Technology Close-Up

Dr. Colin Barron and Kevin Lindsay

Diode-pumped lasers are rapidly growing more powerful as their excitation sources increase in power and as coupling technology improves in efficiency. Pumping a single solid-state laser typically requires the combined emission of several diodes. Mode multiplexing optical coupling devices, generally referred to as multimode power combiners, generally direct output of these diodes into a single fiber.

The development in the early 1980s of fused multimode fiber coupler technology led to few applications. At the time, telecom transmission technology was moving from graded-index to single-mode fibers. Consequently, development of optical couplers focused primarily on single-mode devices…