Student Lecture Series: Feb. 14th 2020

Friday, Feb 14th from 12:00 - 1:00 pm in Elings 1601

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Takako Hirokawa
Schow group
ECE Dept, UCSB

Ring-Assisted Mach-Zehnder Interferometer Switch with Multiple Rings per Switch Element

Wavelength-selective switches have been propsed for datacenter use to help meet ever-increasing traffic demands. We present a 4-port silicon photonic ring-assisted Mach-Zehnder interferometer (RAMZI) switch, fabricated in the AIM Photonics process, with multiple-sized rings per switching element in a Benes network configuration to reduce the number of electrical pads required compared to a crossbar switch. Another advantage the RAMZI switch has over the crossbar switch is that the loss through the switch is not path-dependent due to its balanced path configuration. Finally, we present results from the fabricated switch co-packaged with a custom driver for control and discuss the outlook for further scaling of the switch architecture. 

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Caroline Reilly 
DenBaars Group
Materials Dept, UCSB

Characterization of InGaN quatum dots grown by metal organic chemical vapor deposition (MOCVD)

InGaN quantum dots were grown by metal organic chemical vapor deposition and shown to exhibit a bimodal size distribution. Atom probe tomography was used to characterize the dots in conjunction with atomic force microscopy (AFM), photoluminescence (PL), and x-ray diffraction (XRD). Small dots with low indium contents were found to coexist with larger, very high indium composition dots. The dots showed abrupt interfaces with the surrounding GaN, verifying the ability to cap the dots without causing intermixing for extremely high indium content dots.