Yingli Chen

Electro-optic Solc-type wavelength filter in periodically poled lithium niobate

We demonstrate an electro-optic Solc-type wavelength filter in periodically poled lithium niobate (PPLN). A Solc-type transmission spectrum is observed experimentally in PPLN with four periods from 20.2 to 20.8 microm. Modulation of the transmission power of the filter is realized by application of electric fields along the Y axis of the PPLN. It is observed that the wavelength can also be tuned by temperature.

Improved attenuated-total-reflection technique for measuring the electro-optic coefficients of nonlinear optical polymers

A new technique for measuring the electro-optic coefficient of nonlinear optical polymer is described. In an attenuated-total-reflection experiment the refractive index of the poled polymer is changed because of the Pockels effect. This change causes a shift of the angular position of the surface plasmon modes that corresponds to a change in reflectivity at a fixed angle. By measuring the change of the light reflectivity at the properly chosen angle one can calculate the electro-optic coefficient of the poled polymer. Compared with other, conventional methods, here the electro-optic coefficients are given in a simpler form and the required parameters are easier to measure. The commonly used lock-in amplifier is not required. This technique is a highly sensitive method for measuring the electro-optic coefficient because of the newly chosen working interior angle for which a tiny change in the refractive index leads to a large change in reflectivity.

Low voltage electro-optic polymer light modulator using attenuated total internal reflection

Abstract An improved electro-optic (EO) polymer light modulator based on attenuated-total-internal-reflection (ATR) is demonstrated. The modulator consists of a prism–metal–EO-polymer–metal multilayer structure. An applied electric field across the EO polymer layer electrically modulates the energy coupling efficiency of incoming light into guided wave resonance at fixed angles. Compared with conventional ATR modulators based on surface plasmon resonance, the driving voltage for this modulator has been greatly reduced because of the newly chosen working interior angle. It also offers advantages in terms of insertion loss and aperture size over other techniques for the amplitude modulation of a collimated light beam.

Exact analytical method for planar optical waveguides with arbitrary index profile

We present a novel matrix method that allows the straightforward determination of exact propagation constants as well as the field configuration in the region that is beyond the turning point at the substrate side for arbitrarily graded-index planar waveguides.

Frequency upconversion in Er3+- and Yb3+Er3+-doped silica fibers

Abstract Frequency upconversion has been demonstrated in Er 3+ - and Yb 3+ Er 3+ -doped silica optical fibers pumped by 1064 nm radiation. IR to blue upconversion in Er 3+ -doped fibers and IR to blue, green and red upconversion in Yb 3+ Er 3+ -doped fibers have been observed. Ground state absorption, excited state absorption, two-photon absorption and energy transfer processes are proposed to account for the experimental observations.

Method of improving optical poling efficiency in polymer films

The alignment of dye molecules in optically poled polymer films is modeled. We point out that when writing beams (fundamental and second harmonic) are linearly polarized with their polarization directions parallel, the majority of the dye molecules in a poled film are axially oriented perpendicular to the writing-beam polarization, whereas the minority are polar oriented parallel to the writing-beam polarization. Only the latter, however, contribute to the second-order nonlinearity of the film. This model is verified by experiments. Based on the model, a new method of improving optical poling efficiency is put forward.

Observation of all-optical wavelength conversion based on cascaded effect in periodically poled lithium niobate waveguide

Abstract We experimentally demonstrate multi-channel wavelength conversion through the cascaded second-order nonlinear processes in periodically poled lithium niobate waveguide in the optical communication wavelength band of 1.5 μm . The normalized conversion efficiency as high as 90% W −1 cm −2 is obtained. Wavelength conversion over a broad wavelength range of 66 nm has been confirmed.

Polarization control by use of the electro-optic effect in periodically poled lithium niobate

We propose a method to control the polarization of light by the electro-optic effect in periodically poled lithium niobate. A single integrated chip of Z-cut lithium niobate having two sections is used. The first section is not periodically poled, whereas the second section is. With an electric field applied along the Z axis of the first section and another electric field applied along the Y axis of the second section, light with an arbitrary elliptical polarization can be converted into a fixed linearly polarized state.

Observation of switching phenomena in a nonether polyphenylquinoxaline planar waveguide with two-wavelength nonlinear prism coupling

We present research on nonether polyphenylquinoxaline film waveguides, and a scheme for an all-optical switching operation of waveguides is suggested. We use the m-line spectroscopy technique to characterize the guiding modes in the waveguide, and the switching phenomenon is observed with two-wavelength nonlinear prism coupling. The measured response time of the switching signal is less than 10(-9) s.

Experimental observation of the nonlinearity of the Pancharatnam phase with a Michelson interferometer

Three experiments are proposed for the observation of the nonlinearity of the Pancharatnam phase with a Michelson interferometer. The result of one of these experiments is reported.