This paper proposes a switchable wavelength fiber laser (SWFL) based on an arrayed waveguide grating (AWG) and a gain saturated reflective semiconductor optical amplifier (RSOA). The SWFL was experimentally implemented in the C and L bands. In order to achieve narrow linewidth oscillation, the SWFL was driven by bidirectional injection locked RSOAs. The RSOA was operated in the gain saturated region, using gain compression properties to obtain uniform power over a wide bandwidth. Based on this con figuration, we obtained 40 C band international telecommunication unit (ITU) wavelengths with 100 GHz channel spacing. The SWFL displayed a narrow 3 dB bandwidth (<0.06 nm), a high and uniform peak power (P max > 0.22 dB, ΔP max < 0.26 dB), and a high and uniform side mode suppression ratio (SMSR > 66 dB, ΔSMSR < 1 dB). The peak power and wavelength stabilities were ±0.24 dB and ±0.01 nm, respectively, at room temperature over a 1 h period.