Prof. Avi Zadok is an Associate Prof. in the Faculty of Engineering, a member of theNanophotonics Center at the Bar-Ilan Institute of Nanotechnology and Advanced Materials (BINA), and one of Bar-Ilan’s 2011 Outstanding Lecturers.
He came to Bar-Ilan University from California Institute of Technology, as part of the 2009 cohort of returning scientists, a special program within Bar-Ilan University to recruit young Israeli scientists to return to work in Israel. The research projects of Zadok’s group fall within two main categories: electro-optic devices and fiber optics.
Zadok’s group’s interest in electro-optic devices is primarily focused on silicon photonics, which involves incorporating photonic functionalities—such as the generation, modulation, guiding, filtering and detection of light—within the silicon material platform.
The primary objective of their work in this field is to overcome the material deficiencies of silicon in active photonic devices using the hybrid integration of additional materials on the silicon platform. This vertical integration approach relies on wafer bonding between silicon-on-insulator (SOI) wafers and active electro-optical materials.
Together with Prof. Chaim Sukenik of the Department of Chemistry, Zadok and his team are pursuing an alternative bonding technology based on the deposition of organic self-assembled mono-layers (SAMs) on the surface of one or both wafers.
Since SAM-enhanced bonding brings several unique advantages to the CMOS-integrated platform—their bonds are considerably stronger than the inter-molecular forces used in “direct” bonding to date—significant improvements in yield are expected.
Zadok and his group are also working on projects related to the monolithic integration of laser sources with high-speed silicon-integrated electronic circuits. Their research efforts in this area target the design, fabrication, and characterization of hybrid silicon/III-V lasers of improved efficiency, and hybrid silicon/III-V modulators for advanced modulation formats.
In addition, Zadok and his team are attempting to develop passive, planar light-guide circuits (PLC) in SOI for the all-optical implementation of the discrete wavelet transform. Such an implementation could relieve the bottleneck of high rate digital signal processing that is necessary for the computation of the transform at high data rates.
In the area of fiber optics, Zadok and his group work on projects related to optical communication, distributed sensing, and microwave photonics.
One research project focuses on enhancing Brillouin Optical Time-Domain Reflectometry (B-ODTR), a fiber-optic sensing technology that allows for the distributed monitoring of temperature and mechanical strain. Currently, the resolution of commercially available B-OTDRs is on the order of meters and has a range of a few tens of kilometers.
Zadok and his group aim to improve the resolution to the centimeter range and extend the measurement range towards 100 km using elaborate signal processing. In another research project, the group is working on the photonic generation of ultra-wideband noise waveforms and their potential applications.
Zadok and his group are also working on the photonic implementation of true time-delay for optical beam-forming in radar, where they aim to reach an all-optical, continuously variable delay of up to 50 nsec for broadband radar pulses of arbitrary carrier frequencies.
In addition, they are studying the mitigation of nonlinear impairment in wavelength-division multiplexed coherent optical communication. Their goal is to propose and demonstrate computationally efficient schemes for the electronic mitigation and compensation of nonlinear propagation impairments in multi-channel, coherent optical communication networks.
Zadok and his group are looking to enhance the scope and performance of silicon-photonic devices, bringing together several different materials via a unique wafer bonding technology. The group is also looking to utilize the long reach and broad bandwidth of optical fibers for more accurate distributed sensing, and for the analog processing of radio and microwave signals.