Electrical gain is applied to QAM signal which later, enters in LiNb Mach-Zehnder modulator
. LiNb Mach-Zehnder modulator
combines the electrical QAM signal with the optical signal from CW laser.
Kedia, "Design of Optical I/Q Modulator Using Dual-drive Mach-Zehnder Modulators
in Coherent Optical-OFDM System," Journal of Optical Communications, vol.
The signal [bar.y](n) is converted into the continuous OFDM signal y (t) by a DAC device in order to drive a Mach-Zehnder modulator
These modulation formats are possible to design with in parallel connected Mach-Zehnder modulators
All these optical modulators are [LiNbO.sub.3] Mach-Zehnder modulators
[28.] Liu, X., et al., "Frequency quadrupling using an integrated Mach-Zehnder modulator
with four arms," Optics Communications, Vol.
By choosing an appropriate biased voltage for Mach-Zehnder modulator
(LiNbO3-MZM) and applying a super imposed electrical signal of clock and data, the LiNbO3-MZM allows to generate an optical signal which is RZ data modulated using a single modulator.
Afterwards formed electrical NRZ pulses are sent to Mach-Zehnder modulator
. Finally the CW laser light beam is modulated via the Mach-Zehnder modulator
and optical pulses are formed.
Secondly, to operate the laser in continuous wave (CW) mode and then use an external modulator such as the Mach-Zehnder Modulator
(MZM), to modulate the intensity of the light.
[11.] Zhou et al., "Low-Drive Power Asymmetric Mach-Zehnder Modulator
with Band-Limited Operation," Journal of Lightwave Tech., Vol.
This reduction of external components makes the DAC highly desirable for indium phosphide Mach-Zehnder modulator
(InP MZM) biasing applications.
Multiband signals generation including baseband, frequency-doubled, and frequency-quadrupled has proposed based on a dual-parallel Mach-Zehnder modulator
, following a single-drive Mach-Zehnder modulator
through optical carrier suppression and frequency-shifting techniques .