ABSTRACT
Small-sized optical isolators are a relatively recent invention brought about by the need for protection of optical devices from stray reflected signals [1,2]. The two most common examples are laser diodes and optical amplifiers. The reflected light destabilizes the output of laser diodes, whereas with optical amplifiers, the reflected light could prematurely ‘‘dump’’ the inverted population. The optical isolator package must always be small to fit into optoelectronic device structures; therefore, they require a rather ingenious arrangement of micro-optical components.
