  The gamma-ray-detected blazar 3C 454.3 exhibits dramatic flux and
polarization variations in the optical and near-infrared bands. In December
2010, the object emitted a very bright outburst. We monitored it for
approximately four years (including the 2010 outburst) by optical and
near-infrared photopolarimetry. During the 2010 outburst, the object emitted
two rapid, redder brightenings, at which the polarization degrees (PDs) in both
bands increased significantly and the bands exhibited a frequency-dependent
polarization. The observed frequency-dependent polarization leads us to propose
that the polarization vector is composed of two vectors. Therefore, we separate
the observed polarization vectors into short and long-term components that we
attribute to the emissions of the rapid brightenings and the outburst that
varied the timescale of days and months, respectively. The estimated PD of the
short-term component is greater than the maximum observed PD and is close to
the theoretical maximum PD. We constrain the bulk Lorentz factors and
inclination angles between the jet axis and the line of sight from the
estimated PDs. In this case, the inclination angle of the emitting region of
short-term component from the first rapid brightening should be equal to
90$^{\circ}$, because the estimated PD of the short-term component was
approximately equal to the theoretical maximum PD. Thus, the Doppler factor at
the emitting region of the first rapid brightening should be equal to the bulk
Lorentz factor.
