A thermal analysis has been completed on an injection laser stack based on the electrical power dissipation within the laser stack material during operation. The thermal gradient existing in the laser stack during operation can cause large wavelength variations among individual lasers of the stack if certain fabrication procedures are not followed. For a given electrical power dissipation, a "monochromatic" injection laser stack can be designed (i.e., the spectral peaks of all lasers within the stack being at the same wavelength). A prescription for laser diode preselection prior to fabrication is given. The dominant source of temperature variations within the stack is electrical resistance nonuniformities of solder connections, causing nonuniform heating of the laser stack during a current pulse. Results of an experiment for measuring the temperature distribution of the injection laser stack after a single pulse which demonstrate electrical resistance nonuniformities within the stack are de-scribed. Finally, the minimum receiver filter spectral bandwidth corresponding to this thermally compensated injection laser stack is calculated.