In this work we present the design and the construction of a laser system for cooling an atomic gas of potassium 39K on the D1-Line by gray molasses technique. The seed laser is an Interference-filter-stabilized external-cavity diode laser (ECDL). The laser frequency is stabilized to one of the atomic features of 39K D1-transition thanks to frequency modulation (FM) spectroscopy. The low seed power is then amplified by means of tapered amplifier (TA). Finally, the cooling and repumping beams are generated and blue-detuned from the atomic transitions |F = 2> → |F'= 2> and |F = 1> → |F'= 2> using two acousto-optic modulators (AOMs).