28-Gb/s directly modulated InGaAlAs ACPM DFB lasers with high mask margin of 22% at 55°C. - Kouji Nakahara; Yuki Wakayama; K. Hiruma; Takeshi Kitatani; Kazunori Shinoda; T. Fukamachi; Yasushi Sakuma; Shigehisa Tanaka (OFC/NFOEC, 2013)