The fabrication and performance characteristics of a thermoelectrically tunable single-wavelength integrated external cavity distributed Bragg reflector laser are described. The tunability arises from a variation of the effective index in the external cavity obtained by varying the temperature. The active cavity section of these devices utilises the double-channel planar buried-heterostructure scheme for current confinement. The lasers emit near 1.3 μm. A tunability of ~5Å has been obtained with 100mA of thermoelectric controller current. Lasers of this type are useful for local oscillator applications in coherent transmission.