GaAs spiral optical waveguides for delay-line applications

Spiral optical waveguides can be used to provide moderately long delays for a variety of microwave applications. A brief analysis of the performance limitations of spiral delay lines is presented, together with loss measurement data for spirals having air-equivalent lengths as long as 46 cm. It is shown that the present limitation to longer delay lengths is the straight-guide loss of GaAs/AlGaAs waveguides, and not bending or intersectional losses.<>