– Vladimir A. Prokofiev, senior engineer, MPEI
– Alexander A. Bortsov, initially Ph.D.student, after Ph.D. (2005), MPEI.
We should note the pioneer publication (1985) [44], in which the OEO structure
was substantiated, and with the help of the equation system based on amplitude and
phase balance, the amplitude and frequency of OEO generation were theoretically
calculated. Another publication [45] was devoted to the absolutely new variant of
OEO with the external acousto-optical modulator on the base of the Mach–Zehnder
interferometer with heterodyne mixing of optical harmonics of oscillations with
different frequencies. In this case, the OEO circuit represents the laser, which
emission was modulated by the electro-acoustic modulator and directed in two
optical fibers, which were excited by laser emission passed through the acoustooptical modulator. After that, this emission passed to the photodetector after transfer
through the optical fibers, and then the electric signal was amplified by the RF
amplifier, passed through the narrowband RF filter to the input of the acousto-optical
modulator.
In [46], the OEO structure with two optical fibers of different length was
considered and dependences of frequency tuning at power variation, which passed
into the optical channels were calculated. In essence, a construction presented an
interferometer with the feedback loop. Publications [55, 56] are devoted to examination of transfer functions of the single multi-mode fiber and the fiber-optical delay
line formed by two optical fibers of different lengths. An influence of mode content
of the optical fiber and excitation degrees of various optical fibers of different lengths
included in OEO were studied. A series of patents were obtained on examined OEO
breadboards. In beginning of 1990s, investigations of OEO with the external modulator on the base of the electro-acoustic cell [59].
Researches of the optoelectronic oscillator continued in Russia and in NRU MPEI
during 2003–2018. New method of frequency control was patented by using the
phase-locked loop (PLL) system in OEO on the base of differential fiber-optical
discriminator [60]. The OEO generation was obtained on the frequency 8–10 GHz
using the quantum-well laser diode (2005) [61], OEO with the Mach–Zehnder
modulator was investigated [62]. The new theoretical noisy model of OEO was
created and examined, in which we took into consideration the laser with ultralow
phase noises (less than À100 dB/Hz at offset of 10 kHz from the carrier) [63].
Many earlier misunderstandable phenomena and causal relations of OEO parameters (which were related to the mode choice of the double-channel optical Mach–
Zehnder modulator) were explained. Developed methods of characteristics examination of FODL in OEO permitted to our quantum team from MPEI with colleagues
from other Russian universities (for instance, Bauman State Technical University) to
create and provide patenting of the new technology of the radiation-resistant optical
fiber [64].
The optical fiber of such a type has relatively small loss variations (to 10%) at
radiation affect.
10
1 Introduction
– Alexander A. Bortsov, initially Ph.D.student, after Ph.D. (2005), MPEI.
We should note the pioneer publication (1985) [44], in which the OEO structure
was substantiated, and with the help of the equation system based on amplitude and
phase balance, the amplitude and frequency of OEO generation were theoretically
calculated. Another publication [45] was devoted to the absolutely new variant of
OEO with the external acousto-optical modulator on the base of the Mach–Zehnder
interferometer with heterodyne mixing of optical harmonics of oscillations with
different frequencies. In this case, the OEO circuit represents the laser, which
emission was modulated by the electro-acoustic modulator and directed in two
optical fibers, which were excited by laser emission passed through the acoustooptical modulator. After that, this emission passed to the photodetector after transfer
through the optical fibers, and then the electric signal was amplified by the RF
amplifier, passed through the narrowband RF filter to the input of the acousto-optical
modulator.
In [46], the OEO structure with two optical fibers of different length was
considered and dependences of frequency tuning at power variation, which passed
into the optical channels were calculated. In essence, a construction presented an
interferometer with the feedback loop. Publications [55, 56] are devoted to examination of transfer functions of the single multi-mode fiber and the fiber-optical delay
line formed by two optical fibers of different lengths. An influence of mode content
of the optical fiber and excitation degrees of various optical fibers of different lengths
included in OEO were studied. A series of patents were obtained on examined OEO
breadboards. In beginning of 1990s, investigations of OEO with the external modulator on the base of the electro-acoustic cell [59].
Researches of the optoelectronic oscillator continued in Russia and in NRU MPEI
during 2003–2018. New method of frequency control was patented by using the
phase-locked loop (PLL) system in OEO on the base of differential fiber-optical
discriminator [60]. The OEO generation was obtained on the frequency 8–10 GHz
using the quantum-well laser diode (2005) [61], OEO with the Mach–Zehnder
modulator was investigated [62]. The new theoretical noisy model of OEO was
created and examined, in which we took into consideration the laser with ultralow
phase noises (less than À100 dB/Hz at offset of 10 kHz from the carrier) [63].
Many earlier misunderstandable phenomena and causal relations of OEO parameters (which were related to the mode choice of the double-channel optical Mach–
Zehnder modulator) were explained. Developed methods of characteristics examination of FODL in OEO permitted to our quantum team from MPEI with colleagues
from other Russian universities (for instance, Bauman State Technical University) to
create and provide patenting of the new technology of the radiation-resistant optical
fiber [64].
The optical fiber of such a type has relatively small loss variations (to 10%) at
radiation affect.
10
1 Introduction