Hongwei Zhao
Postdoc Researcher
Phone:
805-893-5955
Email:
hwzhao.at.ece.ucsb.edu
Address:
Engineering Science Building
University of California, Santa Barbara
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I am a postdoc researcher at University of California, Santa Barbara. My postdoc research is to investigate monolithic integration of III-V lasers on Si substrates. We are also working on the development of other advanced photonic devices on this platform.
The central theme of my PhD research is to investigate integrated photonic techniques for free space optical communications. I have been focused on the two topics: 1) High-power indium phosphide (InP) photonic integrated circuits (PICs) for free space links; 2) Gate-tunable metasurface based on novel indium silicon oxide material toward beam steering.
EXPERIENCE
2012/09-2020
Lawyer
Mitsubishi Electron Research Lab (MERL), Boston, MA, USA
Working on device simulation and optical test bench setup
2012/09-2020
Lawyer
COMPANY NAME
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EDUCATION
2019/08-now
Postdoc Researcher
Integrated Photonics Lab
University of California, Santa Barbara (UCSB)
2015/05-2015/08
Research Intern
Mitsubishi Electron Research Lab (MERL), Boston, MA, USA
Working on device simulation and optical test bench setup
2012/09-2013/05
Teaching Assistant
Boston University
ECE course: EK307 (Introduction to Circuits )
2015-2019
Ph.D. in Electrical Engineering
Department of Electrical and Computer Engineering
University of California Santa Barbara
Santa Barbara, CA, USA.
Supervisor: Prof. Jonathan Klamkin
2012-2015
Ph.D. Candidate
Department of Electrical and Computer Engineering
Boston University
Boston, MA, USA
Supervisor: Prof. Jonathan Klamkin
2008-2011
M. Eng.in Microelectronics
Insititute of Semiconductors
Chinese Academy of Sciences
Beijing, China
Supervisor: Prof. Buwen Cheng
Research Projects
Project 1. High-power indium phosphide photonic integrated circuits for free space communication
InP PIC mounted to a AlN carrier for meaurment.
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Two PIC transmitters deisgn for high optical ouput power.
Indium phosphide (InP) is the most advanced platform for high-performance large-scale photonic integratedcircuits (PICs). In addition to fiber optic communication systems, InP PICs can impact other applications where high performance is required in conjunction with low cost, size, weight and power (CSWaP). These include microwave photonics and free spacecommunications. PICs are particularly attractive for free space optical communications where low CSWaP is critical while demonstrating high optical output power and power efficient modulation formats. Although some work has been carried out to realize high-power InP lasers and SOAs, little to no work has been carriedout to realize a full high-power InP PIC platform because of thechallenges associated with integrating high-confinement waveg-uides (for seed lasers, modulators, photodetectors, and passives) with low-confinement waveguides (for high-power lasers and SOAs).
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A novel platform for high power InP PICs was demonstrated. This platform is capable of a record output power of nearly 250 mW, which is significantly higher than conventional PIC platforms, reducing the requirements on an external high-power booster amplifier and enabling certain links without the need for an amplifier.
Project 2. Gate-tunable metasurface based on indium silicon oxide
Schematic of metasurface based on novel indium silicon oxide material.
D2 (P = 1 μm , W = 405 nm)
Simulated reflectance spectrum map for a resonator period of 1.0 μm as a function of wavelength and width of the resonator rod
D1: W = 300 nm, D2: W = 405nm, D3: W = 850 nm.
Meaured reflectance from the metasurface by FTIR for D2 (P = 1 μm , W = 405 nm).
As an alternative TCO, indium silicon oxide (ISO) is a good candidate for a transparent electrode, for flexible organicsolar cells, and for thin-film transistors Silicon doping was reported to increase the Hall mobility and reduce the carrier concentration compared with tin in indium oxide (In2O3). Moreover, the Si-compatibility of the ISO material and its wide tunability of the screened plasma frequency across the mid-IR spectrum provide additional degrees of freedom for device engineering.
Tunable metasurface based on novel indium silicon oxide material was demonstrated for the first time. The obtained large resonance shift can be further investigated to realize phased arrays of subwavelength resonators for flat optical elements, LIDAR and beam steering/pointing in free space optical communications.
Project 3. Broadband elatra-absorption modulator based on ITO.
Schematic of compact silion modulator.
The light propagating from the front end to the back end in the butt-couple scheme at λ = 1.31 μm: (a) N1=4.33e19cm-3 ; (b) N2 = 9.58e19cm-3.
CMOS-compatible transparent conducting oxides (TCOs) [e.g., indium tin oxide (ITO), aluminum zinc oxide, and gallium zinc oxide] have shown promise for integrated electro-absorptionmodulators. The permittivity of TCOs can be tuned by actively adjusting the carrier density (N), therefore these materials respond to applied electric signals with absorption modulation. We proposed a compact silicon (Si) electroabsorption modulator based on a slot waveguide with epsilon-near-zero (ENZ) indium tin oxide (ITO) materials.