ABOUT ME & MY RESEARCH

I am a Postdoctoral Fellow in the Edward S. Rogers Sr. Department of Electrical & Computer Engineering at the University of Toronto, in the same research group that I did my doctoral studies under the supervision of Dr.  Frank  R.  Kschischang. My Ph.D. studies were mainly focused on fiber-optic communication systems under direct detection, whose main application is in short-reach data transmission schemes, e.g., in intra-data-center communication systems.

In direct detection, one uses a photodiode as a transducer to convert the received lightwave into an electrical waveform, called a photocurrent. Unfortunately, the relationship between the amplitude of the received lightwave and the amplitude of the generated photocurrent is nonlinear and, in particular, it is quadratic. This makes data detection under deploying a single photodiode more challenging than their coherent counterparts, whose optical input and electrical output waveforms are related linearly. However, direct detection receivers have very simple optical front-ends which make those receivers play a crucial role in intra-data-center interconnects, where the transceiver simplicity is vital.

For a long time, there was an erroneous impression that the simplicity of square-law detectors trades off with a huge loss in their achievable data rate compared to coherent detectors. However, it can be shown that the data-rate loss under direct detection is at most 1 bit per degree-of-freedom compared to a phase-unlocked coherent detector. As a part of my doctoral research, I designed transceivers compatible with square-law detectors to achieve a data-rate within the discovered 1 bit per degree-of-freedom gap to the achievable data rate under coherent detection.

A non-inclusive list of my research interests is

• coding and modulation,
• information theory,
• data-center interconnects,
• optical communications,
• deep-space optical communication,
• DNA storage.

In my leisure time, I usually read novels, play setar (don't mix it up with sitar ), watch movies and series (specially detective stories, fantasy, and sci-fi), go for a hike or bike ride, etc.

MY EDUCATIONAL TIMELINE

• Ph.D. in electrical and computer engineering—telecommunications (2016—2022)
• University of Toronto
• Supervised by Dr.  Frank  R.  Kschischang
• Thesis title: Fiber-optic Communications Under Direct Detection: Capacity Bounds & Tukey Signalling
• Thesis defense committee members:
  • Dr.  Frank  R.  Kschischang
  • Dr.  George  C.  Papen
  • Dr.  Stark  C.  Draper
  • Dr.  Wei  Yu
  • Dr.  Ben  Liang
  • Dr.  Hoi-Kwong  Lo
• GPA: 4/4
• M.A.Sc. in electrical and computer engineering—telecommunications (2014—2016)
• University of Waterloo
• GPA: 88.4/100
• B.Sc. in electrical engineering—telecommunications (2010—2014)
• Tehran Polytechnic
• GPA: 18.41/20

Journal Papers

• A. Tasbihi and Frank R. Kschischang, "Practical Considerations in Direct Detection Under Tukey Signalling," submitted to J. Lightw. Technol. on Mar. 3, 2022. ( arXiv )
• A. Tasbihi and Frank R. Kschischang, "Direct Detection Under Tukey Signalling," J. Lightw. Technol., vol. 39, no. 21, pp. 6845–6857, 2021. ( arXiv )
• A. Tasbihi and Frank R. Kschischang, "On the Capacity of Waveform Channels Under Square–Law Detection of Time–Limited Signals," IEEE Trans. Inf. Theory, vol. 66, no. 11, pp. 6682–6687, 2020. ( arXiv )
• A. Tasbihi and Frank R. Kschischang, "Maximum Likelihood Detection in a Four–Dimensional Stokes–Space Receiver," IEEE Trans. Commun., vol. 67, no. 10, pp. 7016–7026, 2019. ( arXiv )

Conference Papers

• A. Tasbihi and Frank. R. Kschischang, "Nonlinearity tolerance of Tukey signalling with direct detection," in Eur. Conf. Opt. Commun. (ECOC), Basel, Switzerland, Sep. 2022.

• A. Tasbihi and Frank. R. Kschischang, "Successive four–dimensional Stokes–space direct detection," in Opt. Fiber Commun. Conf. Expo. (OFC), San Diego, CA, USA, Mar. 2018. ( arXiv )

Teaching Experience

University of Toronto

• ECE537: Random Processes
• ECE302: Probability and Applications
• ECE367: Matrix Algebra and Optimization
• CSC336: Numerical Methods
• ECE355: Signal Analysis and Communication
• ECE216: Signals and Systems
• ECE110: Electrical Fundamentals

University of Waterloo

• ECE316: Probability Theory and Random Processes
• ECE204A, NE217L: Numerical Methods
• MATH215: Linear Algebra

FUN FACTS

In this section, I write interesting miscellaneous scientific facts that I find in books, websites, papers, etc.

• 23456789 is a prime number!
• The electromagnetic equations that were written by James C. Maxwell consisted twenty equations with twenty variables. Later, Oliver Heaviside used the curl and divergence notions from vector calculus and shrank the number of Maxwell equations to only four with four variables!