Proton Exchange Technology Research Articles

Design of Double Y Branch Waveguide in Acceleration Seismic Geophone

Dual M-Z interferometer is the sensitive element of three-component acceleration seismic geophone, while Y branch waveguide is the basic optical components composed of dual M-Z interferometer, so the design of Y branch waveguide directly affects the performance of three-component acceleration seismic geophone. Firstly, branch waveguide and S-shaped bent waveguide are introduced, and symmetrical double Y branch S-shaped bent waveguide is designed based on this. Secondly, the bending loss of the branch waveguide is analyzed and calculated. The transmission of 1/2Y branch waveguide and 1/4Y branch waveguide , and the bending loss changes with the length of 1/2Y branch waveguide and 1/4Y branch waveguide is simulated by MATLAB. The result shows that the maximum bending loss of 1/2 Y branch waveguide is the 0.156dB, and the bending loss is close to 0 after L >320μm; the maximum bending loss of 1/4 Y branch waveguide is 0.058dB, and the bending loss is close to 0 after L >200μm. The design of double Y branch meets the requirement of low loss. Thirdly, the optical power conversion of branch waveguide in 3dB coupler is simulated and analyzed. Finally, proton exchange and Ti diffusion technique are compared; the advantages of proton exchange technology are summarized; the principle of proton exchange is introduced; and a good proton exchange annealing condition is summarized.

Optimisation of the proton-exchange technology for fabricating channel waveguides in lithium niobate crystals

We have studied the effect of process parameters on the mode profile in lithium niobate channel waveguides produced by low-temperature proton exchange. A model has been proposed for the processes underlying waveguide formation, and has been used to numerically calculate the mode profile for various fabrication parameters. We have identified low-temperature proton exchange conditions which ensure high electro-optical performance of the waveguides and stability towards fabrication errors. The obtained results may be helpful in optimising integrated optical devices and matching them to various types of optical fibres.

Characterisation of proton-exchanged and annealed proton-exchanged planar waveguides in z-cut LiNbO3

Mode index measurements of planar waveguides fabricated by proton-exchange and annealed proton-exchange in z-cut LiNbO3 have been made. A Fermi function was found to accurately model the index profile in a PE waveguide resulting in a better agreement between the measured mode indices and the computed dispersion curves compared to the conventional step-index profile. In addition, the effects of various fabrication parameters on the propagation characteristics of single-mode annealed proton-exchange waveguides have been investigated in detail. Such information will be useful in the analysis, design, and optimisation of devices to be fabricated with the proton-exchange and annealed proton-exchange technology.