This book investigates design methodologies of electro-optical short-range transmitter and receiver front-ends. Focus is laid on energy-efficiency and high-speed optimization. Highly-scaled CMOS technologies with 80 nm, 28 nm and 22 nm nodes are used that were developed for very-large scale integrated digital design, making mixed-signal systems possible. To improve the high-frequency performance, new peaking and bandwidth enhancement methods are developed, while the conventional are improved. Offset is addressed and compensation schemes are designed. On the transmitter side circuit techniques are developed to operate the optical devices at high voltages. The electro-optical front-ends designed in this work are included, together with commercial optical devices on custom-designed printed cable boards that provide both the DC as well as high-frequency connections. These assemblies are used to perform extensive optical and link measurements. The presented design methodologies are hereby validated with measurement results. Transmitter front-ends are measured optically up to 30 Gbit/s while on the receiver side operation at 54 Gbit/s is reached. The designs occupy very small areas, are energy efficient and implement power/data-rate adaptivity.