Nikon Metrology Nv

Nikon Corporation

Digital Signal Corporation

Other

Metris USA Inc.

Anthony R Slotwinski

Mina A Rezk

Daniel Gene Smith

Alexander H Cooper

Eric Peter Goodwin

Thomas M Hedges

Frank E Goodwin

Stephen C Kenyon

Pavel Slyusarev

Michael S Hersman

Andrew L Bennett

Laser radar systems include a pentaprism configured to scan a measurement beam with respect to a target surface. A focusing optical assembly includes a corner cube that is used to adjust measurement beam focus. Target distance is estimated based on heterodyne frequencies between a return beam and a local oscillator beam. The local oscillator beam is configured to propagate to and from the focusing optical assembly before mixing with the return beam. In some examples, heterodyne frequencies are calibrated with respect to target distance using a Fabry-Perot interferometer having mirrors fixed to a lithium aluminosilicate glass-ceramic tube.

Low drift reference for laser radar

An optical delay between a first fiber and a second fiber is temperature compensated by combining fibers with different thermal path length changes. In some examples, fibers with different buffer coatings exhibit different path length changes per unit length and temperature. Combining such fibers in a fiber array provides a path length difference that is substantially independent of temperature.

Thermally compensated fiber interferometer assembly

Laser radar with remote local oscillator

Radar systems with dual fiber coupled lasers

Scan mirrors for laser radar

A system and method for determining a measured distance between a measuring device (A) and an object (), the system including a first laser source () for producing a first light beam (A) having a first waveform () and a first frequency; a second laser source () for producing a second light beam (IA) having a second frequency, said second light beam (HA) having a second waveform (), wherein said first frequency is chirped up at the first rate as said second frequency is chirped down at the first rate, and said second frequency is chirped up at the second rate as said first frequency is chirped down at the first rate; an optical element () for combining said first light beam (A) with said second light beam (HA) into a combined light beam path (), said optical element () splitting a returning portion of said combined light beam path () into a third light beam (); and a single detector () for receiving said third light beam () including two different beat frequencies that are proportional to the measured distance.

Compact fiber optic geometry for a counter chirp FMCW coherent laser radar

This disclosure presents a version of a coherent laser radar system that is immune to environmental effects on Mach-Zehnder-configured interferometers and reference length standards comprising such systems. The present disclosure also describes methods and materials which alleviate interferometer drift due to vapor absorption using a polyimide coated polarization maintaining fiber to reduce the change in the length of a reference arm.

Precision length standard for coherent laser radar

This disclosure presents a non-contact precision optical device, including methods for measuring distances to an arbitrary target and various configuration geometries, for using polarization maintaining (PM) optical fiber components in a polarization diplexing scheme to construct a version of a dual chirp coherent laser radar that is immune to environmental effects.

Compact fiber optic geometry for a counter-chirp FMCW coherent laser radar

A system for measurement of a distance to a target. Light is emitted from a multi-mode laser and coupled to a sensor assembly. A portion of the light at the sensor assembly is reflected back into the fiber optic cable from which it came. The other portion of the light from the sensor assembly is projected towards the target. Light is reflected from the target and also connected into the optical cable as a target beam. The target beam and the reference beam then are connected through a path of variable length. When the target beam and the reference beam interface with one another, the path length is determined to be equal to the length to the target.

Integrated fiber optic coupled proximity sensor for robotic end

A precision optical distance measuring device utilizes coherent optical detection for extreme precision, and polarization preserving fiber to enable its use in limited access environments. A laser diode provides a linearly polarized source light beam which is directed to a polarizing beam splitter. The source beam passes through the beam splitter and is focused by a lens into a polarization preserving fiber where it travels along one optical axis toward a probe head disposed at the target location. In the probe head, the source beam is focused by a lens onto the target. After focusing, the source beam is passed through a quarter-wave plate. The interface between ambient air and the target-side of the quarter-wave plate reflects a local oscillator beam back through the quarter-wave plate. Meanwhile, the source beam is reflected from the target as a return beam. Mixing of the two beams occurs at the interface and the mixed beam is focused back into the polarization preserving fiber where it is transmitted along a second transmission axis of the fiber. The mixed beam emerges from the fiber and is reflected by the polarizing beam splitter along a second optical axis. The mixed beam is then focused by a detection lens onto a photo detector which coherently detects the mixed beam. The source laser beam is frequency swept so that the photo detector provides an output signal regarding the precise distance between the probe head and the target.

Optical position sensor using coherent detection and polarization

A laser proximity sensor for a projectile includes a laser diode having front and rear facets. The diode generates a main laser signal and directs a first portion thereof out of the front facet as a source beam. Focusing means focuses the source beam on a target, and focuses the return beam reflected from the target into the laser diode through the front facet. The laser diode receives the return light beam, provides it with a positive gain, mixes it with the main laser signal, and guides it out the rear facet as a mixed beam. A detection focusing device focuses the mixed beam onto a PIN detector. The PIN detector coherently detects the mixed beam and provides an output signal having a perturbation where the target enters the focal field of the focusing optics. A processor detects the output signal from the PIN detector and may activate a fuse on the projectile. The processor is also capable of determining the relative velocity between the projectile and the target from measurement of the Doppler shifted signal or from the shape of the perturbation of the output signal from the PIN detector.

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Reston, VA, United States of America

Anthony R Slotwinski