises in oscillators participate in
formation of its spectral liney. The most of known methods for noise measurement
are useless concerning the reference oscillator due to their inability to analyze extranarrowband signals. The oscillator noise can be described more convenient with the
help of such concepts as power spectral densities of amplitude S a ( f ), W/Hz, and
phase S φ (f), rad
2 /Hz, noises, which are functions of the analysis frequency f. The
power spectral density of the oscillator phase noise defines the short-term frequency
instability. So, the low-noise oscillator with the disk dielectric resonator from the
leuco-sapphire, which has a generation frequency about 10–12 GHz, has the best
short-term frequency instability [25, 29, 30, 65] (Table 2.3).
YIG oscillators and oscillators on Gunn diodes, which are electrically tuned in the
wide ranges, have the high output power of 40–400 mW [66], small dimensions
(20 Â 40 Â 40 mm
3 ) and the low cost ($300–$3000) and have advantages in this
regard over low-noise oscillators on the leuco-sapphire dielectric resonators. But
these oscillators have the low short-term and long-term frequency stability and have
low quality of spectrum purity. Their PSD of the phase noise is À50 to 70 dB/Hz at
standard offset 10 kHz from the carrier in the range 2–8 GHz. The utilization of
modern CAD tools allows optimization for the accurate YIG oscillator, which results
in a phase noise performance below À133 dBc/Hz at the frequency offset of 100 kHz
over the entire range of 6–12 GHz [66].
Oscillators on dielectric resonators from ceramics can be attributed to more
efficient models. Their PSD of the phase noise of frequency offset 10 kHz from
the carrier in the range 2–22 GHz is À100 to À90 dBc/Hz [67, 68]. Their cost is from
$2000 to $15,000. SAW oscillators with frequency multiplication take the intermediate place between quartz oscillators and oscillators with dielectric resonators in
their technical specifications. Their cost is from $100 to $7000.
PSD of phase noises in traditional electronic oscillators is determined by the
resonator or the delay line Q-factor. Overall dimensions of oscillators depend on
resonator sizes, because active element (transistors) used in such oscillators have the
overall dimensions by 100 and 1000 times less than the resonator dimensions.
2.8.2 Q-factors of Oscillator Resonance Systems
For comparison, Fig. 2.14a shows the loaded Q-factors of resonators of traditional
oscillators and OEO with RF FODL, and Fig. 2.14b shows the normalized (to delay
time) power losses at oscillation propagation. From analysis of resonator (and delay
50
2 Nanostructural Optoelectronic Oscillators with the Fiber-Optical Delay Line