PhD Defense: "Wavelength Tunable Coherent Receivers and All Optical Switches on InP for Optical Transmission Systems"

Phillip J. Skahan

July 31st (Friday), 2:00pm
Engineering Science Building (ESB), Room 2001

Internet traffic is projected to reach 2 zettabytes per year by 2019. To meet this demand, new methods must be developed to scale existing network infrastructure in a cost-effective manner. One approach to improving network bandwidth is to increase the spectral efficiency of the existing bandwidth by using more complex modulation formats to encode the data onto the polarization and phase of a carrier wave. However, these formats require more complex transmitters and receivers which increase system cost and complexity. One solution to this problem is to monolithically integrate all of the components necessary onto a single die; by fabricating all of the functions at once, transmitter and receiver costs can be greatly reduced.

To this end, we present results on novel photonic integrated circuits (PICs) on an InP substrate for next generation optical communication systems. These include the world’s first monolithically integrated DP-QPSK receiver with a widely tunable local oscillator capable of 100 Gbps as well as the first 16×40 Gbps all-optical switch based on wavelength conversion which integrates 81 optical functions on a single die. By using a widely tunable local oscillator in the receiver, existing network bandwidth can be more flexibly allocated, reducing the need for redundant receiver arrays. By using wavelength conversion and a tunable SG-DBR laser in the optical switch, switching times can be greatly reduced compared to existing MEMs solutions. In addition to the system demonstrations, we will also detail several improvements made to the existing offset quantum well development platform to enable these devices, including development of multiple quantum well waveguide photodetectors with a 30 GHz 3-dB bandwidth without the use of a butt-joint regrowth and a novel waveguide dry etch which reduces the series resistance of the diodes by more than 5x. Through this work, we show that larger-scale photonic integration is not only possible, but inevitable for the continued growth of optical networks.

About Phillip J. Skahan:

photo of phillip skahan Phillip obtained his B.S. in Electrical Engineering from the University of Tennessee in 2010 with highest honors and M.S. from the University of California, Santa Barbara in 2011. He is currently pursuing his Ph.D. in Electrical Engineering at the University of California, Santa Barbara. His current research interests include photonic integrated circuits and novel photonic devices for applications in optical communication systems.

Hosted by: Professor Daniel Blumenthal