[Briana, Ian]

We mounted the DBR780PN Distributed Bragg Reflector (DBR) butterfly laser. First, we placed the configuration card for the Type I laser into the mount (LM14S2). Then, we unclasped the mount's latches and placed in the laser on top of the pins. The laser output was put into the laser input from the vapor cell schematic. The temperature and current controller (TED200C and LDC205C respectively) are placed on top of the central table overhang (facing the entrance to the lab) and connected to the mount. The maximum current limit for the laser diode is 250 mA and the ideal operating power is 39.6 mW, so first the current limit was set to 250 mA, then the actual current increased until the reading of laser power from a powermeter placed directly in front of the laser output was around 39.6 mW (this current was ~230 mA). Then, the current limit was set to this value. The temperature controller was then powered on. It only has the thermistor sensor which reads out in kilo Ohms, so the conversion to temperature is done using the Steinhart-Hart equation (see spec sheet). The temperature controller's current and resistance seem to be coupled. The coefficients used for the equation are under the Absolute Maximum Ratings table on the spec sheet, relating resistance (kilo Ohms) and temperature (Kelvin). We confirm that the temperature controller works using Figure 2 on the spec sheet. For example, when we set the temperature to 29 Celsius (converting to resistance using the SH equation) and set the current applied by the temperature controller to 140, 180, and 220 mA, the output power (measured by the powermeter) was between that of the 25 and 35 Celsius curves. We initially had some issues because the temperature measurement tool did not show a significant increase in temperature when we decreased resistance. This was probably because the tool measured the surface which might not accurately represent the actual internal temperature of the diode. 

The spec sheet is found at https://wiki.mccullerlab.com/DCC/S2400003. Video tutorials lfor laser setup are found here: Setting Up a TO Can Laser Diode (Viewer Inspired) | Thorlabs Insights (youtube.com), https://www.youtube.com/watch?v=LAixCOso-FE