Active homodyne feedback control can be used to stabilize an interferometer against unwanted phase drifts introduced by, for example, temperature gradients. The technique is commonly used in fiber-optic sensors to maintain the fiber at its most sensitive (quadrature) position. We describe an extension of the technique to introduce stabilized, π/2-rad phase steps in a full-field interferometer. The technique was implemented in a single-mode, fiber-optic interference fringe projector used for shape measurement and can be easily applied to other fiber- or bulk-optic interferometers, for example, speckle pattern and holographic interferometers. Fresnel reflections from the distal fiber ends undergo a double pass in the fibers and interfere at the fourth port of a directional coupler. The interference intensity (and hence phase) is maintained at quadrature by feedback control to a phase modulator in one of the fiber arms. Stepping between quadrature positions (separated by π rad for light undergoing a double pass) introduces stabilized phase steps in the projected fringes (separated by π/2 rad for a single pass). A root-mean-square phase stability of 0.61 mrad in a 50-Hz bandwidth and phase step accuracy of 1.17 mrad were measured.

© 2002 Optical Society of America

[Optical Society of America ]

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Log in to access OSA Member Subscription

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Log in to access OSA Member Subscription

You do not have subscription access to this journal. Article level metrics are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Log in to access OSA Member Subscription

Related Journal Articles

• Interference Imaging for Aspheric Surface Testing (AO)
• Measurement and Calibration of Interferometric Imaging Aberrations (AO)
• Phase Recovery from a Single Undersampled Interferogram (AO)
• Laser Doppler distance sensor using phase evaluation (OE)
• Phase-error analysis and elimination for nonsinusoidal waveforms in Hilbert transform digital-fringe projection profilometry (OL)

Related Conference Papers

• Analysis of Geometric Wavefront Sensing
• Tomographic Wavefront Sensors for Advanced Gravitational Wave Interferometers
• Phase Locking of a Rapidly Frequency-Chirped Laser
• Novel Method of Optical Pulse Characterization Using Sinusoidal Optical Phase Modulations
• Continuous, Real-Time, Full-Field Waveform Measurements via Spectral Slicing and Parallel Digital Coherent Detection