RESUMO
A design method for ultrahigh-Q microring resonators (MRRs) based on Bezier free-form curves was proposed and demonstrated. An MRR consisting of a specially designed 180° waveguide bend, a directional coupler, and two low-loss multi-mode strip waveguides was designed. The free-form curves were used to increase the degree of freedom in the design, shaping the waveguide bend with a gradient width and curvature. This design effectively reduced the propagation loss caused by the roughness of waveguide sidewalls and the mode mismatch loss caused by the excitation of high order modes. The small effective radius of only 20µm enabled the MRR to have a large free spectral range (FSR) and a compact and flexible structure. The MRR was manufactured using a standard process provided by foundry and measured to have an ultrahigh loaded Q factor of 1.86 × 106 and a FSR of about 1â nm.
RESUMO
The laser output characteristics of N d:L u 2 O 3 crystals were investigated in detail to obtain a dual-wavelength all-solid-state laser. Using 806 nm LD end-face pumped N d:L u 2 O 3 crystals with lengths of 6 mm, a 1076 & 1080 nm laser outputs with a maximum output power of 3.73 W were obtained, with a slope efficiency of 30.4%, an optical-to-optical conversion efficiency of 28.5%, and a power stability of 0.41% for 4 h of continuous measurement. Furthermore, by suppressing the higher-order modes, a high beam quality laser output with beam quality factors of 2.092 and 1.589 in the x and y directions, respectively, and a maximum output power of 1.27 W were obtained. In addition, it was experimentally verified that both wavelengths of the output laser were elliptically polarized.
RESUMO
An algorithm for calculating a phase-only computer-generated hologram (CGH) for 3D color display using single chip liquid crystal on silicon (LCOS) is proposed. As an evolution of the G-S iteration, the proposed algorithm was obtained by replacing the Fresnel diffraction of single wavelength in the G-S algorithm with a color Fresnel diffraction process. Moreover, combined with "Ping-Pong" iteration, this algorithm was used to calculate 3D color holograms. Finally, a hologram that is capable of projecting a color 3D image was generated. Numerical simulation was performed, and an optical reconstruction system based on single spatial light modulation (SLM) was built to prove this method. Both numerical and optical reconstruction results indicated that the proposed method realized 3D color holographic display using single chip LCOS.