In this work we present a deeply-etched MEMS based swept ring laser source with enhanced performance. Performance enhancement is enabled by lensing the single mode (SM) input/output fibers of the MEMS tunable filter. An experimental comparison between the performance using graded-index (GRIN) lensed fibers and cleaved SM fibers in the MEMS-based swept laser system is presented. The GRIN lensed fiber produces a minimum waist radius of about 11.8 μm at 1550 nm, compared to 5 μm for the cleaved fiber. The experimental results show that the insertion loss of the MEMS filter is improved from -11.4 dB to -6.3 dB, while the filter 3-dB linewidth is improved from 9 nm to 5 nm when using the GRIN lensed-fibers. The corresponding threshold current of the swept laser is reduced from 70 mA to 52 mA and the output power is increased by 7.5 dB.