Mach-Zehnder Interferometer Setup Research Articles

Precision measurement of the refractive index of carbon dioxide with a frequency comb

We report a higher precision measurement of the refractive index of carbon dioxide using a frequency comb as the light source in a Mach-Zehnder interferometer setup. The experimental sensitivity can reach the level of 8.8x10(-9). Taking into account the measurement accuracy of temperature and pressure, the experimental accuracy has a value of 1.2x10(-8). The measurement result has a deviation from the commonly quoted result [Old , J. Opt. Soc. Am.61, 89 (1971)] by 6.4x10(-7) at 800 nm.

Infrared holography using a microbolometer array

We describe a series of experiments to demonstrate holography at far-infrared wavelengths using an uncooled microbolometer array. Simple interference patterns and Fresnel zone holograms are recorded with a 10 W cw CO(2) laser illumination in a Mach-Zehnder interferometer setup. A sparse-sampling method is used to sample the hologram at a rate dependent on the bandwidth of the object wavefront rather than the carrier frequency. The samples are then used to reconstruct the complex object wavefront in the hologram plane, which is Fresnel backpropagated for image reconstruction. Uncooled microbolometer arrays are most commonly used in passive mode to image the thermal-blackbody radiation. Their technology has matured to include the wavelength range of far-infrared to submillimeter radiation. The use of microbolometers with active illumination for holography, as described in this paper, suggests their interesting future applications.

Mach–Zehnder Interferometer-Based High-Speed OTDM Add–Drop Multiplexing

We propose a modified semiconductor-optical-amplifier-based Mach-Zehnder interferometer (SOA-MZI) setup for high-speed optical time division multiplexing add/drop multiplexing (ADM) operation. It has the property of enabling an independent phase optimization for clear and drop ports simultaneously. It provides, therefore, an improvement of standard SOA-MZI configurations where only one output port can be optimized at each time. A detailed analysis of the ADM performance for operation from 320-Gb/s aggregate bit rates to 10- and 40-Gb/s base data rates is carried out. Theoretical results show an excellent performance for a wide range of operation conditions

Fourier-domain low-coherence interferometry for differential mode delay analysis of an optical fiber

We propose a novel mode analysis and differential mode delay measurement method for an optical fiber using Fourier-domain low-coherence interferometry. A spectral interferometer based on a Mach-Zehnder interferometer setup was used with a broadband source and an optical spectrum analyzer to detect relative temporal delays between the guided modes of a few-mode optical fiber by analyzing spectral interference signals. We have shown that experimental results of the proposed method agree well with those results obtained by using a conventional time-domain measurement method. We have demonstrated that this new mode analysis technique has high sensitivity (<60 dB) and very good resolution (<1 ps/m).

Versatile chromatic dispersion measurement of a single mode fiber using spectral white light interferometry

We present a versatile and accurate chromatic dispersion measurement method for single mode optical fibers over a wide spectral range (200 nm) using a spectral domain white light interferometer. This technique is based on spectral interferometry with a Mach-Zehnder interferometer setup and a broad band light source. It takes less than a second to obtain a spectral interferogram for a few tens of centimeter length fiber sample. We have demonstrated that the relative group velocity, the chromatic dispersion and the dispersion slope of a sample fiber can be obtained very accurately regardless of the zero-dispersion wavelength (ZDW) of a sample after frequency dependent optical phase was directly retrieved from a spectral interferogram. The measured results with our proposed method were compared with those obtained with a conventional time-domain dispersion measurement method. A good agreement between those results indicates that our proposed method can measure the chromatic dispersion of a short length optical fiber with very high accuracy.

Electro-optic and photorefractive two-beam coupling properties of lead barium niobate crystals

Lead barium niobate crystals (Pb1−xBaxNb2O6) are attractive photorefractive materials for holographic data storage. The electro-optic coefficients r33 and r13 are determined using a Mach–Zehnder interferometer setup, and are measured to be 160±20 and 32±4 pm/V, respectively. The angular dependence of the photorefractive two-beam coupling gain is also investigated, and the products of the electro-optic coefficients and the electron-hole competition factor rζ are determined and compared with the electro-optic coefficients obtained using the interferometric method. It is found that the electron-hole competition factor is at least 0.7, indicating that the photorefractive process is mostly due to electrons. The effective trap densities at several wavelengths are also determined from the gain dispersion measurements, and are found to be 1.3–2.2×1016 cm−3.

Nonresonant n2 and two-photon-absorption dispersion measurements of DPOP-PPV and DP-PPV/DP-PFV polymer strip waveguides

A very stable and accurate semi-integrated Mach-Zehnder interferometer setup, that was used to obtain the sign and magnitude of the nonlinear coefficient n 2 of two different main chain organic poly(phenylene-vinylene) polymer derivatives in the wavelength region between 880–990 nm, is presented. The nonlinear refractive index coefficient n 2 is of the order of 10 −14 cm 2/W for both polymers. Power dependent transmission measurements provided the two-photon absorption coefficient β. It ranges from almost zero to 0.16 cm/GW depending on the wavelength. The results show that the poly(phenylene-vinylene)-derivatives are promising candidates for opto-optical waveguide switching elements.

Performance of a highly sensitive optical waveguide Mach-Zehnder interferometer immunosensor

We describe a highly sensitive sensor which uses the evanescent field of a reusable planar optical waveguide as the sensing element. The waveguide used is optimized to obtain a steep dependence of the propagation velocity on the refractive-index profile near the surface. The adsorption of a layer of proteins thus results in a phase change, which is measured interferometrically using a Mach-Zehnder interferometer set-up. The stability of the interferometer is such that phase changes ≈ (1 × 10 −2)2π per hour can be measured. Immunoreactions have been monitored down to concentrations of 5 × 10 −11 M of a 40 kDa protein.

Determination of fracture parameters using embedded fiber-optic sensors

The applicability of embedded fiber-optic sensors for the determination of fracture parameters is demonstrated. A Mach-Zehnder interferometric setup is used and mode-1 stress-intensity factors are obtained by embedding single-mode fibers in single-edge-notched specimens fabricated from Plexiglas. Optical fibers are embedded in-plane to measure axial strains at various depths and also in the transverse direction to measure the transverse strains, from which stress-intensity factors are determined. In both cases the experimental results compare well with the theoretical predictions.