An optical inclination sensor is provided having at least one reflective
surface and at least two separate optical fibers having ends spaced from
a reflective surface. As the reflective surface tilts with respect to a
pre-determined reference position the gap lengths between the fiber ends
and the reflective surface change and the differences in these gap
lengths is used to calculate an angle of inclination with respect to a
reference position. The optical inclination sensor can include at least
one mass attached to a housing and moveable with respect to the housing
as the mass and housing are rotated about one or more axes. Optical
strain sensors are disposed a various locations between the mass and
housing so that as the mass moves with respect to the housing, each one
of the optical strain sensors are placed in compression or tension. The
housing can be a generally u-shaped housing having two arms and a base
section with the mass disposed within the housing. Alternatively, the
housing includes a first beam, and the mass is a second beam arranged
generally orthogonal to the first beam and pivotally attached thereto.
The optical strain sensors are disposed between the first beam and the
second beam. The optical strain sensors are placed in tension or
compression as the second beam pivots with respect to the first beam.