WO1996018922A1 - Nonlinear optical generator with index of refraction perturbed reflector arrangement - Google Patents
Nonlinear optical generator with index of refraction perturbed reflector arrangement Download PDFInfo
- Publication number
- WO1996018922A1 WO1996018922A1 PCT/US1995/014407 US9514407W WO9618922A1 WO 1996018922 A1 WO1996018922 A1 WO 1996018922A1 US 9514407 W US9514407 W US 9514407W WO 9618922 A1 WO9618922 A1 WO 9618922A1
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- WIPO (PCT)
- Prior art keywords
- radiation
- source
- fiber
- frequency
- nonlinear
- Prior art date
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
- H01S5/14—External cavity lasers
- H01S5/146—External cavity lasers using a fiber as external cavity
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/106—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity
- H01S3/108—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity using non-linear optical devices, e.g. exhibiting Brillouin or Raman scattering
- H01S3/109—Frequency multiplication, e.g. harmonic generation
Definitions
- the present invention relates to nonlinear optical frequency generators and, more particularly, to such a generator having an improved source for pumping radiation.
- blue and green light are referred to as forms of optical radiation - radiation having a frequency of a value falling within the typical frequency ranges referred to as the near infrared, the visible, and the ultraviolet ranges, i.e., radiation having a frequency of between about .2 ⁇ m and 5 ⁇ m.
- One way of obtaining optical radiation of a desired frequency is to convert other radiation such as that of one or more frequencies issuing from a diode laser to the desired radiation.
- An example is the frequency "doubling" of a selected frequency by a nonlinear generator of a type referred to typically as a second harmonic generator (SHG) .
- SHG second harmonic generator
- One of the problems associated with this approach is that for efficient conversion it is desirable that the radiation issuing from the source diode laser be within highly prescribed frequency limits.
- One way to only obtain a selected frequency for the pump radiation (the diode radiation) is to provide a reflector which is made up of indices of refraction transitions selected to confine the source radiation output to the selected frequency. This is known.
- the approaches to obtaining it in the past have problems. Reference is made, for example, to Shinozaki et al. U.S. Patent No. 5,247,528 which describes a nonlinear optical generator which utilizes quasi-phase atching to provide output radiation having the second harmonic wavelength of the incoming pump or, in other words, fundamental radiation. Shinozaki et al.
- the present invention relates to a nonlinear optical frequency generator having a multitude of transitions of the effective index of a guided mode, and yet not having the problems mentioned above.
- the invention includes the combination in one unit of a source of radiation, a nonlinear material and an optical fiber (a type of waveguide) positioned to receive the radiation from the source and provide the multitude of transitions of the effective index of a guided mode.
- the multitude of transitions in the effective index of a guided mode are provided by perturbations in the indices of refraction of the fiber along the path therein of the source radiation.
- the nonlinear material preferably is a ferroelectric one having spontaneous polarization, and the frequency interaction in the material is obtained by quasi-phasematching. Quasi-phasematching allows one to use a nonlinear material that cannot be birefringently phasematched.
- the generator is also most simply a second harmonic generator, and a channel waveguide for the interacting radiation frequencies is defined in the nonlinear material. A second harmonic is the strongest harmonic, and the use of a channel waveguide increases the single pass conversion efficiency.
- the invention also includes a method of making the generator, as well as a method of producing radiation of a desired frequency.
- FIG. 1 is an isometric and schematic illustration of a first preferred embodiment of the invention
- FIG. 2 is a view that is similar to FIG. 1, showing another embodiment of the invention.
- FIG. 3 is also a view similar to FIG. 1, showing yet a third embodiment of the invention.
- a nonlinear optical generator of the invention is generally indicated in FIG. 1 by the reference numeral 11.
- Such generator includes a source of pumping radiation represented at 12. This source most simply is furnished as a diode laser of the Fabry-Perot type.
- the gain medium can be, for example, AlGalnP, GaAlAs, GaAs, InGaAs, or InGaAsP if optical gain in the wavelength region of 670-1550 nm is desired.
- a typical example is the Model SDL-AR-5410 diode laser which is commercially available from Spectra Diode Laboratories, Inc., San Jose, California.
- the source 12 actually be a laser - only a gain medium and one reflector (which, of course, can be a facet of the gain medium) is needed for the invention.
- the diode laser is chosen so that radiation emanating from it includes radiation having the selected pumping frequency. This radiation will be focused as is represented by focusing lens 14 onto the entry end of a single (lowest order) transverse mode, polarization preserving, optical fiber 16. (Beam shaping or polarization rotation optics also could be provided between the diode laser and the fiber.)
- the fiber 16 most desirably has an elliptical core for better mode matching. It includes a reflector location along its length, defined by a multitude of transitions between differing indices of refraction. The dotted lines 17 represent the transitions, although it will be recognized that such transitions are not actually visible.
- the radiation produced by the gain medium of the diode laser has a multitude of actual or potential frequencies, including a frequency to be selected for pumping.
- the value of the indices of refraction and the spacings between the transitions 17 are chosen to segregate the selected pumping frequency from all of the others. (The production of such transitions in optical fibers is not new. It can be done, for example, by interference of ultraviolet radiation.)
- This grating (spaced transitions) functions as a wavelength- selective mirror and acts with the high reflective coating 13 on the far end of the diode laser 12 to define a lasant optical cavity. Because of the frequency selective grating provided by the transitions 17, only the selected frequency will lase.
- the reflectivity of the grating is chosen to maximize the output power, i.e. , to maximize the output power of the selected pumping frequency.
- the selection of the indices of refraction and the spacing between transitions is, of course, dependent upon the selected frequency and the range of frequencies from which it is to be selected.
- a grating of period 1 provides reflection of a guided mode with effective index n eff at the wavelength ⁇ .
- the optimum reflectivity is a function of the single-pass gain of the laser gain medium, the efficiency with which light is coupled from the gain medium into the fiber, and optical losses in the laser cavity. These optical losses will include, of course, the transmission losses in the fiber and the absorption losses at the reflector.
- the material from which the optical fiber 16 is made must be selected to be one which can transmit the desired radiation frequencies.
- such material was germanium doped silica glass.
- An appropriate fiber is the E-Series single mode, polarization maintaining fiber (part No. 48280, 1060S-1) of the Andrew Corporation of Orland Park, Illinois. It meets all of the characteristics listed above.
- the diode laser as furnished in the generator of the invention does not necessarily act as a laser itself.
- the front facet of the diode laser is provided with an anti-reflective coating 18 to reduce or eliminate the internal lasing one typically expects from a diode laser.
- the source is therefore a "modified" diode laser, which source includes the optical cavity defined within the fiber 16. Some in the field look at this phenomenon simply as “feedback" to the diode laser from the grating defined by the transitions 17.
- a laser of this type also has been referred to as a "hybrid" laser (See the Morton et al.
- the reflector is "chirped" with the spacing between transitions being reduced in the direction away from the diode laser. It is believed that this arrangement results in more stable operation of the laser. What is important, though, is that the distributed reflector defined by the transitions 17 act to select the desired pumping frequency from the other frequencies which might emanate from the lasing media.
- the selected frequency is conveyed by the fiber 17 to the entry end of a channel waveguide 19 within a nonlinear material.
- nonlinear materials There are many different nonlinear materials. Some are: LiNb0 3 , LiTa0 3 , KTiOP0 4 , KNb0 3 , BaB 2 0 4 , LiB 3 0 5 , GaAs and AlGaAs.
- a ferroelectric one preferably is selected and periodic reversals in the directions of spontaneous polarization are provided along the length of the waveguide. As is indicated by applicant's earlier patent, such an arrangement is quite effective for quasi-phasematching to convert the frequency of pump radiation to a desired frequency.
- the walls between the sections of differing spontaneous polarization are represented in the figure by dotted lines 22.
- Output radiation having the desired frequency emanates from the waveguide 19.
- This output is represented in the figures by the arrow 23.
- the nonlinear material may be LiNb0 3 , LiTa0 3 , or KTiOP0 4 .
- the conversion efficiency to the desired output frequency can be maximized by finely tuning the temperature of the waveguide 19. Such temperature variation can be achieved by placing the nonlinear material in an oven or by having it in thermal contact with a thermoelectric cooler, as appropriate.
- the box 24 in thermal contact with the nonlinear material represents such temperature control.
- the temperature of the fiber transitions can be varied to change the frequency of the pumping radiation, thereby also changing the frequency of the output radiation.
- FIG. 2 illustrates such an arrangement in which it does not deliver the pump radiation to the waveguide.
- the highly reflective coating 13 is provided on the front facet of the diode laser 12
- the antireflection coating is provided on the facet of the diode laser closest to the optical fiber.
- the hybrid laser is defined between the facet 13 and the reflector defined by the transitions 17.
- the diode high reflection coating 13 is selected to permit some transmission of the selected frequency for transmission to the waveguide.
- a second focusing lens 26 is provided to focus the selected radiation into the channel waveguide 19 for quasi-phasematching production of radiation of the desired frequency.
- FIG. 2 broadly has the same parts as the earlier described embodiment, and like reference numerals are used to represent like elements.
- FIG. 3 illustrates an arrangement in which the channel waveguide 19 is positioned between the diode laser 12 and the fiber 17. Focusing lens 14 focuses the output of the diode laser into the nonlinear material rather than into the end of the fiber. In this connection, it must be remembered that in general this output will only be made up of the selected pumping frequency - the other actual and projected frequencies will be segregated from the same by the reflector defined by the transition 17 so as not to lase. The output radiation will emanate from the end of the optical fiber 23.
- the above arrangement provides intracavity frequency conversion.
- the nonlinear material receives more power at a selected wavelength than it would if placed outside the laser cavity. This greater power improves the nonlinear conversion efficiency.
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Optics & Photonics (AREA)
- Nonlinear Science (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Lasers (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP95940636A EP0797783A4 (en) | 1994-12-12 | 1995-11-16 | Nonlinear optical generator with index of refraction perturbed reflector arrangement |
JP8518801A JPH11509933A (en) | 1994-12-12 | 1995-11-16 | Nonlinear optical generator with perturbed refractive index reflector device |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/354,316 | 1994-12-12 | ||
US08/354,316 US5544271A (en) | 1994-12-12 | 1994-12-12 | Nonlinear optical generator with index of refraction perturbed reflector arrangement |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1996018922A1 true WO1996018922A1 (en) | 1996-06-20 |
Family
ID=23392773
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1995/014407 WO1996018922A1 (en) | 1994-12-12 | 1995-11-16 | Nonlinear optical generator with index of refraction perturbed reflector arrangement |
Country Status (4)
Country | Link |
---|---|
US (1) | US5544271A (en) |
EP (1) | EP0797783A4 (en) |
JP (1) | JPH11509933A (en) |
WO (1) | WO1996018922A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19700731C1 (en) * | 1997-01-11 | 1998-09-03 | Laser & Med Tech Gmbh | Longitudinal temperature gradient compensation arrangement in non-linear crystal |
Families Citing this family (15)
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US5905745A (en) * | 1997-03-17 | 1999-05-18 | Sdl, Inc. | Noise suppression in cladding pumped fiber lasers |
US5898718A (en) * | 1997-05-19 | 1999-04-27 | Altos Inc. | Method and apparatus for optimizing the output of a multi-peaked frequency harmonic generator |
WO2004025363A1 (en) | 2002-09-10 | 2004-03-25 | The Furukawa Electric Co., Ltd. | Wavelength conversion module |
US6996140B2 (en) * | 2002-12-23 | 2006-02-07 | Jds Uniphase Corporation | Laser device for nonlinear conversion of light |
US7103075B2 (en) * | 2003-06-18 | 2006-09-05 | Shimadzu Corporation | Solid laser apparatus |
WO2006016410A1 (en) * | 2004-08-12 | 2006-02-16 | Mitsubishi Denki Kabushiki Kaisha | Fundamental wave light source and wavelength converter |
US7605973B2 (en) | 2004-12-03 | 2009-10-20 | Mitsubishi Electric Corporation | Optical wavelength conversion light source |
US7899105B1 (en) * | 2005-06-15 | 2011-03-01 | Cvi Laser, Llc | Temperature control system for a frequency converted diode laser |
US10114213B2 (en) | 2008-04-04 | 2018-10-30 | Cvi Laser, Llc | Laser systems and optical devices for manipulating laser beams |
US8975572B2 (en) * | 2008-04-04 | 2015-03-10 | Cvi Laser, Llc | Compact, thermally stable fiber-optic array mountable to flow cell |
US7903706B2 (en) | 2008-04-04 | 2011-03-08 | O'shaughnessy John | Compact, thermally stable multi-laser engine |
US9413130B2 (en) | 2012-12-12 | 2016-08-09 | Cvi Laser, Llc | Optical systems |
TWI401521B (en) * | 2009-11-17 | 2013-07-11 | Univ Nat Taiwan | Apparatus and method for converting laser beam energy |
US11378808B2 (en) | 2018-07-18 | 2022-07-05 | Idex Health & Science Llc | Laser systems and optical devices for laser beam shaping |
DE102018129623A1 (en) * | 2018-11-23 | 2020-05-28 | Forschungsverbund Berlin E.V. | Device for generating laser radiation |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4913507A (en) * | 1988-09-08 | 1990-04-03 | The United States Of America As Represented By The Secretary Of The Navy | Mode field conditioner |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE462352B (en) * | 1988-10-25 | 1990-06-11 | Optisk Forskning Inst | GUARDIANS AND PROCEDURES FOR PREPARING SUCH THINGS |
JPH04507299A (en) * | 1989-02-01 | 1992-12-17 | ザ ボード オブ トラスティーズ オブ ザ リーランド スタンフォード ジュニア ユニバーシティ | Nonlinear optical oscillator and method for controlling ferroelectric polarization region of semiconductor |
FR2660493A1 (en) * | 1990-03-30 | 1991-10-04 | Thomson Csf | MONOLITHICALLY INTEGRATED FREQUENCY CHANGER LASER DEVICE. |
JP2721436B2 (en) * | 1990-11-07 | 1998-03-04 | 沖電気工業株式会社 | Second harmonic generator |
JP3052501B2 (en) * | 1990-11-30 | 2000-06-12 | 松下電器産業株式会社 | Manufacturing method of wavelength conversion element |
US5253259A (en) * | 1991-02-07 | 1993-10-12 | Matsushita Electric Industrial Co., Ltd. | Frequency doubler and visible laser source having a heater |
SG55125A1 (en) * | 1991-12-30 | 2000-06-20 | Koninkl Philips Electronics Nv | Device in which electromagnetic radiation is raised in frequency and apparatus for optically scanning an information plane comprising such a device |
US5305336A (en) * | 1992-01-29 | 1994-04-19 | At&T Bell Laboratories | Compact optical pulse source |
JPH05257184A (en) * | 1992-03-13 | 1993-10-08 | Hitachi Ltd | Waveguide resonance type shg light source and its manufacture |
-
1994
- 1994-12-12 US US08/354,316 patent/US5544271A/en not_active Expired - Lifetime
-
1995
- 1995-11-16 JP JP8518801A patent/JPH11509933A/en active Pending
- 1995-11-16 EP EP95940636A patent/EP0797783A4/en not_active Withdrawn
- 1995-11-16 WO PCT/US1995/014407 patent/WO1996018922A1/en not_active Application Discontinuation
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4913507A (en) * | 1988-09-08 | 1990-04-03 | The United States Of America As Represented By The Secretary Of The Navy | Mode field conditioner |
Non-Patent Citations (1)
Title |
---|
See also references of EP0797783A4 * |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19700731C1 (en) * | 1997-01-11 | 1998-09-03 | Laser & Med Tech Gmbh | Longitudinal temperature gradient compensation arrangement in non-linear crystal |
Also Published As
Publication number | Publication date |
---|---|
JPH11509933A (en) | 1999-08-31 |
US5544271A (en) | 1996-08-06 |
EP0797783A4 (en) | 1998-09-02 |
EP0797783A1 (en) | 1997-10-01 |
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