A travelling-wave laser with a linear configuration cavity has been de
monstrated. The travelling-wave operation is provided by orthogonality
of the polarisation states of counterpropagating waves. In a fibre ve
rsion of the scheme proposed, lasing was obtained at 1.559 - 1.564 mu
m, and wavelength tuning was performed by a loop polarisation controll
er. A linewidth of less than 15MHz and maximum output power of 18mW we
re obtained.