A detailed theoretical and experimental study of buried ion-exchanged waveguides is reported. The model of the ion
concentration distribution in Ag+-Na+ ion exchanged glass, which is analyzed by numerical calculations, agrees well with
our experiments showing that after the first ion-exchange, a half oval-shaped ion concentration distribution can be
obtained in the substrate; and after the second ion-exchange, the radio-shaped ion concentration distribution presents.
These results may be used to establish the necessary correlation between the ion-exchange process parameters and the
In this work, we propose a method to measure the Mueller matrix of biological tissues rapidly. Firstly, the effect of
biological tissues on the incident light can be represented as absorption, phase retardance and depolarization. This paper
defines four parameters as absorption coefficient, phase retardance coefficient, depolarization proportion and azimuth of
incident light, respectively. Secondly, we decompose the incident light into two parts: one is totally depolarized, the
other is absorbed and its phase is retarded. The two processes are characterized by two corresponding Mueller
submatrixes. Then two Mueller submatrixes are derived based on the relation between the Stokes vectors of incident
light and output light. Moreover, on the basis of a linear combination of the two Mueller submatrixes, we obtain the
Mueller matrix of biological tissues, which contains the unknown parameters. Lastly, we employ the pellicle cell of
magnolia for the sample and acquisition of it's polarization images. Then this paper applies the method to construct
calculation model from the image data. And just 6 intensity measurements are needed to calculate the four parameters.
Liquid crystal modulator(LCM) is now widely applied, especially in optical telecommunication networks. However,
according to the electro-optic characteristic of liquid crystal, we will obtain nonlinear phase response when LCM is
driven by the voltage varying with time linearly(v=kt+v0). And in practical application this nonlinear phase response will
affect the modulation precision, communication modulation efficiency and so on. This paper presents a logarithm driving
signal model to linearize the nonlinear phase response of LCM between 0 and π. When driven by a periodic signal whose
voltage varies from 2.0 to 10.7V in the way of logarithm in every periods, the LCM's phase response hops in the point of
intersection of two voltage periods. Therefore, we advance another periodic logarithm driving signal, whose voltage
ascends from 2.0 to 10.7V in first half periods and descends from 10.7 to 2.0V in the other half periods. Furthermore, We
find that the degree of phase response linearization of LCM decreases with the frequency of driving signal increasing.
This paper proposes mapping the nonlinear phase response to linear one to overcome this problem. The experimental
results indicate that obtaining the linear phase response of liquid crystal between 0 and π with different-frequency driving
signals is feasible.
This paper presents a polarimeter for simultaneous measurement of variation in magnitude phase retardation, azimuth and principal axis angle of the incident light. The configuration is based on dual-liquid-crystal-modulator (Dual-LCM) which is used to enhance the measurement's S/N and resolution. The changes of these three parameters are measured by a very simple digital signal processing system. Compared to the conventional configurations, the proposed polarimeter offers an easier setup, high system stability and repeatability. The results show that our system has the advantages of wide measurable domain for the whole-polarization and high measurement precision. The results indicate that the maximum absolute errors of the phase retardation, azimuth and principal axis angle are 0.24°, 0.14° and 0.31°, respectively. Finally, the dynamic ranges of the principal-axis angle measurement and the phase-retardation measurement extend as far as 360° and the measurement precision is below 0.31°.