To simultaneously modulate and transmit 10-Gb/s baseband and 20-GHz microwave signals on a single wavelength
using single-sideband (SSB) modulation technique, a novel ROF scheme is proposed and verified by simulation. Based
on a Dual-Parallel Mach-Zehnder Modulator (DPMZM) the scheme can carry the microwave signal on the upper
sideband(USB) and the baseband signal on the lower sideband(LSB). It is to be seen from the simulated results that the
crosstalk between the signals with dual services is very small. By means of subcarrier-multiplexing (SCM) technique, the
optical 20-GHz microwave wave carrier is generated to carry 155-Mb/s baseband signal and 10-Gb/s baseband signal is
imposed on the original optical carrier via SSB modulation. The simulated results of BER and the eye diagram are
achieved separately. The signals with dual services are successfully transmitted over 50-km single-mode fiber.
Simultaneous generation and transmission of 10-Gb/s baseband signal and 20-GHz microwave signal with 155-Mb/s
on-off-keying (OOK) data on a single wavelength over 50-km-long fiber link based on a dual-parallel Mach-Zehnder
modulator (DPMZM) are investigated. After simultaneous modulation of the baseband signal and microwave signal at
central office (CO), the hybrid signals are separated by interleaver(IL) or fiber Bragg grating (FBG) at base station (BS).
The center wavelength spacing and bandwidth of IL, also the reflection ratio, center wavelength and bandwidth of FBG
are to be considered carefully as the baseband and microwave signal are only tens of GHz spacing and hard to be
separated with each other. Through theoretical analyses and simulation, for the demonstrated hybrid transmission system,
the relations of Q factor with the reflection ratio and bandwidth of FBG are analyzed separately in different fiber links
(SMF and DSF).
Acousto-optic tunable filter (AOTF) is one of important optical switch components in optical networks. The possibility of tellurium dioxide acousto-optic tunable filter (TeO<sub>2</sub> AOTF) as an optical add/drop multiplexer (OADM) is studied on the basis of the theory of the anomalous acousto-optic Bragg diffraction and the design principle of non-collinear AOTF. Its main performances and structure are analyzed and discussed, and the significance of incident angles and interaction lengths for its performances is presented. The model for optimization design is built under some limitation and the transducer areas is adopted as a regulator for performance, the designed example of the TeO<sub>2</sub> AOTF for WDM systems is given by the optimized method.
In the paper, a weighted-coupling scheme of a SiO<sub>2</sub> film-loaded Ti:LiNbO<sub>3</sub> quasi-collinear integrated acousto-optic mode converter is reported, in which an angular offset between the acoustic and optical waveguides is introduced to implement an optimized Hamming weighted function for realization of ultralow sidelobe level. Acoustic wave guiding properties have been investigated for films such as SiO<sub>2</sub>, ZnO on LiNbO<sub>3</sub> firstly. SiO<sub>2</sub> film on LiNbO<sub>3</sub> was selected as acoustic waveguide. With the mode analysis of the acoustic wave guide and the theory of coupling mode the limit of the width, weighted coupling coefficient and the characteristics of the conversion of acousto-optic modes are obtained. As the angle between acoustical and optical waveguides is 0.45°, the worst sidelobe level is -16dB and the theoretical values of bandwidths of -3dB and -10dB is 1.37nm and 2.31nm respectively, which have excelled the domestic reported level.