KR20080065478A - Multi-Surface Light Laser and Optical Communication System Using It - Google Patents

Abstract

Disclosed are a multi-surface light laser and an optical communication system employing the same. The disclosed multi-surface light laser is a multi-surface light laser having a plurality of surface light laser elements, and at least two surface light laser elements of the plurality of surface light laser elements have different polarization directions. The optical communication system also includes such a surface light laser and one or a plurality of light transmission paths coupled to the surface light laser.

Description

Multi surface emitting laser and optical communication system using same

1 is a schematic top view of a multi-surface light laser according to a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view taken along the line A-A of the multi-surface light laser of FIG. 1.

3 shows a lattice structure of the aperture of the multi-surface light laser of FIG. 1.

4A and 4B are graphs showing polarization characteristics by a lattice structure.

5 is a schematic top view of a multi-surface light laser according to a second embodiment of the present invention.

FIG. 6 is a vertical cross-sectional view taken along line B-B of the multi-surface light laser of FIG. 5.

7A and 7B are graphs showing polarization characteristics by the aperture structure.

8 is a schematic top view of a multi-surface light laser according to a third embodiment of the present invention.

9 is a schematic top view of a multi-surface light laser according to a fourth embodiment of the present invention.

10 is a schematic configuration diagram of an optical communication system employing a surface light laser according to a fifth embodiment of the present invention.

FIG. 11 is a schematic diagram illustrating coupling of a multi-surface light laser and a light transmission path in FIG. 11.

FIG. 12 is a schematic diagram illustrating a modification of the configuration of coupling the multi-surface light laser and the light transmission path in FIG. 11.

<Explanation of symbols for the main parts of the drawings>

100,200,300,400,510 ... multi surface light laser

110,120,210,220,310,320,330,410,420,430,440 ... surface light laser device

105,205 ... substrate

111,121,211,221,311,321,331,411,421,431,441 ... opening

211,221 ...

530,620,530 ... optical fiber

550 ... PBS

570 ... PD

630 ... optical coupler

The present invention relates to a multi-surface light laser and an optical communication system employing the same, and more particularly, to a multi-surface light laser that emits a plurality of laser beams of different polarization directions at the chip scale and an optical communication system employing the same. .

Technology that transmits information using light is being used exclusively in the backbone network, including oversea communication, and recently, it is being used in communication in buildings, short distances, and devices. In such communication, a multiplexing technique, which is a technique of forming a plurality of channels capable of simultaneously transmitting and receiving individual signals by dividing one transmission path in order to increase communication efficiency, is applied.

The multiplexing technique typically includes a frequency division multiplexing (FDM) scheme in which a single line is divided into multiple frequency bands and multiplexed, and similarly, a wavelength division multiplexing scheme for dividing a wavelength. (Hereinafter, referred to as WDM) and Time Division Multiplexing (hereinafter, referred to as TDM) in which one circuit is divided and multiplexed into a plurality of very short time intervals.

However, this multiplexing method has been used only for expensive optical communication systems such as backbone networks because of the high wavelength stability and accuracy required for the light source, the precise alignment between the light source and the multiplexer, and the like. However, FTTH (fiber-to-the home), local area network (LAN), or communication between personal devices requires higher transmission speeds due to higher definition of display quality, while lower manufacturing costs must be satisfied. Multiplexing schemes such as FDM, WDM or TDM are difficult to use. Alternatively, Polarization Division Multiplexing (hereinafter, referred to as PDM), which carries data on two orthogonal linear polarizations of a light source, is considered, but this also includes component cost of a polarizer and vertical polarization. There are many limitations to lower manufacturing costs due to the alignment costs for maintenance.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a multi-surface light laser that emits laser beams having different polarization directions and an optical communication system employing the same.

In order to achieve the above object, a multi-surface light laser according to the present invention is a multi-surface light laser having a plurality of surface light laser elements, wherein at least two surface light laser elements of the plurality of surface light laser elements are polarization directions This is characterized by different things.

At least two surface light laser elements of the plurality of surface light laser elements may be disposed such that polarization directions of the emitted beams are perpendicular to each other.

At least three surface light laser elements of the plurality of surface light laser elements may be arranged such that the polarization directions of the emitted beams maintain constant angular intervals from each other.

At least two surface light laser devices of the plurality of surface light laser devices may emit beams having different wavelengths.

At least one of the polarization direction and the wavelength of the emitted beam of the plurality of surface light laser devices is preferably different from each other.

The polarization direction may be determined by gratings respectively provided in the openings of the plurality of surface light laser elements.

By asymmetrically resonating conditions of each of the plurality of surface light laser elements, the polarization direction can be determined.

In this case, the polarization direction may be determined by asymmetrical current limiting structures of the plurality of surface light laser elements.

The plurality of surface light laser elements may be driven independently.

The plurality of surface light laser devices may be collectively formed on the same substrate.

The plurality of surface light laser elements may be mounted on the same die.

The plurality of surface light laser elements are preferably aligned such that each output surface is on the same plane.

In addition, in order to achieve the above object, the optical communication system according to the present invention includes the above-mentioned surface light laser; And one or a plurality of optical transmission paths coupled to the surface light laser.

The plurality of surface light laser elements are preferably arranged adjacent to each other and coupled to the one optical transmission path.

The plurality of light transmission paths include: a plurality of first light transmission paths coupled to each of the plurality of surface light laser elements; And one second optical transmission path coupled to the plurality of first optical transmission paths.

Hereinafter, a multi-surface light laser and an optical communication system using the same according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 to 3 schematically show a multi-surface light laser according to a first embodiment of the present invention.

Referring to FIG. 1, the multi-surface light laser 100 of the present embodiment includes first and second surface light laser elements 110 and 120 that emit laser beams of polarized light that are perpendicular to each other. The first and second surface light laser devices 110 and 120 have a structure of a vertical cavity surface emitting laser (hereinafter, referred to as VCSEL) formed on the same substrate 105.

Referring to FIG. 2, the first surface light laser device 110 includes a lower reflecting layer 112, an active layer 113 including a gain layer giving a gain, and a current limiting layer 115 that controls the flow of current. The upper reflective layer 117, the upper electrode 118, and the first opening 111 have a first semiconductor stacked structure 119 sequentially stacked on the substrate 105. The second surface light laser device 210 also has a second semiconductor stacked structure 129 having substantially the same configuration as the first surface light laser device 110 except for the second opening 121. A common lower electrode 101 is provided on the bottom of the substrate 105. The first and second semiconductor stacked structures 119 and 129 may be collectively stacked on a common substrate 105 through a conventional semiconductor manufacturing process.

More specifically, for example, the substrate 105 may be an n-type semiconductor substrate, and InP, InGaAs, GaN, GaAs, GaP, or the like may be used. The lower and upper reflective layers 112 and 117 have a semiconductor DBR (Distributed Bragg Reflector) structure in which a plurality of layers having a high refractive index and a layer having a low refractive index are alternately stacked. Dopants may be formed by doping, respectively. In addition, the active layer 113 may include an n-type cladding layer, a gain layer, and a p-type cladding layer, and the gain layer may have a multi quantum well structure. In addition, the current limiting layer 115 may be divided into a region 115a through which a current flows and a region 115b where a current is insulated using oxidation.

The first and second surface light laser elements 110 and 120 irradiate a laser beam of a single polarization. In this embodiment, the polarization is reduced through the first and second openings 111 and 121 of the lattice structure as shown in FIG. Controlled. The grating structure is formed with the period and depth of the grating on a submicron scale to control the polarization of the laser beam. Such a lattice structure may be formed collectively through a photoresist process or the like in the first and second openings in a form orthogonal to each other.

4A and 4B show polarization characteristics of a surface light laser device having an opening of such a lattice structure and a comparative example. Referring first to FIG. 4A, one can see the polarization characteristics of a typical VCSEL without openings in a lattice structure. That is, the optical powers of the vertically polarized beam P _이나 and the horizontally polarized beam P _∥ are almost similar, and thus, the conventional VCSEL exhibits no polarization characteristics. On the other hand, referring to FIG. 4B, the VCSEL of the present embodiment with the opening of the lattice structure shows a single polarization characteristic. That is, it can be seen that the optical power of the horizontally polarized beam P _∥ is almost zero, and the optical power of the vertically polarized beam P _거의 is close to the total optical power. In this case, the standard of the vertical polarization and the horizontal polarization is arbitrarily set, and merely intended to distinguish the linear polarization perpendicular to each other for convenience. Referring to the result in FIG. 4B, when the direction of the grating is changed by 90 degrees, the optical power of the reversely vertically polarized beam P _거의 becomes nearly zero, and the optical power of the horizontally polarized beam P _∥ becomes It is obvious that it will be close to the total optical power. Therefore, when the first opening (111 in FIG. 1) and the second opening (121 in FIG. 1) are formed to orthogonally cross the directions of the gratings, the first and second surface light laser elements (110 and 120 in FIG. 1) are polarized. It emits laser beams that are orthogonal to each other.

Since the first and second surface light laser elements 110 and 120 have the first and second upper electrodes 118 and 128 and the common lower electrode 101 respectively, they can be driven independently. On the other hand, since the first and second surface light laser elements 110 and 120 are collectively stacked on a wafer basis, the respective output surfaces, that is, the first and second openings 111 and 121, are placed on the same plane. In addition, since the first and second surface light laser elements 110 and 120 may be manufactured at the chip scale, the first and second openings 111 and 121 may be adjacent to each other within several hundred μm, preferably within several tens of μm. Accordingly, as will be described later, when the optical fiber is to be coupled to the multi-surface light laser 100, a single optical fiber may be directly bonded and coupled to cover all of the first and second openings 111 and 121.

Since the first and second surface light laser devices 110 and 120 may be manufactured on a wafer basis through a conventional semiconductor manufacturing process, the first and second surface light laser devices 110 and 120 may be easily coupled to an optical fiber as described below, so that an optical communication system is used as a transmission device. Suitable.

In the above-described example, the case in which the first and second surface light laser elements 110 and 120 are collectively formed on the common substrate 105 is described, but the present invention is not limited thereto. For example, each of the first and second surface light laser elements 110 and 120 may be manufactured separately and then mounted on a die or sub-mount in a chip unit.

5 and 6 schematically show a multi-surface light laser according to a second embodiment of the present invention.

Referring to FIG. 5, the multi-surface light laser 200 of the present embodiment includes first and second surface light laser elements 210 and 220 that emit laser beams of polarized light that are perpendicular to each other. Since the first and second surface light laser devices 210 and 220 are substantially similar to the first embodiment described with reference to FIGS. 1 and 2, the first and second surface light laser devices 210 and 220 will be described.

Referring to FIG. 6, the first surface light laser device 210 may include a lower reflective layer 212, an active layer 213, a first current limiting layer 215, an upper reflective layer 217, an upper electrode 218, and a first electrode. The opening 211 has a first semiconductor stacked structure 219 sequentially stacked on the substrate 205. The second surface stacked laser device 220 also has a second semiconductor stacked structure 229 having substantially the same configuration as the first surface light laser device 210 except for the second current limiting layer 225 and the second opening 221. Has

The first and second surface light laser devices 210 and 220 of this embodiment emit a laser beam of single polarization through the modification of the resonance mode inside the device. For example, in the present embodiment, polarization is controlled by forming an ellipsoidal region in which the currents of the current limiting layers 215 and 225 flow, and further forming an ellipsoidal shape of the openings 211 and 221.

Referring to FIG. 6, the shape of the region 215a through which the current flows in the first current limiting layer 215 flows is the side surface of the first semiconductor stacked structure 219 after the first semiconductor stacked structure 219 is stacked. Is selectively oxidized to expand and form the region 215b in which the current is insulated. That is, as shown in FIG. 5, when viewed from the upper side of the first surface light laser element 210, the width of the side where the opening 211 is located is made smaller and the width thereof is increased, whereby the width of the first semiconductor laminate structure 219 is increased. When the side surface is selectively oxidized to form the first current limiting layer 215, the width and width of the region 215a through which the current flows may be asymmetric.

The second surface light laser device 220 also reduces the width and width of the second semiconductor stacked structure 219 on the side where the opening 221 is located, thereby making the width and width of the current flow region asymmetric. Can be.

Further, the shapes of the openings 211 and 221 of the first and second surface light laser devices 210 and 220 also correspond to the asymmetric structure of the current confining layer so that the width and the width thereof are asymmetrical.

7A and 7B show the polarization characteristics of a surface light laser device having such a current limiting layer and an opening and a comparative example thereof. First, referring to FIG. 7A, it is possible to see a single polarization characteristic of a VCSEL having a transversely long region in which a current flows and an opening. That is, when the beam polarized in the longitudinal direction of the region and the opening in which the long current flows is called the horizontally polarized beam (P _∥ ), and the vertically polarized beam is called the vertically polarized beam (P _⊥ ), It can be seen that the optical power of the beam P _게 is near zero, and the optical power of the horizontally polarized beam P _∥ is close to the total optical power. On the other hand, referring to FIG. 7B, in the case of the VCSEL having a vertically long region in which the current flows and the opening, the optical power of the horizontally polarized beam P _∥ is almost zero, and the vertically polarized beam P _⊥ The optical power of can be seen to be close to the total optical power.

As such, the shapes of the first and second semiconductor stacked structures 219 and 229 of FIG. 5 are elongated in directions perpendicular to each other when viewed from above, so that the first and second surface light laser elements 210 and 220 of FIG. 5 are polarized. It emits laser beams that are orthogonal to each other.

8 schematically shows a multi-surface light laser according to a third embodiment of the present invention.

Referring to FIG. 8, the multi-surface light laser 300 of the present embodiment includes first to third surface light laser elements 310, 320, and 330 which emit laser beams of a single polarization. Here, the first to third surface light laser devices 310, 320, and 330 are arranged so that the polarization directions of the emitted laser beams are different by 120 degrees. This arrangement is possible by appropriately adjusting the opening directions of the first to third surface light laser elements 310, 320 and 330.

Each of the first to third surface light laser elements 310, 320, and 330 may have a VCSEL structure of the first embodiment described with reference to FIGS. 1 and 2, a VCSEL structure of a second embodiment described with reference to FIGS. 5 and 6, Or a surface light laser device which emits a laser beam of a single polarization of another structure known in the art.

The multi-surface light laser 300 of this embodiment emits a laser beam having a polarization direction difference of 120 degrees. Therefore, when the surface light laser 300 of the present embodiment is applied to optical communication, different polarization beams may be separated using a PDM method. However, since the polarization directions are not orthogonal, the surface light laser 300 of the present embodiment may be applied to communication where some noise is tolerated, or may be applied together with a conventional WDM, FDM, or TDM scheme. In addition, any surface light laser element can be used as a dummy element.

When the multi-surface light laser 300 of the present embodiment is employed in a complex multiplexing method using the WDM or FDM method together with the PDM method, the first to third surface light laser devices 310, 320, and 330 have lasers having different wavelengths. It is formed to emit a beam. When stacking the first to third surface light laser elements 310, 320 and 330, the first to third surface light laser elements 310, 320 and 330 may have different wavelengths by varying the composition ratio or the doping ratio of the semiconductor material. Can be released.

9 schematically shows a multi-surface light laser according to a fourth embodiment of the present invention.

9, the multi-surface light laser 400 of the present embodiment includes first and second surface light laser elements 410 and 420 having a first polarization direction, and a second polarization direction orthogonal to the first polarization direction. And third and fourth surface light laser elements 430 and 440 having a. Each of the first to fourth surface light laser elements 410, 420, 430, and 440 is a VCSEL structure of a first embodiment described with reference to FIGS. 1 and 2, or a VCSEL structure of a second embodiment described with reference to FIGS. 5 and 6. Or a surface light laser device that emits a single polarized laser beam of other structures known in the art.

When the surface light laser of the present embodiment is applied to optical communication, the polarization directions of the laser beams emitted from the first and second surface light laser elements 410 and 420 and the lasers emitted from the third and fourth surface light laser elements 430 and 440. Since the polarization directions of the beams are orthogonal to each other, the polarized beams orthogonal to each other can be transmitted in a PDM manner. On the other hand, the first and second surface light laser elements 410 and 420 emit laser beams in the same polarization direction, and the third and fourth surface light laser elements 430 and 440 emit laser beams in the same polarization direction. Therefore, in order to use the multi-surface light laser 400 of this embodiment as a transmission element for optical communication, it is necessary to apply other multiplexing methods other than the PDM method together to separate the optical signals carried on the laser beams in the same polarization direction. As such a multiplexing method, for example, WDM, FDM or TDM are known.

When the optical signal is separated by using TDM, the wavelengths of the laser beams emitted from the first to fourth surface light laser elements 410, 420, 430, and 440 do not need to be different from each other, except that the signal driver (not shown) or the signal processor ( Signal processing is performed so that the optical signal carried in the laser beam of the same polarization can be separated.

On the other hand, when the optical signal is separated using WDM or FDM, the first surface light laser device 410 and the second surface light laser device 420 emit laser beams having different wavelengths, and the third surface light laser. The device 430 and the fourth surface light laser device 440 may emit laser beams having different wavelengths.

10 schematically shows an optical communication system according to a fifth embodiment of the present invention.

Referring to FIG. 10, the optical communication system according to the present embodiment includes a multi-surface light laser 510 which is a transmitter, an optical fiber 530 that transmits an optical signal transmitted from the multi-surface light laser 510, and an optical fiber 530. And a receiver 570 for receiving an optical signal separated from a polarized beam splitter 550 for separating the transmitted optical signal according to the polarization direction.

The multi-surface light laser 510 includes two laser diodes LD _⊥ , LD _∥ which emit beams of orthogonal polarization, and may be, for example, the multi-surface light laser of the first embodiment described above. . The optical fiber 530 is an example of an optical transmission path for transmitting an optical signal. On the other hand, the PBS 550 is an example of a polarization selective element, and there are not only flat-type to cubic-type PBS having a polarization separation film of a multilayer thin film, but also a metal wire grid polarizer. The receiver 570 includes two photodiodes PD _⊥ and PD _∥ which convert each of the separated polarization beams into an electrical signal.

In this case, an example of a configuration in which the optical fiber 530 is coupled to the multi-surface light laser 510 is illustrated in FIG. 11.

Referring to FIG. 11, the multi-surface light laser 510 includes first and second surface light laser elements 510 and 520 as in the first embodiment described above, and these first and second surface light laser elements 510 and 520. ) Is coupled in direct contact with one optical fiber 530. Here, each of the first and second surface light laser elements 510 and 520 corresponds to the laser diodes LD _⊥ , LD _∥ shown in FIG. 10.

In the conventional PDM optical communication system, a plurality of laser diodes are coupled to a plurality of optical fibers in a one-to-one manner, and then coupled to a single optical fiber. In addition, two polarizing plates are used to obtain a single polarization perpendicular to each other. In the case of the conventional PDM method, the configuration is complicated in that a separate polarizer is used, and thus the manufacturing cost is increased. Accordingly, after first-to-one coupling of each laser diode and an optical fiber, this is again a single one. Since the second coupling to the optical fiber has to maintain polarization characteristics in the optical fiber after the first coupling, sophisticated alignment is required to use expensive optical fibers that make this possible or to create orthogonal polarization in the secondary coupling.

On the other hand, in the optical communication system of the present embodiment, since a single polarized laser beam is emitted from the multi-surface light laser 510 itself, a separate polarizing plate is not required. Further, in the optical communication system of the present embodiment, the openings 511 and 521 of the respective surface light laser elements 510 and 520 are disposed adjacent to each other within several hundred micrometers, preferably several tens of micrometers, and are on the same plane. 530 may be used to cover all openings 510, 520 at the same time. That is, one optical fiber 530 may be directly bonded to and coupled to the light output surface of the multi-surface light laser 510. Accordingly, since the beams of polarization orthogonal to each other are simultaneously input to and transmitted to one optical fiber, an optical fiber having a precise alignment for maintaining polarization in the primary coupling or the secondary coupling or a polarization maintaining characteristic therefor is not required. The coupling structure can be made simpler. In addition, the simple coupling structure makes it possible to easily configure the optical communication system of the PDM method. Here, the optical communication system of the present invention is not limited to butt-coupling, and coupling schemes that are commonly employed may be employed.

In this embodiment, since the surface light laser device 510 having polarization perpendicular to each other can be used, an optical signal can be loaded in each polarization direction, and the transmission speed can be simply doubled as compared with the conventional multiplexing method. Therefore, the present invention is applicable to the case where high data transmission is required by using a limited optical path, and especially when a low cost system configuration is required.

Furthermore, in the present embodiment, the multi-surface light laser 510 is described as an example in which two laser beams are emitted. However, the multi-surface light laser 510 is not limited thereto. Can be implemented. In this case, the optical signal can be separated in a complex manner by using a PDM scheme and another multiplexing scheme.

FIG. 12 is a schematic diagram illustrating a modification of the configuration in which an optical fiber is coupled to the multi-surface light laser in FIG. 11. Hereinafter, only the differences from FIG. 11 will be described.

Referring to FIG. 12, the multi-surface light laser 610 includes first and second surface light laser elements 610 and 620, and an optical transmission path coupled to the multi-surface light laser 610 is used for each surface light laser element. The first optical transmission path 620 is primarily coupled to 610 and 620, and the second optical transmission path 640 is secondarily coupled to the first optical transmission path 620.

The distance between the openings of the first and second surface light laser elements 610 and 620 of this embodiment does not need to be adjacent to each other in the above-described example in FIG. For example, the first and second surface light laser elements 610 and 620 may be manufactured separately and have a structure mounted on one die.

Meanwhile, the first optical transmission path 620 includes two optical fibers 621 and 622 and is primarily coupled to the first and second surface light laser elements 610 and 620 in direct one-to-one contact.

In order to easily align the polarization components, the optical fibers 621 and 622 preferably have a waveguide structure having polarization characteristics that effectively preserve the specific polarization components.

The first optical transmission path 620 is secondarily coupled to the second optical transmission path 640 of one optical fiber. This secondary coupling may be made via the optical coupler 630. The optical coupler 630 may be a conventional polarization combining unit. Furthermore, the first optical transmission path 620 and the second optical transmission path 640 may be integrally formed of an optical fiber having a 'Y' shape without the optical coupler 630.

Although the VCSEL is described as an example of the surface light laser element in the above-described embodiments, the present invention is not limited thereto, and for example, VECSEL may be possible. The surface light laser element that can be used for the multi-surface light laser of the present invention is enough to be able to emit a single polarized laser beam from a surface on the same plane. Furthermore, the surface light laser element that can be used for the multi-surface light laser of the present invention is preferably one that can be packaged on the same die, and more preferably one that can be manufactured collectively in wafer units on the same substrate.

Meanwhile, in the first to fourth embodiments described above, the case in which the surface light laser elements constituting the multi-surface light laser are 2, 3, or 4 is described as an example. Multi-surface light lasers composed of surface light laser elements are also possible. However, at least two of the plurality of surface light laser elements have different polarization directions, and in the case of laser beams having different polarization directions, optical signals are separated by the PDM method. If the polarization directions are the same or have polarization components common to each other, the optical signal may be separated by applying a different multiplexing method in combination with the PDM method.

As described above, the multi-surface light laser and the optical communication system employing the same according to the present invention have the following effects.

First, the multi-surface light laser of the present invention can arrange elements emitting polarized beams in different directions very close together, and the output surface of these elements, i.e., the openings, can be located on the same plane, so that The optical fiber can be directly coupled to a multi-surface light laser.

Secondly, by directly coupling one optical fiber to a multi-surface light laser, it is not necessary to separately provide a polarizing plate, and the coupling structure can be simplified as described above. Therefore, an optical communication system of a PDM type can be easily configured. Can be.

Third, the optical communication system of the present invention can simply obtain a double transmission speed by using a PDM scheme using different polarizations in combination with a conventional multiplexing scheme.

Such a multi-surface light laser and the optical communication system using the same have been described with reference to the embodiments shown in the drawings for clarity, but these are merely exemplary, and those skilled in the art can variously modify and It will be appreciated that other equivalent embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the appended claims.

Claims (15)

In a multi-surface light laser having a plurality of surface light laser elements, And at least two surface light laser elements of the plurality of surface light laser elements have different polarization directions. The method of claim 1, At least two surface light laser elements of the plurality of surface light laser elements are arranged such that the polarization directions of the emitted beams are perpendicular to each other. The method of claim 1, And at least three surface light laser elements of the plurality of surface light laser elements are arranged such that polarization directions of the emitted beams are maintained at a constant angular distance from each other. The method of claim 1, And at least two surface light laser elements of the plurality of surface light laser elements emit beams having different wavelengths. The method of claim 4, wherein And said at least one of the polarization direction and the wavelength of the emitted beam is different from each other. The method of claim 1, And a polarization direction is determined by a grating provided in each of the openings of the plurality of surface light laser elements. The method of claim 1, A polarization direction is determined by asymmetrically resonating conditions of each of said plurality of surface light laser elements. The method of claim 7, wherein And a polarization direction is determined by asymmetrical current limiting structures of the plurality of surface light laser elements. The method of claim 1, And said plurality of surface light laser elements are driven independently. The method of claim 1, And said plurality of surface light laser elements are formed on the same substrate. The method of claim 1, And said plurality of surface light laser elements are placed on a same die. The method of claim 1, And said plurality of surface light laser elements are arranged such that each output surface is on the same plane. A surface light laser according to any one of claims 1 to 12; And one or a plurality of light transmission paths coupled to the surface light lasers. The method of claim 13, And said plurality of surface light laser elements are disposed adjacent to each other and coupled to said one optical transmission path. The method of claim 13, The plurality of light transmission paths, A plurality of first optical transmission paths coupled to each of the plurality of surface light laser elements; And a second optical transmission path coupled to the plurality of first optical transmission paths.

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