Hybrid integrated external cavity laser using 1.5% ΔPLC

An integrated external cavity laser (ECL) using planar lightwave circuits (PLCs) with a higher than usual refractive index contrast has been successfully demonstrated. The small modefield of the PLCs enables use of a laser diode without a spot-size converter and eliminates the need for a Si terrace structure. The oscillation characteristics of the ECL are as good as those of a conventional ECL with a lower contrast.