A display subsystem for a virtual image generation system for use by an end user comprises a display, an optical fiber having a polarization-maintaining (PM) transmission fiber section and a non-PM scanning fiber section, a light source configured for injecting a linearly polarized light beam into the transmission fiber section, such that the linearly polarized light beam is emitted from the scanning fiber section, a mechanical scanning drive assembly in which the scanning fiber section is affixed, wherein the mechanical scanning drive assembly is configured for displacing the scanning optical fiber section is order to scan the emitted light beam, and a display configured for receiving the scanned light beam and generating an image to the end user.