No description available.

No description available.

A low-loss polyimide/Ta2O5/SiO2 antiresonant reflecting optical waveguide (ARROW) at quasi-antiresonant condition is presented for the first time. The ARROW device was fabricated using both the organic and dielectric thin film technologies. It consisted of the fluorinated polyimide, tantalum pentoxide (Ta2O5) and silicon dioxide (SiO2) hybrid layers deposited on a Si substrate. For TE polarized light, the propagation loss of the waveguide as low as 0.4 dB/cm was obtained at 1.3 mm. The propagation loss for TM polarized light was 1.5 dB/cm. An ARROW waveguide fabricated using the polyimide/Ta2O5/polyimide material system is also presented for comparison. In addition, anisotropic etching of Si-V grooves were formed using the EDP solution, and room temperature sputtered Ta2O5 was used as the etching mask. At a etching temperature of 1200C, the under cut of the V-groove is 1.6mm

The speed and simplicity of the metal-semiconductor-metal (MSM) detector has made it a prime candidate for use in integrated optoelectronic circuits. While in most applications the optical input is coupled in through the top surface of the device, it is also possible to distribute the optical signal by means of transparent waveguides that are located below the absorbing detector layer. By controlling the degree of coupling between the waveguide and detector layers the detectors can be made to act as optical taps. The optical signal can thus be shared among a series of detectors as required in optoelectronic switching applications. We have made a series of simple ridge waveguides, each with a number of MSM structures designed for the characterization of absorption, responsivity and frequency response. A 4x4 optoelectronic switch was also fabricated and analyzed. We show that balancing the switch is accomplished by tailoring the absorption coefficient in the detector region so that all detectors absorb equal amounts of optical power. / Thesis / Master of Engineering (ME)

The speed and simplicity of the metal-semiconductor-metal (MSM) detector has made it a prime candidate for use in integrated optoelectronic circuits. While in most applications the optical input is coupled in through the top surface of the device, it is also possible to distribute the optical signal by means of transparent waveguides that are located below the absorbing detector layer. By controlling the degree of coupling between the waveguide and detector layers the detectors can be made to act as optical taps. The optical signal can thus be shared among a series of detectors as required in optoelectronic switching applications. We have made a series of simple ridge waveguides, each with a number of MSM structures designed for the characterization of absorption, responsivity and frequency response. A 4x4 optoelectronic switch was also fabricated and analyzed. We show that balancing the switch is accomplished by tailoring the absorption coefficient in the detector region so that all detectors absorb equal amounts of optical power. / Thesis / Master of Engineering (ME)

No description available.

The purpose of this paper is to fabricate optical waveguide reflectors to reflect the incident optical mode of multi-mode interference coupler by the etched vertical mirror surfaces. We used the design of etched vertical mirror surfaces to bend the incident optical mode, and changed the length of multi-mode interference coupler for the power splitting ratio. By the simulation and design, we could use the multi-mode interference coupler to fabricate optical waveguide reflectors. A 1.52µm symmetric quantum well InGaAlAs/InGaAs epitaxial wafer is used to fabricate the devices. In the device design, we designed a optical waveguide reflector of two inputs and outputs with 90¢X angle. We fabricated a Fabry-Perot laser by two optical waveguide reflectors with 90¢X angle, a 1x2 multi-mode interference coupler and a ring cavity. In addition, we designed optical waveguide reflectors of one input and two inputs, and utilized them to fabricate a Fabry-Perot laser. We also utilized an optical waveguide reflector of one input or two inputs directly to fabricate Fabry-Perot lasers. In fabrication process, firstly, we etched the waveguide to the depth of about 1.81µm by multi-step wet etching. In order to reduce bending loss, we made deep etching for the outside of curve waveguide. Then, we etched the mirror to the depth of about 6µm by multi-step wet etching to have a greater variation of refractive index to reflect the mode of optical waveguide reflectors. Finally, we used polyimide to flatten the sides of the ridge waveguides and evaporated metal pad over the polyimide.

The purpose of this thesis is to design and fabricate optical waveguide reflectors by the etched vertical mirror surfaces. In order to reflect the incident optical mode of multi-mode interference coupler, we fabricate the etched vertical reflective mirror surface with wet etch and dry etch processes. We used the design of etched vertical mirror surfaces to bend the incident optical mode, and changed the length of multi-mode interference coupler for the power splitting ratio and high power output. In order to reduce bending and transition losses and make the incident optical mode total internal reflection in the etched vertical mirror surfaces, we used ICP-RIE dry etch process to add the depth about 4 µm of the etched vertical mirror surfaces. A 1.52 µm symmetric multiple quantum well InGaAlAs/InGaAs epitaxial wafer is used to fabricate the devices. In the device design, we designed optical waveguide reflectors of one input and two inputs respectively, and utilized them to fabricate Fabry-Perot lasers. We also utilized a reflector of one input and two inputs directly to fabricate a Fabry-Perot laser. In addition, We fabricated a Fabry-Perot laser by two reflectors with 90¢X angle corner, a 1x2 3dB multi-mode interference coupler and a ring resonator. In fabrication process, firstly, we etched the epitaxial wafer the depth of about 1.79µm by multi-step wet etch to form waveguides. In order to reduce bending loss, we made deep etching for the outside of curve waveguides and optical waveguide reflectors. Then, we etched the reflective mirror to the depth of about 4µm by ICP-RIE dry etch process to have a greater variation of refractive index to reflect the optical mode of reflectors. Finally, we used polyimide to flatten the sides of the ridge waveguides and evaporated metal pad over the ridge waveguides to form the signal pad.

A Y-branch optical power splitter based on the buried waveguide and the micro-prism waveguide bends is presented. The 132 splitter consists of a beam expanding region, a conventional Y-branch region, and two micro prisms providing large angle waveguide bends of device. The 132 splitter are fabricated by first depositing a 10-£gm-thick PECVD oxide (SiO2) on Si s ubstrates. The guiding core of the device was fabricated by etching trenches in SiO2 cladding, and filled with Benzocyclobutene (BCB) polymer. After etch-back process, the thin layer of spin on glass (SOG) is used to further planarized the surface of the device. The propagation loss of the waveguide is 0.47dB/cm at £f=1.3£gm. The normalized power transmission efficiency of the 132 splitter as large as 3.7dB was obtained. Simulation results based on beam propagation method (BPM) of the splitter is also presented.

No description available.