Jingli Lei

Research on the controllable frequency octupling technology for generating optical millimeter-wave by external modulator

A novel scheme is proposed for frequency octupling mm-wave generation based on an integrated triple-parallel MZM without filter. Two kinds of redundant sidebands are well eliminated by adopting 90 degrees of the electric phase-difference about two sub Mach-Zehnder modulators (sub-MZMs), driven by radio frequency (RF) signal. Then bias of the third sub-MZM is tailored to get best signal. The results indicate that the radio frequency spurious suppression ratio (RFSSR) is as high as 38.3315 dB under the condition of conventional extinction ratio (30 dB). Moreover, optical sideband suppression ratio (OSSR) can reach as high as 61.22878 dB at ideal extinction ratio (100 dB). Compared with previous schemes, it not only optimizes the method but get high RFSSR in the conventional condition.

Photonic generation of frequency quadrupling signal for millimeter-wave communication utilizing three parallel Mach-Zehnder modulators

In this work, we propose a new scheme of generating high quality frequency quadrupling signal for millimeter-wave wireless communication system. The frequency quadrupling scheme is achieved by using three parallel Mach-Zehnder modulators (MZMs) and an optical phase shifter. The first two MZMs are driven by the RF signals to operate at the maximum transmission point. The third MZM is operated with no RF signal and an extra π-phase difference is introduced for it by the optical phase shifter. The advantage of the proposed scheme is that the optical carrier and the fourth optical sideband can be suppressed simultaneously. The performance of proposed scheme is investigated theoretically and evaluated by simulations. Numerical results show that the radio frequency spurious suppression ratio (RFSSR) higher than 44.18 dB and the optical sideband suppression ratio (OSSR) higher than 21 dB can be obtained without optical filter when the extinction ratio (ER) of the MZM is 30 dB. The impact of the non-ideal RF driven voltage and phase difference of RF driven signal applied to the first two sub-MZMs on OSSR and RFSSR is also discussed and analyzed.

Investigation on nonlinearity of optical fiber with uniaxial crystal material cladding

A fiber with cladding made of uniaxial anisotropic crystal material whose optical axis is parallel to the axis of fiber was proposed, and the nonlinear parameter γ of this kind of fiber was investigated theoretically. The ratio (k_cl) of the extraordinary to the ordinary ray index was introduced and the influence of parameter k_cl upon γ was examined by exact vector modes method. The calculated results indicate that the parameter k_cl has a strong impact on γ, and the parameter γ can be effectively modified through tailoring k_cl while keeping other parameters of fiber as constant.

Polyatomic photonic crystal waveguides with semi-slow light and tailored dispersion properties

In this work, the slow light modes of the polyatomic photonic crystal (PhC) which has multiple different holes in the smallest unit cell are investigated. The slow light waveguide with nearly constant group index over large bandwidth is achieved using this new photonic crystal geometry based on square lattice. The feasibility of controlling the dispersion relation through subtle structural modification is also investigated.