The vertical mirrors are used with top entry photodetectors and for wafer level test. Fig. 5 shows the construction and performance (0.5dB coupling loss) achieved by the vertical mirrors when coupled to a PD.

Those results are I beleive 2 years old. They have issued  very significant patents since then that expand coupling precision. Further adding to their ability to shape the mirror for spot size conversion into the target device  interface for precise mode changes (coupling accuracy) removing device mismatch. Along with the ability to steer the light to where it needs to couple. So shaping and steering the beam for high coupling efficient.