Journal of Lasers, Optics & Photonics

This paper presents a highly birefringent dispersion compensating microstructure modified decagonal photonic crystal fiber for broadband transmission communication system. According to simulation, negative dispersion coefficient of -610 ps/(nm.km) and a relative dispersion slope (RDS) close to that of single mode fiber of about 0.0036 nm^-1 with birefringence of the order 2.1×10^-2 was obtained at 1550 nm. The variation of structural parameters is also studied to evaluate the tolerance of the fabrication. Moreover, effective area, residual dispersion, effective dispersion, confinement loss, and nonlinear coefficient of the proposed modified decagonal photonic crystal fiber (M-DPCF) are also mentioned and discussed.

Long-term stability of a laser system is crucially important for applications such as ultrafast laser spectroscopy. Unfortunately, this topic received little attention in novel pulse compression schemes. Through the ultra-stable beam pointing of the 50 kHz laser system, the long-term stability of nonlinear pulse compression (NPC) was measured for up to 17 hours at different peak powers in a fiber core. The required spectral broadening was achieved in largemode- area photonic-crystal-fibers with linearly and circularly polarized light. The optimal parameters of a NPC system operating close to the fundamental limit of the critical self-focusing peak power were found. A further compression to sub-10 fs pulses in a second fiber stage is also discussed.

Mass detection of molecules using single layer graphene sheet is investigated in the present paper. A nanoelectromechanical system resonator device is proposed which is modeled as single layer graphene coupled to electronic transport through such device via two metallic leads. The conductance of such device is deduced by solving eigenvalue differential equation. The influence of both photon energy of an induced ac-field and magnetic field are taken into consideration. The present results show that both the resonant frequency shift and the quality factor are very sensitive to the mass of certain molecule. Also, the photon energy of the induced ac-field enhances the sensitivity of these parameters. The present research is very important for detecting the mass of both chemical molecules and bio-molecules. This can be achieved experimentally by measuring the quantum conductance of the present device, which is related to the resonant frequency shift and the quality factor.

Zhang et al. efforts on the explore of InP-based Sb-free 2-3 μm band lasers and photodetectors are introduced, including the 2-2.5 μm band type I InGaAs MQW lasers under pseudomorphic triangle well scheme, 2.5-3.0 μm band type I InAs MQW lasers under metamorphic strain compensated well scheme, as well as InGaAs photodetectors of high indium contents with cut-off wavelength large than 1.7 μm. All device structures are grown using gas source MBE method, and CW operation above room temperature have been reached for the lasers with wavelength less than 2.5 μm. Pulse operation of 2.9 μm lasers at TE temperature also have been reached The dark current of 2.6 μm InGaAs photodetectors have been decreased notably with the inserting of supperlattice electron barriers, those types of epitaxial materials have been used to the development of FPA modules for space remote sensing applications.