Abstract
Multi-wavelength lasers are interesting devices with applications in telecom, optical sensing and terahertz generation. Controlling the optical power in each mode has proven to be difficult. Some solutions need many different parameters to control the emission, others show simultaneous emis- sion but controlling is not possible. To overcome these issues the research group VUB B-PHOThas proposed a novel control technique, based on phase-controlled optical feedback. It is expected that this control scheme can control the power in each mode of dual-wavelength laser (DWL). To investigate this further, multiple DWL schemes, together with the novel control technique, have been integrated on a photonic integrated circuit (PIC). These PICs need to be experimentally
studied to determine the validity of the control technique. Also, a comparison study between the different lasers schemes can indicate which performs best. This thesis discusses characterization of the wavelength selective elements (distributed Bragg reflectors(DBRs)), characterization of the solitary lasers, and feedback induced switching behavior.
Characterization of the DBRs showed that the central wavelength always was within specifications. Tuning this central wavelength is possible by injection a current, however, the experiments indicate that the shift is less than 1 nm, which is lower than specificated. Characterization of the solitary lasers indicated all are capable of lasing, although not all lase at multiple wavelengths.
However, this is not attributed to a specific design. For three different structures, switching between modes could be achieved, induced by a change in the feedback phase. A switching speed measurement, performed on one structure, indicated that the switch occurred in 4 ns. These findings show that the novel control technique is a promising tool to switch a DWL quickly by tuning only one, easily controllable, parameter.
| Date of Award | 2019 |
|---|---|
| Original language | English |
| Supervisor | Robert Pawlus (Advisor) |