Instrumentation for narrow linewidth semiconductor laser

This contribution presents a design of the circuitry for operation of a high stability and high coherence laser diode emitting in the visible region of spectra. The laser diode is used in a laser system with an external cavity with a large mode-hop free tuning range. This system can be used in spectroscopic and interferometric applications. The laser diode intrumentation consists of a low noise and high stability current source, high frequency modulation circuitry and electromagnetic interference protection. Special attention is guid to the protection against fast transients induced from the outside or generated by swiching leading to the degradation of the laser diode active channel or its damage. Details concerning stability, noise and interference shielding are presented.