A display engine assembly comprises a first imager and a second imager to generate a left image and a right image, respectively, in a head-mounted display device. The left and right images are left and right components, respectively, of a single stereoscopic image. The display engine further comprises an optical waveguide optically coupled to the first imager and the second imager. The optical waveguide is part of a first optical path to convey the left image to a left eye of a user of the head-mounted display device and is also part of a second optical path to convey the right image to a right eye of the user of the head-mounted display device.