We present our work towards a 3.5 μm Er³⁺:ZBLAN femto-second laser inscribed waveguide laser. The waveguide was made by extruding bulk ZBLAN glass into a slab for the first time, to the best of our knowledge. The slab was then cut and polished with multiple concentric-ring waveguides of 28 - 36 μm core diameter written into the glass along its long axis resulting with a 125 mm long waveguides embedded within a glass rectangle of 7×10×125 mm. The waveguide structures are pumped by two single mode pump sources at 976 nm and 1973 nm employing the dual-wavelength pumping method for obtaining 3.5 μm operation. Numerical analysis of the system will be presented as well as our latest experimental results.