Lightwave Electronics Corporation

Jds Uniphase Corporation

Other

Leland Stanford Junior University

Lightwave Electronics Co.

Fasortronics LLC

Thomas James Kane

Gregory Lee Keaton

Mark Alan Arbore

Robert L Byer

Jeffrey Dellert Kmetec

James J Morehead

Thomas E Kane

John Lawrence Nightingale

Richard W Wallace

Loren A Eyres

Leonard P Pearson

Joseph J Alonis

David C Gerstenberger

David R Balsley

Tracy S Kubo

George J Dixon

A passively, Q-switched laser operating at an eye safe wavelength of between 1.2 and 1.4 microns is described. The laser may operate at a lasing wavelength of 1.34 microns and use a gain element of Nd:YVOand a saturable absorber element of V:YAG. The position of the resonator axial mode spectrum relative to a gain peak of the gain element is controlled to yield desired characteristics in the laser output.

Passively Q-switched laser and laser system for ranging applications

Pulsed, coherent light is generated by optical mixing which takes place inside the resonator of a pulsed laser oscillator. One of the beams to be mixed is generated by the pulsed laser, and the other by a distinct, external laser oscillator. If the light from the external oscillator is modulated, that modulation will be transferred onto the light generated by the optical mixing. Using sum frequency generation, light for sodium excitation, such as for a guide star, can be generated with the optimal modulation of spectral and temporal properties. If the pulse repetition frequency is chosen to be at or near the magnetic (Larmor) resonance of the sodium, then the amount of scattered light due to sodium excitation is enhanced, and the magnetic field at the location of the sodium atoms can be measured.

Internal optical mixer pulsed at larmor frequency

A non-linearly frequency-converted Q-switched laser is 'injection seeded' with short pulses from another laser, called a seed laser. Radiation produced by the Q-switched laser is frequency converted in a non-linear process. The injection seeding can enhance peak power and frequency conversion efficiency while reducing damage to a non-linear medium used to frequency convert radiation generated by the Q-switched laser.

Injection seeding of frequency-converted Q-switched laser

A laser apparatus is disclosed. The apparatus includes a Neodymium-doped lasing material having first and second surfaces and a passive Q-switch optically coupled to the second surface. The first-surface is substantially transparent to a pump radiation and substantially reflective to laser radiation generated by an interaction between the pump radiation and the Neodymium-doped lasing material. The laser radiation is characterized by a vacuum wavelength corresponding to an atomic transition from theFlevel to theIlevel of Neodymium in the lasing material. The second surface transmits at least a portion of the laser radiation. The lasing material and Q-switch are configured to produce pulses of the laser radiation characterized by a pulse length of greater than zero and less than about 1.5 nanoseconds and a pulse repetition rate greater than about 100 kHz. A PQSL laser, an apparatus for generating blue light and a display system based on the laser apparatus are also disclosed.

High repetition rate passively Q-switched laser for blue laser based on interactions in fiber

A light source is disclosed having a pulsed laser, a fiber amplifier optically coupled to the pulsed laser, and a nonlinear frequency converting element optically coupled to the fiber amplifier. The pulsed laser, e.g., a passively Q-switched laser, is configured to generate light pulses characterized by a pulse length of less than about 1.7 nsec and sufficiently large that a frequency bandwidth of the pulses after they emerge from the fiber amplifier is less than an acceptance bandwidth of the nonlinear frequency converting element. The laser is pulsed at a pulse repetition rate sufficiently large that the fiber amplifier does not spontaneously emit radiation between pulses. In such a source, the fiber amplifier is substantially free of stimulated Brillouin scattering and self-phase modulation may be held to a level that does not reduce conversion of infrared radiation to visible radiation. Such a light source can be combined with an image generator and a scanner in an image projection system.

Fiber amplifier system for producing visible light

A method of producing a short-pass fiber by drawing a preform for a depressed cladding fiber at a predetermined drawing ratio. The preform has a core of refractive index n, a depressed cladding surrounding the core and having a refractive index n, and a secondary cladding surrounding the depressed cladding and having a refractive index n. The core has a core cross-section and the depressed cladding has a depressed cladding cross-section that is larger than the core cross-section. The drawing ratio is determined based on the parameters of the preform measured along the axis of the preform and based on a desired minimum fundamental mode cutoff wavelength &#x3bb;. The final core cross-section defines a fundamental mode cutoff wavelength &#x3bb;such that &#x3bb;&#x2267;&#x3bb;along the axis. Then the preform is pulled by the thus-determined drawing ratio to produce the short-pass fiber. In some embodiments a test section of the fiber is pulled first before pulling the short pass fiber.

Method of making a short-pass fiber with controlled cut-off wavelength

Methods and apparatus for controlling a passively Q-switched laser (PQSL) that use a Q-switched laser as a voltage controlled oscillator (VCO) in a phase-locked loop control circuit are disclosed. The PQSL may be optically coupled to a detector. The detector may be coupled to a an input of a phase lock loop controller. A reference oscillator may be coupled to a reference input of the phase lock loop controller. An output of the phase lock loop controller may be coupled to an integrator. The integrator may be coupled to a means for controlling an amount of power provided to the PQSL.

Phase-locked loop control of passively Q-switched lasers

A Thulium-doped silica fiber normally has its strongest gain at 1.9 microns and thus is not suitable for communication use. By engineering a W-profile or depressed cladding fiber with an appropriate index profile having a fundamental mode cut-off between 1.9 microns and the shorter wavelength of desired operation, an optical amplifier based on the W-profile Thulium-doped silica fiber operates at wavelengths shorter than conventional amplifiers, just above what is currently called the Erbium L-band. In a preferred embodiment, the cut-off wavelength is at or near 1.7 &#x3bc;m, eliminating longer wavelengths from the fiber. Amplifiers engineered according to the principles and techniques of the present invention can operate in the wavelength range between about 1.6 to 1.8 microns, which is particularly useful for telecommunications.

L-band optical amplifier based on thulium-doped silica fiber with cut-off

A system and method for using pulses of laser light delivered in a non-overlapping sequence of first pulses at a green wavelength, second pulses at a blue wavelength and semi-continuous pulses at a red wavelength to illuminate a color generation unit for generating a color. Typically, the color generating unit is an image generating unit for producing color images and is equipped with transmissive or reflective pixels which are adjusted to select portions of the laser light generated at the green, blue and red wavelengths to obtain a desired output color. The first and second pulses preferably have a narrow pulse width and an interpulse separation equal to at least 100 times the narrow pulse width, while the semi-continuous pulses at the red wavelength have a wide pulse width equal to at least 100 times the narrow pulse width.

Pulse sequencing for generating a color image in laser-based display systems

A system employing a solid state light source for writing Bragg gratings in fibers and for other photolithographic applications. The solid state light source preferably has a passively Q-switched laser, a fiber amplifier and two or more nonlinear conversion elements for delivering a pulsed exposure beam at an exposure wavelength in the UV wavelength range. The exposure beam is generated in a single pass through the nonlinear elements, for example by cascaded second harmonic generation yielding the fourth harmonic. The system is effective at covering the UV wavelengths from 200 nm to 330 nm and particularly effective at producing an exposure wavelength between 240 and 250 nm at average power levels of 500 milliWatts and more within a photosensitive range of fiber cores in which Bragg gratings are to be written.

Solid state laser generating UV radiation for writing fiber bragg gratings

An approach to blue light in a single, integrated system is disclosed. An oscillator generates source radiation at a wavelength near 0.91 microns and a few milliwatts of power. This power is amplified to multi-Watt levels in a Neodymium-doped cladding-pumped fiber device that has its gain suppressed at 1.05 microns. A harmonic generator frequency-doubles the output of the fiber device to produce radiation at a blue wavelength near 0.455 microns. Mirrors, gratings or other means in the fiber expel wavelengths of light at or near 1.05 microns while allowing 0.91 micron radiation to remain in the fiber. Gain at 1.05 microns may alternatively be suppressed by adjusting the refractive index profile of the fiber to eliminate bound-modes at 1.05 microns or by bending the fiber to attenuate radiation at 1.05 microns. The laser may include a high brightness pump to enhance the transition that produces 0.91 micron radiation. Short-pulse, high-peak power-oscillators may be used to facilitate operation of the harmonic generator. The blue light source may be incorporated into a three-color projection or image display system.

Blue laser based on interactions in fiber

An apparatus and a method for separating a light of a first wavelength &lgr; from a second wavelength &lgr; , where &lgr; <&lgr; , in a waveguide such as an optical fiber is described. The apparatus includes a core surrounded by a depressed cladding, which itself is surrounded by a secondary cladding. The core cross-section, the depressed cladding cross-section, the secondary cladding cross-section, and the refractive indices of the core, the depressed cladding and the secondary cladding are selected to produce a fundamental mode cutoff wavelength &lgr; such that &lgr; &lgr; <&lgr; , and produce a high loss at the secondary wavelength &lgr; . The apparatus can be used as a filter, an amplifier, a laser, or in a nonlinear optical switch.

Optical wavelength filtering apparatus with depressed-index claddings

A stabilized solid-state laser in a thermal imaging system in which a laser diode pumps the solid-state laser and a modulator modulates the laser beam according to graphical data to be recorded in a thermally sensitive medium, as is used in the graphics industry. The solid-state laser is stabilized against relaxation oscillations induced in the laser by modulated light reflected back from the thermally sensitive medium. The light reflected from the medium is allowed to reenter the solid-state laser, but the optical output of the solid-state laser is sampled in the frequency band in which relaxation oscillations occur. The detected intensity is then used in a feedback circuit to control the intensity of the diode laser that is optically pumping the solid-state laser. Thereby, the data modulation does not cause the solid-state laser to oscillate, and neither a Faraday rotator nor use of a diffracted beam is required.

Electronic suppression of optical feedback instabilities in a

A method and apparatus for applying a lubricant to an object is disclosed. The lubrication apparatus includes a rotatable and cylindrically shaped brush for applying the lubricant to the object, a housing for holding the brush, and a pump for applying the lubricant to the brush located in a chamber positioned below the brush. A vertical slide cylinder moves the brush in a generally vertical direction along the central axis in and out of the chamber, and a horizontal slide cylinder moves the brush in a generally horizontal direction transverse to the central axis to contact the object. The chamber has a sloped chamber cap connected to the top portion of the chamber for collecting lubricant that drips from the brush. The brush is preferably rotated by a motor. The method of applying the lubricant to the object includes the steps of applying the lubricant to the brush in the chamber, moving the brush to a vertical position equal that of the object, moving the brush horizontally to contact the object, and lubricating the object by rotating the object and the brush.

Automatic wheel lubricator

A laser material for a solid-state laser that, when pumped by light having a wavelength in a suitable pump band, emits electromagnetic radiation having a wavelength lying in the range 2.0.ltoreq..lambda..ltoreq.2.1 .mu.m. The laser host material includes thulium-doped lutetium yttrium aluminum garnet (Tm:LuYAG) of approximate chemical composition (Tm.sub.x (Y.sub.w Lu.sub.1-w).sub.1-x).sub.3 Al.sub.5 O.sub.12, with x lying approximately in the range 0.01.ltoreq.x.ltoreq.0.5 and w lying in the range between 0.01 and 0.99. In particular, the Tm:LuYAG material produces light with wavelengths in the range .lambda.=2.020-2.024 .mu.m, where the normally-absorbing atmosphere has a transmission window with markedly reduced (or, alternatively, markedly enhanced) absorption. Another suitable group of laser materials has the chemical composition (Tm.sub.x (Y.sub.w Lu.sub.1-w-z Sen.sub.z).sub.1-x).sub.3 Al.sub.5 O.sub.12, with x lying approximately in the range 0.01.ltoreq.x.ltoreq.0.5, w lying in the range 0.01.ltoreq.w.ltoreq.0.99 and z lying in the range 0.001.ltoreq.z.ltoreq.0.2, and Sen denotes an optical sensitizer such as Er, Yb and/or Cr. Other suitable laser materials, for production of light with wavelengths in the range 1.9-2.2 .mu.m, are thulium-doped yttrium lithium fluoride and lithium-doped yttrium scandium aluminum garnet, with the respective approximate chemical compositions Tm.sub.x (Y.sub.w Lu.sub.1-w).sub.1-x LiF.sub.4, and (Tm.sub.x (Y.sub.w Lu.sub.1-w).sub.1-x).sub.3 Sc.sub.2 Al.sub.3 O.sub.12, with x lying approximately in the range 0.01.ltoreq.x.ltoreq.0.5 and w lying in the range between 0.01 and 0.99. If the Tm doping fraction and the Lu fraction in Tm:LuYAG are no greater than 0.03 and 0.5, respectively, the material Tm:LuYAG exhibits useful ranges of monotonically changing emission wavelength as temperature is varied over a reasonable range.

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Menlo Park, CA, United States of America

Thomas James Kane