Aluminum complexes, [O3PMe]AlR(R = OtBu, OPh), containing tris-(3,5-di-tert-butyl-2-hydroxy-phenyl)phosphine ([O3P]H3) which is a novel tridentate ligand have been synthesized and characterized by NMR, X-ray diffraction and elemental analysis. Theses complexes were used as catalysts for ring-opening polymerization of £`-caprolactone. We suggested that the stereo effect of catalysts is the main factor in the ring-opening polymerization and compared the mechanism with DFT. In additional, we studied the electronic states and electronic chemistry of [O3PMe]AlR by DFT, UV and PLE. The novel ligand, bis(3,5-tert-butyl-2-phenoxy) tert-butylphosphine ([tBuOPO]H2), reacted with alkali metals such as n-BuLi, NaH and KH to form a series metal complexes, [tBuOPO]M2(Solvent)x (M = Li, Na, K). These metal complexes are all dimeric molecules characterized by X-ray diffraction, NMR and elemental analysis. Moreover, we reacted {[tBuOPO]Li2(DME)}2 with metal complexes of group 4, TiCl3 and MCl4(THF)2 (M = Ti, Zr, Hf), and we received [tBuOPO]2M and [tBuOPO]MCl2(THF) (M = Ti, Zr, Hf). We also synthesized alkoxide complexes of the series metal complexes and studied the catalytic reactivity for ring-opening polymerizations. Furthermore, tantalum complexes, [tBuOPO]2TaX (X = F, Cl) and [tBuOPO]TaCl3, have been synthesized and characterized. Especially synthesizing [tBuOPO]TaCl3 should be carefully controlled by lowering the concentration of TaCl5.

SOI-based micro-ring resonators can be ultra-compact and highly sensitive for sensing applications. In order to obtain deeper notches and enlarge the detection area, the concentric double-ring resonators have been proposed. To further increase the sensing area and promote the sensing sensitivity, we add one more inner ring into the double-ring structure to form the triple-ring resonator. In this thesis, we have derived the transfer functions of the multi-ring structures and calculated the resonance properties of the triple-ring resonators by using the 3-D FDTD method. We have investigated the effects of the ring radius on the transmission spectra and discussed the variations of spectral response between the double-ring and triple-ring resonators. We also demonstrate the applications of the triple-ring resonator as the refractive index sensors. The triple-ring resonator can obtain deeper dips and higher detection sensitivity of 12.85 nm/RIU. Enlarging the gap can increase the sensing area and is shown to be able to promote the sensing sensitivity. Besides, the influences of the light polarization and the optical absorption on the spectral responses have been discussed as well.

Micro-ring devices are based on resonance principle and inherently are wavelength selective. Thus it is an important optical component for WDM based applications. To fully utilize the available capacity in an optical network, large full spectral range (FSR) and narrow passband are key performance targets of ring device designs. In this paper we report the design and analysis results of micro-ring filters with 4000+ GHz FSR and 25 to 50 GHz passband, based on symmetric add-drop filter structure. We optimize the passband shape (using a box-like factor), drop loss coefficient and off-resonance through loss via the coupling coefficients and ring loss parameters.

A procedure is introduced for increasing the sensitivity of measurements in integrated ring resonators beyond what has been previously accomplished. This is demonstrated by a high-frequency, phase sensitive lock to the ring resonators. A prototyped fiber Fabry-Perot cavity is used for comparison of the method to a similar cavity. The Pound-Drever-Hall (PDH) method is used as a proven, ultra-sensitive method with the exploration of a much higher frequency modulation than has been previously discussed to overcome comparatively low finesse of the ring resonator cavities. The high frequency facilitates the use of the same modulation signal to separately probe the phase information of different integrated ring resonators with quality factors of 8.2 x10^5 and 2.4 x10^5. The large free spectral range of small cavities and low finesse provides a challenge to sensing and locking the long-term stability of diode lasers due to small dynamic range and signal-to-noise ratios. These can be accommodated for by a calculated increase in modulation frequency using the PDH approach. Further, cavity design parameters will be shown to have a significant affect on the resolution of the phase-sensing approach. A distributed feedback laser is locked to a ring resonator to demonstrate the present sensitivity which can then be discussed in comparison to other fiber and integrated sensors. The relationship of the signal-to-noise ratio (S/N) and frequency range to the cavity error signal will be explored with an algorithm to optimize this relationship. The free spectral range and the cavity transfer function coefficients provide input parameters to this relationship to determine the optimum S/N and frequency range of the respective cavities used for locking and sensing. The purpose is to show how future contributions to the measurements and experiments of micro-cavities, specifically ring resonators, is well-served by the PDH method with high-frequency modulation.

A chalcogenide glass (arsenic-trisulfide, As2S3) optical waveguide is vertically integrated onto titanium-diffused lithium-niobate (Ti:LiNbO3) waveguides to add optical feedback paths and to create more compact optical circuits. Lithium-niobate waveguides are commonly used as building blocks for phase and amplitude modulators in high speed fiber communication networks due to its high electrooptic coefficient and low mode coupling loss to single-mode optical fibers. Although it can easily be modulated using an RF signal to create optical modulators, it lacks the intrinsic trait to create optical feedback loops due to its low core-to-cladding index contrast. Ring resonators are main building blocks of many chip-scale optical filters that require these feedback loops and are already demonstrated with other material systems. We have, for the first time, incorporated As2S3 as a guiding material on Ti:LiNbO3 and fabricated s-bends and ring resonators. We have examined As2S3-on-Ti:LiNbO3 waveguides at simulation, microfabrication, and optical characterization levels.

This paper presents design and fabrication of ring cavity semiconductor lasers and optical filters with simple fabrication process. A 1.55

Bluetooth is a low-cost, low-power and short-range wireless communication technology, which operates in the global unlicensed 2.4GHz ISM band. Recently many people have paid close attention to do a lot of relevant research and product development on it. In addition to the scatternet formation problem, two major issues of Bluetooth, scheduling and routing, also greatly interest the researchers. In this paper, we propose new scatternet topology architecture for Bluetooth networks, called multi-ring scatternet. The scatternet formation and packet routing method are presented. The self-routing property of multi-ring scatternet makes its routing method efficient and low overhead. Comparing to the Bluetree scatternet, the proposed scatternet is more reliable and relieves the bottleneck at root nodes. As compared with the BlueRing scatternet, it reduces the network diameter and average routing path. The simulation results reveal that our multi-ring scatternet topology gains better performance by the three metrics of number of piconets, average routing path length and throughput.

In this thesis, we use InP based multiple quantum well epi-wafer with modulation doping in the active layer to design the semiconductor optical amplifier and ring laser for the optical communication at 1.55£gm wavelength. We also finish the mask design and fabrication of theses two devices. Besides, we have established an optical measurement system, including the L-I measurement, the optical spectrum measurement and the far field measurement, to test the device parameters. In the device process, we use the new method, called the Multi-Step Undercutting, to precisely control the undercut in the wet etching process. With this technique, we can get a smooth and vertical sidewall for our devices. For the semiconductor optical amplifier, we design two different types, one is the Fabry-Perot Amplifier and the other is the Traveling Wave Amplifier. We use the Multi-Step Undercutting process in the fabrication of these two devices. The main parameters for semiconductor optical amplifier are the change of the output power versus the input current, the spontaneous emission spectrum and the photocurrent spectrum. For the ring laser, we combine the concept of Loop Mirror and Asymmetric Mach-Zehnder Interferometer to obtain the laser with good side mode suppression for a single wavelength light source.

Abstract In this dissertation a rigorous analysis is performed on the reentrant non-planar ring laser cavity constructed by the Herriott-type multi-pass cell. Since the non-planar ring cavity is a non-orthogonal cavity, so the ABCD matrix method used to analyze the beam propagation is not valid. A rigorous method using Gaussian beam propagation is needed. The beam rotation, astigmatism, and spherical aberration are considered to obtain a self-consistent solution of the Gaussian beam. It turns out that spherical aberration is a very important issue for this non-planar resonator. Without taking into account the spherical aberration, a stable resonator would be difficult to realize. By using a self-consistent Gaussian beam propagation method, the characteristic of laser beam was analyzed and compared with that of the ABCD approximation method. The reentrant ring cavity is very sensitive to cavity length, especially when the planar and non-planar configurations have the same output beams; therefore, it is very important to consider a rigorous method using Gaussian beam propagation. By considering the coordinate transformation of the beam after mirror reflection, a non-planar figure-8 ring cavity can be treated as an orthogonal cavity except for an exchange of tangential and Sagittal planes after each reflection. A simple astigmatic Gaussian beam approach is used to analyze the non-planar figure-8 ring cavity, and an analytic solution is obtained. For the general case of the multi-pass non-planar ring cavity, a general astigmatic Gaussian beam approach is used to treat the problem. The general form of mirror phase shift is used, and two important differences compared to the ABCD method were found. Firstly, the spot size is always elliptical while the spot size is circular using the ABCD approximation. Secondly, a second stable region is found in the cavity, the width of the second stable region is smaller than the first stable regi

In this thesis, we focus on the investigation of semiconductor optical amplifier and ring laser. We use InP based multiple quantum well epi-wafer with modulation doping in the active layer to design the semiconductor optical amplifier and ring laser for the optical communication at 1.55£gm wavelength. We combine the concept of Loop Mirror and Asymmetric Mach-Zehnder Interferometer to obtain the laser with good side mode suppression for a single wavelength light source. For the semiconductor optical amplifier, we design two different types, one is the Fabry-Perot Amplifier and the other is the Traveling Wave Amplifier. Furthermore, We use the Multi-Step Undercutting process in the fabrication of these two devices. We have established an optical measurement system, including the L-I measurement, the optical spectrum measurement and the far field measurement, to test the device parameters. After annealing, these devices with two different serial number exhibited the contact resistances of 9£[ and 16£[, respectively. Under CW operation, these FPA exhibited the threshold current of 62mA and 70mA at 20¢J, respectively. The stimulated emission wavelength was at 1531nm and 1522nm, respectively.