An optical subassembly includes an opto-electronic device, an optics block and a spacer, separate from the optics block and providing spacing between the opto-electronic device and the optics block. The opto-electronic device, the optics block and the spacer are aligned and bonded together. This subassembly is particularly useful when coupling light between the opto-electronic device and a fiber. The optical subassembly may also include an opto-electronic device, an optics block and a sealing structure surrounding the opto-electronic device. The opto-electronic device, the optics block and the sealing structure are aligned and bonded together.