80-GHz AlGaInAs/InP 1.55 µm colliding-pulse mode-locked laser with low divergence angle and timing jitter

In this paper we report a new epitaxial laser wafer design and the performance of an 80-GHz AlGalnAs/InP λ~l .55 μm CPM laser with a low divergence angle and timing jitter. Based on a standard epi-wafer, an additional thin layer (160-nm-thick 1.1Q), hereafter referred to as the far-field reduction layer (FRL), was inserted in the lower n-cladding layer with a 750-nm-thick InP spacer between the active layer and FRL. This design increases the spot size and reduces the internal loss of the cavity, while suppressing higher transverse mode lasing.