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Two hybrid waveguide structures formed using an electro-optic polymer are described. They are a vertically stacked coupler and a serially grafted waveguide. These structures were fabricated by spin-coating, photolithographic, and reactive ion etching processes. Directional coupling was successfully demonstrated between the vertically stacked waveguides, and the crosstalk was −15 dB. This waveguide structure was applied to an optical intensity modulator. The serially grafted waveguide allows butt coupling between the functional waveguide and passive waveguides, and the connection loss at a grafting point was as low as 0.005 dB. This waveguide structure was applied to a Mach–Zehnder optical intensity modulator and a quasi-phase-matched second-harmonic generator.

A simple reflection technique proposed by Teng and Man [Appl. Phys. Lett. 56, 1734 (1990)] as well as independently by Schildkraut [Appl. Opt. 29, 2839 (1990)] for measuring the electro‐optic coefficients of poled polymer films is applied to measure the r33 values of both z‐cut lithium niobate crystal and diazo‐dye‐substituted polymer films. The measured r33 value of the lithium niobate crystal is in excellent agreement with the known value, and the observed r33 values of the poled polymer films agree well with those predicted from the second‐harmonic‐generation measurements.

Quasi‐phase‐matched (QPM) second harmonic generation in a poled polymer waveguide has been realized. A waveguide with a periodic structure was fabricated by conventional photolithography and reactive ion etching. The waveguide with a QPM structure was composed of poled polymer and UV cured epoxy resin. Phase‐matched second harmonic generation was observed, using laser light with a fundamental wavelength 1.48–1.65 μm. This phase matched condition was dependent on the periodic length. The waveguide had a typical second harmonic generation efficiency of about 4×10−1% W−1 cm−2 around a wavelength of 1.55 μm.

A serially grafted connection between polymer waveguides is realized. This technique allows a passive polymer waveguide to be connected to a functional polymer waveguide with a connection loss of 0.005 dB. It is also applied to a Mach–Zehnder modulator using an electro‐optic polymer, and optical intensity modulation in the serially grafted modulator is successfully demonstrated.

A vertically stacked directional coupler incorporating electro‐optic poled polymer was fabricated by spin coating, photolithography, and reactive ion etching processes, based on the fabrication technique used for polymeric single‐mode channel waveguides. Vertically coupled operation at 1.3 μm have been achieved between two stacked channels which were kept 3.5–5 μm apart by a narrow cladding layer. The intensity modulation has been clearly demonstrated in the coupler with electrodes when a voltage is applied at 10 kHz between them.

This paper describes the transient properties of the second‐order nonlinear optical processes of a diazo‐dye‐substituted poled polymer. The temperature dependences of bulk susceptibilities and Pockels coefficients are measured below the glass transition temperature to estimate relaxation times. The activation energy of 43 kcal/mol determined from the Arrhenius plots of the relaxation times is assigned to that of the α relaxation of the diazo‐dye‐substituted polymer. The relaxation of the induced alignment of diazo‐dye side groups is restricted because of both the large dye molecular volume of greater than 500 A3 and the very small cumulative distribution of local free volumes which are greater than the dye molecular volume in the polymer.