Tunable 16 DFB laser array with unequally spaced passive waveguides for backside wavelength monitor. - Y. Sasahata; K. Matsumoto; T. Nagira; H. Sakuma; K. Kishimoto; M. Suzuki; D. Suzuki; Yuichiro Horiguchi; M. Takabayashi; Keita Mochizuki; M. Gotoda; Hiroshi Aruga; et al. (OFC, 2014)