8.5.5 OEOs for Formation of Optical and Electric Pulses
with Durations Less than 1 ps with the Low Jitter
OEO of the microwave range with the Mach–Zehnder modulator can be used for
formation of optical pulses with the duration of 1 ps with the low jitter [10].
The OEO formed by in-series closed into a loop, the modulated light source
(Fig. 8.20) consisting of the laser diode (LD) and the MZ modulator, the fiber light
guide (FLG), the photodiode (FD), the wideband amplifier and a filter, constitute the
formation unit. With the help of directional couplers DC 1 and DC 2 , the optical
emission formed by the fiber-optical ring laser (FORL) with the erbium active
medium, passes through the MZ modulator in opposite direction from its output to
its input. When OEO excitation condition satisfies, the electric voltage of precision
oscillations with the frequency about 10 GHz acts on the modulator. Owing to this,
the optical emission circulated in the ring FORL is also modulated in intensity, and
FORL synchronization is performed. At FORL synchronization, the optical pulse
duration at its output decreases to T i ¼ 1 ps, and the jitter value is several
femtoseconds.
The simpler variant of the short pulse formation with duration of tens picoseconds
with the relatively low jitter is the formation circuit using OEO with the MZ
modulator or with the absorptive electro-optical modulator. OEO formed by in series
closed into a ring the modulated light source consisting of the laser diode and the
absorptive electro-optical modulator, the fiber light guide with the length up to 2 km,
Fig. 8.20 The block diagram of OEO with the ring laser operating in the mode of longitudinal
mode synchronization
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8 Experimental Investigations and Practical Circuits of Optoelectronic. . .
with Durations Less than 1 ps with the Low Jitter
OEO of the microwave range with the Mach–Zehnder modulator can be used for
formation of optical pulses with the duration of 1 ps with the low jitter [10].
The OEO formed by in-series closed into a loop, the modulated light source
(Fig. 8.20) consisting of the laser diode (LD) and the MZ modulator, the fiber light
guide (FLG), the photodiode (FD), the wideband amplifier and a filter, constitute the
formation unit. With the help of directional couplers DC 1 and DC 2 , the optical
emission formed by the fiber-optical ring laser (FORL) with the erbium active
medium, passes through the MZ modulator in opposite direction from its output to
its input. When OEO excitation condition satisfies, the electric voltage of precision
oscillations with the frequency about 10 GHz acts on the modulator. Owing to this,
the optical emission circulated in the ring FORL is also modulated in intensity, and
FORL synchronization is performed. At FORL synchronization, the optical pulse
duration at its output decreases to T i ¼ 1 ps, and the jitter value is several
femtoseconds.
The simpler variant of the short pulse formation with duration of tens picoseconds
with the relatively low jitter is the formation circuit using OEO with the MZ
modulator or with the absorptive electro-optical modulator. OEO formed by in series
closed into a ring the modulated light source consisting of the laser diode and the
absorptive electro-optical modulator, the fiber light guide with the length up to 2 km,
Fig. 8.20 The block diagram of OEO with the ring laser operating in the mode of longitudinal
mode synchronization
496
8 Experimental Investigations and Practical Circuits of Optoelectronic. . .