| A mode-locked laser naturally produces a spectral comb of many optical wavelengths. Such a laser could potentially replace a multitude of discrete wavelength lasers in future short distance WDM interconnect systems. We propose and investigate a fully integrated Long Vertical Cavity Surface Emitting Laser (LVCSEL) platform in this thesis which we believe is capable of being mode-locked. In such a mode-locked form, this kind of device may find use as a low-cost optical source solution for future WDM interconnects.; We first introduce the LVCSEL platform by discussing the design, fabrication, and testing of continuous wave lasers. This includes discussion of optical loss in the laser, and how to understand its coupled cavity nature. These lasers exhibited highly Gaussian transverse mode output and reached powers of up to 29mW at a wavelength of 980nm. We find that the loss associated with the long glass cavity portion of the device is larger than we expected.; We then move on to discuss the passive mode-locking of such a structure which requires the insertion of a saturable absorber (SA) into the laser cavity. This SA must have low saturation fluence, low loss, and a fast absorption recovery time (<23ps). We develop a quantum dot (QD) based SA which meets the requirements for mode-locking the LVCSEL platform. We then integrate this SA into the LVCSEL platform and test for mode-locking. No device was found which exhibited mode-locked behavior. We argue that mode-locking was not achieved because the SA could not be sufficiently saturated due to low intra-cavity optical power. While increasing the reflectivity of the GaAs-glass interface may increase the intra-cavity power, we show that improving the thermal characteristics of the device platform can also yield a very large improvement. Combined, these improvements should lead to the realization of a fully monolithic mode-locked VCSEL. |
