Post-Doct Digital design and signal processing for satellite optical com systems

Post-Doctoral Researcher in Digital Design and Signal Processing for Satellite Optical Communication Systems

• Doctorate, Bac+8
• Post-doctoral position

Mission

CONTEXT:

Digital optical telecommunications have enabled the construction of very high-speed terrestrial fiber networks, but microwaves remain the primary physical layer in satellite communications. Optical technologies have proven effective for inter-satellite links, and satellite-to-ground optical transmissions are being considered for new platforms, particularly in satellite constellation programs. The advantages are similar to terrestrial links: very high data rates, directional beams, and secure communications. Future generations of high-capacity satellites (SATCOM) in low Earth orbit (LEO) and geostationary orbit (GEO) will need to include optical components to guarantee increased throughput. However, the robustness and resilience of the link are highly dependent on atmospheric conditions, such as cloud cover, optical background noise, and atmospheric turbulence. In LEO, the Doppler effect will also impact data availability. These disturbances compromise link reliability and degrade the signal-to-noise ratio. Various transmitted waveforms and detection types have been studied, but complex modulation formats (QPSK, 8PSK, etc.) and coherent detection, similar to terrestrial networks, have proven most effective, albeit with more complicated implementations (sensitivity to frequency fluctuations). The CALICO project aims to study and design a new coherent detection technique at the interface between optics and digital electronics to compensate for the Doppler effect and improve the detection threshold. The objectives include designing a phase-locked loop to recover the phase and amplitude of the signal. This will involve an original hybrid approach to recover a carrier and a clean signal as soon as they leave the physical and electronic layer, combining an optical phase-locked loop (OPLL) with digital processing on a DSP.

MISSION:

The post-doctoral researcher will contribute to the CALICO project, focusing on the development and optimization of advanced detection techniques for optical satellite communications. Their responsibilities will include:

1. Design and Implementation of Control Loop Hardware Architecture:
   Develop the hardware architecture for a control loop from a Simulink model that integrates an optical phase-locked loop (OPLL) with digital signal processing (DSP). Translate simulation models into optimized hardware designs using VHDL for FPGA implementation.
2. Simulation and Optimization of Hardware Models:
   Simulate the control loop using advanced modeling tools to evaluate performance under varying conditions, including Doppler shifts, atmospheric turbulence, and noise. Optimize the design to ensure robust operation and low error rates in challenging environmental conditions.
3. Real-Time System Testing on Laser Test Bench:
   Conduct real-time tests of the hardware on a dedicated laser test bench to validate system functionality and performance. Develop testing protocols and adapt the system to ensure compatibility with experimental setups.
4. Analysis and Scientific Contribution:
   Analyze test results to assess the performance of the control loop and identify areas for further improvement. Collaborate with the research team to synthesize findings into scientific publications and present results at relevant conferences.

This role offers a unique opportunity to contribute to cutting-edge research at the interface of optics and digital electronics, with potential applications in next-generation satellite communication systems.

Profile

Note that the selected candidate must be validated by the DGA (French Government Defence Procurement and Technology Agency); European nationality is mandatory.

We are seeking a highly motivated post-doctoral researcher with a strong background in digital design and signal processing for telecommunications, specifically in high-speed satellite optical communication systems. The ideal candidate will possess the following qualifications and skills:

• A Ph.D. in Electrical Engineering, Telecommunications, Signal Processing, or a related field.
• Expertise in digital hardware design, including hands-on experience in VHDL/Verilog and FPGA programming.
• Strong understanding of signal processing techniques for telecommunications, focusing on modulation formats (e.g., QPSK, 8PSK) and coherent detection methods.
• Experience in designing and implementing control loops, including phase-locked loops (PLLs).
• Proficiency in simulation and modeling tools such as MATLAB, Simulink, or equivalent.
• Familiarity with real-time system testing and debugging in laboratory environments.
• Ability to analyze and interpret experimental results to identify areas for optimization.
• Strong written and verbal communication skills, with the ability to contribute to scientific publications.

The candidate should demonstrate a proactive and innovative mindset, capable of working independently while collaborating effectively within a multidisciplinary team. Please send a cover letter and a CV detailing your experience to: