multi-channel interference (mci) laser is a monolithic inp based widely tunable semiconductor laser, as shown in fig. 1. the mci laser is electronically/thermally tuned, which can address any wavelength in a range of more than 40 nm. mode selection of the mci laser is based on constructive interference of eight arms with unequal length difference [1]. by injecting currents into or heating the eight arm phase sections, we can make the eight arms in phase at any desired wavelength so as to generate a narrow strong reflection peak at the desired wavelength, as shown in fig. 2. therefore, the mci laser can be fabricated easily with standard photolithography, which can reduce the fabrication cost. besides, due to the independent arm phase sections, the mci laser is insensible to the initial phases of the eight arms, which makes the mci laser have a large fabrication tolerance. the mci laser has been demonstrated to have a tuning range of more than 53.6 nm and side mode suppression ratios (smsrs) larger than 40 db across the tuning range [2]. by adjusting the bandgap of the mqws, tuning range of the mci laser can cover the whole c band or l band. semiconductor optical amplifier (soa) has also been successfully integrated with the mci laser by a two port multi-mode interference reflector (mir) [3]. the two port mir can be fabricated simultaneously with the deeply-etched waveguides of the mci laser without increasing the fabrication complexity. the soa can be used to control the output power and compensate the power variation between different channels. when reverse biased, the soa acts as a shutter so as to enable dark tuning between channels.