We report here on the development of a multi-Watt power tunable single frequency ultra-low noise laser system emitting around 620 nm. More than 5 W of output power is obtained between 616.5 nm and 630.8 nm using sum frequency generation of 1050 nm and 1550 nm tunable laser sources in a periodic poled lithium niobate crystal. The tunability is achieved through temperature and channel shift, and only limited by the crystal characteristics. An output power of 10.1 W and an optical-optical efficiency of 45% are reached at 624.5 nm. The relative intensity noise properties of the conversion process have been experimentally investigated in different configurations showing excellent agreement with the analytical prediction.