Showing papers on "Mach–Zehnder interferometer published in 1980"

Measurement of small phase shifts using a single-mode optical-fiber interferometer.

Abstract: Periodic phase changes in the 10(-6) -rad region have been induced and detected in a single-mode all-fiber Mach- Zehnder interferometer by stretching the fiber with a piezoelectric cylinder driven at frequencies between 40 and 10(4) Hz.

Fiber optic accelerometer and method of measuring inertial force

Abstract: A mass is attached between light reflective ends of a pair of rectilinearly aligned optic fibers and maintained in such position with the fibers under a slight tension. The pair of fibers comprise a portion of two arms of a Mach Zehnder or Michelson interferometer so that an acceleration along the longitudinal axis of the rectilinearly aligned optic fibers increases the length of one of the pair of fibers and shortens the length of the other, whereby electromagnetic rays traveling in the pair of fibers, travel different distances resulting in a phase shift which phase shift is directly proportional to the force applied to the fibers by the mass and therefore directly proportional to the acceleration. Accelerations in directions perpendicular to the longitudinal axes of the fibers cause equal phase shifts in each arm and therefore would not be detected. Thermal expansion of the fibers and acoustical noises should also balance out.

Method for measuring the rf modulation characteristics of Mach-Zehnder-type modulators

Abstract: We derive the frequency spectrum of the light output from Mach‐Zehnder‐type waveguide modulators and demonstrate the excellent agreement of the experimental results with theory. From the measurement of the frequency spectrum the rf modulation characteristics can be deduced. This method is advantageous as it permits the evaluation of the modulator performance up to frequencies above 1 GHz without requiring high optical power, thus eliminating the risk of optical damage in the waveguides. The tested modulator shows a 3‐dB cutoff frequency of 1.1 GHz; the figure of merit is Q≈130 μW/MHz.

Dual surface interferometer

Abstract: A double-pass interferometer is provided which allows direct measurement of relative displacement between opposed surfaces. A conventional plane mirror interferometer may be modified by replacing the beam-measuring path cube-corner reflector with an additional quarter-wave plate. The beam path is altered to extend to an opposed plane mirrored surface and the reflected beam is placed in interference with a retained reference beam split from dual-beam source and retroreflected by a reference cube-corner reflector mounted stationary with the interferometer housing. This permits direct measurement of opposed mirror surfaces by laser interferometry while doubling the resolution as with a conventional double-pass plane mirror laser interferometer system.

Integrated astable optical multivibrator using Mach-Zehnder interferometric optical switches

Abstract: An integrated astable optical multivibrator has been analysed and demonstrated experimentally for the first time using a couple of Mach-Zehnder interferometric optical switches with crossed and straight electronic feedback. Fairly good agreement is found between experimental and analytical results.

Interference Patterns Produced By a Mach-Zehnder Interferometer and A multiline HF Laser

Abstract: : The fringe pattern produced by a Mach-Zehnder interferometer illuminated with the light from a hydrogen fluoride (HF) laser operating on a large number of laser lines was investigated. Emphasis was placed on the intensity variations of the infrared fringes that are observed when one element of the interferometer is translated, thereby changing the length of one optical path. An intensity maximum similar to 'white-light fringes' is observed when the two arms of the interferometer have equal optical lengths. The experimental results are compared with numerically predicted fringe patterns calculated from the spectral content of the illuminating laser beam. A method is suggested for actively controlling the phases of a number of parallel HF laser amplifiers in high-power phased-array devices.

Alignment Of A Two-Beam Interferometer

Abstract: Two beam interferometers have been proposed for space applications such as sensing the shape of a large antenna. Since alignment and adjustment of interferometers have long been considered difficult laboratory tasks, the question of making their operation sufficiently automatic for space applications is a serious one. As a first step in addressing this question certain manual procedures, which may not be well known, have been collected from widely scattered sources. These techniques are illustrated by two examples: (1) the alignment of a Mach-Zehnder interferometer and the adjustment of fringe location. (2) The adjustment of a Michelson interferometer for zero path difference (white light fringes).