Projects

RANGER : Ranging Techniques Using Advanced Semiconductor Lasers TEC2012-38864- C03-01

Laser systems are used for distance measurement in many different contexts, from thousands of km down to fraction of micrometers. LIDAR (Light Detection and Ranging) systems produce an image in two or three dimensions, or provide in-depth information of particle or molecule concentration. Laser ranging has been traditionally performed with pulsed solid state lasers or with low power semiconductor lasers in the near infrared region. Fuelled by the development of the optical communication technology, a new generation of high speed and high power semiconductor lasers in the eye-safe region of 1.5 µm, has recently come to the stage. These new laser sources can be used to improve laser ranging systems and techniques.

The objective of this project is to study, both from a theoretical and an experimental point of view, advanced semiconductor lasers emitting around 1.5 µm and their applications in laser ranging systems. The basic emitter will be a Master Oscillator Power Amplifier (MOPA), either hybrid or integrated. The hybrid version will be either a high speed Vertical-Cavity Surface-Emitting Laser (VCSEL) or a multi-section semiconductor mode-locked laser as seed and an Erbium Doped Fibre Amplifier (EDFA). The integrated version will be based on a DFB laser and a tapered semiconductor amplifier.

Different ranging techniques making use of the advanced semiconductor lasers, such as time of flight (TOF), CW pseudo-random modulation LIDAR, and chaotic LIDAR will be investigated. The dynamic properties of the devices, including polarization issues, will be investigated theoretically and experimentally. Demo-systems, including the complete detector and driving/analysis electronics will be fabricated and used for evaluating the performance of the different ranging approaches. Different range distances will be measured.

 

COMBINA : Frequency combs generated by semiconductor lasers TEC2015-65212-C3-3-P

Optical frequency combs are used for metrology, absolute frequency measurement, remote sensing, THz generation, microwave photonics and coherent optical communications. The ideal method for comb generation depends on the target application. While Mode-locked lasers can generate ps pulse trains with repetition rates of tens of GHz that are useful for Optical-Time Domain Multiplexing, combs for optical communications are usually generated by using electro-optical modulators. Recently gain switching of single-mode semiconductor lasers has appeared as an alternative to electro-optical modulation due to the lower cost and complexity of the transmitter.


The objective of this project is to study, both from a theoretical and experimental point of view, the characteristics of frequency combs generated by semiconductor lasers. Different types of semiconductor lasers and techniques will be used to generate frequency combs: from mode-locked lasers to gain-switching of semiconductor lasers like VCSELs, discrete model lasers, DFBs, and multi-section lasers.

Novel techniques, such as optical injection, will be introduced to improve the frequency comb characteristics. Combs generated by using different techniques and devices will be evaluated and compared. Optimization of the comb characteristics relevant for applications in THz generation, microwave photonics, optical communications and remote sensing will be performed.