Tunable lasers with high side-mode suppression ratios (SMSRs) are cost-effective solutions to replace multiple DFB lasers in wavelength-division multiplexing (WDM) systems. Two arm interference-based devices, such as C3- and Y-branch lasers, have advantages over grating- and ring-resonator-based counterparts in terms of cost and fabrication complexities; however, it is fundamentally difficult to achieve high SMSRs and wide tuning ranges simultaneously. In our proposed three-branch MMI laser, an additional long cavity is added to a Y-branch structure to improve the SMSRs and widen the tuning range of the laser at the same time. More importantly, the proposed structure is not limited either by the material platform or the operation band of choice. With this device architecture, we have obtained tuning ranges over 30-nm in O-band and 44-nm in C-band.
Project end date: 01/23/20