PhD Thesis on Optical Fiber Sensing

Nokia

  • Massy, Essonne
  • CDI
  • Temps-plein
  • Il y a 5 heures
Job Category: Applied R&DDegree Level: Master's degreeJob Description:Often referred to as “The Idea Factory” or “The Crown Jewel,” Nokia Bell Labs has an unparalleled history of innovation output since 1920's up to now. Researchers at Nokia Bell Labs have been behind or involved in many critical technological milestones for the last century. We built the first lasers and transistors, created C and C++, discovered the origins of the universe, proved the wave-like behavior of electron in the lab, and connected the world using communications satellites. We also invented implementable technologies like the solar battery and the first hearing aids and made great theoretical leaps forward with the likes of Information Theory. For more information on who we are, and reading about our history, including 10 Nobel Laureates to-date, please have a look at About us - Nokia Bell Labs (bell-labs.com).The proposed PhD thesis will be held in the Optical Transmission Department, as part of the Optical Systems and Devices Research lab of Nokia Bell Labs. The Optical Transmission Department, located in the vibrant center of Massy, 10 km south of Paris, has a long track-record of innovation in advanced models of transmission effects and breakthrough hero experiments in the field of high-speed and long-haul fiber-optic transmission systems.Outside the scope of data transmission, we are placing our expertise in coherent optical systems and digital signal processing at the service of distributed acoustic sensing systems based on optical fiber sensors (the fibre is transformed into an array of virtual microphones). The goal of this PhD thesis work is to further improve the performance of our sensing system to capture mechanical and to differentiate between various acoustic events captured along the fiber. This requires to preliminary extract relevant parameters as spectral signatures that will later feed a classifier to achieve the optimal discrimination performance.Therefore, this PhD thesis requires knowledge of:
  • Digital signal processing algorithms
  • Basic physics of optical fiber propagation
  • Basics in acoustic signals detection/classification
  • Experimental skills
Responsibilities:
  • Building a general model of frequency dependent phase noise for ultra-low linewidth laser sources. Quantification of impact on the noise floor of our sensing system as a function of the dominant frequency bands of the source phase noise. Optimisation of the phase noise control loop of laser sources at low frequencies.
  • Deconvolution of linear effects generated by the MIMO sensing setup: optimisation of algorithms. Estimation of the gain on the sensing system noise floor.
  • Investigation through simulation and experimental traces of polarisation changes observed at a fiber location when subject to high intensity mechanical perturbations. Search for the most suitable space to characterize the perturbations.
  • Time-frequency analysis of captured perturbations through alternatives to short-time Fourier transform, mainly wavelet decomposition. Building of a library of discriminating patterns. First classification tests.
The PhD student will be encouraged and supported to publish her/his work in leading conferences of optical communications. In addition, she/he will be collaborating with other researchers in Bell Labs and create and maintain strong relationships with partners in the external research community.Qualifications:
  • Candidates must hold a Master of Science or Engineering diploma (M2) in the field of communication theory or any related field.
  • Skills in modeling, digital signal processing.
  • Matlab (preferable), C or Python (alternatively), VHDL or Verilog (appreciated).
  • Experimental skills to build an optical testbed and validate the model (preferable).
  • Strong written and spoken communications skills and the ability to participate in robust discussions in English (mandatory).
About Us:Come create the technology that helps the world act togetherNokia is committed to innovation and technology leadership across mobile, fixed and cloud networks. Your career here will have a positive impact on people's lives and will help us build the capabilities needed for a more productive, sustainable, and inclusive world.
We challenge ourselves to create an inclusive way of working where we are open to new ideas, empowered to take risks and fearless to bring our authentic selves to workWhat we offerNokia offers continuous learning opportunities, well-being programs to support you mentally and physically, opportunities to join and get supported by employee resource groups, mentoring programs and highly diverse teams with an inclusive culture where people thrive and are empowered.Nokia is committed to inclusion and is an equal opportunity employerNokia has received the following recognitions for its commitment to inclusion & equality:
  • One of the World's Most Ethical Companies by Ethisphere
  • Gender-Equality Index by Bloomberg
  • Workplace Pride Global Benchmark
At Nokia, we act inclusively and respect the uniqueness of people. Nokia's employment decisions are made regardless of race, color, national or ethnic origin, religion, gender, sexual orientation, gender identity or expression, age, marital status, disability, protected veteran status or other characteristics protected by law.
We are committed to a culture of inclusion built upon our core value of respect.Join us and be part of a company where you will feel included and empowered to succeed.

Nokia