Demonstration of Multi-Channel Interference Widely Tunable Semiconductor Laser

In this letter, we report the first experimental demonstration of the multi-channel interference (MCI) widely tunable semiconductor laser. Mode selection of the MCI laser is achieved by the constructive interference of eight arms with unequal length difference. Compared with conventional widely tunable semiconductor lasers based on distributed Bragg reflectors, fabrication of the MCI laser is simpler with large fabrication tolerances. A quasi-continuous tuning range of about 52.3 nm (1538.96-1591.26 nm) has been demonstrated at a temperature of 23 °C with side-mode suppression-ratios greater than 44 dB across the whole tuning range (typically greater than 48 dB).