Tunable optical filters that cover the entire range of the C-band (1530-565 nm) are designed by using the Vernier effect, ie series coupling of microring resonators of different sizes, and the micromechanical tuning method. The micromechanical tuning method employs lateral comb-drive actuators to control the evanescent coupling between the resonators and index modulators. Single crystalline silicon is used as the material for all major components including waveguide cores, resonators, index modulators, and comb-drive actuators. A finite-difference time-domain method is used for optical analysis of the filter. The simulation results show good agreement with those analytical methods, previously reported. The width of the index modulator is found to play an important role in the filter characteristics. A wider modulator (eg, width: 100 nm) can cover the full tuning range of 35 nm without switching between different bands. While a narrow modulator (eg, width: 50 nm), on the other hand, induces moderate loss to the filter, it requires multiple bands to cover the full range of incredible changes. In order to achieve linear tuning characteristics in the cascaded-resonator filters, the shape-finger comb-drive actuator design method is applied. The design method based on two-dimensional slice approximation is further examined by three-dimensional finite element analysis for verification. It is shown that the design method can also work for the cascaded-resonator filters, even for the one that needs band hopping. Effects of fabrication imperfections on designed device characteristics are studied as well. While a narrow modulator (eg, width: 50 nm), on the other hand, induces moderate loss to the filter, it requires multiple bands to cover the full range of incredible changes. In order to achieve linear tuning characteristics in the cascaded-resonator filters, the shape-finger comb-drive actuator design method is applied. The design method based on two-dimensional slice approximation is further examined by three-dimensional finite element analysis for verification. It is shown that the design method can also work for the cascaded-resonator filters, even for the one that needs band hopping. Effects of fabrication imperfections on designed device characteristics are studied as well. While a narrow modulator (eg, width: 50 nm), on the other hand, induces moderate loss to the filter, it requires multiple bands to cover the full range of incredible changes. In order to achieve linear tuning characteristics in the cascaded-resonator filters, the shape-finger comb-drive actuator design method is applied. The design method based on two-dimensional slice approximation is further examined by three-dimensional finite element analysis for verification. It is shown that the design method can also work for the cascaded-resonator filters, even for the one that needs band hopping. Effects of fabrication imperfections on designed device characteristics are studied as well. It requires multiple bands to cover the full range of incredible changes. In order to achieve linear tuning characteristics in the cascaded-resonator filters, the shape-finger comb-drive actuator design method is applied. The design method based on two-dimensional slice approximation is further examined by three-dimensional finite element analysis for verification. It is shown that the design method can also work for the cascaded-resonator filters, even for the one that needs band hopping. Effects of fabrication imperfections on designed device characteristics are studied as well. It requires multiple bands to cover the full range of incredible changes. In order to achieve linear tuning characteristics in the cascaded-resonator filters, the shape-finger comb-drive actuator design method is applied. The design method based on two-dimensional slice approximation is further examined by three-dimensional finite element analysis for verification. It is shown that the design method can also work for the cascaded-resonator filters, even for the one that needs band hopping. Effects of fabrication imperfections on designed device characteristics are studied as well. The design method based on two-dimensional slice approximation is further examined by three-dimensional finite element analysis for verification. It is shown that the design method can also work for the cascaded-resonator filters, even for the one that needs band hopping. Effects of fabrication imperfections on designed device characteristics are studied as well. The design method based on two-dimensional slice approximation is further examined by three-dimensional finite element analysis for verification. It is shown that the design method can also work for the cascaded-resonator filters, even for the one that needs band hopping. Effects of fabrication imperfections on designed device characteristics are studied as well.