A filtered laser array assembly (202, 204, 304) characterised by: an array of continuous wave laser emitters (310-1 to 310-n, 410), each of the laser emitters (310-1 to 310-n, 410) including a gain region for emitting light across a range of wavelengths including a plurality of channel wavelengths (λ 1, λ 2,... λ n) and an exit reflector for reflecting at least a portion of light from the laser emitters (310-1 to 310-n, 410); an arrayed waveguide grating including a plurality of input ports (332-1 to 332-n) coupled to the laser emitters (310-1 to 310-n, 410), respectively, and an output port, the AWG being configured to filter light received on each of the input ports (332-1 to 332-n) at different respective channel wavelengths (λ 1, λ 2,... λ n) for each of the input ports (332-1 to 332-n) and to provide the filtered light to the output port; a back reflector coupled to the output port of the AWG, the back reflector being configured to reflect the filtered light back to the gain region in the respective laser emitters (310-1 to 310-n, 410) such that a plurality of extended lasing cavities are formed between the back reflector and the exit reflectors of respective ones of the laser emitters (310-1 to 310-n, 410), wherein each of the plurality of extended lasing cavities is completed after the AWG and is configured for lasing only at the respective channel wavelengths (λ 1, λ 2,... λ n) reflected back to the respective gain regions of the respective laser emitters (310-1 to 310-n, 410); and a plurality of external modulators (320-1 to 320-n) coupled to the laser emitters (310-1 to 310-n, 410), respectively, and configured to modulate laser light exiting from respective ones of the laser emitters (310-1 to 310-n, 410), wherein the exit reflectors of each of the laser emitters (310-1 to 310-n, 410) is sufficiently partially reflective to achieve lasing at the associated channel wavelength (λ 1, λ 2,... λ n), and wherein each of the laser emitters (310-1 to 310-n, 410) is anti-reflective on a side opposite the exit reflectors. an array of continuous wave laser emitters (310-1 to 310-n, 410), each of the laser emitters (310-1 to 310-n, 410) including a gain region for emitting light across a range of wavelengths including a plurality of channel wavelengths (λ 1, λ 2,... λ n) and an exit reflector for reflecting at least a portion of light from the laser emitters (310-1 to 310-n, 410); an arrayed waveguide grating including a plurality of input ports (332-1 to 332-n) coupled to the laser emitters (310-1 to 310-n, 410), respectively, and an output port, the AWG being configured to filter light received on each of the input ports (332-1 to 332-n) at different respective channel wavelengths (λ 1, λ 2,... λ n) for each of the input ports (332-1 to 332-n) and to provide the filtered light to the output port; a back reflector coupled to the output port of the AWG, the back reflector being configured to reflect the filtered light back to the gain region in the respective laser emitters (310-1 to 310-n, 410) such that a plurality of extended lasing cavities are formed between the back reflector and the exit reflectors of respective ones of the laser emitters (310-1 to 310-n, 410), wherein each of the plurality of extended lasing cavities is completed after the AWG and is configured for lasing only at the respective channel wavelengths (λ 1, λ 2,... λ n) reflected back to the respective gain regions of the respective laser emitters (310-1 to 310-n, 410); and a plurality of external modulators (320-1 to 320-n) coupled to the laser emitters (310-1 to 310-n, 410), respectively, and configured to modulate laser light exiting from respective ones of the laser emitters (310-1 to 310-n, 410), wherein the exit reflectors of each of the laser emitters (310-1 to 310-n, 410) is sufficiently partially reflective to achieve lasing at the associated channel wavelength (λ 1, λ 2,... λ n), and wherein each of the laser emitters (310-1 to 310-n, 410) is anti-reflective on a side opposite the exit reflectors.