We present a vertical external cavity surface-emitting laser system based on a multi-quantum-well structure with 20 compressively strained GaInP quantum wells for an operation wavelength of around 665 nm with a monolithic integrated distributed Bragg reflector. With the help of an intra-cavity diamond heatspreader the laser operates in continuous-wave mode. Operation with a TEM00 Gaussian beam profile and a beam propagation factor of M2≤1.05 is shown as well as a high resolution spectrum of the laser line, which shows the etalon effect of the diamond. The laser can be operated at a maximum output power exceeding 1.2 W with a slope efficiency of ηdiff=18%. At maximum output power the wavelength of the laser resonance is at 670 nm, which is shortest reported until now at powers exceeding 1 W. By rotating a birefringent filter in an extended folded cavity arrangement a wavelength tuning of 21 nm was attained.