External cavity, multiple wavelength laser transmitter

A multiple channel transmitter usable for wavelength division multiplying includes a grating and a curved reflector. A diode array generates a plurality of parallel, spaced apart radiant energy beams which are incident on the grating at an acute angle. The plurality of beams is deflected in part, into the reflector. Back reflected radiant energy is deflected, in part, to the members of tile array causing them to lase at a plurality of different frequencies. The zeroth order deflection of the forward propagating beams off of the grating forms a parallel output.