In high-speed optoelectronics, components such as laser diodes and positive-intrinsic-negative (PIN) photodiodes with low impedance are used in conjunction with 50 Ω circuits, and little is done to minimize the serious effects of the impedance mismatch. Here, we describe a transmission line transformer (TUT) that works as a high-speed coupler, matching impedances with large bandwidth. The TLT confines the electromagnetic field more and more along the structure, gradually reducing the impedance.

© 1991 Optical Society of America

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