1.5-μm and 10-Gb s-1 etched mesa buried heterostructure DFB-LD for datacenter networks

We report a 1.5 mu m and 10 Gb s(-1) etched mesa buried heterostructure lambda/4-shifted distributed feedback laser diode (DFB-LD) for the low-cost application of WDM-based datacenter networks. To reduce the threshold current and improve the modulation bandwidth in a conventional p-/n-/p-InP current blocking structure, a thin undoped-InP (u-InP) layer was inserted between the side walls of the active region and the p-InP layer (i.e., a u-/p-/n-/p-InP structure), and the region containing the active region and the current blocking structures was etched in a mesa form (i.e., an etched mesa). From this work, it was found that a 300 mu m long anti-reflection (AR)-AR DFB-LD with a mesa width of 8 mu m is reduced by about 25% while a side mode suppression ratio is >50 dB and a 3 dB bandwidth is >10 GHz at a current of 40 mA; in addition, it shows a clear eye-opening with a dynamic extinction ratio of >4.5 dB at 10 Gb s(-1), and a power penalty of <1 dB after a 2 km transmission.