Densely packed 1.1 μm band vertical cavity surface emitting laser array for co-packaged optics

We demonstrated the 1.1 μm band 16-channel vertical cavity surface emitting laser (VCSEL) array for multi-core fiber (MCF) transmission towards co-packaged optics. Single-mode 16-ch top and bottom emitting VCSEL arrays were fabricated by either 3 inch or 6 inch wafer foundry process. The thermal crosstalk is estimated by wavelength shift. When the distance between adjacent VCSELs is 40 μm, the total thermal crosstalk is as low as 7 K. Bottom emitting metal-aperture VCSEL array were also fabricated via a full 3 inch wafer process. It shows low resistance and good single mode characteristic with an oxidation aperture of 7 μm thanks to an intra-cavity metal aperture. A large mode field diameter of 6 μm enables low coupling loss between bottom VCSEL array and MCF through a GaAs substrate for a flip-chip bonding process.