Top laser diode companies include Coherent, Inc., IPG Photonics Corporation, OSRAM, TRUMPF, and Jenoptik AG, among others. What Is a Laser Diode? What Is a Laser Diode? A laser diode is a device. A Laser Diode is a type of semiconductor device that produces coherent light through the process of stimulated emission. Stay ahead with the latest trends and market analysis. Our list of suppliers for that category contains 108 suppliers. Understand the Technical Background To support your technical evaluation, this section includes links to. As per the analysis by IMARC Group, the top laser diode companies are focusing on continuous investments in research and development activities to introduce new and advanced products with better performance, efficiency, and reliability.