The discovery of the visible light-emitting diode (LED) 50 years ago by Holonyak and Bevacqua and the associated demonstration of the viability of the III-V semiconductor alloy created a foundational basis for the field of optoelectronics. Key advances which enabled the progression from the first visible LED to today's III-V photonic integrated circuits (PICs) are described. Furthermore, the current state-of-the-art 500-Gb/s and 1-Tb/s large-scale InP transmitter and receiver PICs and their essential role in the optical communications networks are reviewed.

An automated system has been developed for visually inspecting the solder joints of SMDs (Surface Mounted Devices). The system is capable of inspecting fine pitch components down to 0.3 mm pitch QFPs (Quad Flat Packages). A unique image detection method was also developed to obtain precise 3-D images of solder joints. The principle of a confocal microscope is employed but plural sensors are used to detect reflected light at different focusing positions simultaneously. The system is unaffected by secondary reflection and dead angles. The warp in a PC (Printed Circuit) board surface is calculated in real time using the detected 3-D images, and board height to be detected in successive areas is predicted based on this calculation. Real-time automatic focusing control is then performed using newly developed defect detection algorithms, the system can recognize leads, pads and solder fillets from the detected images. Because 3-D shape features are extracted and used for defect judgment, user-defined parameters have been made easy to understand and/or to modify. Operational evaluation of the system confirms a 100% defect detection rate and a very low false alarm rate (0.16%).