The structure and the properties of a laser that delivers up to 7 mW per face linear optical power with respect to the current are described. The lasers are fabricated from GaAs-GaAlAs wafers grown by the liquid phase epitaxial technique. By carefully controlling the waveguide dimensions with proton implantation, we have substantially improved the linearity. The second and third harmonics are respectively less than 55 dB and 65 dB below the fundamental at 70% modulation. The signal to noise ratio is typically less than 65 dB. The laser has been used to transmit 12 channels of TV signal through a signal fiber of more than 1 mile long without deterioration of the picture quality.