CN103532012B - Ecld - Google Patents

Abstract

A kind of ECLD, including semiconductor optical amplifier and be set in turn in described semiconductor optical amplifier output light light path on collimating lens, Brewster window, rotatable single-chamber all dielectric membrane process FP optical filter, partially reflecting mirror, and actuating mechanism；It is Brewster's angle that the emergent light of described collimating lens incides the angle of incidence on described Brewster window；Described partially reflecting mirror is perpendicular to the light path of described single-chamber all dielectric membrane process FP optical filter emergent light；Described actuating mechanism is in transmission connection with described single-chamber all dielectric membrane process FP optical filter and described partially reflecting mirror, so that described single-chamber all dielectric membrane process FP optical filter rotates, and makes described partially reflecting mirror move along the normal direction of self.Above-mentioned ECLD can realize the LINEAR CONTINUOUS tuning of output wavelength, and the direction exporting light does not changes with wavelength tuning.

Description

ECLD

Technical field

The present invention relates to laser equipment, particularly relate to a kind of ECLD.

Background technology

ECLD low cost, volume are little, can well realize high-power single mode emission, its business Product have been widely used in the system such as frequency division multiplexing and coherent light communication.

At present, external cavity semiconductor laser has had been developed that various structures, although different, but Their design principle all as, it is simply that in exocoel, insert beam splitter, by regulation beam splitter and chamber Outer feedback mechanism realizes the tuning of optical maser wavelength.

Two kinds of traditional outer-cavity structures are Littrow structure based on diffraction grating and Littman-Metcalf knot Structure, the wavelength of its output beam can not be by Linear Tuning, and the direction of output beam can be along with the tune of wavelength Humorous and change.

Summary of the invention

Based on this, it is necessary to for the problems referred to above, it is provided that a kind of output light wavelength can Linear Tuning and output light The ECLD that direction does not changes with wavelength tuning.

A kind of ECLD, including:

Semiconductor optical amplifier and the collimation being set in turn in the light path of described semiconductor optical amplifier output light Lens, Brewster window, rotatable single-chamber all dielectric thin film Fabry-Perot filter, partially reflective Mirror, and actuating mechanism；

It is Brewster that the emergent light of described collimating lens incides the angle of incidence on described Brewster window Angle；

Described partially reflecting mirror is perpendicular to the light of described single-chamber all dielectric thin film Fabry-Perot filter emergent light Road；

Described actuating mechanism and described single-chamber all dielectric thin film Fabry-Perot filter and described partially reflective Mirror is in transmission connection, so that described single-chamber all dielectric thin film Fabry-Perot filter rotates, and makes described part Reflecting mirror moves along the normal direction of self.

Wherein in an embodiment, also include that the first fully reflective mirror of plane and the second plane are fully reflective Mirror, described single-chamber all dielectric thin film Fabry-Perot filter outgoing is located at by the described first fully reflective mirror of plane In the light path of light, the light path of the reflection light of the described first fully reflective mirror of plane is perpendicular to described partially reflecting mirror； The described second fully reflective mirror of plane is located in the light path of described partially reflecting mirror emergent light.

Wherein in an embodiment, described actuating mechanism includes drive link, drive ball and pushing block, institute The one end stating drive link is connected with described single-chamber all dielectric thin film Fabry-Perot filter, and the other end is with described Drive ball connects, and described pushing block promotes described drive ball can make described single-chamber all dielectric membrane process Fabry-Perot-type Optical filter rotates counterclockwise, and pushing block close to and promote anti-along its incident light beam strikes of described partially reflecting mirror Direction is moved.

Wherein in an embodiment, also include the thermoelectricity system for controlling described semiconductor optical amplifier temperature Cooler, makes described semiconductor optical amplifier run at 25 DEG C.

Wherein in an embodiment, the light-emitting window of described semiconductor optical amplifier is coated with antireflective film, with described It is coated with high-reflecting film on the face that light-emitting window is relative.

Wherein in an embodiment, described Brewster window is made up of uncoated K9 glass, rounded, Its a diameter of 20mm, physical thickness is 2mm, and described Brewster's angle is 56.6 degree.

Wherein in an embodiment, described single-chamber all dielectric thin film Fabry-Perot filter is interference filter Sheet, the film structure of described single-chamber all dielectric thin film Fabry-Perot filter is as follows:

Air|(HL)^PH-2L-H(LH)^P|Glass

Wherein, Air is air, and Glass is substrate, and H is the Ta of quarter-wave optical thickness₂O₅Refraction Dielectric layer, L is the SiO of quarter-wave optical thickness₂Refractive medium layer, P is the weight of respective media layer Multiple number.

Wherein in an embodiment, described Ta₂O₅The refractive index of refractive medium layer is 2.06, and physical thickness is 193.57nm, described SiO₂The refractive index of refractive medium layer is 1.46, and physical thickness is 273.12nm, institute Stating substrate is K9 glass substrate, and physical thickness is 2mm, and refractive index is 1.5168, described respective media layer Repetition number be 7.

Wherein in an embodiment, the substrate of described single-chamber all dielectric thin film Fabry-Perot filter plates Having antireflective film, its film structure is as follows:

Air|(HL)^PH-2L-H(LH)^P|Glass|AR

Wherein, AR is antireflective film.

Wherein in an embodiment, described partially reflecting mirror is made up of K9 glass, rounded, and a diameter of 25.4 Mm, its plane of incidence is concave surface, and radius of curvature is 500mm, and concave surface being coated with and is coated with reflectance is 50% ~ 90% Partially reflective film, the exit facet of described partially reflecting mirror is plane, in described plane be coated be coated with antireflective film, The face that the concave surface of described partially reflecting mirror is coated with high-reflecting film with the painting of described semiconductor optical amplifier constitutes flat-recessed resonance Chamber.

Wherein in an embodiment, the reflectance of described partially reflective film is 60%.

Above-mentioned ECLD, makes single-chamber all dielectric membrane process Fabry-Perot-type filter by actuating mechanism Sheet rotates, and makes partially reflecting mirror move along its normal direction, to regulate single-chamber all dielectric thin film Fabry-Perot The centre of homology wavelength of sieve optical filter and the external cavity longitudinal mode wavelength of laser instrument, due to centre of homology wavelength and External cavity longitudinal mode wavelength, all with the displacement linear change of actuating mechanism, therefore can realize linearly connecting of output wavelength Continuous tuning, and light path will not be impacted when tuning, the direction of output light does not changes with wavelength tuning.

Accompanying drawing explanation

Fig. 1 is the structural representation of the ECLD of an embodiment；

Fig. 2 is the actuating mechanism schematic diagram of an embodiment；

Fig. 3 is that the centre of homology wavelength of the single-chamber all dielectric thin film Fabry-Perot filter of an embodiment is corresponding The variation diagram of mark modulus.

Detailed description of the invention

As it is shown in figure 1, a kind of ECLD, including semiconductor optical amplifier 10 with set gradually Export in described semiconductor optical amplifier 10 collimating lens 20 in the light path of light, Brewster window 30, The rotatable single-chamber all dielectric thin film Fabry-Perot filter fully reflective mirror of the 40, first plane 50, part The reflecting mirror fully reflective mirror of the 60, second plane 70, and actuating mechanism 80.

The light-emitting window 11 of semiconductor optical amplifier 10 be coated with reflectance less than 0.01% antireflective film, with described go out It is coated with the reflectance high-reflecting film more than or equal to 90% on the face 12 that light mouth 11 is relative, constitutes reflective semiconductor Image intensifer (RSOA).For the light-emitting window 11 being coated with antireflective film, it is to semiconductor optical amplifier 10 The reflectance of interior lights should be the lowest more good, typically should be less than 10^-3Magnitude；Semiconductor optical amplifier 10 has relatively High Polarization-Dependent Gain, the near infrared light of output be mainly TE polarized light (polarization direction is perpendicular to horizontal plane, Horizontal plane refer to the paper at Fig. 1 and Fig. 2 place), in addition with a small amount of TM polarized light (polarization side To being parallel to horizontal plane)；Additionally, semiconductor optical amplifier 10 needs to control with thermoelectric refrigerator (TEC) Its temperature so that it is stably operate at 25 DEG C；Meanwhile, the driving electric current of semiconductor optical amplifier 10 is set It is set to 230mA.Design parameter is shown in Table 1.

Table 1

Collimating lens 20 is used for being calibrated near infrared light near-infrared directional light, the incident described cloth scholar of its emergent light The angle of incidence of this special window 30 is Brewster's angle.

Brewster window 30 is made up of uncoated K9 glass, rounded, its a diameter of 20mm, thing Reason thickness is 2mm, and its place plane is vertical with described near-infrared directional light with the intersection of horizontal plane, and this window Sheet 30 is 33.4 degree with the angle of horizontal plane, makes described near-infrared directional light with the Brewster's angle of 56.6 degree Incide on Brewster window 30, to filter the TM polarized light in described collimated light beam, thus ensure to swash Light device be finally output as pure TE polarized light.

The emergent light of described Brewster window 30 is located at by single-chamber all dielectric thin film Fabry-Perot filter 40 Lu Shang, can rotate around the axle 9 being perpendicular to described light path.

Single-chamber all dielectric thin film Fabry-Perot filter 40 is spike interference filter, single-chamber all dielectric thin film The film structure of Fabry-Perot filter is as follows:

Air|(HL)^PH-2L-H(LH)^P|Glass

Wherein, Air is air, and Glass is substrate, and it is made up of K9 glass, and physical thickness is 2mm, Refractive index is 1.5168；H be quarter-wave optical thickness, refractive index be 2.06, physical thickness be 193.57 The Ta of nm₂O₅Refractive medium layer；L be quarter-wave optical thickness, refractive index be 1.46, physics thick Degree is the SiO of 273.12nm₂Refractive medium layer, P is the repetition number of respective media layer, preferably 7, this Time can filter the multiple starting of oscillation longitudinal modes in exocoel, leave behind the output of single longitudinal mode.

In order to prevent light beam roundtrip in the substrate, can on substrate coating antireflective film, the list after plated film The film structure of chamber all dielectric thin film Fabry-Perot filter 40 is Air|(HL)^PH-2L-H(LH)^P| Glass | AR, wherein, AR is antireflective film.

As in figure 2 it is shown, the centre of homology wavelength of single-chamber all dielectric thin film Fabry-Perot filter 40 can lead to Cross and change the size of its inclination angle theta and change: inclination angle theta is the biggest, and centre of homology wavelength is the least.Further, for For transverse electric field light (TE polarized light) or transverse magnetic light (TM polarized light), single-chamber all dielectric membrane process cloth In-centre of homology wavelength of Perot filter 40 is the most linear with the cosine of its inclination angle theta.

Described single-chamber all dielectric thin film Fabry-Perot filter is located at by the described first fully reflective mirror of plane 50 On the emitting light path of 40, the light path of the reflection light of the described first fully reflective mirror of plane 50 is perpendicular to described part Reflecting mirror 60；The described second fully reflective mirror of plane 70 is located on the emitting light path of described partially reflecting mirror 60, The emergent light of partially reflecting mirror 60 is the output light of laser instrument, and it is through the described second fully reflective mirror of plane 70 Reflection after export.

Described partially reflecting mirror 60 is made up of K9 glass, rounded, a diameter of 25.4mm, its plane of incidence For concave surface, radius of curvature is 500mm, concave surface is coated with and is coated with the partially reflective film that reflectance is 50% ~ 90%, The exit facet of partially reflecting mirror 60 is plane, plane is coated with and is coated with antireflective film；The concave surface of partially reflecting mirror 60 The face being coated with high-reflecting film with semiconductor optical amplifier 10 painting constitutes flat-recessed resonator cavity, so that resonator cavity is formed surely Fixed vibration, after light beam is on the concave surface inciding partially reflecting mirror 60, it will gathers and is reflected back light source.When When the reflectance of partially reflective film is 60%, the flat-Output of laser wavelength value of recessed resonator cavity, live width, output work Rate is up to most preferably.

Described actuating mechanism 80 and described single-chamber all dielectric thin film Fabry-Perot filter 40 and described portion Reflecting mirror 60 is divided to be in transmission connection, so that described single-chamber all dielectric thin film Fabry-Perot filter 40 rotates, And make described partially reflecting mirror 60 move along the normal direction of self, to regulate described single-chamber all dielectric membrane process The centre of homology wavelength of Fabry-Perot-type optical filter 40 and the external cavity longitudinal mode wavelength of laser instrument, thus adjust linearly The wavelength of humorous Output of laser.

Specifically, described actuating mechanism 80 includes drive link 81, drive ball 82 and pushing block 83, described One end of drive link 81 is connected with described single-chamber all dielectric thin film Fabry-Perot filter 40, the other end with Drive ball 82 connects, and described pushing block 83 can bilateral reciprocation in the horizontal plane.When pushing block 83 is along water Square to turn right motion time, it will promote described drive ball 82 so that described single-chamber all dielectric membrane process background of cloth- Perot filter 40 rotates counterclockwise around axle 9；Meanwhile, pushing block 83 will be the most close when turning right motion And connect described partially reflecting mirror 60, and then promote described partially reflecting mirror 60 rearward movement (i.e. incident along it The opposite direction of light moves).When pushing block 83 moves the most forward, it will drive described part anti- Penetrate mirror 60 to move along the direction of its incident illumination；Meanwhile, described single-chamber all dielectric thin film Fabry-Perot filter 40 self entrained elastic recovery device can make it move along with pushing block 83 and rotate clockwise around axle 9.

Specifically, drive ball 82 can make the good standard ball of surface smoothness, and frictional resistance is minimum, The contact plane that pushing block 83 is used for Contact Transmission ball 82 makes the good plane of surface smoothness equally, rubs Wipe drag minimization, it can be ensured that single-chamber all dielectric thin film Fabry-Perot filter 40 is at the band of pushing block 83 The sensitivity of dynamic lower motion.Along about horizontal plane direction, drive pushing block 83, single-chamber all dielectric thin film can be made Fabry-Perot filter 40 rotates around axle 9；Before and after horizontal plane direction, drive pushing block 83, also can Partially reflecting mirror 60 is made synchronously to seesaw.

Elastic recovery device can apply one along up time to single-chamber all dielectric thin film Fabry-Perot filter 40 The elastic force (restoring force) in pin direction, drives when pushing block 83 deviate from initial position (i.e. position 1 in Fig. 2) When dynamic single-chamber all dielectric thin film Fabry-Perot filter 40 and partially reflecting mirror 60 move, elastic force will be overcome, When pushing block 83 returns initial position, single-chamber all dielectric thin film Fabry-Perot filter 40 is made because of elastic force With and follow pushing block 83 and move.

It is understood that the first complete transmitter of plane fully reflective mirror of the 50, second plane 70 can also letter Change, if the position of changing section reflecting mirror 60, and make described partially reflecting mirror 60 be perpendicular to described single-chamber The emitting light path of all dielectric thin film Fabry-Perot filter 40, and make actuating mechanism 80 can promote described portion Dividing reflecting mirror 60 to move along the opposite direction of its incident illumination, now the output light of laser instrument is anti-by described part Penetrate mirror 60 directly to export.

As in figure 2 it is shown, single-chamber all dielectric thin film Fabry-Perot filter 40 is perpendicular to Brewster window Position during emitting light path is designated as initial position (position 1 in Fig. 2), when not showing in pushing block 83(Fig. 2 Go out) when advancing by initial position, have two athletic meeting to occur: 1 the most simultaneously) single-chamber all dielectric thin film Rotating counterclockwise of Fabry-Perot filter 40；2) (its incident illumination that travels forward of partially reflecting mirror 60 Incident opposite direction).Rotating counterclockwise of single-chamber all dielectric thin film Fabry-Perot filter 40 can make it Centre of homology wavelength progressively reduces；Travelling forward of partially reflecting mirror 60 can make the exocoel of whole laser system Round light path progressively reduces, thus external cavity longitudinal mode wavelength progressively reduces.May certify that, when pushing block 83 is by just When beginning position is advanced to a certain region, the centre of homology ripple of single-chamber all dielectric thin film Fabry-Perot filter 40 Length will keep synchronously reducing with some external cavity longitudinal mode wavelength.Now, output wavelength continuously may be used by laser instrument Adjust the single longitudinal mode laser of (without mode hopping), and light path will not be impacted during tuning, the direction of output beam Will not change with the tuning of wavelength.And laser structure is simple, and cost is relatively low.

Assuming when initial position, whole exocoel comes and goes light path overall length (i.e. initial exocoel comes and goes light path overall length) For OPL (0)；Not shown in pushing block 83(Fig. 2) pushed ahead x (mm) by initial position after (arrive Position 2 in Fig. 2), it is OPD (x) that exocoel comes and goes the knots modification of optical path length；Single-chamber all dielectric membrane process cloth In-the substrate physical thickness of Perot filter 40 is h, the refractive index of substrate is n, from the center of rotating shaft 9 to The distance of the centre of sphere of spheroid 82 is L.Expression formula according to Fig. 2, OPD (x) is:

$\mathrm{OPD}\left(x\right)=2[\mathrm{nh}-\frac{n^2\mathrm{hL}}{\sqrt{n^2{L}^2+x^2-2\mathrm{xL}}}-h+x+\frac{2\mathrm{xhL}-x^{2}h+h(L-x)\sqrt{n^2{L}^2+x^2-2\mathrm{xL}}}{L\sqrt{n^2{L}^2+x^2-2\mathrm{xL}}}]---\left(1\right)$

So, when pushing block 83 is advanced x (mm) by initial position, new exocoel comes and goes light path overall length and is OPL(x)=OPL(0)-OPD(x).Thus, it is possible to obtain the pushing block 83 exocoel after being advanced to new position Come and go light path overall length.

Meanwhile, after pushing block 83 pushes ahead x (mm), by following formula, single-chamber all dielectric can be obtained thin Anglec of rotation θ of film Fabry-Perot filter 40,

$\cos \mathrm{\θ}=\frac{L-x}{L}---\left(2\right)$

Here θ the most now laser beam is at single-chamber all dielectric thin film Fabry-Perot filter 40 Angle of incidence.For a given single-chamber all dielectric thin film Fabry-Perot filter 40, its centre of homology ripple Long λ_sX () is the function of its beam incident angle θ, owing to incidence angle θ has been obtained, so λ now_sX () also It is a definite value, can obtain accordingly.Transmission according to single-chamber all dielectric thin film Fabry-Perot filter 40 The lasing principle of characteristic and ECLD, single-chamber all dielectric thin film Fabry-Perot filter 40 Centre of homology wavelength change and the change of ECLD external cavity longitudinal mode wavelength between also exist one Plant almost linear relation.

Thus, corresponding to the centre of homology wavelength of definition single-chamber all dielectric thin film Fabry-Perot filter 40 Mark longitudinal mode number is m_sX (), after pushing block 83 has pushed ahead x (mm), has

$m_s\left(x\right)=\frac{\mathrm{OPL}\left(x\right)}{{\mathrm{\λ}}_s\left(x\right)}---\left(3\right)$

Along with the continuous change of x, m_sX () also changes occurring.

Here, h=2 (mm), n=1.5168.

If the center of axle 9 is 81mm to the distance of the centre of sphere of drive ball 82, then the initial exocoel of laser instrument is past Return light path overall length (to be i.e. coated with from semiconductor optical amplifier 10 and be coated with one end 13 of high-reflecting film to partially reflecting mirror 60 The round optical path length of concave surface) OPL (0) is 449.9mm.So, 5.9 ~ 6.7 are pushed ahead when pushing block 83 During mm, the output wavelength of ECLD will be in without the continuously adjustable scope of mode hopping, this continuously The adjustable output wavelength displacement linear change with pushing block 83 showing as ECLD.Due to outward It is longer that the exocoel of cavity semiconductor laser comes and goes light path, it is possible to obtains narrow Output of laser live width. In actual output performance test, along with pushing block 83 pushes ahead 5.9 ~ 6.7mm, cavity semiconductor swashs The output wavelength of light device presents basic linear change, defeated in the range of 1547.203 ~ 1552.426nm Go out power to be maintained between 40 ~ 50microwatts the most relatively stablely, export longitudinal mode pattern and be always Dan Zong Mould, its live width are maintained between 100 ~ 150MHz the most relatively stablely.Based on above-mentioned parameter, we are permissible ECLD 100 is packaged and shapes.Certainly, above-mentioned parameter can have ± 5% floating Dynamic.

Fig. 3 is " m_s(x) x " curve chart, as seen from the figure, along with pushing block 83 by initial position by Step advances, and the mark corresponding to the wavelength of the centre of homology of single-chamber all dielectric thin film Fabry-Perot filter 40 is indulged Modulus will first increase, reduce afterwards.A stable transitional region is had, in this region between increasing and reducing Mark longitudinal mode this maintenance of base stablize constant, illustrate in the region, single-chamber all dielectric thin film Fabry-Perot The centre of homology wavelength of sieve optical filter 40 is just remain with some external cavity longitudinal mode wavelength and is synchronously changing.The most just Being to say, in this region, the output wavelength of ECLD is in without the continuously adjustable state of mode hopping.

Embodiment described above only have expressed the several embodiments of the present invention, and it describes more concrete and detailed, But therefore can not be interpreted as the restriction to the scope of the claims of the present invention.It should be pointed out that, for this area Those of ordinary skill for, without departing from the inventive concept of the premise, it is also possible to make some deformation and Improving, these broadly fall into protection scope of the present invention.Therefore, the protection domain of patent of the present invention should be with appended Claim is as the criterion.

Claims (10)

1. an ECLD, it is characterised in that including:

Semiconductor optical amplifier and the collimation being set in turn in the light path of described semiconductor optical amplifier output light Lens, Brewster window, rotatable single-chamber all dielectric thin film Fabry-Perot filter, partially reflective Mirror, and actuating mechanism；

It is Brewster that the emergent light of described collimating lens incides the angle of incidence on described Brewster window Angle；

Described partially reflecting mirror is perpendicular to the light of described single-chamber all dielectric thin film Fabry-Perot filter emergent light Road；

Described actuating mechanism and described single-chamber all dielectric thin film Fabry-Perot filter and described partially reflective Mirror is in transmission connection, so that described single-chamber all dielectric thin film Fabry-Perot filter rotates, and makes described part Reflecting mirror moves along the normal direction of self；

Wherein, described actuating mechanism includes drive link, drive ball and pushing block, one end of described drive link Being connected with described single-chamber all dielectric thin film Fabry-Perot filter, the other end is connected with described drive ball, institute Stating pushing block promotes described drive ball that described single-chamber all dielectric thin film Fabry-Perot filter can be made to revolve counterclockwise Turn, and pushing block is close and promotes described partially reflecting mirror to move along the opposite direction of its incident light beam strikes.

ECLD the most according to claim 1, it is characterised in that also include that first is flat The fully reflective mirror in face and the fully reflective mirror of the second plane, described list is located at by the described first fully reflective mirror of plane In the light path of chamber all dielectric thin film Fabry-Perot filter emergent light, the described first fully reflective mirror of plane The light path of reflection light is perpendicular to described partially reflecting mirror；Described part is located at by the described second fully reflective mirror of plane In the light path of reflecting mirror emergent light.

ECLD the most according to claim 1 and 2, it is characterised in that also include using In the thermoelectric refrigerator of the described semiconductor optical amplifier temperature of control, make described semiconductor optical amplifier at 25 DEG C Lower operation.

ECLD the most according to claim 3, it is characterised in that described semiconductor light The light-emitting window of amplifier is coated with antireflective film, and the face relative with described light-emitting window is coated with high-reflecting film.

ECLD the most according to claim 4, it is characterised in that described Brewster Window is made up of uncoated K9 glass, rounded, its a diameter of 20mm, and physical thickness is 2mm, Described Brewster's angle is 56.6 degree.

ECLD the most according to claim 5, it is characterised in that described single-chamber is situated between entirely Matter thin film Fabry-Perot filter is interferometric filter, and its film structure is as follows:

Air|(HL)^PH-2L-H(LH)^P|Glass

Wherein, Air is air, and Glass is substrate, and H is the Ta of quarter-wave optical thickness₂O₅Refraction Dielectric layer, L is the SiO of quarter-wave optical thickness₂Refractive medium layer, P is the weight of respective media layer Multiple number.

ECLD the most according to claim 6, it is characterised in that described Ta₂O₅Folding The refractive index penetrating dielectric layer is 2.06, and physical thickness is 193.57nm, described SiO₂The refraction of refractive medium layer Rate is 1.46, and physical thickness is 273.12nm, and described substrate is K9 glass substrate, and physical thickness is 2mm, Refractive index is 1.5168, and the repetition number of described respective media layer is 7.

ECLD the most according to claim 7, it is characterised in that described single-chamber is situated between entirely Antireflective film it is coated with on the substrate of matter thin film Fabry-Perot filter, described single-chamber all dielectric membrane process background of cloth- The film structure of Perot filter is as follows:

Air|(HL)^PH-2L-H(LH)^P|Glass|AR

Wherein, AR is antireflective film.

ECLD the most according to claim 8, it is characterised in that described partially reflective Mirror is made up of K9 glass, rounded, a diameter of 25.4mm, and its plane of incidence is concave surface, and radius of curvature is 500 Mm, concave surface is coated with and is coated with the partially reflective film that reflectance is 50%～90%, the outgoing of described partially reflecting mirror Face is plane, described plane is coated with and is coated with antireflective film, the concave surface of described partially reflecting mirror and described semiconductor light Amplifier painting is coated with the face of high-reflecting film and constitutes flat-recessed resonator cavity.

ECLD the most according to claim 9, it is characterised in that described part is anti- The reflectance penetrating film is 60%.