Advances in optoelectronic technologies for ROADM subsystems

Summary form only given. Until recently, reconfigurable optical add/drop multiplexer (ROADM) systems did not exist, their components were unselected, and their market was unclear. Today every major system vendor has a ROADM offering, and a large number of component vendors have announced ROADM products based on a variety of technologies, some more mature than others. We review the different optoelectronic component technologies that have been developed for use in ROADM subsystems, and describe their principles of operation, designs, features, advantages, and challenges.