Background
Multi level coherent optical communication systems are under research with the aim of allowing 10-100 Tb/s transmission capacity over thousands of kilometers of fiber distances. These high constellation systems are mostly coherent systems with semiconductor lasers as transmitter and local oscillator. As such the systems are
subject to heavy influence of (laser) phase noise. Phase noise is a fundamental feature of semiconductor lasers and it is imperative to choose system designs that minimize the phase noise influence. Here, the digital signal processing (DSP) configuration in the system transmitter and receiver is important.
Project
The project will develop and investigate new methods for constructing communications that are tolerant to phase noise:
• ways of incorporating features like chromatic dispersion compensation and carrier phase extraction in the receiver, and decide which implementations give the best phase noise tolerance.
• optical systems utilizing an optical reference carrier frequency signal to eliminate fully or partly the phase noise influence using digitally realized phase conjugation.
• modulation techniques that have unique phase noise sensitivities such as coherent n-level Phase Shift Keying (PSK) and Quadrature Amplitude Modulated (QAM) systems as well as coherent and direct-detection Optical Orthogonal Frequency Division Multiplexed (OOFDM) systems.
The PhD study will be based on numerical simulations i.e. using tools like MATLAB, VPI transmission maker etc. The student will be registered with the Royal Technical Institute (KTH) and will follow PhD courses here.
Working at Acreo
Working place will be Acreo AB in Kista near Stockholm, the area prominent for academic and industrial research in the IT technology. Acreo has employees with high academic competence (50 % of the technical staff has PhD degree or equivalent) and our daily work is performed in an open and collaborative format together with internal and external colleagues. We see challenges as a mean for creating novel solutions for the benefit of our customers. We have a multi-cultural working environment and emphasis is on equality.
Qualifications
Applicants must hold or be about to receive an MSc degree in optics/photonics, applied physics, electrical engineering, or related areas. Furthermore, the successful applicant has:
• Strong academic credentials, written and spoken English proficiency, communication and team-work skills.
• Interest in following subjects: electro-optics, optical transmission systems. Strong motivation to perform simulation based research.
• Ability to programme in various languages (C++, MATLAB …) and be able to verify and design advanced computer (simulation) software model implementations.
Application
An application (in English) should include:
• Cover letter, one-page summary of your application
• CV including relevant documents demonstrating achievements and experience and two personal references
• An official copy of the MSc degree certificate and academic transcript
Optional: Copy of MSc thesis report (in PDF format), List of publications (if applicable) and Reference letter(s).
Please send your application to phd(at)acreo.se as soon as possible and no later than March 5. We will meet with applicants as applications are submitted.
For additional information, please contact
• Prof. G Jacobsen, +46 70 278 83 97 gunnar.jacobsen(at)acreo.se
• Assoc. Prof. S. Popov, sergeip(at)kth.se
