PhD Defense: "Tunable Lasers with Ring-based Mirrors for Photonic Integrated Circuits on Heterogeneous Silicon-III/V"

Jared Hulme

October 13th (Thursday), 9:30am
Elings Hall (CNSI), Rm 1601

Semiconductor tunable diode lasers have application in various fields are used as sources in wavelength division multiplexing systems, as local oscillators in coherent detection schemes, and as a key component in various photonic integrated circuits. In recent years there has been increasing interest in heterogeneous silicon-III/V as a platform for photonics. Combining silicon with active III/V materials such as InP allows a higher level of integration on a single chip and allows for new types of tunable lasers to be created that utilize the strengths of both materials. This work explores the design, fabrication and measurement of several ring-based tunable lasers and their application in two photonic integrated circuits.

The first PIC is the first fully integrated two-dimensional beam-steering chip. The tunable wavelength from the laser is utilized to change the angle of emission from an output surface grating array. The second dimension of tuning is controlled by an optical phased array. Coherent light is split into multiple channels with individually tuned phases which are emitted from an array of surface gratings. By proper tuning of the phases an arbitrary beam angle can be formed from the interfering outputs of the array. Beam-steering from a fully-integrated chip is demonstrated over 23˚ x 3.6˚ with respective beam widths of 1˚ x 0.6˚, allowing for 138 resolvable points.

The second PIC is a tunable photonic microwave signal generator. This is created by heterodyning the output from two lasers on a fast photodetector and reading the beat tone at the frequency difference between them. The output frequency of the device can be shifted by tuning one of the laser sources relative to the other laser thus creating a tunable microwave source. The photodiode exhibits 65 GHz 3 dB bandwidth. Microwave signals from 1 to 112 GHz are demonstrated from a fully integrated PIC.

About Jared Hulme:

Photo of Jared Hulme Jared Hulme received his B.S in Electrical Engineering from Brigham Young University in 2008. He worked in power distribution for two years then came to the University of California, Santa Barbara where he received a Masters in 2012 in Electronics and Photonics. His research is focused on hybrid III/V-silicon ring-based tunable lasers and their applications in photonic integrated circuits.

Hosted by: Professor John Bowers