A Multi-Channel Etched-Mesa PBH DFB Laser Array Using an SAG Technique

We present a multi-channel $\lambda $ /4-shifted distributed feedback laser diode array (DFB-LDA) for the low-cost application of wavelength division multiplexing-based datacenter networks. The gain spectrum and lasing wavelength of each channel are controlled by utilizing selective area growth and E-beam lithography techniques, respectively. To reduce the power consumption and improve the channel uniformity of the proposed array, a planar-buried hetero-structure (PBH) is introduced and the region containing the active region and the current blocking structures are etched in a mesa form (i.e., an etched mesa PBH). From this study, it was found that an 8-channel 300- $\mu \text{m}$ -long anti-reflection (AR) $\lambda $ /4-shifted DFB-LDA has a threshold current of 10 mA, ±1.5 mA, and a side mode suppression ratio of over 50 dB for all channels. A transmission test for this LDA showed a clear eye opening with a dynamic ratio of over 4.5 dB at 10 Gb/s, and a power penalty of less than 2 dB after a 2-km transmission.