CN1509507A - Adjustable extemal cavity laser - Google Patents

Abstract

Apparatus and methods that utilize dual, tunable elements to provide for selective wavelength tuning of a light beam. The apparatus comprises a first tunable wavelength selection element (24) positioned in a light beam and having a first adjustable free spectral range, a second tunable wavelength selection element (26) positioned in the light beam and having a second adjustable free spectral range, with the first and second tunable wavelength selection elements configured to define a joint transmission peak that is adjustable in phase according to tuning of the first and second tunable wavelength selection elements.

Description

Adjustable extemal cavity laser

Background of invention

The demand of the increase bandwidth of optical fiber communication drives the exploitation of the senior generating laser that can be used for dense wave division multipurpose (DWDM) system, and wherein in dwdm system, a plurality of separate data streams are propagated in a single fiber.Each data flow is produced by the modulation output of the semiconductor laser of specific channel frequency or wavelength, and a plurality of modulation output is integrated in the single fiber.International Telecommunication Union proposes the requirement of the channel spacing of approximate 0.4 nanometer or about 50GHz at present, carry up to 128 channels by single fiber in the bandwidth range of current available fiber and fiber amplifier so that allow, in the future, bigger bandwidth demand will cause littler channel isolation probably.

The telecommunications dwdm system is mainly based on distributed Feedback (DFB) laser.Distributed Feedback Laser selects grating to obtain stability by making presetted wavelength in early days.Unfortunately, the statistics variations of related single Distributed Feedback Laser manufacturing causes the distribution of (wavelength) channel center.Therefore, in order to satisfy the demand to stationary grizzly (grid) (ITU grid) operation of telecom wavelengths, DFB is strengthened by outside reference calibrator (etalon), and needs feedback control loop.The variation of DFB operating temperature allows an operative wavelength to enable servo-controlled scope; Yet the inconsistent demand that high luminous power, long-life and low electric power dissipate has hindered need be more than the use of the application facet of single channel or small number of adjacent channels.

Adjustable extemal cavity laser is developed continuously, to overcome the limitation of single DFB device.Many laser tunings mechanism has been developed and has been used to provide external-cavity wavelength to select, such as the tuning grating of mechanical type (grating) that is used to transmit and reflect.External cavity laser is tuning must to provide a stable single mode output on the wavelength of selecting, suppress to be in the laser action that is associated with the exocoel mould within the cavity gain bandwidth simultaneously effectively,

Realize that these purposes cause the increase of size, cost, complexity and the sensitivity of adjustable extemal cavity laser usually.

So have a kind of demand with outside cavity gas laser and mechanical tuning device of following performance: the transmission crest by effective inhibition wavelength different with selecting wavelength is avoided the multi-mode laser effect; Simplicity of design, compactness; Can directly implement.The present invention has satisfied these and other demand, and has overcome the defective of finding in background technology.

Summary of the invention

The present invention relates to a kind of laser apparatus and method, utilize two adjustable elements to provide light beam wavelength tuning.Equipment of the present invention is put it briefly and comprised: one first wavelengthtunable is selected element, is arranged in light beam and has the first adjustable Free Spectral Range (spectral range); One second wavelengthtunable is selected element, is arranged in light beam and has the second adjustable Free Spectral Range; First and second wavelengthtunables select element to be configured to define one can be according to the tuning joint transmission crest (jointtransmission peak) that comes homophase (in phase) to regulate of first and second adjustable elements.

More particularly, first wavelengthtunable selects element to define (define) more than first transmission crest within chosen wavelength range, second wavelengthtunable selects element define more than second transmission crests within chosen wavelength range, and more than first and second transmission crest is configured to unite within can the tuning chosen wavelength range of regulating by two adjustable elements and defines simply connected and close the transmission crest.Wavelengthtunable is selected the tuning adjusting that the Free Spectral Range of element is provided of element, and then regulates two groups of transmission crests, so that provide wavelength to select via fine setting effect (vernier effect).In certain embodiments, the 3rd wavelengthtunable with the 3rd Free Spectral Range selects element to be positioned in the light beam.

Method of the present invention is put it briefly and is comprised: provide one first wavelengthtunable with first adjustable Free Spectral Range to select element and one second wavelengthtunable with second adjustable Free Spectral Range to select element; Select element to be positioned in the light beam described wavelengthtunable; First and second Free Spectral Ranges definition associating (joint) Free Spectral Range according to two elements; Select element regulation associating Free Spectral Range by tuning first and second wavelengthtunables.The adjusting of uniting from Free Spectral Range can comprise: regulate the phase place by the transmission crest of associating Free Spectral Range definition.

The present invention can be incorporated in the laser apparatus, this laser apparatus comprises: a gain media (gain medium), have first and second planes (facet) and launch light beam from first plane, its end reflector is positioned in the light path and is configured to and defines an exocoel with second plane of gain media; First wavelengthtunable selection element that is positioned in the light beam and has the first adjustable Free Spectral Range; Second wavelengthtunable selection element that is positioned in the light beam and has the second adjustable Free Spectral Range; First and second adjustable elements are configured to define a joint transmission crest, and this is united and passes the elm crest and can come homophase to regulate according to the tuning of first and second adjustable elements.

The defined associating Free Spectral Range of two wavelengthtunables selection elements in certain embodiments can be greater than the gain wavelength of gain media.A plurality of planes of gain media can define a wavelengthtunable and select element, make gain media have Free Spectral Range, and first wavelengthtunable select first Free Spectral Range of element can be approximately equal to a plurality of gain media Free Spectral Ranges in certain embodiments.In other embodiments, second wavelengthtunable selects second Free Spectral Range of element also can be approximately equal to a plurality of gain media Free Spectral Ranges.

As unrestriced example, first and second wavelengthtunables select element to comprise: calibrator, grating, interferometric filter and/or other adjustable device, and can operate by heat-light, electrical-optical, sound-optical, piezoelectricity-light, machinery or other mechanical tuning device or effect.Gain media can comprise: but but light-emitting diode or photoflash lamp pumping or electricity pumping crystal, dyestuff, gas or other gain media.

In certain embodiments, first and second adjustable elements comprise hot light adjustable marker respectively as having at the semiconductor-based end on first and second surfaces, and each surface has one or more depositions thin-film dielectric layer thereon.Dielectric layer can comprise that for example, the quarter-wave dielectric layer is right." hot light " used herein tuning temperature-induced variation that is meant the temperature-induced variation by calibrator material refractive index aspect, calibrator physical thickness aspect, perhaps both carry out tuning.The calibrator material can have the coefficient that temperature relies on refractive index and thermal expansion in certain embodiments, makes thermo-optical tunability be accompanied by the synchronous thermal control of calibrator material refractive index and the thermal control of calibrator physical thickness by selectivity heating or refrigeration.Free Spectral Range to each calibrator is selected, and makes the thermal control of calibrator of the whole selection temperature range of calibrator that tuning on the scope that equals Free Spectral Range substantially is provided via thermo-optic effect.

In the operation of the outside cavity gas laser of the two adjustable markers of use of the present invention, the gain media emitted light beams is through two adjustable markers, from the end reflection mirroring, and turns back to gain media through calibrator.The Free Spectral Range of each calibrator provides not transmission crest on the same group, and transmission crest from two calibrators is had only on the gain bandwidth that overlaps or aim at the wave-length coverage that appears at selection such as gain media.This provides only selection of a wavelength and the multi-mode laser effect of having been avoided outside cavity gas laser to cause in this wave-length coverage.Selectivity by two calibrator temperature changes, and the Free Spectral Range of each calibrator changes by thermo-optic effect, with the control of the transmission crest of the calibrator that allows to aim at, thereby selects the outside cavity gas laser output wavelength.Select the acutance (finesse) of calibrator and the difference between the calibrator Free Spectral Range, to avoid the contiguous multi-mode laser effect transmitted crest on related with calibrator.Select full duration half maximum (half maximum) of two calibrators, with the laser action of the exocoel mould of avoiding being adjacent to selected wavelength.

The invention provides a kind of tuning system that is used for outside cavity gas laser and other optics, have following characteristics: directly enforcement, simplicity of design and wide wave-length coverage provide select on the wavelength fast, effectively tuning.Tuning use and the inhibition of active flank mould that allows short outer laser cavity with the use that two adjustable elements that wavelength selects are provided, and provide the mechanical tuning device of an outside cavity gas laser, this mechanical tuning device can easily be adopted or be reconfigured, to satisfy the demand of different DWDM networks.These and other objects of the present invention and advantage are from following detailed description and clearer.

Description of drawings

Below with reference to the accompanying drawing that only is used for illustration purpose the present invention is illustrated more fully.

Fig. 1 is the schematic diagram of adjustable extemal cavity laser of the present invention;

Fig. 2 A is first and second groups of curve charts that transmit crests that first and second adjustable elements of the adjustable extemal cavity laser equipment of Fig. 1 are provided;

Fig. 2 B is the defined curve chart that passes the elm crest of uniting of combination of sets of the transmission crest of Fig. 2 A;

Fig. 3 is the right cross sectional representation of adjustable marker of the present invention;

Fig. 4 is the curve chart of the defined transmission crest of the calibrator of Fig. 3, and this calibrator is tuned to provides the joint transmission of 1550nm crest;

Fig. 5 is the curve chart of uniting the spectral line width that passes the elm crest of Fig. 4, and this joint transmission crest is provided by the combined effect of the calibrator of Fig. 3;

Fig. 6 is the schematic diagram with silicon calibrator of Thermal Control Element;

Fig. 7 is the relation curve of the inclined degree of frequency change of the present invention and silicon calibrator angle tuning;

Fig. 8 is the schematic diagram with outside cavity gas laser equipment of three adjustable elements of the present invention;

Fig. 9 is the schematic diagram with outside cavity gas laser equipment of two tunable gratings of the present invention;

Figure 10 is the schematic diagram with outside cavity gas laser equipment of grating and calibrator adjustable element of the present invention;

Figure 11 A is the schematic diagram of another outside cavity gas laser equipment of the present invention, and wherein the operation of adjustable marker and adjustable extemal cavity is to provide fine setting tuning;

Figure 11 B is the schematic diagram by the transmission crest of the adjustable marker of Figure 11 A and adjustable extemal cavity definition;

Figure 11 C is the tuning schematic diagram of fine setting that is provided by Figure 11 A adjustable marker and adjustable extemal cavity, is shown as the curve chart of corresponding gain and wavelength;

Figure 12 A is the perspective view of another outside cavity gas laser equipment of the present invention, and wherein adjustable marker and adjustable extemal cavity are set in the MEMS device;

Figure 12 B and Figure 12 C are the vertical views of the outside cavity gas laser equipment of Figure 12 A, show taper calibrator tuning of Figure 12 A;

Figure 13 A is the schematic diagram of another embodiment of outside cavity gas laser equipment of the present invention, wherein utilizes two adjustable elements by configured in parallel;

Figure 13 B is the tuning curve chart of fine setting that the outside cavity gas laser equipment of Figure 13 A is provided, and is shown as the relation of corresponding gain and wavelength;

Figure 14 A is the vertical view of adjustable air gap calibrator that is used for the equipment of Figure 13 A;

Figure 14 B is the end view of the adjustable air gap calibrator of Figure 14 A, demonstrates along the section of hatching A-A;

Figure 15 is the schematic diagram of another embodiment of outside cavity gas laser equipment of the present invention, and wherein single birefringence calibrator provides by the two adjustable direction of parallel utilization;

Figure 16 is the schematic diagram of another embodiment of outside cavity gas laser equipment of the present invention, and wherein adjustable extemal cavity is used to provide the acutance needs that are reduced of adjustable marker;

Figure 17 A is the perspective view of another outside cavity gas laser equipment of the present invention, and wherein adjustable marker and adjustable extemal cavity are set in the MEMS device;

Figure 17 B and Figure 17 C are the vertical views of the outside cavity gas laser equipment of Figure 12 A, show taper calibrator tuning of Figure 17 A.

Embodiment

More specifically quoted figures is for the present invention at Fig. 1 imbody to the equipment shown in Figure 17 is described.Should be understood that this equipment can change the details of configuration and parts, method also can change the order of details and action, and don't deviates from disclosed basic design.The present invention mainly is disclosed in the mode of outside cavity gas laser use.Yet invention can be used for various types of laser aids and optical system.Should be understood that employed term only is used to illustrate the purpose of specific embodiment, rather than limits here, because scope of the present invention only is defined by the claims.The relative size of each parts shown in the drawings and between distance be for clear and therefore many examples that amplify not will be understood that it is to limit.

Referring to Fig. 1, there is shown laser apparatus 10 of the present invention.Equipment 10 comprises gain media 12 and end or external reflective element 14.Gain media 12 can comprise a traditional Fabry-Perot diode emitters chip, and has antireflection (AR) coating frontal plane 16 and reflection or partial reflection back plane 18.Reflecting element 14 can reflective mirror of envelope or other reflection or retroreflective elements.Outer laser chamber is by back plane 18 and end reflector 14 expressions.Gain media 12 is from frontal plane 16 emission coherent beams 19, and this associated beam is by lens 20 collimations that limit light path 22.Traditional output optical coupler (not shown) can be associated with back plane 18, is used for the optical fiber (not shown) is coupled in the output of back plane.

First and second adjustable elements 24,26 are positioned within the exocoel that is limited by tail end reflective mirror 14 and plane 18. Adjustable element 24,26 co-operate preferentially feed back to gain media 12 to the light of selected wavelength in the operating period of laser apparatus 10.For exemplary object, adjustable element 24,26 forms with the first and second adjustable Fabry-Perot calibrators illustrate, the calibrator that comprises parallel-plate solid, liquid or gas barrier, and can come tuning by the measure of precision of optical thickness or path.In other embodiments, calibrator 24 and/or calibrator 26 can substitute with a grating, adjustable thin film interferometric filter or other adjustable element, and be as described below.First calibrator 24 comprises surface 28,30, and has the first Free Spectral Range FSR that the material refractive index with surperficial 28,30 spacing and calibrator 24 adapts ₁ Second calibrator 26 comprises surface 32,34, and has the second Free Spectral Range FSR by the material refractive index definition of surface 32,34 and calibrator 26 ₂ Calibrator 24,26 can comprise identical materials or have the different materials of different refractivity.

Each of calibrator 24,26 come tuning by the optical thickness of regulating them, so that FSR to be provided ₁And FSR ₂Adjusting or tuning, the tuning of the laser apparatus 10 that will further specify also is provided below. Calibrator 24,26 tuning can comprise the adjusting of the refractive index of the adjusting of distance between the surface 28,30 and surperficial 32,34 and/or calibrator material, and can adopt following technology to realize, comprise: change heat-light, electrical-optical, the sound-optical and piezoelectricity-magic eye of refractive index, and the mechanical angle adjusting and/or the thermal tuning that change the calibrator surface spacing.More than one this tuning effect can be applied to simultaneously one or two calibrator 24,26, this depends on specific embodiment of the present invention.

In the embodiment shown in fig. 1, first and second calibrators 24,26 are tuning by thermoelectric effect respectively.Term " hot light " is tuning to be meant tuning that temperature sense by calibrator material refractive index changes, the temperature sense of the physical thickness of calibrator changes or both carry out.The calibrator material that uses among some embodiment has temperature and relies on refractive index and thermal coefficient of expansion, by selectivity heating or refrigeration, makes thermo-optical tunability follow the thermal control of calibrator material refractive index and the thermal control of calibrator physical thickness simultaneously like this.Further specify the selection of the calibrator material that is used for the available heat magic eye below.

For thermo-optical tunability is provided, hot light control element 36 operationally is coupled to calibrator 24, and Thermal Control Element 38 operationally is coupled to calibrator 26, so that rely on heat condition that heating or refrigeration are provided. Thermal Control Element 36,38 also operationally is coupled to controller 40.Controller 40 can comprise a traditional data processor, and according to the Wavelength-selective information of storing in the look-up table or other wavelength choice criteria to being used for the calibrator thermal conditioning or tuning Thermal Control Element 36,38 provides harmonic ringing.Calibrator 24,26 also comprises the temperature monitoring element 37,39 that is operatively coupled to controller 40, is used for during laser operation the surveillance calibration actuator temperature and will calibrates actuator temperature information passing to controller 40.Each Thermal Control Element 36,38 comprises the heating element (not shown) of a permission according to the instruction adjusting temperature of controller 40.

The thermal control of the calibrator 24,26 that Thermal Control Element 36,38 is carried out can by pass to, convection current or both realize.In many examples, heat conduction is the hot-fluid and the thermoregulator main path of calibrator 24,26, and should suppress to cause harmful or convection effect (convective effect) that pseudo-heat rises and falls in the calibrator 24,26.Outside cavity gas laser equipment 10 can be designed or be configured in addition to allow or compensate the hot-fluid effect that is caused by thermal convection on the operating temperature of whole laser.For example, equipment 10 can be configured to limit near the air-flow the calibrator 24,26.In other embodiments, calibrator 24,26 can be isolated separately in low conductive rings border or vacuum.Arrive the big gas circuit of structure of the different temperatures of contiguous calibrator 24, and can also be used to suppressing arriving or from the heat transmission of calibrator near the use of the heat insulator of the parts of calibrator 24,26.Branch layer of air and air flow near calibrator can additionally be provided provide in the design of equipment 10, thereby avoids the potential harmful thermal effect relevant with turbulent flow.

Thermal Control Element 36,38 allows each calibrator 24,26 to place independent thermal control. Thermal Control Element 36,38 can be used to provide jointly or parallel heating (a plurality of calibrators being heated and refrigeration with essentially identical rate of temperature change) and differential heating (a plurality of calibrators being heated or refrigeration with different substantially rate of temperature changes), is used for following wavelength tuning.As described below, Thermal Control Element 36,38 can be integrated on the surface or a plurality of surface of each calibrator 24,26, Thermal Control Element 36,38 can be corresponding to radiator or thermal storage device (thermal reservoir), to allow Fast Heating or cooling calibrator 24,26.

In certain embodiments, calibrator 24,26 is configured and is configured to make single heat controller or radiator that the effectively tuning of two calibrators 24,26 can be provided simultaneously.Heat sensor or monitor (not shown) are placed on the calibrator 24,26 or are placed in a distant place, with the calibrator temperature of supervisory controller 40.Calibrator 24,26 can connect or combination by an assembly (not shown), wherein adopts the harmful light coupled modes of avoiding between the calibrator 24,26 to settle calibrator 24,26 or make 24,26 angulations of calibrator.Installation has the calibrator 24,26 of the material of appropriate thermal characteristic can avoid undesirable thermal coupling between the calibrator 24,26 at stand-by period.

The plane 16,18 of gain media 12 limits the Fabry-Perot calibrators, and Thermal Control Element 42 is coupling gain media 12 operatively, so that keep the thermally-stabilised of distance between the plane 16,18 and the stable output of gain media 12 is provided.Thermal Control Element 42 is operatively coupled to controller 40.Can also be via the Thermal Control Element (not shown) that is operatively coupled to tail end reflective mirror 14 and controller 42, the optical path length of the outer laser chamber that adjusting is limited by tail end reflective mirror 14 and plane 18, and according to error detecting system or the system that operatively is coupled to controller 42 regulate the thermal control of tail end reflective mirror 14 and/or gain media 12.The thermal control of exocoel optical path length is fully described in the U.S. Patent application of submitting June 6 calendar year 2001 the 09/900th, 443, and the disclosure is quoted at this as the reference file.

Calibrator 24,26 is tuning via the selective wavelength that the fine setting effect is provided for equipment 10.Referring to Fig. 2 A, first group of the structure of first calibrator 24 and configuration definition or multi-unit message band, mould or transmission crest P ₁(showing with solid line), the maximum of the distance of being separated by equals FSR ₁26 second group of definition of same second calibrator or multi-unit message band, mould or transmission crest P ₂(being shown as dotted line) is at a distance of the crest P of a distance ₂The transmission maximum equal FSR ₂First and second calibrators 24,26 are configured in many examples and are configured to: during laser operation, and FSR ₁And FSR ₂The ground amplitude is similar but unequal.

By providing the difference of optical path length to realize FSR for each of calibrator 24,26 ₁With FSR ₂Between the difference of Free Spectral Range.Provide the structure and the configuration of the calibrator 24,26 of different Free Spectral Ranges to realize by the different technologies scheme.For example, can obtain expecting after the thickness little poor only with the Free Spectral Range that obtains two calibrators of the single parallel substrate of division again from processing and polishing.Then half of substrate carried out additional operations, wherein extract material, perhaps increase the additional substrate material layer by the common material deposition technique that increases thickness by the grinding, polishing or the etching that reduce thickness.Like this, two pairs of branches of former substrate will provide two calibrators of inconsistent a little optical path length and different Free Spectral Ranges.Should be pointed out that two calibrators, also can realize the little difference of Free Spectral Range by temperature difference or differential seat angle between two calibrators or other difference that acts on the tuning effect of calibrator for same material and same nominal thickness.

The difference δ FSR of the Free Spectral Range of two calibrators 24,26 is crest P qualification or that select that make two groups of transmission crests ₁And P ₂Overlap or aim at, make residue P simultaneously ₁And P ₂Do not overlap each other or misalignment.In Fig. 2 A, crest P ₁And P ₂Coincidence or alignment point in wavelength X ₀On.Crest P ₁And P ₂Additional coincide point appear at outside the zone shown in Fig. 2 A.Crest P ₁And P ₂Coincidence definition or cause joint transmission crest P _j(shown in Fig. 2 B) has by associating (joint) spectral region or FSR two calibrators 24,26 _jCut apart and uniting of wavelength pass elm crest P _j

Calibrator 24,26 can be made (being respectively calibrator 24,26) the calibrator order M that comprises the joint transmission crest by continuous tuning ₁With calibrator order M ₂Change frequency with the phase same rate.This can heat simultaneously with identical in fact rate temperature change or cool off two calibrators 24,26 o'clock and realize at for example calibrator 24,26.In the case, within single associating Free Spectral Range, regulate associating crest P _jWavelength location.Apply the differential heating of the calibrator 24,26 of a different temperatures rate of change to each calibrator, can allow the fine setting displacement of the bat difference between the mould, thereby make different crest P ₁And P ₂Aimed at, so that substantially greater than FSR _jA scope on regulate discontinuously to unite and pass elm crest P _jWavelength location.

Like this, joint transmission crest P _jWavelength corresponding to the optional optical maser wavelength of equipment 10, and can control and select according to calibrator 24,26 tuning.Each transmission crest P that does not aim at mutually ₁And P ₂During laser operation, be suppressed.Joint transmission crest P _jWavelength can be for example corresponding to the transport channel of a communication band.FSR _jAmplitude (and thereby being the amplitude of δ FSR) can be selected, make single joint transmission crest P _jOccur over just in the wave-length coverage of care, as in the gain bandwidth of gain media 12 or in the part of its selection, to avoid a plurality of joint transmission crest P _jOn the multi-mode laser effect takes place simultaneously.As selection, pass elm crest P when more than one the associating _jWhen being present within the bandwidth of gain media 12, can in equipment 10, use one or more suitable filters (not shown), to suppress calibrator 24,26 feedback to gain media 12 on a plurality of wavelength.

Select the acutance and the FSR of calibrator 24,26 ₁And FSR ₂Amplitude, to avoid contiguous joint transmission crest P _jMisalignment crest P ₁And P ₂The multi-mode laser effect.The acutance of calibrator 24,26 is equivalence or in fact equal in certain embodiments, and other embodiments of the invention are then unequal.

Be defined in by the laser external cavity of tail end reflective mirror 14 and gain media 12 planes, 18 representatives and be shown as exocoel mould crest P among Fig. 2 A _ECA plurality of exocoel moulds.Exocoel mould crest P _ECExpand to the whole wave-length coverage of Fig. 2 A, but for the sake of clarity only shown a part of exocoel mould crest P _ECSelect joint transmission crest P for use _jFull duration half maximum (according to the configuration of calibrator 24,26), to prevent contiguous joint transmission crest P _jChamber mould crest P _ECHarmful laser action at place.

Calibrator 24,26 can be configured to make FSR ₁And FSR ₂Each is approximately equal to the Free Spectral Range (not shown) of gain media 12, so that keep the approximate match condition (commensurate condition) about the reflection coefficient plane of gain media 12.Yet, when reflection coefficient plane is enough to be suppressed by antireflecting coating, do not need a kind of like this condition.Select the absolute thickness of calibrator 24,26, make Thermal Control Element 36,38 can be provided at associating Free Spectral Range FSR _jWithin tuning or regulate joint transmission crest P _jThe required temperature range in position.Calibrator thickness also depends on the calibrator material selection that further specifies below.

The difference of the fine setting spacing that calibrator 24,26 provides, i.e. FSR ₁With FSR ₂Difference or the amplitude of δ FSR can be used for changing according to the wave-length coverage of wavelength selectivity expected to rank, care and special the making of equipment 10.In many examples, calibrator 24,26 is configured and is configured to make FSR ₁To fall into FSR ₂Several percentages within.Thereby, for example in certain embodiments, FSR ₁Can be FSR ₂Approximate 99% to 101% between, and in other embodiments, FSR ₁Can be FSR ₂Approximate 98% to 102% between.In certain embodiments, the difference of the Free Spectral Range of calibrator 24,26 can be bigger, makes FSR ₁Be FSR ₂Approximate 90% to 105% between, in some cases, FSR ₁Can be FSR ₂Approximate 90% to 110% between or more.

To select the FSR of calibrator 24,26 in certain embodiments ₁And FSR ₂(and thereby FSR _j), with the multi-mode laser effect within other wave-length coverage of the gain bandwidth of avoiding gain media 12 or care, as mentioned above.Just, calibrator 24,26 only provides the simply connected within the wave-length coverage to close transmission crest P _j, make FSR _jBe equal to or greater than the wave-length coverage of care, and provide contiguous the associating passing elm crest P _jThe inhibition of transmission crest.In certain embodiments, selected wave-length coverage can comprise the specific communications band, and is tuning by the selectivity of calibrator 24,26 such as " C " band, joint transmission crest Pj in location on the expection wavelength in the communication band.

The FSR of calibrator 24,26 ₁And FSR ₂Difference can also limit according to the quantity of discrete transmissions channel or wavelength in the selected wave-length coverage.Therefore, FSR ₁And FSR ₂Following relational expression can be arranged:

FSR≈(M/M±N) (FSR ₂)

Wherein M selects the interior wavelengthtunable of wave-length coverage or the total quantity of transmission channel for use, and N is non-integer or the integer that different embodiment according to the subject invention is selected.In other words, FSR ₁Can be approximately equal to the quantity of tunable wavelength and tunable wavelength quantity add deduct quantity N the merchant again with FSR ₂It is long-pending to multiply each other.Quantity N can be for example about 0.01 littler and about 10 or bigger between scope within.Usually, any reasonable ratio of Free Spectral Range can provide a fine setting effect.In certain embodiments, N can fall within the scope between approximate 0.1 and approximate 5, in certain embodiments, N perhaps fall into approximate 1 be similar within 2 the scope.

The present invention also utilizes " broadband " fine setting tuning, wherein the Free Spectral Range of one of calibrator 24,26 definition usually with in the corresponding a plurality of transmission crests of choosing wavelength that pass the elm grid, and other calibrator has a Free Spectral Range, makes this spectral region only define the single transmission crest that transmits within the grid.The tuning permission of calibrator 24,26 adopts a plurality of transmission crest selectivity by other calibrator definition to aim at the single transport crest of one of many calibrators.

In the operation of equipment 10, light beam 19 leaves the plane 16 of gain media 12, through calibrator 24,26, reflects from tail end speculum 14, and turns back to gain media 12 via calibrator 24,26.Difference in the Free Spectral Range 24,26 causes above-mentioned single associating the by calibrator 24,26 definition to pass the elm crest, and the wavelength glazing of joint transmission crest returns or turns back to gain media 12 from calibrator 24,26, so that the laser action of equipment 10 is provided at joint transmission crest wavelength.Simultaneously, the parallel tuning of each calibrator 24,26 causes at its Free Spectral Range FSR _jPerhaps mould intrinsic displacement or tuning joint transmission crest P _jEach crest P _jDifferential tuning mould or the transmission crest P of causing ₁And P ₂Between the displacement of fine setting beat, with actually greater than FSR _jA scope on wavelength shift is provided.Equipment 10 can provide fast offset tuning between the broad separate wavelengths like this.

In 10 operating periods of laser apparatus, the tuning of the joint transmission crest of calibrator 24,26 can be realized according to a specific group communication channel such as International Telecommunication Union's communication grid.A wavelength standard (not shown) is as a grid maker (grid generator), and perhaps other wavelength standard can be used in combination with equipment 10, and can be placed within the exocoel of equipment 10 or outside.Yet it is dynamic day by day or reconfigurable that dwdm system is actually, and the operation of the adjustable extemal cavity laser of fixed wave length grid is more and more undesirable.Laser apparatus 10 of the present invention can mode fixing not rely on wide wave-length coverage, the predetermined wavelength grid provides continuously, choosing wavelength is tuning, thereby allows the configuration more fast of dwdm system.

The needs that carry out mechanical tuning at present at the grating adjustable extemal cavity laser have been eliminated in the use that is used for the two hot light adjustable marker 24,26 that the wavelength of outside cavity gas laser selects, because.It is solid-state that thermo-optical tunability is actually, thereby allow the enforcement compacter than situation possible in the grating tunable laser, and have tuning faster and corresponding time, the mode coupling efficient to shaking and vibrate better impedance and increasing.Tuning providing than single adjustable marker used the better laser tuning of the laser tuning that can realize with the static calibration device in the time of two adjustable marker.

Two uses of adjustable marker simultaneously of the present invention provide the substantial advantage that surpasses based on the laser tuning mechanism of single adjustable marker or other single adjustable element.An important advantage is to have simplified the calibrator manufacturing.The use of two (perhaps more) adjustable markers that wavelength is selected allows the structure of reflection cover layer (below further specify) simpler, and the bigger tolerance that is used for substrate defects is provided.Therefore this simple cover layer allows the wider bandwidth of tuner operation usually than required thinner of single tuning calibrator.

The fine setting of adopting two or more adjustable marker of the present invention to carry out is tuning, compares with the possible situation of using single adjustable marker, has the advantage that allows thermo-optical tunability on littler operating temperature range.This lower integrated operation temperature has reduced above-mentioned undesirable convection effect, has reduced power consumption, and has avoided the temperature dissipation effect that raises in many calibrator materials when material heats on than large-temperature range or cools off.This dissipation raises perhaps from following variation: the release of thermal excitation free carrier changed when the stress that the material thermo-optical coeffecient changes, the variation of the material coefficient of thermal expansion is brought out or the variation of strain and temperature raise.For example, when tuning required high-temperature because of calibrator in thermal excitation free carrier when causing excessive loss, the thermo-optical tunability of single calibrator element can only provide wavelength tuning according to the needs of large-temperature range on the finite bandwidth scope.

The available heat magic eye need carry out the calibrator material or represent the selection of the material of good thermo-optic effect (promptly varying with temperature the material that big variations in refractive index is provided).High index of refraction and high-temperature sensitivity material will provide about the available work temperature range of adjustable marker than wide tunable range.High-index material also provides effective angle tuning, and the high index of refraction of calibrator material helps to suppress thermal gradient and allows tuning faster and better temperature control.Suitable thermal coefficient of expansion makes calibrator material heating and cooling that the increase or the minimizing of calibrator physical thickness are provided, and this thermal coefficient of expansion also helps thermo-optical tunability.

Semi-conducting material such as Si, Ge and GaAs have represented the high-temperature sensitivity and the high thermal diffusivity of higher refractive index, refractive index, thereby provide good calibrator material for the adjustable embodiment of hot light of the present invention.Many micro-fabrication technologies are effective to semi-conducting material, therefore the use of semiconductor calibrator material allows thermal control and other electric work can directly be integrated in the calibrator, and higher tuning precision, power consumption, assembly operation still less and the compacter enforcement of reduction are provided thus.Silicon has significant advantage as the calibrator material, and it has approximate 3.478 refractive index and approximate 2.62 * 10 at ambient temperature ^-6The thermal coefficient of expansion (CTE) of/° K.Silicon be disperse and have a group refractive index N _g=3.607.Here also have a large amount of silicon treatment technologies, with allow Thermal Control Element directly to be integrated on the silicon calibrator or within, as described below.

Thermal tuning via the silicon calibrator of a Free Spectral Range need increase or reduce the amount that equals λ/2 in calibrator optical path length OPL.The refractive index that optical path length OPL equals the calibrator material is long-pending with the physical thickness of crossing over calibrator or distance, i.e. OPL=nL, and wherein n is the refractive index of calibrator material, L is the physical distance of crossing over calibrator.Variation about the optical path length of temperature can be represented as:

$\frac{\mathrm{dOPL}}{\mathrm{dT}}=n\frac{\mathrm{dL}}{\mathrm{dT}}+L\frac{\mathrm{dn}}{\mathrm{dT}}$

Wherein T is temperature (° K), α=thermal coefficient of expansion (1/ ° of K), and

$\frac{\mathrm{dOPL}/\mathrm{dT}}{\mathrm{OPL}}=\frac{1}{L}\frac{\mathrm{dL}}{\mathrm{dT}}+\frac{1}{n}\frac{\mathrm{dn}}{\mathrm{dT}}=\mathrm{\α}+\frac{1}{n}\frac{\mathrm{dn}}{\mathrm{dT}}$

So the variation of optical path length Δ OPL can be expressed from the next:

$\mathrm{\ΔOPL}=\mathrm{\ΔT}\left(\frac{\mathrm{dOPL}}{\mathrm{dT}}\right)=\mathrm{OPL}(\mathrm{\α}+\frac{1}{n}\frac{\mathrm{dn}}{\mathrm{dT}})\mathrm{\ΔT}$

When temperature was 25 ℃, silicon had approximate 3.48 refractive index, therefore

$\mathrm{\α}+\frac{1}{n}\frac{\mathrm{dn}}{\mathrm{dT}}=49.2{\×10}^{-6}$

In 1500 nanometers, the silicon calibrator of 100 micron thickness on λ/2=750 nanometer wavelength range tuning,

$\mathrm{\ΔOPL}=\mathrm{OPL}(\mathrm{\α}+\frac{1}{n}\frac{\mathrm{dn}}{\mathrm{dT}})\mathrm{\ΔT}$

Be equivalent to (3.48) (0.0001m) (49.2 * 10 ^-6/ ° K) (Δ T), perhaps 43.8 ° of K of Δ ≈.

This is equivalent to about 20 ℃-64 ℃ temperature range again, and changing temperature range can be provided by commercial Thermal Control Element.

Referring to Fig. 3, hot light adjustable marker is to the 44 tuning uses that are configured to power letter reflector outside cavity gas laser.Calibrator comprises first calibrator 46 and second calibrator 48 that is positioned in the light beam 50 to 44. Calibrator 46,48 use that is associated with the laser external cavity (not shown) is as mentioned above with shown in Figure 1.The respective thickness of each layer of calibrator 46,48 shown in Figure 3 is for clarity sake extended, nor must show its yardstick.

First calibrator 46 comprises the 100 micron thickness silicon layers 52 that are arranged between wavelength (λ/4) the dielectric layer reflective mirror 54,56.Dielectric mirror 54 is shown as and comprises a pair of high index of refraction and low-refraction λ/4 layers 58,60, low-index layer 60 adjacent silicon 52.Dielectric mirror 56 comprises a pair of high index of refraction and low-refraction λ/4 layers 62,64, low-index layer 62 adjacent silicon 52 equally.Silicon layer 52 for example can comprise: traditional commercialization 100 micron thickness polished silicon wafers form deposition techniques quarter- wave layer 58,60,62,64 by the layer that steaming is crossed, sputter or other are traditional thereon.

In the described embodiment of Fig. 3, dielectric mirror 54,56 each only comprise single to λ/4 layer, although can use a large amount of this quarter-wave layers in other embodiments.Low- index layer 60,62 comprises silicon dioxide (SiO ₂), and high refractive index layer 58,64 comprises silicon.Various other height and low-index material are known in the field, and can select to be used for quarter-wave layer 58-64.Silicon has high index of refraction, and allows only to adopt in each dielectric mirror 54,56 single to the hot light adjustable marker of quarter-wave layer manufacturing than high sharpness.

Second calibrator 48 comprises the silicon layer 66 that is arranged on 102 micron thickness between quarter-wave (λ/4) the layer dielectric mirror 68,70.Dielectric mirror 68 comprises high index of refraction λ/4 layers 72 and low-refraction λ/4 layers 74, wherein low-index layer 74 adjacent silicon 52.Dielectric mirror 56 also comprises a pair of high index of refraction and low-refraction λ/4 layers 76,78, wherein low-index layer 62 adjacent silicon 66.In calibrator 48, silicon layer 66 is shown as the silicon wafer 80 that comprises one 100 micron thickness, and deposition two microns silicon covering layers 82 thereon, and 102 microns whole thickness is provided for layer 66.Silicon layer 82 and quarter-wave layer 72,74,76,78 can deposit via various traditional layer formation technology, as mentioned above.Low-refraction quarter-wave layer 74,76 is shown as and comprises SiO ₂, and high refractive index layer 72,78 is shown as silicon, but can substitute or exchange with other height and low-index material.Can in speculum 68,70, use the individual layer shown in the ratio to more height of quantity and low-refraction ripple layer.As mentioned above, use silicon to allow only to adopt list that the quarter-wave layer is had higher calibrator acutance as the high index of refraction quarter-wave layer.

The different-thickness of the center silicon layer 52,66 of calibrator 46,48 (100 microns to 102 microns) provides 2% difference in the Free Spectral Range of calibrator.Calibrator 46,48 is configured and is configured to provide the interior wavelength tuning of telecommunications band between approximate 1528 nanometers and approximate 1561 nanometers.Referring to Fig. 4, calibrator 46,48 definition are shown as a series of transmission crests or the order of series 1 and series 2 respectively, in the curve of Fig. 4, show wavelength on the trunnion axis, and show corresponding gain on the vertical axis.The Free Spectral Range of calibrator 46,48 differs δ FSR each other, to set up the fine setting distance, make the single coincide point of the biography elm crest of series 1 and series 2 appear at about 1525 and about 1575 nanometers between wave-length coverage within (surrounding above-mentioned telecommunications band).The crest coincide point of series 1 and series 2 is displayed on the wavelength of 1550 nanometers.The relation of series 1 between 1550 nanometers and 1575 nanometers (not shown among Fig. 4) and series 2 crest is approximately the mirror image that crest concerns between 1525 and 1550 nanometers shown in Figure 4.

Like this, calibrator 46,48 provides transmission on 1531 above-mentioned nanometers and the single wavelength in the telecommunications band between 1563.5 nanometers, and the associating Free Spectral Range that calibrator 46,48 provides has surpassed this wave-length coverage.International Telecommunication Union proposes the requirement of the channel isolation of approximate 0.4 nanometer or about 50GHz at present, and this requirement is easy to be achieved by the thermal tuning of calibrator 46,48.This channel isolation allows in the bandwidth range of current available optical fiber and fiber amplifier by simple optical fiber carrying 128 channels nearly.

On wide wave-length coverage, in the thermal tuning of calibrator 46,48, should make providing accurately tuning various additional considerations.Aspect two of the temperature controls of refractive index and refractive index, silicon have in the infrared band of above-mentioned telecommunications than high dispersive.Therefore yet the character of silicon is known, can draw and identify the dispersion in the thermal tuning of the calibrator 46,48 that is presented on any particular range of wavelengths, and make suitable tuning adjusting to compensate this dispersion.In addition, the refractive index of deposition silicon layer is different slightly with the refractive index of bulk silicon chip, and therefore in certain embodiments, the difference of this refringence must be paid attention in design aligners.

Fig. 5 shows about the single calibrator 46 and the single-pass of the calibrator 46,48 of alignment with figure and crosses plane wave transmission or response, and wavelength is displayed on the trunnion axis, and transmission is displayed on the vertical axis.As shown in Figure 5, be with (as shown in Figure 4) to have the spectral line width narrower by the series 1 of calibrator 46,48 and the coincidence of series 2 to pass elm uniting of 1550 nanometers foundation than the corresponding single transport tape of calibrator 46.

As implied above, micro-fabrication technology can allow tuber function directly is integrated on the calibrator.Referring to Fig. 6, shown the Thermal Control Element 86 on silicon calibrator 84 and the surface 88 that is positioned at calibrator 84 here.Shown Thermal Control Element 86 is that learnt from else's experience Thermal Control Element 86 is regulated the annulus of light beam (not shown) passages.Thermal Control Element 86 comprises a conductive material, and this material applied current heating is to provide above-mentioned thermo-optical tunability required variations in temperature to calibrator 84.Conductor 90,92 is electrically connected to the current source (not shown) with Thermal Control Element 86.Temperature monitoring device such as electro-hot regulator (not shown) can be integrated on the calibrator 86 or away from calibrator 86 and be provided with.

Thermal Control Element 86 and conductor 90,92 can 88 formation on the calibrator surface by lithoprinting and material deposition technique.For example, can be coated in the photoresist (not shown) on the surface 88 and form pattern, develop then to remove the photoresist of exposure according to the configuration of control element 86 and conductor 90,92.Then can be in the pattern that develops the deposited conductor material, and from sur-face peeling residue photoresist, so that Thermal Control Element 86 and conductor 90,92 to be provided, as shown in Figure 6.As selection, can be by pattern etching surface 88 corresponding to Thermal Control Element 86 and conductor 90,92, conductor material is deposited in the groove so that provide with respect to surperficial 88 recessed Thermal Control Element 86 and conductors 90.In another embodiment, Thermal Control Element 88 can comprise the transparent layer of being made by tin indium oxide (ITO) that passes to.Use known technology that the tracing of diffusion resistance and various configurations directly is formed into silicon calibrator 84.

Calibrator 86 can be installed in the framework (frame) 94.Framework 94 is equally by the silicon microfabrication, so the thermal coefficient of expansion of framework 94 and calibrator 86 is complementary.High thermal diffusivity in the framework 94 promotes or strengthens the symmetry of the temperature of calibrator 86, and prevents the inhomogeneous heating and cooling of stand-by period to calibrator 86.Framework 94 and calibrator 86 can be obtained from batch silicon materials or be obtained from the Different Silicon material.Framework 94 is convenient to the operation and installation of calibrator 86.Framework 94 also is convenient to the location of temperature probe 95 of the temperature of surveillance calibration device framework 94, and calibrator framework 94 serves as the accumulation of heat storehouse of the thermal control of calibrator 86.

Except above-mentioned thermo-optical tunability, the wavelength of two adjustable markers is selected can realize by mechanical angle is tuning equally.Angle tuning comprises with respect to the light beam rotation or the tilt calibration device that are passed through, with the phase difference of continuous reflection in increase or the reduction calibrator, thereby increases and reduce Free Spectral Range.Referring to Fig. 7, show inclination (milliradian) effect with figure here for the frequency change (hertz) of the thick silicon calibrator of 50GHz, zero wavelength that tilts is in approximate 1550 nanometers.The angle tuning of calibrator can use various traditional meticulous micropositions or translation (translation) device to realize, the accurate angle location of calibrator is provided for wavelength tuning.

By providing identical angle tuning to each of two calibrators in fact simultaneously, the continuous tuning of two calibrators of Fig. 1 allows the joint transmission crest of tuning calibrator within the associating Free Spectral Range that calibrator is stipulated.Differential angle tuning provides fine setting apart from interior displacement, is used for carrying out on the scope greater than the associating Free Spectral Range tuning.The high index of refraction of silicon provides good nargin for the angle tuning of calibrator, and the tuning of two silicon calibrators provides the effective wavelength on the wide wave-length coverage tuning.Other material with high index of refraction also can be used for the calibrator of adjustable angle.As mentioned above, in one or two calibrators, also can use the angle tuning of calibrator in conjunction with thermo-optical tunability.Can realize the tuning of calibrator in the following manner in addition or alternatively, these modes comprise: apply strain with change calibrator refractive index, to calibrator material injection current, perhaps apply electromotive force to change the calibrator refractive index to the calibrator surface, the variation that the calibrator optical path length perhaps can be provided is to allow calibrator of the present invention tuning any other phenomenon or effect.

For fear of the multi-mode laser effect phenomenon of utilizing two adjustable markers, calibrator can be configured to only to make simply connected to close the transmission crest to appear within the gain bandwidth for the gain media of calibrator use, as mentioned above.Although this requirement realizes easily, brought design limit concerning two calibrator.In certain embodiments, preferably has the 3rd adjustable marker, control wave-length coverage when it is used in execution by first and second adjustable markers tuning.Referring to Fig. 8, show a laser apparatus 96 here, wherein similar reference number is used to represent identical parts.This equipment comprises one the 3rd adjustable marker 98, and it and first and second calibrators 24,26 are used to the output wavelength of selection equipment 10 jointly by triple fine setting effects.Calibrator 98 comprises plane 100,102, and be similar to the material that calibrator 24,26 comprises the thermo-optical tunability that allows calibrator 98, be similar to calibrator 24,26, calibrator 98 can be alternatively or is undertaken tuning by angle or inclination, strain, electro optic effect or other mechanical tuning device or effect in addition.

Calibrator 98 is configured to suppress one or more fully by the joint transmission crests of calibrator to 24,26 foundation or definition.Be similar to calibrator 24,26, calibrator 98 is configured to set up a plurality of transmission crests fully in the gain bandwidth in chamber.By uniting use, three calibrators 24,26,98 only allow a joint transmission crest of three calibrators foundation to appear within the gain bandwidth in chamber.In certain embodiments, adjustable marker 98 can replace with traditional static interferometric filter such as bandpass filter, to allow to use the part of gain bandwidth.Yet this embodiment of use bandpass filter does not allow to select to use the different piece of the gain bandwidth that provides as equipment 96.

In the equipment 96 of Fig. 8, each of three calibrators 24,26,98 is coupled to public heat radiation or thermal storage device 104 with being operated. Calibrator 24,26,28 comprises Thermal Control Element 106,108,110 respectively, and these elements are to be integrated on the calibrator material in conjunction with the described mode of Fig. 6.Thermal Control Element 106,108,110 is coupled to controller 40 with being operated respectively, and controller 40 provides the selection wavelength control by selecting heating or cooling via element 106,108,110.Control element 106,108,110 provides the independent temperature control of calibrator 24,26,98 respectively, and thermal storage device 104 allows calibrator 24,26,98 to readjust fast on the basal temperature that is defined by thermal storage device 104 by conduction.

Being used for the use that the present invention finely tunes tuning two adjustable elements can realize by the various adjustable elements that are different from calibrator.Referring to Fig. 9, show a double grating tunable laser equipment 112 here, wherein represent similar parts with similar reference number.Equipment 112 comprises first and second gratings 114,116 that are placed on the light path 22 and carry out reflective operation.Grating 114,116 provides diffraction to light beam 119, causes the joint transmission crest of aforesaid way with the combination diffraction effect of grating 114,116.The output wavelength of the wavelength of joint transmission crest and the equipment that brings thus 112 can be by grating 114,116 rotation and/or translation locate and regulate.

Grating 114,116 continuously or parallel tuning (wherein grating 114,116 places the speed of essentially identical rotation and/or translation simultaneously) displacement of joint transmission crest of grating 114,116 or tuning is provided in the combined spectral scope of grating 114,116.In fact the differential rotation of grating and/or translation provide tuning greater than on the wave-length coverage of associating Free Spectral Range.Various traditional positioners and system are public, thereby provide the peaceful transposition of accurate rotation of grating 114,116 humorous for the wavelength tuning of equipment 112.

Grating 114,116 is shown as two reflective operation in Fig. 9.In other embodiments, one or two of grating 114,116 can be used for transmission, rather than reflection.At the embodiment that two gratings are used for transmitting, tail end speculum (not shown) is positioned in the grating light path 22 afterwards.

Referring to Figure 10, the figure shows another laser apparatus 118 of the present invention, wherein identical reference number is represented parts in the same manner.The double tunning element is set in the equipment 118 with as calibrator 24 and grating 114.Calibrator 24 can be regulated by thermo-optical tunability, angle tuning and/or other tuning effect.Grating 114 can be undertaken tuning by rotation; Perhaps also can fix and arrange mobile tail end speculum 14, provide tuning by grating 114 according to traditional Littman-Metcalf.Calibrator 24 and the above-mentioned joint transmission crest of grating 114 common definition are via continuous tuning tuning this joint transmission crest within the associating Free Spectral Range of calibrator 24 and grating 114 qualifications of calibrator 24 and grating.The differential tuning fine setting displacement that the wavelength tuning of going up in a big way is provided of calibrator 24 and grating 114, as mentioned above.

Can select to can be used for finely tuning tuning various other wavelengthtunables and select element.For example, also can use for the present invention by taper calibrator and the taper interferometric filter of regulating with respect to the beam center translation, the U.S. Patent application 09/814,464 of 21 propositions in March calendar year 2001 discloses the technology of this respect, and the disclosure is quoted as a reference.Also can in the disclosure scope, consider to be used for the use of this tuning other adjustable element of class of fine setting of the present invention.

Referring to Figure 11 A, the figure shows another outside cavity gas laser equipment 120 of the present invention, the wherein similar similar parts of reference number representative.Equipment 120 comprises from anti-reflective coating layer plane 16 gain media 12 of speculum 14 emission light beams 19 caudad, and wherein adjustable marker 12 is positioned in the light beam 19 after the tail end speculum 14.The above-mentioned outer laser cavity 124 of plane 18 common qualifications of tail end speculum 14 and gain media 12.Calibrator 122 changes its optical path length OPL and changes Free Spectral Range thus by electro optic effect is tuning, and comprises the zone or the layer 126 of electrooptical material.Apply the variations in refractive index that electromotive force will cause layer 126 via the transparency electrode (not shown) to layer 126 surface, change the optical path length and the Free Spectral Range of calibrator 122 thus.Tail end speculum 12 is shown as partial reflection, so light beam 19 leaves speculum 14 and can be coupled in the optical fiber (not shown).

In equipment 120, exocoel 124 serves as second adjustable element, and it and adjustable marker 122 provide laser fine setting of the present invention tuning double tunning element jointly.In other words, tail end mirror 14 and gain media surface 18 limits a calibrator.Thus, tail end speculum 14 or exocoel usually can be tuning by other mechanism of machinery, heat, electric light or control chamber length.Be applied to the optical path length of the voltage change exocoel 124 on the layer 128.Feed back the wavelengthtunable selection that is provided for equipment 120 to the combination of gain media 12 from adjustable marker 122 and exocoel 124.

Referring to Figure 11 B, laser external cavity 124 has a Free Spectral Range FSR who limits a plurality of moulds or biography elm crest 130 _CavityAs shown in the figure, per the 4th exocoel transmission crest is perhaps aimed at it corresponding to selecting transmission channel 132,134,136,138,140,142.Channel 132-142 can be corresponding to the wavelength channel of above-mentioned ITU grid.The Free Spectral Range FSR of exocoel 124 _CavityFree Spectral Range FSR with calibrator _EtalonFollowing relational expression can be arranged:

K(FSR _Etalon)≈(M/M±N)(FSR _Cavity)

Wherein K is a rational fraction, and M selects the interior wavelengthtunable of wave-length coverage or the sum of transmission channel for use, and N is can be according to the non-integer or the integer of different embodiments of the invention selection.Referring to Figure 11 C, the tuning ITU channel grid that is used for K=3 that is shown as of the fine setting of outside cavity gas laser 120 is for each displacement of fine setting distance provides tuning translation on each the 3rd exocoel mould crest.

Shown in Figure 11 C, calibrator 122 definition are by FSR _EtalonThe a plurality of transmission crest P that separate _EtFigure 11 C has shown six different tuning configuration A, B, C, D, E and F that are used for calibrator 122 and exocoel 124, and its each wavelength of corresponding respectively on each of channel 132-142 is selected.Additional optional channel (not shown) is present between each channel 132-1.42.Like this, at tuning adjusting A place, single calibrator transmission crest P _EtAim at the chamber mould crest 130 on the channel 142, shown in Figure 11 C, channel 142 is corresponding to the wavelength of 1563.5 nanometers.Other calibrator transmission crest P on the tuning A _EtDo not aim at any chamber mould 130.At tuning adjusting B place, single calibrator transmission crest P _EtAim at the chamber mould crest 130 on the channel 140.Equally, on tuning configuration C, D, E and F, calibrator transmission crest P _EtAim at chamber mould crest respectively corresponding to channel 138,136,134 and 132.The differential tuning displacement that the fine setting distance is provided of exocoel 124 and calibrator is to provide the tuning A-F shown in Figure 11 C.Above-mentioned parallel tuning permission is fine tuning more, thereby realizes the channel selection in the scope between the tuning A-F of each shown in Figure 11 C.

Referring to Figure 12 A to Figure 12 C, shown another embodiment of outside cavity gas laser equipment 144 here, the wherein similar similar part of label representative.Equipment 144 is micro electronmechanical or microelectronics mach (MEMS) device, is made by monolithic semiconductor substrate 146.Substrate 146 comprises the groove 148 that holds gain media 12, holds the groove 150 of taper calibrator 152 and holds the groove 153 of tail end reflective mirror 14, has electrooptic cell 128 on it.The material of substrate 146 is transparent on gain media 12 whole gain bandwidths, and from the light beam 19 of the planar transmit of gain media 12 through substrates 146.

Taper or wedge collimator 152 are used to be presented to distance between the local reflex plane of the thickness of calibrator 152 of light path 22 or calibrator 152, selective channel between a plurality of communication channels by change.This can be by along vertical or be basically perpendicular to the direction translation of light path 22 or drive calibrator 152 and realize.When calibrator 152 advanced or move in the light path 22, the light beam of propagating along light path 19 was through calibrators 152 thickness portion gradually, this gradually thickness portion support the constructive interference of 154,156 of opposite faces on the longer-wavelength channels.When calibrator 152 left light path 22, light beam 16 will be through the gradually thin part of calibrator 152, and exposed passbands or transmission crest to light path 22, with the wavelength channel of supporting to shorten gradually.

Calibrator 152 is connected in the substrate 146 by flexible arm or hinge element 158,160.Hinge element 158,169 is supported the calibrator 152 in the groove 150 of substrate 146 movably.Calibrator 152 also connects a plurality of electrode pieces 162.The a plurality of electrode pieces 164 that connect substrate 146 are staggered between electrode 162.Electrode 162,164 is placed in the groove 150 of substrate 146.Electric contact 166 is via conductor path 168 electrode electrically connecteds 162, and electric contact 170 is via conductor path 172 electrode electrically connecteds 164.Change the voltage on the electrode 162,164, thereby drive or translation electrode 162 with respect to electrode 164.This action correspondingly drives or translation calibrator 152 with respect to light path 22.

In equipment 144 operation, by with respect to the tuning calibrator 152 of the translation of light path 22 changing Free Spectral Range, thereby change the relation of the biography elm crest that limits by calibrator 152.Figure 12 B has shown the calibrator 152 of locating according to the thinnest part mode within the light path 22 that is positioned in that makes the calibrator 152 between the plane 154,156, and Figure 12 C shows according to making approaching of calibrator 152 partly be positioned in the calibrator 152 that the modes in the light path 22 are located.As mentioned above, calibrator 152 is realized by via contact 166,170 and conductor path 168,172 selectivity staggered electrode 162,164 being applied voltage with respect to the location of light path 22.Hinge element 158,160 is according to the location warpage or the bending of calibrator 152.

The surface 174,176 of the groove 150 of contiguous calibrator 152 can scribble anti-reflecting layer, and the whole tuning effect of calibrator 152 itself is provided by calibrator 152.In other embodiments, the surface 174,176 can be local reflex, makes the combination feedback on the surface 174,176 of tuning surface 154,156 that is obtained from calibrator 152 and groove 150, selects to realize wavelength.At calibrator 152 stand-by periods, can also by apply to electrooptic cell 128 selectivity voltage it is carried out tuning, to change exocoel path optical path length 124.Therefore, can realize in the manner described above, use the biography elm crest of calibrator 152 definition and the fine setting carried out jointly corresponding to the transmission crest of exocoel mould tuning.

MEMS equipment 144 can adopt the already known semiconductor materials treatment technology to make.Calibrator 152, hinge element 158,160 and electrode piece 162,164 adopt with calibrator 152 and substrate 146 identical materials and make, and by the micro-cutting processing of substrate 144 semi-conducting materials, from substrate 146 definition calibrator 152, hinge element 158,160 and electrode pieces 162,164.The use that is used for the staggered electrode of MEMS parts action is a known technology, and be disclosed in author that ArtechHouse company (Norwood MA (2000)) published in " Introduction to Microelectromechanical SystemsEngineering " literary composition of Nadim Maluf, the disclosure is quoted as a reference.Gain media 12 can comprise the separator that is installed in the groove 148, and groove 148 forms after to substrate 146 machine works.

Above-mentioned various outside cavity gas laser equipment utilizations the double tunning element of serial location or configuration.Also can use tuned cell, come tuning outside cavity gas laser of the present invention by parallel rather than serial.Referring to Figure 13 A, shown outside cavity gas laser equipment 178 here, wherein similar reference number is used for representing similar parts.Equipment 178 comprises along the gain media 12 of light path 22 from antireflecting coating planar transmit light beam 19.Polarizing beam splitter/optical combiner (combiner) 180 is positioned in the light path 22, make 182 pairs of light beam 19 beam split of local reflex layer of beam splitter 180, make light beam 19a propagate into tail end reflector 14a, and make light beam 19b reflex to tail end reflector 14b along light path 22b along light path 22a.Tail end reflector 14a can be local reflex, so that the part of light beam 19a passes through, and it can be collected as the light of equipment 178 outputs.The back plane 18 of gain media can or be replaced in addition possesses partial reflection, so that can settle optical fiber 184 to receive the light of output thus.

First wavelengthtunable selects element 186 to be positioned among the light path 22a between optical splitter 180 and the tail end reflective mirror 14a, and second wavelengthtunable selection element 188 is positioned among the light path 22b between optical splitter 180 and the tail end reflective mirror 14b.Adjustable element 186,188 can comprise grating, calibrator, interferometric filter, and perhaps other and above-mentioned relevant wavelengthtunable choice device can drive or tuning MEMS according to other above-mentioned mechanism.In the embodiment shown in Figure 13 A, adjustable element 186 is solid-state calibrators, can carry out tuning according to hot light, electric light, other mechanically actuated or above-mentioned mechanical tuning devices.Second adjustable element 188 is adjustable air gap calibrators, is elaborated below.From calibrator 186,188 along light path 22a, 22b to optical splitter/optical combiner 180 combination feedback, thereby be to provide adjustable feedback from the feedback of optical splitter/optical combiner to gain media 12 along light path, it is used to provide wavelength and selects.

Calibrator the 186, the 188th, exercisable, so that provide fine setting of the present invention tuning.Figure 13 B figure shows a kind of so tuning form of finely tuning, and wherein first calibrator 186 has a plurality of biography elm crest P of qualification ₁The first Free Spectral Range FSR ₁, second calibrator 188 has a plurality of transmission crest P of qualification ₂The second Free Spectral Range FSR ₂The second Free Spectral Range FSR ₂Differing on amplitude with first Free Spectral Range can be according to an amount of the selection of configuration of calibrator 186,188.Transmission crest P ₂Be shown as the center that is positioned at choosing wavelength channel 190,192,194,196,198 and 200, these channels can be corresponding to the channel of above-mentioned ITU grid.Tuning configuration A, the B of Figure 13 B, C, D, E, F are corresponding to the tuning configuration of different calibrators, and its each configuration is one of them selection of channel wavelength 190-200.Like this,, regulate calibrator 186,188, make crest P for example at tuning A ₁With crest P ₂Aim at, the transmission on the choosing wavelength channel 200 is provided, in the particular instance of Figure 13 B, this channel 200 is shown and is positioned at 1563.5 nanometers.Crest P does not appear in the scope of choosing wavelength channel 190-200 ₁With crest P ₂Other aligning.Tuning relation B has realized the crest P of wavelength 198 ₁With crest P ₂Single aligning.Equally, tuning C, D, E, F show the crest P on channel wavelength 196,194,192 and 190 respectively ₁With crest P ₂Aligning.

The differential tuning of calibrator 186,188 provides fine setting apart from the ground displacement, so that the tuning A-F shown in Figure 13 B to be provided.The above-mentioned parallel tuning permission interior channel of scope between each the tuning A-F shown in fine tuning realization Figure 13 B is selected.In the embodiment shown in Figure 13 A and Figure 13 B, tail end reflective mirror 14a, 14b are positioned as and make exocoel mould crest P _ECBe presented on each of choosing wavelength channel 190-200, and make an exocoel mould crest P _ECBe positioned between each of choosing wavelength channel 190-200.Exocoel by tail end reflective mirror 14a and/or tail end reflective mirror 14b definition can use above-mentioned technology to regulate, so that change exocoel mould crest P when needing _ECRelation with the choosing wavelength channel.

Referring to Figure 14 A and Figure 14 B, shown an adjustable air gap calibrator (-ter) unit 188 of the present invention here.Calibrator (-ter) unit 188 is shown as with the single semiconductor-based ends 202 making of determining greatly.Solid-state calibrating element 204 connects four flexible arms 206, and this flexible arm connects pedestal 208 again.Pedestal 208 is installed in the substrate 202.Substrate 202 is also supported plane electrode portion 210 by support 211 (as shown in Figure 14B), and electrode part 210 is separated with calibrating element 204 and be parallel.Calibrating element 204 and electrode part 210 first air gap 212 of being separated by is with substrate 202 interstice 214 of being separated by.Electrode part 210 and calibrating element 204 are configured to potential difference to be applied to electrode part 210 and calibrating element 204 respectively.Change potential difference and can control the position of calibrating element 204 with respect to electrode member 210, thus the yardstick of control air gap 212,214.The surface 216 of calibrating element 204 can become mirror image with the surface 218 of substrate 202, makes the adjustable air gap calibrator that air gap 214 serves as can provide feedback to the gain media 12 that is used for the wavelength selection.

In other embodiments, can comprise a conductor (not shown) on the surface 218 of substrate 202, to allow current potential to regulate and to carry out Position Control with respect to 202 pairs of calibrating elements of substrate 204.In addition, the surface 220,222 of calibrating element 204 and electrode part 210 can be become mirror image by the part respectively, makes air gap 212 serve as the adjustable air gap calibrator.

Illustrate in more detail as Figure 15, also can use, wherein show another example of outside cavity gas laser equipment 224 of the present invention, the similar here similar parts of reference number representative at the parallel mode that single birefringence wavelength is selected to realize adjustable element in the element.Equipment 24 comprises gain media 12, and it has one first anti-reflective coating layer plane 16 and one second reflection or local reflex plane 18.Plane 16 is along light path reflective mirror 14 emission light beams 19 caudad, and tail end reflective mirror 14 and plane 18 be common to limit above-mentioned exocoel.Tail end reflective mirror 14 is shown as local reflex, enters the optical fiber (not shown) as output so the part of light beam 19 can be left speculum 14 and be collected.

Birefringence calibrating element 226 is positioned in tail end speculum 14 light path 22 before.Calibrating element 226 can comprise provides high level birefringent liquid crystal material.Can use various all even inhomogeneous nematics and smectic crystal.On the surface of the calibrator 226 shown in the alignment 228,230 that can comprise the polyimide of grinding is comprised in, so that the aligning of each liquid crystal molecule (not shown).Transparency electrode 232,234 is adjacent to alignment 228,230, to allow applying voltage on calibrator 226.

Birefringence calibrating element 226 has different refractivity along different optical axises.In Figure 15, first common optical axis 236 (dotted line) has refractive index n ₀, the second special optical axis 238 (solid line) has refractive index n _e, n wherein _e＞n ₀These optical axises are with respect to polarization axle rotation 40 degree of laser.Polarised light effectively is divided into along the multi beam separating light beam of the optical axis of birefringence calibrator.The optical thickness of the calibrator 226 on the primary optic axis 236 has Free Spectral Range FSR _e, and the optical thickness of the calibrator 226 on second optical axis 238 has Free Spectral Range FSR ₀, because the different refractivity that presents in the birefringence calibration materials, so FSR _eBe not equal to FSR ₀In other words, " e " light experiences different optical path lengths with " o " light light path 236,238 respectively on the same physical thickness of calibrator 226, because refractive index n _eWith n _oBetween there are differences.

On electrode 232,234, select to apply voltage and/or the adjusting of calibrator 226 directional inclinations, allow to provide fine setting of the present invention tuning mode independent regulation FSR _eAnd FSR _oJust, different Free Spectral Range FSR _eAnd FSR _oCause two groups of transmission crest P _eAnd P _o(not shown), these the two groups positions of transmission crest scalable to select the control crest to overlap, thus provide fine setting tuning in the above described manner.The FSR of fine setting apart from displacement is provided _eAnd FSR _oDifferential tuning, and provide wavelength tuning in the Free Spectral Range FSR _eAnd FSR _oParallel tuning, can be by on calibrator 226, applying voltage to change refractive index n _eRealize.In addition, perhaps, can change FSR by tilt adjustment or thermal conditioning calibrator 226 as selecting _o, to provide differential and parallel tuning.Therefore, single birefringence calibrator 226 provides and the identical effect of two adjustable markers of using the foregoing description.

Referring to Figure 16, shown another outside cavity gas laser equipment 240 here, wherein similar reference number is represented similar parts.Equipment 240 comprises along light path 22 from the anti-reflective coating layer plane the caudad gain media 12 of speculum 14 emission light beams 19, tail end speculum 14 and the aforesaid outer laser cavity 124 of plane 18 common definition.The first and second adjustable adjustable markers 242,244 are positioned within the exocoel 124 between gain media 12 and the tail end reflective mirror 14.In this embodiment, calibrator 242 comprises above-mentioned hot luminescent material, and the hot light control element (not shown) that is arranged to by the above-mentioned type carries out thermo-optical tunability.Calibrator 242 is operatively coupled to controller or tuner 40.Second calibrator 244 comprises electric light calibrator material and has in its surface transparency electrode 246,248, is used for the refractive index (thereby control calibrator optical path length) according to the voltage Selective Control calibrator 244 that applies on the calibrator 244.Calibrator 244 can also operatively be coupled to tuner 40.

The exocoel 124 that plane 18 and tail end reflector 14 limit provides the 3rd adjustable element in the equipment 240.Just, tail end reflective mirror 14 and gain media plane 18 limit adjustable marker, and the location has a part or the layer 128 that voltage relies on the electrooptical material of refractive index in chamber 124.On layer 128, apply the optical path length that voltage has changed exocoel 124 by the electrode (not shown).Provide wavelengthtunable to select via equipment 96 described triple fine setting effects to equipment 240 from the combination feedback of adjustable marker 242,244 and 124 pairs of gain media 12 of adjustable extemal cavity in conjunction with Fig. 8.

Adjustable extemal cavity 124 and the common use of two adjustable markers 242,244 have reduced the acutance requirement of transmission crest of the calibrator 242,244 of the transmission crest that is used to suppress corresponding with not selecting wavelength for use.This has increased the tolerance of calibrator 242,244 again, and has simplified calibrator 242.The character of 244 lip-deep local reflex coatings, this is very desirable for some embodiment of the present invention.Therefore, in equipment 240, the acutance of the joint transmission crest (not shown) that the transmission crest group of calibrator 242,244 is limited may be not enough to provide during laser operation to not selecting effective inhibition of channel wavelength for use.Yet the additional optical filtering that triple fine setting effects of regulating via electrooptic cell 128 by exocoel 124 provide allows exocoel mould (not shown) to aim at selected channel, thereby adopts the adjustable marker of fairly simple configuration to provide effective fine setting tuning.

Have three wavelengthtunables and select the outside cavity gas laser equipment of elements to can be embodied in the MEMS device shown in the equipment 250 of Figure 17 A to Figure 17 C, wherein similar reference number is represented similar parts.Equipment 250 usefulness monolithic semiconductor substrates 146 are made.Substrate 146 comprises: hold the groove 148 of gain media 12, hold the groove 252 of first adjustable marker 242, hold the groove 150 of second adjustable marker 152 and hold the groove 153 of tail end reflective mirror 14, this reflective mirror has electrooptic cell 128.The material of substrate 146 is transparent on the gain bandwidth of whole gain media 12, and from the 19 process substrates 146 of gain media 12 emitted light beams.

Calibrator 152 forms above-mentioned wedge shape or conical in shape, and be used for changing in the above described manner the distance between the local reflex plane 154,156 of the thickness of the calibrator 152 that is presented on the light path or calibrator 152, carry out the selection between a plurality of communication channels.Calibrator 152 is connected to substrate 146 by flexible arm or hinge element 158,160, and described hinge element is supported the calibrator 152 in the groove 150 of substrate 146 movably.According to above-mentioned voltages via electric contact 166,170 and conductor 168 and 172 introducings, aforesaid interaction takes place with a plurality of electrode pieces 164 that are connected substrate 146 in the electrode piece 162 of a plurality of connection calibrators 152, the selectivity of the voltage on the electrode 162,164 is changed and driving or translation electrode 162, it is moved, so calibrator 152 drives or translation with respect to light path with respect to electrode 164.

Figure 17 B has shown the calibrator 152 of locating according to the thinnest part mode on the light path 22 that is positioned in that makes the calibrator 152 between plane 154 and 156, and Figure 17 C illustrates according to the calibrator 152 of locating than the thickness portion mode on the light path 22 that is positioned in that makes calibrator 152 between plane 154 and 156.Can there be antireflecting coating on the surface 174,176 that is adjacent to the groove 150 of calibrator 152, makes calibrator 152 that the whole tuning effect of calibrator 152 is provided self.In other embodiments, the surface 174,176 can be local reflex, makes the combination feedback on the surface 174,176 of tuning surface 154,156 that is obtained from calibrator 152 and groove 150, selects to realize wavelength.Stand-by period at calibrator 152, electrooptic cell 128 can also be tuning by via the contact its selectivity being applied voltage in the manner described above, be used for the tuning exocoel of triple fine settings footpath optical path length 124 with change, these triple fine settings are tuning have been utilized by the transmission crests of calibrator 242 and 152 definition and corresponding to the transmission crest of exocoel mould.

Although the present invention is illustrated in conjunction with specific embodiment, those skilled in the art will appreciate that under the condition that does not deviate from spirit and scope of the invention, can make various modifications and be equal to alternative the present invention.In addition, can carry out various changes, so that particular case, material, material are synthetic, processing, operation are adapted to theme of the present invention, spirit and scope.All these type of modifications all mean within the scope that falls into claims.

Claims (54)

1. magic eye equipment comprises:

(a) one first wavelengthtunable is selected element, is arranged in light beam and has the first adjustable Free Spectral Range; With

(b) one second wavelengthtunable is selected element, is arranged in light beam and has the second adjustable Free Spectral Range;

(c) described first and second wavelengthtunables select element to be configured to define an associating Free Spectral Range that can be used for tuning described light beam.

2. equipment according to claim 1, wherein said first and second wavelengthtunables select element to limit the joint transmission crest that can select the tuning adjusting of element according to described first and second wavelengthtunables.

3. equipment according to claim 1 also comprises a gain media, has first and second planes and launch described light beam from described first plane, and described gain media has a Free Spectral Range.

4. equipment according to claim 3, wherein said associating the Free Spectral Range gain bandwidth with described gain media at least are big equally.

5. equipment according to claim 3, wherein said first Free Spectral Range are approximately equal to a multiple of described gain media Free Spectral Range.

6. equipment according to claim 5, wherein said second Free Spectral Range are approximately equal to a multiple of described gain media Free Spectral Range.

7. equipment according to claim 3 also comprises a reflecting element that is positioned in the first and second wavelengthtunables selection element described light beam afterwards, and described second plane of described reflecting element and described gain media limits an outside cavity gas laser.

8. equipment according to claim 1, wherein said first and second wavelengthtunables select element to comprise a calibrator at least.

9. equipment according to claim 1, wherein said first and second wavelengthtunables select element to comprise a grating at least.

10. equipment according to claim 1, wherein said first and second wavelengthtunables select element to comprise first and second calibrators.

11. equipment according to claim 10, at least one calibrator of wherein said first and second calibrators is a thermo-optical tunability.

12. equipment according to claim 10, at least one calibrator of wherein said first and second calibrators is an electro-optical tuning.

13. equipment according to claim 10, at least one calibrator of wherein said first and second calibrators is an angle tuning.

14. equipment according to claim 10, wherein at least one described calibrator comprises semi-conducting material.

15. equipment according to claim 10, wherein at least one described calibrator comprises first and second surfaces, and each described surface has at least one quarter-wave dielectric disposed thereon to layer.

16. equipment according to claim 14, wherein said calibrator comprises the Thermal Control Element that is integrated thereon.

17. equipment according to claim 11, wherein said calibrator operationally are coupled to a heat controller.

18. equipment according to claim 11, wherein said calibrator operationally are coupled to a thermal storage device.

19. a tuner that is used for light beam comprises:

(a) one first wavelengthtunable is selected element, is arranged in described light beam, and described first adjustable element is configured to limit more than first transmission crest; With

(b) one second wavelengthtunable is selected element, is arranged in described light beam, and described second adjustable element is configured to limit more than second transmission crest; With

(c) the single joint transmission crest within chosen wavelength range of described more than first and second transmission crest definition; With

(d) described first and second wavelengthtunables select element to can be used for regulating described joint transmission crest according to the adjusting of described first and second adjustable elements.

20. equipment according to claim 19 also comprises a gain media, described gain media has first and second planes and launch described light beam from first plane, and described gain media has a Free Spectral Range.

21. equipment according to claim 20 also comprises a reflecting element that is positioned in the first and second wavelengthtunables selection element described light beam afterwards, described second plane of described reflecting element and described gain media limits an outside cavity gas laser.

22. equipment according to claim 20, wherein said first wavelengthtunable select element to have first Free Spectral Range of a multiple that is approximately equal to described gain media Free Spectral Range.

23. equipment according to claim 20, wherein said second wavelengthtunable select element to have second Free Spectral Range of a multiple that is approximately equal to described gain media Free Spectral Range.

24. equipment according to claim 20, wherein said associating the Free Spectral Range gain bandwidth with described gain media at least are big equally.

25. equipment according to claim 19, wherein said first and second wavelengthtunables select element to comprise a calibrator at least.

26. equipment according to claim 19, wherein said first and second wavelengthtunables select element to comprise a grating at least.

27. equipment according to claim 19, wherein said first and second wavelengthtunables select element to comprise first and second adjustable markers.

28. equipment according to claim 27, at least one of wherein said first and second adjustable markers is thermo-optical tunability.

29. equipment according to claim 27, at least one of wherein said first and second adjustable markers is electro-optical tuning.

30. equipment according to claim 27, at least one of wherein said first and second adjustable markers is angle tuning.

31. equipment according to claim 27, wherein at least one described adjustable marker comprises semi-conducting material.

32. equipment according to claim 27, wherein at least one described adjustable marker comprises first and second surfaces, and each described surface has at least one quarter-wave dielectric disposed thereon to layer.

33. equipment according to claim 31, wherein said adjustable marker comprise a Thermal Control Element that is integrated thereon.

34. equipment according to claim 28, wherein said adjustable marker operationally are coupled to a heat controller.

35. equipment according to claim 28, wherein said adjustable marker operationally are coupled to a thermal storage device.

36. a laser apparatus comprises:

(a) gain media of an emission light beam;

(b) one first wavelengthtunable is selected element, is arranged in described light beam and has the first adjustable Free Spectral Range;

(c) one second wavelengthtunable is selected element, is arranged in described light beam and has the second adjustable Free Spectral Range; With

(d) described first and second wavelengthtunables are selected single joint transmission crest within a chosen wavelength range of element definition, and described single joint transmission crest can select the tuning of element to come homophase to regulate according to described first and second wavelengthtunables.

37. equipment according to claim 36, wherein said associating the Free Spectral Range gain bandwidth with described gain media at least are big equally.

38. according to the described equipment of claim 37, wherein said first Free Spectral Range is approximately equal to a multiple of the Free Spectral Range of described gain media.

39. according to the described equipment of claim 38, wherein said second Free Spectral Range is approximately equal to a multiple of the Free Spectral Range of described gain media.

40. a method that is used for tuning light beam comprises:

(a) select element to be positioned in the described light beam first wavelengthtunable, described first wavelengthtunable selects element to have the first adjustable Free Spectral Range; With

(b) select element to be positioned in the described light beam second wavelengthtunable, described second wavelengthtunable selects element to have the second adjustable Free Spectral Range;

(c) from first and second Free Spectral Ranges, limit an associating Free Spectral Range; With

(d) select element to regulate described associating Free Spectral Range by tuning described first and second wavelengthtunables.

41. according to the described method of claim 40, the described associating Free Spectral Range of wherein said qualification comprises the single joint transmission crest that limits within the chosen wavelength range.

42. according to the method for claim 41, the described associating Free Spectral Range of wherein said adjusting comprises regulates described joint transmission crest.

43., also comprise according to the described method of claim 40:

(a) provide a gain media with first and second planes;

(b) the described light beam of emission from described first plane; With

(c) reflecting element is positioned at described first and second wavelengthtunables and selects in the element described light beam afterwards, described second plane of described reflecting element and described gain media limits an outer laser cavity.

44. according to the described method of claim 43, the wherein said associating Free Spectral Range gain bandwidth with described gain media at least is big equally.

45. according to the described method of claim 43, wherein said first Free Spectral Range is approximately equal to a multiple of the Free Spectral Range of described gain media.

46. according to the described method of claim 45, wherein said second Free Spectral Range is approximately equal to a multiple of described gain media Free Spectral Range.

47. according to the described method of claim 40, wherein:

(a) described first wavelengthtunable in described location is selected element to comprise first adjustable marker is positioned in the described light beam; With

(b) described second wavelengthtunable in described location is selected element to comprise second adjustable marker is positioned in the described light beam.

48. according to the described method of claim 47, the described associating Free Spectral Range of wherein said adjusting comprises described first and second adjustable markers of thermo-optical tunability.

49. according to the described method of claim 48, wherein said thermo-optical tunability comprises:

(a) refractive index of described first adjustable marker of thermal conditioning; With

(b) refractive index of described second adjustable marker of thermal conditioning.

50. according to the described method of claim 49, wherein said thermo-optical tunability also comprises:

(a) physical thickness of described first adjustable marker of thermal conditioning;

(b) physical thickness of described second adjustable marker of thermal conditioning.

51. the method for a laser operation comprises:

(a) from first plane of gain media, launch light beam;

(b) the tail end reflector is positioned in the described light beam, second plane of described tail end reflector and described gain media limits an outer laser cavity;

(c) first and second wavelengthtunables are selected element be positioned in the described tail end reflector described light beam before, described first and second wavelengthtunables select element to be configured to limit more than first and second transmission crest respectively;

(d) from described more than first and second transmission crests, limit a single joint transmission crest; With

(e) select element to regulate described joint transmission crest by tuning described first and second wavelengthtunables.

52. a laser apparatus comprises:

(a) be used to launch the gain apparatus of light beam; With

(b) first and second tunable arrangements are used for being undertaken by the fine setting effect wavelength selection of described light beam.

53. according to the described equipment of claim 52, also comprise the device that is used to limit outer laser cavity, described first and second tuners are positioned in the described outer laser cavity.

54. according to the described equipment of claim 52, wherein said first and second tunable arrangements comprise the first and second hot optical alignment apparatuses of the wavelength selection that is used for described light beam.

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