In this letter, we propose a novel multiwavelength fiber laser based on fiber loop mirror formed by a high-birefringence fiber, a polarisation controller, and a 3 dB directional coupler. By setting the polarisation controller as half-wave-plate, the fiber loop mirror acts as a polarisation-independent wavelength filter; Erbium-doped fiber (EDF) cooling by liquid nitrogen acts as gain medium. The wavelength spacing between the adjacent modes of the laser can be varied accurately by adjusting the length of the High-Birefringence (HiBi) fiber.