Practical cases

RES - Kit enseignement Transformée de Fourier et caractérisation Laser - IUT Grenoble

How to address laser spectrum analysis and signal processing in a practical way with undergraduate students?

In order to answer this question, we asked Dr. Guillermo Martin, professor at Grenoble Alpes University, which practical cases he set up to address these topics with his students. Hello Guillermo. Could you please introduce yourself and describe your professional background? I did a joint Ph.D between ENS-Cachan and the University of Madrid on the study of nonlinear optics in organic material for frequency conversion. In 2006 I joined the IPAG (Institut de Planétologie et d’Astrophysique de Grenoble) laboratory where…

Practical case- Tunable DFB laser diode - header

Tuning a DFB laser diode with temperature

Distributed Feedback (DFB) lasers are commonly used as tunable lasers over a range of a few nanometers. This is generally achieved by adjusting the temperature of the chip, thanks to a driver that can also monitor the current flowing through the DFB. This is a straightforward way of obtaining a tunable laser for a narrow range, typically one or two nanometers. However, temperature tuning can lead to unexpected behaviors which can be critical in many applications. A distributed feedback (DFB)…

Strainmeter to detect earth tide and seismic waves from earthquakes

Strainmeter based on laser wavelength monitoring

We have seen in a previous article that a set-up based on a laser and Optical Fiber Bragg grating (FBG) sensors can be used for strain and temperature monitoring. This technique is based on the monitoring of reflected laser wavelength. FBG sensors find one application in seismology. Strain monitoring is well known in the field of seismology for earth science observation purposes. Strainmeters measure deformation over periods of days, months, and years. This allows them to measure signals at lower…

Multimode VCSEL unstability

VCSEL are now used as singlemode and multimode laser sources in many application fields. Many users are not laser expert and may discover VCSEL unstability late in a development …VCSEL Unstability can be related to two mains parameters : drive current and temperature. The following videos can help feeling how sensitive VCSEL unstability can be for a specific application. Here is a video of the spectrum of VCSEL when changing its current from 90 mA to 140 mA. From a…