This paper reviews and discusses recent developments in passively mode-locked vertical external cavity surface emitting lasers (ML-VECSELs) for short pulse generation at 1.55 μm. After comparing MLVECSELs to other options for short pulse generation, we reviewed the results of ML-VECSELs operating at telecommunication wavelength and point out the challenges in achieving sub-picosecond operation from a MLVECSEL at 1.55 μm. We described our recent work in the VECSELs and semiconductor saturable absorber mirrors (SESAMs), their structure design, optimization and characterization, with the goal of moving the pulse width from picosecond to sub-picosecond.