fiber-optical coupler. Usually, the geometrical length of the optical activated fiber is
0.4–10 m. The optical emission power of the low-noise fiber lasers is 1–100 mW.
The power spectral density (PSD) of the phase noise in the fiber laser is À100 to
À132 dB/Hz (at offsets from the optical carrier of 1–10 kHz). Such small parameters
of the phase noise are obtained by means of the utilization of the phase-locked loop
(PLL) system at optical frequency. Without PLL utilization (curve 1 in Fig. 2.10),
the phase noise in the fiber laser are more by À10 to À15 dB/Hz at the same
frequency offset. The line width of the optical emission in this fiber laser is about
1 kHz.
2.7.4 The Optical Modulator in OEO and Modules
Recently, the commercially available electro-optical Mach–Zehnder modulators in
the planar implementation appears (Fig. 2.11) with high characteristics: the low
control half-wave voltage of 0.3–1 V, the high entry optical power—up to 50 mW,
with low optical power losses of À3 dB. Figure 2.12 shows the disk phase electrooptical modulator (Fig. 2.12a) with the control voltage less than 0.01 V, and the
optical toroidal resonator (Fig. 2.12b) with Q-factor about 10
6 [45–47]. The construction of the phase RF modulator at 60 GHz has a special interest [48]. At that, for
effective modulation, the principle of the phased antenna array is used. Several
signal electrodes are deposited along the optical channel of a modulator. Excitation
of such the “antenna array” is provided by the RF oscillator with the 60 GHzfrequency with the 20 mW power. The RF oscillator with the frequency of 60 GHz is
located above the optical channel with signal electrodes.
On the base of modern QWLD and modulators, new integrated photonic elements
with optical amplifiers and micro-resonators are developed. The commercially
available integrated module consists of the quantum-well laser (with the emission
line width of 1 MHz) with the MZ modulator with modulation frequency band of
15 GHz and the half-wave voltage 2 V. This laser is attended with the electro-optical
Mach–Zehnder modulator. The overall dimensions of this combined module is about
30 mm  50 mm  100 mm, and its cost is about $2500–$5000. Figure 2.13a–d
shows profiles of commercial “perforated” optical fibers with the nano-dimension
structure of the light-guiding thread.
2.7.5 Optical Fibers for OEO and Photodiodes
Such optical fibers (Fig. 2.13) are used in optoelectronic devices for formation of
microwave and mm-wave oscillations foe obtaining of the second harmonic of the
optical frequency at nonlinear optical transformation.
Plots of optical losses for different types of optical fibers are shown in Fig. 2.13d.
From this plot we can make conclusion fibers with the perforation of the HALF type
44
2 Nanostructural Optoelectronic Oscillators with the Fiber-Optical Delay Line
0.4–10 m. The optical emission power of the low-noise fiber lasers is 1–100 mW.
The power spectral density (PSD) of the phase noise in the fiber laser is À100 to
À132 dB/Hz (at offsets from the optical carrier of 1–10 kHz). Such small parameters
of the phase noise are obtained by means of the utilization of the phase-locked loop
(PLL) system at optical frequency. Without PLL utilization (curve 1 in Fig. 2.10),
the phase noise in the fiber laser are more by À10 to À15 dB/Hz at the same
frequency offset. The line width of the optical emission in this fiber laser is about
1 kHz.
2.7.4 The Optical Modulator in OEO and Modules
Recently, the commercially available electro-optical Mach–Zehnder modulators in
the planar implementation appears (Fig. 2.11) with high characteristics: the low
control half-wave voltage of 0.3–1 V, the high entry optical power—up to 50 mW,
with low optical power losses of À3 dB. Figure 2.12 shows the disk phase electrooptical modulator (Fig. 2.12a) with the control voltage less than 0.01 V, and the
optical toroidal resonator (Fig. 2.12b) with Q-factor about 10
6 [45–47]. The construction of the phase RF modulator at 60 GHz has a special interest [48]. At that, for
effective modulation, the principle of the phased antenna array is used. Several
signal electrodes are deposited along the optical channel of a modulator. Excitation
of such the “antenna array” is provided by the RF oscillator with the 60 GHzfrequency with the 20 mW power. The RF oscillator with the frequency of 60 GHz is
located above the optical channel with signal electrodes.
On the base of modern QWLD and modulators, new integrated photonic elements
with optical amplifiers and micro-resonators are developed. The commercially
available integrated module consists of the quantum-well laser (with the emission
line width of 1 MHz) with the MZ modulator with modulation frequency band of
15 GHz and the half-wave voltage 2 V. This laser is attended with the electro-optical
Mach–Zehnder modulator. The overall dimensions of this combined module is about
30 mm  50 mm  100 mm, and its cost is about $2500–$5000. Figure 2.13a–d
shows profiles of commercial “perforated” optical fibers with the nano-dimension
structure of the light-guiding thread.
2.7.5 Optical Fibers for OEO and Photodiodes
Such optical fibers (Fig. 2.13) are used in optoelectronic devices for formation of
microwave and mm-wave oscillations foe obtaining of the second harmonic of the
optical frequency at nonlinear optical transformation.
Plots of optical losses for different types of optical fibers are shown in Fig. 2.13d.
From this plot we can make conclusion fibers with the perforation of the HALF type
44
2 Nanostructural Optoelectronic Oscillators with the Fiber-Optical Delay Line