Jun 11 (Tue) @ 2:30pm: ”Coherent Receivers for O-band, Short Reach Optical Links,” Stephen Misak, ECE PhD Defense

Date and Time
Engineering Science Building (ESB), Room 2001

Zoom Meeting: Meeting ID: 828 9647 6616 | Passcode: 202410


High bandwidth optical links are required to support the continual increases in the demand for high-resolution video, high-performance computing, machine learning, cloud computing, the Internet of Things (IoT), 5G networks, and other applications. In particular, the bandwidth requirements for short reach inter- and intra-data center optical links are reaching the capability limits of the industry standard intensity modulation, direct detection (IMDD) links. Coherent modulation, while more complex for a single optical link, can operate at higher data rates and spectral efficiency by encoding multiple bits per symbol. The high sensitivity of coherent links also enables data centers to replace electrical switches with optical switches, reducing overall power consumption and hardware cost. O-band coherent receivers (RX) on indium phosphide (InP) and silicon photonics (SiP) platforms designed for analog coherent links will be discussed in this dissertation. The design, fabrication, and measurements from two generations of InP O-band coherent RX PICs will be described. Two generations of O-band coherent RX PICs fabricated using Intel’s SiP process (with and without integrated lasers) and a dual-mode coherent RX using Global Foundries 45SPCLO will also be shown. A sampled-grating distributed Bragg reflector (SG-DBR) laser designed for O-band coherent RXs using Intel’s SiP process will be presented. To demonstrate the RX PICs, they are packaged with high-speed electronic integrated circuits (EICs) and measured with multiple coherent modulation formats. Architectures using reduced DSP or analog electronics both show promise for energy efficient, short reach coherent links.


Stephen Misak received a B.S. degree in engineering physics with a minor in optical engineering in 2017 from Rose-Hulman Institute of Technology and a M.S. degree in electrical engineering in 2019 from the University of California, Santa Barbara, where he is currently pursuing the Ph.D. degree in electrical engineering. His research focuses on photonic integrated circuits for coherent communications on InP and silicon photonics platforms with an emphasis on the design, fabrication, and testing of O-band coherent receivers.

Hosted by: Professor Clint Schow

Submitted by: Stephen Misak <smisak@ucsb.edu>