A laser array mux assembly comprising: an array of laser emitters (320-1 to 320-n, 420-1 to 420-n, 520-1 to 520-n), each of the laser emitters including a gain region for emitting light across a range of wavelengths including channel wavelengths of an optical communication system and a back reflector for reflecting light from the laser emitters, wherein the back reflector of each of the laser emitters is highly reflective, and wherein each of the laser emitters includes an anti-reflective coating on an opposite side, the anti-reflective coating providing a reflectivity of less than 1 %, and wherein the laser emitters are essentially the same gain chips; an optical multiplexer (330, 430, 530) including a plurality of input ports (532-1 to 532-n) coupled to the laser emitters, respectively, using a microlens array or a fiber tip array and an output port, wherein the optical multiplexer is an arrayed waveguide grating configured to filter light received on each of the input ports at different respective channel wavelengths for each of the input ports and to provide the filtered light to the output port, wherein the back reflector of each of the laser emitters is highly reflective, and wherein each of the laser emitters is antireflective on an opposite side coupled to the optical multiplexer; and a partial reflector (340, 440, 540) coupled directly to the output port of the optical multiplexer, the partial reflector being partially reflective across the channel wavelengths and configured to reflect at least a portion of the filtered light back to the gain region in the respective laser emitters such that at least one lasing cavity is completed after the optical multiplexer and formed between the back reflector of at least one of the laser emitters and the partial reflector and lasing occurs at the channel wavelength(s) reflected back to the gain region of the respective laser emitters. an array of laser emitters (320-1 to 320-n, 420-1 to 420-n, 520-1 to 520-n), each of the laser emitters including a gain region for emitting light across a range of wavelengths including channel wavelengths of an optical communication system and a back reflector for reflecting light from the laser emitters, wherein the back reflector of each of the laser emitters is highly reflective, and wherein each of the laser emitters includes an anti-reflective coating on an opposite side, the anti-reflective coating providing a reflectivity of less than 1 %, and wherein the laser emitters are essentially the same gain chips; an optical multiplexer (330, 430, 530) including a plurality of input ports (532-1 to 532-n) coupled to the laser emitters, respectively, using a microlens array or a fiber tip array and an output port, wherein the optical multiplexer is an arrayed waveguide grating configured to filter light received on each of the input ports at different respective channel wavelengths for each of the input ports and to provide the filtered light to the output port, wherein the back reflector of each of the laser emitters is highly reflective, and wherein each of the laser emitters is antireflective on an opposite side coupled to the optical multiplexer; and a partial reflector (340, 440, 540) coupled directly to the output port of the optical multiplexer, the partial reflector being partially reflective across the channel wavelengths and configured to reflect at least a portion of the filtered light back to the gain region in the respective laser emitters such that at least one lasing cavity is completed after the optical multiplexer and formed between the back reflector of at least one of the laser emitters and the partial reflector and lasing occurs at the channel wavelength(s) reflected back to the gain region of the respective laser emitters.