Abstract
Optical fibers are used to provide object and reference illumination in the context of the electronic speckle-pattern interferometry technique. An all-fiber Michelson interferometer is used, with an electronic servo and a piezoelectric phase modulator, to obtain compensation for environmentally induced phase coupling into the fiber arms. © 1990 Optical Society of America.

Abstract
A system employing optical fibres for electronic speckle pattern interferometry is demonstrated. Single mode optical fibres are used to provide a reference beam and illumination of the object. The Michelson interferometer formed by the reference fibre and the fibre illuminating the target is used to compensate for environmentally induced phase noise. This compensation is achieved by using an electronic servo and a piezoelectric phase modulator to lock the Michelson at its quadrature point.

Abstract
A time division multiplexing technique is described in which the frequency of a laser source is modulated with a sampled ramp. The concept is demonstrated with two Mach-Zehnder interferometers in a parallel configuration, separated by a fibre delay line whose length is determined by the characteristics of the sampling waveform. Pseudo-heterodyne processing was used to recover the phase information from each interferometer. The expansion of the technique to a combined frequency and time division multiplexed fibre-optic sensing system is considered.

Abstract
A time division multiplexing technique is described in which the frequency of a laser source is modulated with a sampled ramp. The concept is demonstrated with two Mach-Zehnder interferometers in a parallel configuration, separated by a fibre delay line whose length is determined by the characteristics of the sampling waveform. Pseudo-heterodyne processing was used to recover the phase information from each interferometer. The expansion of the technique to a combined frequency and time division multiplexed fibre-optic sensing system is considered. © 1990.

Abstract
We report on the experimental evaluation of the intensity-dependent index of refraction of a new family of polymers, using guided-wave techniques. The materials are 'DANx-polymers', and the measurements were performed at 1.064 µm with 30 ps pulses employing nonlinear distributed grating coupling into spin coated planar waveguides. The analysis shows large electronic and nonresonant n2 coefficients. The examined materials have outstanding potentialities for all-optical signal processing in an integrated optics format.

Abstract
Optical third harmonic generation at 1.904, 1.579 and 1.064 µm experiments have been performed on thin films fabricated from side chain polymers containing effectively 4-dialkylamino-nitro-benzene, 4-dialkylamino-4'-nitro-stilbene, 4-dialkylamino-4'-nitro-diphenylbutadiene, 4-dialkylamino-4'-nitro-diphenylhexatriene as the side groups. We have measured values of ?(3) (-3?; ?, ?, ?) in the range of 0.54 × 10-12 to 7.42 × 10-12 esu, at 1.904 µm incident radiation, which are comparable to the nonresonant values found in fully conjugated back-bone polymers [1]. The values of ?(3) at both 1.904 and 1.579 µm change by a factor of 15 as the conjugation length is increased. © 1990.