Passively mode locked fiber lasers are of great interest since they are versatile light sources for many applications in frequency metrology or as seed sources for tungstate amplifiers. However, common systems are sensitive to environmental influences, e.g. vibration and thermal stress. One way for avoiding this and to obtain an environmental stable laser is the use of polarization maintaining (PM)-fibers where only light polarized along the slow axis is coupled in. In this contribution we report on experimental results of an ultra-short pulse all-PM fiber laser in linear cavity design.