Chapter 5 Conclusions

Chapter 5 Conclusions

According to the analysis of various shapes one-dimensional resonant PBG filter waveguide devices based on SOI wafer with computer-aided BPM software mentioned in Chapter 2, the conclusions are given in following texts. We examine their potential for applying to integrated optics, the different length, width, lattice constant, width of the holes, shape of the holes, number of the holes and phase shift length relation of one-dimensional resonant PBG filter structure are analyzed compared and designed. Through the analysis of these five different one-dimensional resonant PBG filter structure with optical field distribution algorithm. We have found that these five one-dimensional resonant PBG filter structure combination or variation among 1-D resonant rectangular holes PBG filter waveguide, 1-D resonant square holes PBG filter waveguide, 1-D resonant triangular holes PBG filter waveguide, 1-D resonant circular holes PBG filter waveguide and 1-D resonant hexagonal holes PBG filter waveguide exhibited in Table III.

From the comparisons in Table III, the author also analyzed the characteristics of guiding light in various shapes one-dimensional resonant PBG filter waveguide devices with transmission power, insertion loss, uniformity (imbalance) and quality factor. No matter on 1-D resonant rectangular holes PBG filter waveguide, 1-D resonant square holes PBG filter waveguide, 1-D resonant triangular holes PBG filter waveguide, 1-D

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resonant circular holes PBG filter waveguide and 1-D resonant hexagonal holes PBG filter waveguide, we have demonstrated that the performance of light propagating along one-dimensional resonant PBG filter waveguide devices will have high transmission, loss insertion loss, high uniformity (imbalance) and high quality factor with difference one-dimensional resonant PBG filter waveguide. That is, the guided-wave propagated along SOI waveguide devices with one-dimensional PBG method corresponding difference five PBG structure can be more confined with reducing the cross talk between the silicon guiding layer and the cladding layer.

Through the analysis of 2-D PBG sharp bend waveguide with a square lattice of several shapes of air columns mentioned in Chapter 3. The several shapes of air columns are included circle, square and hexagon. From the comparisons in Table IV, V and VI, we have demonstrated that the performance of the light wave propagating along SOI PBG sharp bend waveguide devices will have high photonic bandgap width and high transmission loss with difference lattice constant

, the radius

or width of the air hole and the several shape of air columns no matter on circular, square and hexagonal air columns PBG sharp bend waveguide. The light wave is confined in sharp bend waveguide successful in several shapes of air columns and propagates in the PBG defect line. That is, PBG sharp bend waveguide would make possible the realization of guiding the light wave in PBG defect line with been proposed and demonstrated in several shapes of air columns structure and these structures are applied to optical communication device.

w

According to the analysis of 32 × 32 PBG wavelength switch

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mentioned in Chapter 4. The length and width relation of MMI structure is analyzed compared and designed. The number and size of the localized fingered electrode pads are analyzed compared and designed. The length and width of the 32 channels single mode input and output rib waveguide are also analyzed compared and designed. We examine their potential for applying to integrated optics. Through the analysis of the 32×32 PBG wavelength switch structure with field distribution algorithm. The author also analyzed the characteristics of guiding light in SOI waveguide device with adding various voltages on 256 fingered electrode pads to control the 32×32 PBG wavelength switch. In this chapter, we have demonstrated that the performance of light propagating along SOI waveguide devices will have higher wavelength select and higher transmittance. That is, 32×32 PBG wavelength switch waveguide would make possible the realization with tuning the voltages on 256 localized fingered electrode pads and use the different change of refractive index on several regions to control the light wave propagation path. In addition to all of the above, we can switch the light wave propagate from one of 32 input channels to one of 32 output channels at will. These structures are applied to optical communication device of WDM network.

Finally, we compare our designed 32×32 PBG wavelength switch to

other optical switch. The size of all optical switch, our designed 32×32

PBG wavelength switch is the smallest than others. Due to the technology

of the conventional waveguide fabrication, the size of the optical

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communication device is very large. Hence, we use the novel technology of photonic crystal to reduce the size of the optical communication device and integrate with the nano-semiconductor technology. The final purpose of our design is working to face the photonic communication system on chip (PCSoC).

The major compromise with this architecture is that it requires more switching elements. Because of the WDM technology application is moving from the long haul connection to metropolitan network. For non-uniform traffic, dynamic reconfiguration of the wavelength routing interconnections is required in response to changing traffic patterns.

Dynamic wavelength routing can be realized by introducing optical space

switches at the wavelength routing nodes. In the future, after the WDM

access networks growing up, the high-speed WDM network full functional

switching will become very important.