Behavior of longitudinal modes in a separately pumped, multiple twisted double‐heterostructure laser is investigated. A single longitudinal mode operation is observed in the current range up to 1.3Ithunder uniform pumping. The lasing wavelength is locked to a single longitudinal mode over a temperature range of 12 °C under uniform pumping. A continuous tuning range of 3.3 A˚ is obtained in one longitudinal mode. The wavelength shifts at a rate of 0.07 A˚/mA in the continuous tuning range.