公开(公告)号：DE19642925B4

公开(公告)日：2007-07-12

申请号：DE19642925

申请日：1996-10-17

Applicant: IMRA AMERICA INC

Inventor： FERMANN MARTIN E

IPC: H01S3/098 ,  H01S3/06 ,  H01S3/067 ,  H01S3/083 ,  H01S3/0941 ,  H01S3/108 ,  H01S3/11

Abstract: The generation of ultrashort pulses with adjustable repetition rates from passively modelocked fiber lasers is demonstrated. By inserting semiconductor saturable absorbers with life-times of the order of 10 nsec into fiber lasers with cavity round-trip times of the order of 100 nsec, passive harmonic modelocking is obtained, leading to the stable generation of pulses at integer multiples of the fundamental cavity frequency. For polarization states that allow for optical limiting of the lasers, pulses are obtained in a frequency range between 20 and 500 MHz., where different repetition rates can be simply selected by changing the pump power level to the cavity. The pulse jitter within one cavity round-trip time is measured to be between 300 psec and 50 psec, where side bands in the frequency domain may be suppressed by up to 70 dB. The saturable absorber acts to both stabilize the cavity repetition rate and to initiate passive modelocking, where nonlinear-polarization evolution is used to sustain modelocking and to suppress amplitude fluctuations of the pulses by providing for optical limiting. Practical embodiments can be obtained by employing environmentally stable cavity designs in polarization preserving single-clad and double clad fibers, where the latter fiber designs allow the pumping of the fiber lasers with broad area-diode array lasers.

公开(公告)号：DE19535809B4

公开(公告)日：2006-09-07

申请号：DE19535809

申请日：1995-09-26

Applicant: IMRA AMERICA INC

Inventor： GALVANAUSKAS ALMANTAS ,  HARTER DONALD J

IPC: G02F1/35 ,  H01S3/10 ,  H01S3/00 ,  H01S3/108 ,  H01S5/00 ,  H01S5/042 ,  H01S5/06 ,  H01S5/0625 ,  H01S5/12

Abstract: A method of, and apparatus for controlling and compensating for high order frequency chirp in a fast tuned laser. Optical means in the form of chirped Bragg gratings, preferrably in-fiber gratings, are used to compensate for one or more orders of the frequency chirp. Alternatively, or in combination with the optical compensation, an electrical compensation scheme employs integrators in one or more parallel compensation channels to create a composite compensation signal to compensate for specific order nonlinearities. The present invention allows for the generation of shorter bandwidth-limited optical pulses with spectra containing the complete tuning range of the tunable laser.

公开(公告)号：DE19635919B4

公开(公告)日：2005-09-08

申请号：DE19635919

申请日：1996-09-04

Applicant: IMRA AMERICA INC

Inventor： FERMANN MARTIN E ,  HARTER DONALD J

IPC: H01S3/098 ,  H01S3/06 ,  H01S3/067 ,  H01S3/094 ,  H01S3/0941

Abstract: A technique for the generation of picosecond (psec) and femtosecond (fsec) pulses from modelocked double-clad fiber lasers cladding pumped with broad area diode laser arrays is disclosed. Using an erbium/ytterbium fiber oscillator, 560 fsec pulses with pulse energies up to 40 pJ are generated at a wavelength of 1560 nm. In a dispersion-compensated cavity, pulses as short as 170 fsec with pulse energies up to 50 pJ are obtained. By adding a negatively chirped fiber Bragg grating for additional intracavity dispersion control, pulse widths of 3 psec with pulse energies up to 1 nJ are obtained. A saturable absorber is used for pulse start up, whereas nonlinear polarization evolution is exploited for steady-state pulse shaping. An environmentally stable design is ensured by employing birefringent fibers and a compensation scheme for linear and nonlinear polarization drifts in the cavity.

公开(公告)号：DE10249188A1

公开(公告)日：2003-05-15

申请号：DE10249188

申请日：2002-10-22

Applicant: IMRA AMERICA INC

Inventor： PATEL RAJESH S ,  BOVATSEK JAMES M

IPC: B23K26/00 ,  B23K26/08 ,  B23K26/38 ,  F02M61/18

Abstract: The method involves directing a laser beam with adequate energy to ablate the material along an axis of incidence and at a point of incidence on a first surface of the material, whereby the incidence axis is offset from the normal at the point of incidence, and moving the material and laser beam relative to each other on a closed path.

公开(公告)号：DE69801719D1

公开(公告)日：2001-10-25

申请号：DE69801719

申请日：1998-06-19

Applicant: IMRA AMERICA INC

Inventor： DELNICK DR

IPC: H01M6/48 ,  B41J2/01 ,  H01M2/36 ,  H01M4/04 ,  B41J2/14

Abstract: A process for manufacturing an electrochemical cell comprising the steps of providing an electrode and applying electrolyte to the electrode using an ink-jet printer. In the preferred embodiment of the present invention, an ink-jet printing process is utilized to print the electrolyte onto the surface of the electrodes and separators or the electrode/separator bilayers. The ink-jet printing accurately meters and uniformly distributes the electrolyte throughout the pore structure of the separator and the electrode without contaminating the cell gasket. Preferably, a drop-on-demand ink-jet printing head is used to facilitate the electrolyte printing process. The ink-jet printing head is electronically pulsed to form and eject the electrolyte droplets from a nozzle of printing-head. The volume and the distribution of each electrolyte droplet are accurately determined and controlled by varying the pulse width and the pulse frequency of the printing head.

公开(公告)号：DE19828154A1

公开(公告)日：1999-01-07

申请号：DE19828154

申请日：1998-06-24

Applicant: IMRA AMERICA INC

Inventor： FERMANN MARTIN E DR ,  HARTER DONALD J DR

IPC: H01S3/10 ,  G02F1/37 ,  H01S3/06 ,  H01S3/067 ,  H01S3/08 ,  H01S3/094 ,  H01S3/23 ,  H04B10/02 ,  H04B10/18 ,  G02F1/39 ,  G02B6/10 ,  G02B6/22

Abstract: To amplify and compress optical pulses in a multi-mode (MM) optical fiber, a single-mode is launched into the MM fiber by matching the modal profile of the fundamental mode of the MM fiber with a diffraction-limited optical mode at the launch end. The fundamental mode is preserved in the MM fiber by minimizing mode-coupling by using relatively short lengths of step-index MM fibers with a few hundred modes and by minimizing fiber perturbations. Doping is confined to the center of the fiber core to preferentially amplify the fundamental mode, to reduce amplified spontaneous emission and to allow gain-guiding of the fundamental mode. Gain-guiding allows for the design of systems with length-dependent and power-dependent diameters of the fundamental mode. To allow pumping with high-power laser diodes, a double-clad amplifier structure is employed. For applications in nonlinear pulse-compression, self phase modulation and dispersion in the optical fibers can be exploited. High-power optical pulses may be linearly compressed using bulk optics dispersive delay lines or by chirped fiber Bragg gratings written directly into the SM or MM optical fiber. High-power cw lasers operating in a single near-diffraction-limited mode may be constructed from MM fibers by incorporating effective mode-filters into the laser cavity. Regenerative fiber amplifiers may be constructed from MM fibers by careful control of the recirculating mode. Higher-power Q-switched fiber lasers may be constructed by exploiting the large energy stored in MM fiber amplifiers.

公开(公告)号：DE19812203A1

公开(公告)日：1998-09-24

申请号：DE19812203

申请日：1998-03-19

Applicant: IMRA AMERICA INC

Inventor： GALVANAUSKAS ALMANTAS DR ,  HARIHARAN ANAND DR ,  HARTER DONALD J DR

IPC: G02F1/35 ,  B23K26/06 ,  B23K26/40 ,  G02F1/39 ,  H01S3/00 ,  H01S3/06 ,  H01S3/10 ,  H01S3/108 ,  H01S3/115 ,  H01S3/11

Abstract: The optical pulse amplification system includes a pump source (100; 210; 710) which produces optical pump pulses of a predetermined duration, a signal source (130; 200; 440; 705; 740) which produces optical signal pulses, and combining optics (106, 160; 221, 223; 460) which receives and combines the optical pump pulses and the optical signal pulses, to provide thereby combined optical pulses. A parametric amplifier (170; 220; 470) includes a quasi-phase adjusted crystal which receives the combined optical pulses and amplifies the optical signal pulses under application of energy from the optical pump pulses.

公开(公告)号：DE19642925A1

公开(公告)日：1997-04-24

申请号：DE19642925

申请日：1996-10-17

Applicant: IMRA AMERICA INC

Inventor： FERMANN MARTIN E DR

IPC: H01S3/098 ,  H01S3/06 ,  H01S3/067 ,  H01S3/091

Abstract: The laser has an optical pumping device, an optical resonator and devices for initiating and maintaining short optical pulses within the resonator, e.g. through Kerr non-linearities. Also provided is a fibre amplification material to transmit the optical impulse. The material transmits the impulse at a repetition rate which is a whole multiple of the fundamental resonator frequency. The separation of the pulses within the resonator is effected via a saturable semiconductor absorber with a charge carrier lifetime which is shorter than the fundamental resonator circulation time and longer than a hundredth of the latter. An optical limitation within the resonator is used for minimising pulse amplitude fluctuations.

公开(公告)号：DE19531059A1

公开(公告)日：1996-02-29

申请号：DE19531059

申请日：1995-08-23

Applicant: IMRA AMERICA INC

Inventor： GALVANAUSKAS ALMANTAS DR ,  FERMANN MARTIN E DR

IPC: G02F1/35 ,  G02B6/34 ,  H01S3/00 ,  H01S3/23 ,  H01S3/106

Abstract: Chirped Bragg gratings are used both for stretching and compressing of ultrashort optical pulses in a chirped pulse amplification system, so that even femtosecond pulses can be stretched and recompressed back to their initial shape and duration. When used in chirped pulse amplification systems instead of bulk diffraction grating stretchers and compressors, Bragg gratings offer unprecedented compactness, robustness and system efficiency.

公开(公告)号：WO2015108991A3

公开(公告)日：2015-10-15

申请号：PCT/US2015011420

申请日：2015-01-14

Applicant: IMRA AMERICA INC

Inventor： OTA MICHIHARU ,  ARAI ALAN Y ,  LIU ZHENLIN

IPC: B23K26/36 ,  B23K26/06 ,  B23K26/08 ,  B23K26/38 ,  B23K26/40

CPC classification number: B23K26/0624 ,  B23K26/0604 ,  B23K26/082 ,  B23K26/36 ,  B23K26/364 ,  B23K26/38 ,  B23K26/382 ,  B23K26/40 ,  B23K26/402 ,  B23K2203/50 ,  B23K2203/54 ,  C03B33/102

Abstract: In certain embodiments a method and system for laser-based material processing of a material is disclosed. In at least one preferred implementation temporally overlapping pulse series are generated with separate pulsed laser sources, for example nanosecond (NS) and ultrashort pulse (USP) sources (NS-USP). Pulses are delivered to the material as a series of spatially and temporally overlapping pulse pairs. The material can, but need not, be a transparent material. In some applications of transparent material processing, it was found the combination of pulses both substantially more material modification and high machining quality than obtainable with either individual pulse series taken alone. Other micromachining methods and arrangement are disclosed for formation of fine features on or within a substrate. Such methods and arrangements may generally be applied with a NS-USP combination, or with other sources.

Abstract translation: 在某些实施例中，公开了用于材料的基于激光的材料处理的方法和系统。 在至少一个优选实施方式中，利用分离的脉冲激光源，例如纳秒（NS）和超短脉冲（USP）源（NS-USP）产生时间重叠的脉冲序列。 脉冲作为一系列空间和时间重叠的脉冲对被传送到材料。 材料可以但不必是透明材料。 在透明材料加工的一些应用中，发现脉冲组合可以实现更多的材料修改和高的加工质量，而不是单独采用单个脉冲序列可获得的。 公开了其他微加工方法和装置，用于在衬底上或衬底内形成精细特征。 这些方法和装置通常可以与NS-USP组合或与其他来源一起应用。