Figures 8.14, 8.15 and 8.16 show the experimental workbench and OEO samples
with QWLD at direct modulation operating in the microwave range 8.2 GHz with
optical fiber length 4464 and 100 m
During experimental works, the operating variant of OEO with the external
Mach–Zehnder modulator of the microwave range was developed and examined.
The functional diagram (a) and the general view (b) of experimental sample of the
low-noise laser optoelectronic oscillator with the Mach–Zehnder external modulator
of microwave range are presented in Fig. 8.16. The operating generated frequencies
are 8.2 and 10.1 GHz at application of different radio-frequency high-Q filters. The
following abbreviations are introduces in Fig. 8.16: QWLD ¼ a laser diode,
MZ ¼ the electro-optical Mach–Zehnder modulator, FOLG ¼ the fiber optical
light guide, PD ¼ the photodetector, NA ¼ the nonlinear amplifier, F ¼ the radiofrequency filter, C ¼ the directional coupler.
A wavelength of a laser diode is about 1550 nm. The line width of the laser
optical emission is less that 1 MHz. The generated signal power of OEO is 1.8 mW.
In OEO, the Mach–Zehnder modulator from Hitachi is used. At that, we use
specially developed by authors regulators of the bias current of the laser diode, the
temperature laser diode regulator, the bias voltage regulator for the Mach–Zehnder
modulator, the supply voltage regulator for an amplifier, and the photodiode current
regulator.
With the aim of demonstration of Q-factor influence of the RF filter on the
PSD of the phase noise of OEO with the Mach–Zehnder modulator, Fig. 8.17
shows the measurement results of the power spectral density of the phase noise at
Fig. 8.14 Experimental workbench for investigations of OEO with RF FODL operating in the
microwave range of 8–12 GHz with the optical fiber length 4464 m. QWLD (or QWLD) ¼ the
quantum-well(dimension) laser diode, PD ¼ the photodetector, FOS ¼ the fiber-optical system,
NA ¼ the nonlinear amplifier, F ¼ RF filter, SU1 ¼ stabilization units of the pumping current of the
laser diode
8.4 Implementation of OEO in the Microwave Range and Its Experimental. . .
487
with QWLD at direct modulation operating in the microwave range 8.2 GHz with
optical fiber length 4464 and 100 m
During experimental works, the operating variant of OEO with the external
Mach–Zehnder modulator of the microwave range was developed and examined.
The functional diagram (a) and the general view (b) of experimental sample of the
low-noise laser optoelectronic oscillator with the Mach–Zehnder external modulator
of microwave range are presented in Fig. 8.16. The operating generated frequencies
are 8.2 and 10.1 GHz at application of different radio-frequency high-Q filters. The
following abbreviations are introduces in Fig. 8.16: QWLD ¼ a laser diode,
MZ ¼ the electro-optical Mach–Zehnder modulator, FOLG ¼ the fiber optical
light guide, PD ¼ the photodetector, NA ¼ the nonlinear amplifier, F ¼ the radiofrequency filter, C ¼ the directional coupler.
A wavelength of a laser diode is about 1550 nm. The line width of the laser
optical emission is less that 1 MHz. The generated signal power of OEO is 1.8 mW.
In OEO, the Mach–Zehnder modulator from Hitachi is used. At that, we use
specially developed by authors regulators of the bias current of the laser diode, the
temperature laser diode regulator, the bias voltage regulator for the Mach–Zehnder
modulator, the supply voltage regulator for an amplifier, and the photodiode current
regulator.
With the aim of demonstration of Q-factor influence of the RF filter on the
PSD of the phase noise of OEO with the Mach–Zehnder modulator, Fig. 8.17
shows the measurement results of the power spectral density of the phase noise at
Fig. 8.14 Experimental workbench for investigations of OEO with RF FODL operating in the
microwave range of 8–12 GHz with the optical fiber length 4464 m. QWLD (or QWLD) ¼ the
quantum-well(dimension) laser diode, PD ¼ the photodetector, FOS ¼ the fiber-optical system,
NA ¼ the nonlinear amplifier, F ¼ RF filter, SU1 ¼ stabilization units of the pumping current of the
laser diode
8.4 Implementation of OEO in the Microwave Range and Its Experimental. . .
487