A Q-Switched All-Fiber Cladding-Pumped Ytterbium-Doped Fiber Lasers using an acoustic-optic waveguide Q-switched (AOW-Q) with a pigtail fiber are studied. For AOW Q-switched, Ti-diffused YX-lithium niobate substrate was applied as optical waveguide, a SiO2/In2O3 film of thickness ~150nm as acoustic waveguide and an acoustic aperture of width 110 μm, in conjunction with N=9 finger pairs.
The thermal effect in the laser diode (LD)-side-pumped solid-state laser is studied. The pump power, the temperature distribution figures and the laser beam parameters are obtained. The thermal effects under different cooling conditions are numerically calculated, as well as those in diode-end-pumped solid-state laser. The calculation results are compared with those in diode-side-pumped solid-state laser.
A novel 16-channel 50-GHz spacing interleaver for dense wavelength-division multiplexing (DWDM) systems has been realized using Ti:LiNbO3 waveguides with the corrugated Si overlays. High refractive-index Si layer on LiNbO3 waveguide enables a large index perturbation to strongly affect the mode index of the composite structure. The reflection spectra strength of each peaks and bandwidths of the individual channels are increased by interleaving several sampled gratings together. The modal characteristics have been analyzed by employing vectoric finite element method. The reflectivity has been obtained by formulating the transmission matrix of the structure. An odd-even channel
separator with a gratings length of approximately 11 mm has been fabricated and its reflection spectrum has been
measured. The -1-dB channel bandwidth is ≥ 0.2 nm and the sidelobes are < -20 dB.
We have demonstrated an effective method for suppression of coupling from a guided mode to cladding modes in a fiber grating. The UV light pulse energy, repeated frequency and exposure time are controlled and optimized during writing process of Bragg grating. We can write advanced Bragg grating using optimum UV light parameters.
TE/TM mode converter is a key element of integrated acoustooptical tunable filter (AOTF). Employing SiO2/In2O3 film as acoustical waveguide can suppress sidelobes effectively and simplify fabrication technique in integrated quasi-collinear AOTF. In this report, the eigenvalue equation and the field solution of such configuration has been obtained by using modified Wenzel-Kramers-Brillouin (WKB) method. The results are compared with those by using vector finite element method (VFEM). When the optical waveguides are covered by such oxide film, the difference of mode indices of both polarizations and the effective propagation velocity of surface acoustical wave (SAW) will decrease, and these decreases lead the shift of optical wavelength, which mainly results in the change of the former.