Abstract: Disclosed is a Vernier effect DBR laser that has uniform laser injection current pumping along the length of the laser. The laser can include one or more tuning elements, separate from the laser injection element, and these tuning elements can be used to control the temperature or modal refractive index of one or more sections of the laser. The refractive indices of each diffraction grating can be directly controlled by temperature changes, electro optic effects, or other means through the one or more tuning elements. With direct control of the temperature and/or refractive indices of the diffraction gratings, the uniformly pumped Vernier effect DBR laser can be capable of a wider tuning range. Additionally, uniform pumping of the laser through a single electrode can reduce or eliminate interfacial reflections caused by, for example, gaps between metal contacts atop the laser ridge, which can minimize multi-mode operation and mode hopping.

Abstract: For epitaxial-side-down bonding of quantum cascade lasers (QCLs), it is important to optimize the heat transfer between the QCL chip and the heat sink to which the chip is mounted. This is achieved by using a heatsink with high thermal conductivity and by minimizing the thermal resistance between the laser active region and said heatsink. In the epi-down configuration concerned, the active region of the QCL is located only a few micrometers away from the heatsink, which is preferable from a thermal standpoint. However, this design is challenging to implement and often results in a low fabrication yield if no special precautions are taken. Since the active region is very close to the heatsink, solder material may ooze out on the sides of the chip during the bonding process and may short-circuits the device, rendering it unusable. To avoid this happening, the invention proposes to provide a trench all around the chip with the exception of the two waveguide facets, i.e. the ends of the active region.

Abstract: Disclosed is a Vernier effect DBR laser that has uniform laser injection current pumping along the length of the laser. The laser can include one or more tuning elements, separate from the laser injection element, and these tuning elements can be used to control the temperature or modal refractive index of one or more sections of the laser. The refractive indices of each diffraction grating can be directly controlled by temperature changes, electro optic effects, or other means through the one or more tuning elements. With direct control of the temperature and/or refractive indices of the diffraction gratings, the uniformly pumped Vernier effect DBR laser can be capable of a wider tuning range. Additionally, uniform pumping of the laser through a single electrode can reduce or eliminate interfacial reflections caused by, for example, gaps between metal contacts atop the laser ridge, which can minimize multi-mode operation and mode hopping.

Abstract: For epitaxial-side-down bonding of quantum cascade lasers (QCLs), it is important to optimize the heat transfer between the QCL chip and the heat sink to which the chip is mounted. This is achieved by using a heatsink with high thermal conductivity and by minimizing the thermal resistance between the laser active region and said heatsink. In the epi-down configuration concerned, the active region of the QCL is located only a few micrometers away from the heatsink, which is preferable from a thermal standpoint. However, this design is challenging to implement and often results in a low fabrication yield if no special precautions are taken. Since the active region is very close to the heatsink, solder material may ooze out on the sides of the chip during the bonding process and may short-circuits the device, rendering it unusable. To avoid this happening, the invention proposes to provide a trench all around the chip with the exception of the two waveguide facets, i.e. the ends of the active region.