In general, in one aspect, the invention features an apparatus including a multi-axis interferometer configured to produce at least three output beams each including interferometric information about a distance between the interferometer and a measurement object along a corresponding measurement axis, wherein at least three of the measurement axes are in a common plane, wherein the output beams each include a component that makes a pass to the measurement object along a common beam path.

An electro-optical device (10) is used to alter characteristics of a light beam passing through it. In a particularly preferred embodiment, the device (10) is used as a phase stop having a dynamically variable aperture whose size is defined by the selected application of an electrical potential across one or more concentric, transparent ring-like electrodes (13, 14, 16 and 18). The electro-optical device (10) finds particular utility in a common-path interferometer (40) where fringe visibility i...

A pair of rigid connectors is disposed in frictional arrangement between an optical flat and its supporting cell joined by resilient connectors. The first, axial connector consists of a block anchored to the cell's inner surface and tilted by a spring so that a line contact is established between the block and the flat's peripheral surface. The second, radial connector consists of a flat clip overlapping the gap between the optical flat and the cell, so that surface contacts are established betw...

Methods and apparatus are employed to enhance the efficiency and applicability of Fabry-Perot interferometers. In existing devices, light introduced at a first off-axis point on the image plane is partially transmitted through the interferometer to the detector and partially reflected to a second off-axis point on the image plane. Broadly, the invention re-uses the light reflected to the second off-axis point rather than discarding it. As one example, the reflected light is guided to a third off...

An interferometer system includes an optical radiation source, an optical circulator connected between the optical radiation source and a sample location for transmitting optical radiation from the optical radiation source to the sample location, an output of the optical circulator connected to direct optical radiation to an optical detector. Various embodiments of such a system are possible. A method of performing OCDR or OCT imaging of a sample which involves the steps of: (a) producing low co...

Optical filters tunable for both center wavelength and bandwidth, having applications such as in astronomy, remote sensing, laser spectroscopy, and other laser-based sensing applications, using Michelson interferometers or Mach-Zehnder interferometers modified with Gires-Tournois interferometers ("GTIs") are disclosed. A GTI nominally has unity magnitude reflectance as a function of wavelength and has a phase response based on its resonator characteristics. Replacing the end mirrors of a Michels...

A passive device for reducing polarization fading in interferometers with significantly degrading the signal-to-noise ratio. In one embodiment, light from an interferometer output is passed through a lens to a polarization mask. The polarization mask comprises at least three distinct polarizers which pass distinct states of polarization. After passing through the polarizers each independently polarized signal is detected, demodulated and passed to a means for signal extraction.

A system for detecting the eigen frequency of a sensing coil in a fiber optic gyro (FOG) that includes a fiber coupler connected to the light source, an integrated optics chip (IOC) capable of modulating light received from the light source via the fiber coupler, a sensing coil in communication with the IOC, a first modulation generator for imparting a first modulation signal to the light, and a photodetector for receiving light returning from the sensing coil that is representative of a rotatio...

In general, in one aspect, the invention features an apparatus including a multi-axis interferometer configured to produce at least three output beams each including interferometric information about a distance between the interferometer and a measurement object along a corresponding measurement axis, wherein at least three of the measurement axes are in a common plane, wherein the output beams each include a component that makes a pass to the measurement object along a common beam path.

An interferometer system includes an optical radiation source, an optical circulator connected between the optical radiation source and a sample location for transmitting optical radiation from the optical radiation source to the sample location, an output of the optical circulator connected to direct optical radiation to an optical detector. Various embodiments of such a system are possible. A method of performing OCDR or OCT imaging of a sample which involves the steps of: (a) producing low co...