Integrated Thin-Film GaSb-based Fabry-Perot Lasers: Towards a Fully Integrated Spectrometer on a SOI Waveguide Circuit

Several molecules of interest have their absorption signature in the mid-infrared. Spectroscopy is commonly used for the detection of these molecules, especially in the short-wave infrared (SWIR) region due to the low water absorption. Conventional spectroscopic systems consist of a broadband source, detector and dispersive components, making them bulky and difficult to handle. Such systems cannot be used in applications where small footprint and low power consumption is critical, such as portable gas sensors and implantable blood glucose monitors. Silicon-On-Insulator (SOI) offers a compact, low-cost photonic integrated circuit platform realized using CMOS fabrication technology. On the other hand, the GaSb material system allows the realization of high performance SWIR lasers and detectors. Integration of GaSb active components on SOI could therefore result in a compact and low power consumption integrated spectroscopic system. In this paper, we report the study on thin-film GaSb Fabry-Perot lasers integrated on a carrier substrate. The integration is achieved by using an adhesive polymer (DVS-BCB) as the bonding agent. The lasers operate at room temperature at 2.02 mu m. We obtain a minimum threshold current of 48.9mA in the continuous wave regime and 27.7mA in pulsed regime. This yields a threshold current density of 680A/cm(2) and 385A/cm(2), respectively. The thermal behaviour of the device is also studied. The lasers operate up to 35 degrees C, due to a 323 K/W thermal resistance