Abstract: Configurations for a photonics assembly and the operation thereof are disclosed. The photonics assembly may include multiple photonics dies which may be arranged in an offset vertical stack. The photonics dies may emit light, and in some examples, an optical element may be a detector for monitoring properties such as the wavelength of the light. The photonics dies may be arranged in a stack as a package and the packages may be stacked or arranged side by side or both for space savings. The PIC may include combining and/or collimating optics to receive light from the photonics dies, a mirror to redirect the light, and an aperture structure. The aperture structure may include a region which is at least partially transparent such that light transmits through the transparent region of the aperture structure. The aperture structure may include an at least partially opaque region which may be used for directing and/or controlling the light launch position.