Single-longitudinal-mode operation of injection laser coupled to a GRINROD external cavity

Abstract

We have demonstrated CW and pulsed single-longitudinal-mode operation of a conventional InGaAsP buried-heterostructure laser butt-coupled to a short GRINROD lens with reflective coating on the far end. The GRINROD lens was prepared using a ≲1/4 pitch graded-index fibre which was used as an external cavity with controlled optical coupling to the laser.