JP2006302955A - Vertical cavity surface emitting laser - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vertical cavity surface emitting laser capable of setting an arbitrary oscillation wavelength without changing the length of a resonator one by one. <P>SOLUTION: The vertical cavity surface emitting laser comprises the resonator 40 that contains an active layer 13, and a lower cladding layer 12 and an upper cladding layer 14 provided while sandwiching the active layer 13, and resonates at a first wavelength; and a longitudinal mode adjustment layer 11-2 whose film thickness has been adjusted, so that it resonates at a wavelength that is different from the first wavelength, thus causing oscillation at a wavelength that is different from the first wavelength by the interaction between the resonator 40 and the longitudinal mode adjustment layer 11-2, regardless of whether the resonator length of the resonator 40 is set based on the first wavelength, and hence emitting laser beams having an oscillation wavelength to the outside. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a surface-emitting type semiconductor laser having a laser light emitting region on an upper surface, for example, a surface-emitting type semiconductor laser that can be suitably applied to applications requiring multimode oscillation.

  Unlike conventional Fabry-Perot resonator semiconductor lasers, surface-emitting semiconductor lasers emit light in a direction orthogonal to the substrate, and a large number of elements are arranged in a two-dimensional array on the same substrate. In recent years, it has attracted attention in the data communication field.

Here, a basic structure and operation of a general surface emitting semiconductor laser will be briefly described. As described in Patent Document 1, a surface emitting semiconductor laser includes a pair of multilayer reflectors formed on a semiconductor substrate, and an active layer serving as a light emitting region between the pair of reflectors and both sides thereof. A laser structure having a resonator comprising a clad layer provided on the substrate. A pair of multilayer-film reflective mirror is a low refractive index layer and the high refractive index layer of lambda _0/4 optical film thickness, respectively (lambda ₀ is the emission wavelength) as one set, it that is configured to include a plurality of sets One multilayer reflector is further provided with a current confinement layer having a structure in which the current injection region is narrowed in order to increase the current injection efficiency into the active layer and lower the threshold current. Further, an n-side electrode is provided on the lower surface side, a p-side electrode is provided on the upper surface side, and an opening for emitting laser light is provided on the p-side electrode. In this surface emitting semiconductor laser, the current confined by the current confinement layer provided in one multilayer reflector is injected into the active layer, and the light emitted from the active layer is reflected by the pair of multilayer reflectors. As a result, the laser beam is emitted as a single longitudinal mode laser beam from an opening provided in the p-side electrode.

JP 2001-332812 A

By the way, in the surface-emitting semiconductor laser described above, the resonator length of the resonator is about one wavelength. Therefore, the wavelength that can exist in the resonator is basically the wavelength of the fundamental wave (corresponding to the emission wavelength λ ₀ described above). Only). Therefore, when changing the wavelength of the fundamental wave, there is a problem that the resonator length of the resonator and the film thickness of the multilayer reflector must be changed one by one. In addition, in the above-described surface emitting semiconductor laser, when the transverse mode is single, the laser light of a single longitudinal mode is emitted stably, so unlike the Fabry-Perot resonator semiconductor laser, the multimode laser light Is difficult to emit. Therefore, when emitting multi-wavelength laser light, it is necessary to prepare a plurality of surface-emitting semiconductor lasers having different emission wavelengths.

  The present invention has been made in view of such problems, and a first object thereof is a surface-emitting type semiconductor laser capable of setting an arbitrary oscillation wavelength without changing the resonator length of each resonator. Is to provide. A second object is to provide a surface emitting semiconductor laser capable of generating oscillation in multiple modes.

  The surface-emitting type semiconductor laser of the present invention includes an active layer, a first cladding layer and a second cladding layer provided with the active layer therebetween, and is configured to resonate at a first wavelength. And a second resonator whose film thickness is adjusted so as to resonate at a wavelength different from the first wavelength.

  In the surface-emitting type semiconductor laser of the present invention, the first resonator and the second resonator interact with each other even though the resonator length of the first resonator is set based on the first wavelength. Oscillation occurs at a wavelength different from one wavelength, and as a result, laser light having the oscillation wavelength is emitted to the outside.

In the case where the optical thickness of the second resonator is set appropriately lambda _0/4 greater than the range, or oscillate at different single wavelength occurs from the first wavelength, or different from the first wavelength Oscillation occurs at multiple wavelengths.

Specifically, when the optical film thickness L of the second resonator is set so as to satisfy the following formula (1) or formula (2), a single wavelength different from the first wavelength is used. Oscillation occurs. Here, a is an integer of 1 or more and less than 10.
_{λ 0/4 <L <2λ} 0/4 ... (1)
_{(2a + 1) λ 0/} 4 ≦ L <2 (a + 1) λ 0/4 ... (2)

When the optical film thickness L of the second resonator is set so as to satisfy the following expression (3), oscillation occurs at a plurality of wavelengths different from the first wavelength. Here, a is an integer of 10 or more.
_{(2a + 1) λ 0/} 4 ≦ L <2 (a + 1) λ 0/4 ... (3)

Even when the optical film thickness L of the second resonator is set to satisfy the following expression (4), oscillation occurs at a plurality of wavelengths different from the first wavelength. Here, a is an integer of 1 or more.
_{(2a) λ 0/4 ≦} L <(2a + 1) λ 0/4 ... (4)

Incidentally, when the displacing the optical thickness L of the second resonator, the oscillation wavelength will be displaced to a different wavelength than the first wavelength, an integral multiple become the mode hopping of the value of the optical thickness L is lambda _0/4 is As a result, the number of oscillation wavelengths also changes.

  According to the surface-emitting type semiconductor laser of the present invention, the first resonator has a cavity length set based on the first wavelength. Since oscillation occurs at two or more wavelengths, an arbitrary oscillation wavelength can be set without changing the resonator length of the first resonator.

  In addition, when the optical film thickness of the second resonator is appropriately set, oscillation can be generated in a plurality of wavelengths different from the first wavelength, that is, in multiple modes.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 shows a cross-sectional structure of a surface emitting semiconductor laser according to an embodiment of the present invention. FIG. 2 specifically shows the longitudinal mode adjustment layer 11-2 (second resonator) of the surface emitting semiconductor laser of FIG. 1 and the structure in the vicinity thereof.

  The surface emitting semiconductor laser according to the present embodiment includes a first lower DBR mirror layer 11-1 (first multilayer mirror), a longitudinal mode adjustment layer 11-2, and a second lower DBR mirror on one surface side of the substrate 10. Layer 11-3 (first multilayer reflector), lower cladding layer 12 (first cladding layer), active layer 13, upper cladding layer 14 (second cladding layer), upper DBR mirror layer 15 (second multilayer reflection) And a laser structure portion in which a p-side contact layer 16 is laminated in this order. Here, a part of the lower cladding layer 12, the active layer 13, the upper cladding layer 14, the upper DBR mirror layer 15, and the p-type contact layer 16 are formed up to the p-type contact layer 16 and then selectively etched from the upper surface. Thus, a convex mesa portion 30 is formed.

  In addition, the surface emitting semiconductor laser is configured by laminating the protective film 17 and the p-side electrode 18 on the mesa portion 30 or the peripheral portion, and the n-side electrode 19 (electrode layer) is the longitudinal mode adjustment layer 11. -2.

  Substrate 10, first lower DBR mirror layer 11-1, longitudinal mode adjustment layer 11-2, second lower DBR mirror layer 11-3, lower cladding layer 12, active layer 13, upper cladding layer 14, and upper DBR mirror layer 15 The p-type contact layer 16 is made of, for example, a GaAs (gallium arsenide) based compound semiconductor. The GaAs compound semiconductor is a compound semiconductor containing at least gallium (Ga) among the 3B group elements in the short periodic table and at least arsenic (As) among the 5B elements in the short periodic table. Say.

  The substrate 10 is made of, for example, n-type GaAs.

  The lower DBR mirror layer 11 is configured by stacking a first lower DBR mirror layer 11-1, a longitudinal mode adjustment layer 11-2, and a second lower DBR mirror layer 11-3 in this order. The first lower DBR mirror layer 11-1 and the second lower DBR mirror layer 11-3 are configured by alternately stacking low refractive index layers 11A and high refractive index layers 11B. Here, the upper layer of the first lower DBR mirror layer 11-1 and the lower layer of the second lower DBR mirror layer 11-1, that is, the first lower DBR mirror layer 11-1 and the second lower DBR mirror layer 11 are used. Each of the layers in contact with the longitudinal mode adjusting layer 11-2 of -1 is one of the low refractive index layer 11A and the high refractive index layer 11B.

Low refractive index layer 11A is, for example optical film thickness is constituted by a lambda _0/4 of n-type _{Al x1 Ga 1-x1 As (} 0 <x1 <1), the high refractive index layer 11B is, for example optical thickness There composed of lambda _0/4 of n-type _{Al x2 Ga 1-x2 As (} 0 <x2 <x1). Note that λ ₀ is the wavelength of a standing wave (wavelength of the fundamental wave) generated in the resonator 40 described later, and corresponds to the first wavelength of the present invention. The n-type impurity is, for example, silicon (Si) or selenium (Se).

When the longitudinal mode adjustment layer 11-2 is a low refractive index layer 11A when the layer on the upper surface of the first lower DBR mirror layer 11-1 and the layer on the lower surface of the second lower DBR mirror layer 11-1 are formed, It has the same composition as the high refractive index layer 11B in the vicinity of the longitudinal mode adjustment layer 11-2, and the upper layer of the first lower DBR mirror layer 11-1 and the lower layer of the second lower DBR mirror layer 11-1 are high. In the case of the refractive index layer 11B, it has the same composition as the low refractive index layer 11A in the vicinity of the longitudinal mode adjustment layer 11-2. The vertical mode adjusting layer 11-2 has a large optical thickness than lambda _0/4, i.e., having different optical thickness and the low refractive index layer 11A and the high-refractive index layer 11B described above. Therefore, the lower DBR mirror layer 11 is configured by alternately laminating layers having a low refractive index property and layers having a high refractive index property, and partially laminates layers having different optical film thicknesses. Configured.

Here, the longitudinal mode adjustment layer 11-2 is preferably provided near the active layer 13 in the lower DBR mirror layer 11. In FIG. 2, the longitudinal mode adjustment layer 11-2 is closer to the active layer 13 in the lower DBR mirror layer 11, specifically, the second high refractive index layer 11 A ₂ and the third high refractive index layer 11 A ₂ from the active layer 13. A configuration example in the case of being provided between the refractive index layer 11A ₃ is shown.

The lower cladding layer 12 is made of, for example, Al _x3 Ga _1-x3 As (0 <x3 <1). The active layer 13 is made of, for example, a GaAs material. The upper cladding layer 14 is made of, for example, Al _x4 Ga _{1 -x4} As (0 <x4 <1). The lower cladding layer 12, the active layer 13, and the upper cladding layer 14 are preferably undoped, but may contain p-type or n-type impurities.

  The lower cladding layer 12, the active layer 13, and the upper cladding layer 14 constitute a resonator 40 (first resonator). For example, a one-wavelength resonator in which the active layer 13 is placed on the antinode of the standing wave of the resonator 40. Alternatively, an ultrashort resonator such as a half-wave resonator in which the active layer 13 is placed at a node of a standing wave of the resonator is formed. Thus, since the resonator length of the resonator 40 is about one wavelength, the wavelength that can exist in the resonator 40 is basically only the wavelength of the fundamental wave.

The upper DBR mirror layer 15 is configured by alternately laminating low refractive index layers 16A and high refractive index layers 16B. The low refractive index layer 16A is, for example optical film thickness is constituted by the lambda _0/4 of p-type _{Al x5 Ga 1-x5 As (} 0 <x5 <1), the high refractive index layer 16B is, for example optical film thickness lambda ₀ / composed of 4 of the p-type _{Al x6 Ga 1-x6 As (} 0 <x6 <x5). Here, the p-type impurity is zinc (Zn), magnesium (Mg), beryllium (Be), or the like.

However, in the upper DBR mirror layer 15, a current confinement layer 15C is formed in place of the low refractive index layer 16A at a portion of the low refractive index layer 16A which is several layers away from the active layer 13 side. The current confinement layer 15C includes a current injection region 15C-1 provided in the central region and a current confinement region 15C-2 provided in a portion surrounding the current injection region 15C-1. The current injection region 15C-1 is made of, for example, Al _x7 Ga _1-x7 As (x5 <x7 <1), and the current confinement region 15C-2 is made of, for example, Al ₂ O ₃ .

  The p-side contact layer 16 is made of, for example, p-type GaAs. The p-side contact layer 16 has, for example, a circular opening in a region facing the current injection region 15C-1, and the upper DBR mirror layer 15 is exposed at the bottom of the opening. This opening corresponds to the laser light emission region. The central region of the opening mainly corresponds to a region where fundamental transverse mode oscillation occurs, and the region other than the central region of the opening mainly corresponds to a region where higher order transverse mode oscillation occurs. Yes.

  The protective film 17 is formed so as to cover the region of the p-side contact layer 16 excluding the peripheral portion of the opening and the side surface of the mesa portion 30, and is made of, for example, an oxide or a nitride.

  The p-side electrode 18 is formed on the peripheral portion of the opening in the p-side contact layer 16 and a part of the surface of the protective film 17. A portion of the p-side electrode 18 formed in the peripheral portion of the opening has a ring shape, and a portion of the p-side electrode 18 formed on a part of the surface of the protective film 17 is a wire. It has a flat plate shape with a sufficient surface area for bonding. The p-side electrode 18 is also configured by, for example, laminating a titanium (Ti) layer, a platinum (Pt) layer, and a gold (Au) layer in this order, and is electrically connected to the p-type contact layer 16. ing.

  The n-side electrode 19 is formed by, for example, laminating a titanium (Ti) layer, a platinum (Pt) layer, and a gold (Au) layer in this order, and is formed on the back side of the substrate 10.

  The surface emitting semiconductor laser according to the present embodiment can be manufactured, for example, as follows.

3A to 3B and FIGS. 4A to 4B show the manufacturing method in the order of steps. For example, in order to manufacture a GaAs (gallium arsenide) based surface emitting semiconductor laser, a compound semiconductor layer on the substrate 10 is formed by, for example, MOCVD (Metal Organic Chemical Vapor Deposition) method. To do. At this time, for example, trimethylaluminum (TMA), trimethylgallium (TMG), trimethylindium (TMIn), or arsine (AsH ₃ ) is used as a raw material for the III-V group compound semiconductor. , H ₂ Se, and dimethyl zinc (DMZ), for example, is used as the acceptor impurity material.

  Specifically, first, as shown in FIG. 3A, on the substrate 10, the first lower DBR mirror layer 11-1, the longitudinal mode adjustment layer 11-2, and the second lower DBR mirror layer 11-3. The lower cladding layer 12, the active layer 13, the upper cladding layer 14, the upper DBR mirror layer 15, and the p-side contact layer 16 are laminated in this order.

  Next, as shown in FIG. 3B, for example, a mask layer (not shown) is formed on the p-side contact layer 16, and the reactive ion etching (RIE) method is used to form the p layer. The side contact layer 16, the upper DBR mirror layer 15, the upper cladding layer 14, the active layer 13, and the lower cladding layer 12 are selectively removed and part of the p-side contact layer 16 is etched to form openings. Form. Thereby, the mesa part 30 which has an opening part in the top is formed.

  Next, as shown in FIG. 4A, oxidation treatment is performed at a high temperature in a water vapor atmosphere, and Al in the AlAs layer 15D that becomes the current confinement layer 15C, for example, is selected from the outside of the mesa portion 30. Oxidizes. As a result, the current injection region 15C-1 is formed in the center region of the layer, and the current confinement region 15C-2 is formed in the other regions. As a result, the current injection region 15C-1 and the current confinement region 15C- A current confinement layer 15C made of 2 is formed.

  Next, as shown in FIG. 4B, an insulating material is stacked on the mesa unit 30 and the peripheral substrate of the mesa unit 30 by, for example, a CVD (Chemical Vapor Deposition) method, and then the insulating material is etched. The portion corresponding to the central region of the opening is selectively removed to expose upper DBR mirror layer 15 and p-side contact layer 16.

  Next, as shown in FIG. 1, after depositing a metal material on the mesa unit 30 and the peripheral substrate of the mesa unit 30 by, for example, vacuum deposition, the upper DBR mirror layer is formed in the opening by, for example, selective etching. 15 is exposed, and a wire bonding pad is formed on the peripheral substrate of the mesa unit 30. In this way, the p-side electrode 18 electrically connected to the p-side contact layer 16 is formed.

  Next, after appropriately polishing the back surface of the substrate 11 to adjust the thickness of the substrate, the n-side electrode 19 is formed on the back surface of the substrate 11. In this way, the surface emitting semiconductor laser is manufactured.

  In the surface emitting semiconductor laser having such a configuration, when a predetermined voltage is applied between the n-side electrode 19 and the p-side electrode 18, the active layer 13 is passed through the current injection region 15C-1 in the current confinement layer 15C. A current is injected, which causes light emission due to recombination of electrons and holes. This light is reflected by the pair of the lower DBR mirror layer 11 and the upper DBR mirror layer 15 and causes laser oscillation at a wavelength at which the phase change when it reciprocates once in the element is an integral multiple of 2π. Is emitted.

Incidentally, the optical thickness L of the longitudinal mode adjusting layer 11-2 is larger than lambda _0/4, the optical thickness L when properly set lambda _0/4 greater than the range is different from the first wavelength oscillation occurs at a single wavelength lambda _1, the one laser beam having an oscillation wavelength lambda ₁ is emitted, or, a plurality of wavelengths lambda ₁ which is different from the first wavelength, λ _2, ...... λn (n is a positive Oscillation occurs at an integer), and laser beams having a plurality of oscillation wavelengths λ ₁ , λ ₂ ,... Λn are emitted from the opening.

For example, when the optical film thickness L of the longitudinal mode adjustment layer 11-2 is set so as to satisfy the following formula (1) or formula (2), a single wavelength different from the first wavelength λ ₀ oscillation occurs at lambda _1, the laser light of the oscillation wavelength lambda ₁ is emitted from the opening. Here, a is an integer of 1 or more and less than 10.
_{λ 0/4 <L <2λ} 0/4 ... (1)
_{(2a + 1) λ 0/} 4 ≦ L <2 (a + 1) λ 0/4 ... (2)

When the optical film thickness L of the longitudinal mode adjustment layer 11-2 is set so as to satisfy the following expression (3), a plurality of wavelengths λ ₁ and λ ₂ different from the first wavelength λ ₀ are set. ... Oscillation occurs at λn, and laser light having a plurality of oscillation wavelengths λ ₁ , λ ₂ ,. Here, a is an integer of 10 or more.
_{(2a + 1) λ 0/} 4 ≦ L <2 (a + 1) λ 0/4 ... (3)

Even when the optical film thickness L of the longitudinal mode adjustment layer 11-2 is set so as to satisfy the following formula (4), a plurality of wavelengths λ ₁ and λ ₂ different from the first wavelength λ ₀ are obtained. ... Oscillation occurs at λn, and laser light having a plurality of oscillation wavelengths λ ₁ , λ ₂ ,. Here, a is an integer of 1 or more.
_{(2a) λ 0/4 ≦} L <(2a + 1) λ 0/4 ... (4)

5, the optical thickness L of the longitudinal mode adjustment layer 11-2 and numerical normalized by lambda _0/4, illustrates a relationship between the number of modes. In FIG. 5, the line segment enclosed by A is in Equation (1), the line segment surrounded by B is in Equation (2), and the line segment surrounded by C is in Equation (4). Flying line segments surrounded by D correspond to Equation (3), respectively. Further, a black circle in the line segment means that a normalized numerical value corresponding to the black circle is included, and a white circle in the line segment means that a normalized numerical value is not included.

  Here, the line segment is skipped, which means that a mode hop occurs when the optical film thickness L of the longitudinal mode adjustment layer 11-2 is changed. For example, when the normalized numerical value is gradually changed from a numerical value greater than 1 to 20 (the normalized numerical value may not be an integer), the mode number hops from 1 to 2 or 2 to 1 You can confirm that you want to hop. Further, when the normalized numerical value is gradually changed from a value larger than 20 to a value smaller than 40, the mode number hops from 2 to 3 without hopping from 2 to 1, or from 3 to 2. You can confirm that you hop. It can be confirmed that there is a tendency similar to the above when the normalized numerical value is 40 or more.

By the way, when the optical film thickness L of the longitudinal mode adjusting layer 11-2 is changed, as illustrated in FIG. 6A, the oscillation wavelength is changed to one or more wavelengths different from the first wavelength λ _0. but the mode hop occurs when the value of the optical thickness L is an integral multiple of lambda _0/4, Thus, as illustrated in FIG. 6 (B), also changes the number of the oscillation wavelength.

  As illustrated in FIG. 6A, the oscillation wavelength is changed by changing the optical film thickness L of the longitudinal mode adjustment layer 11-2 because the optical film thickness L of the longitudinal mode adjustment layer 11-2 is changed. This is because the phase of the reflected light reflected by the end face of the longitudinal mode adjusting layer 11-2 gradually changes as the laser oscillation conditions change.

  As illustrated in FIG. 6B, the number of modes increases by increasing the optical film thickness L of the longitudinal mode adjustment layer 11-2. The optical film thickness L of the longitudinal mode adjustment layer 11-2 increases. As the wave number increases, the wave number of the standing wave formed in the longitudinal mode adjustment layer 11-2 changes, and the resonance wavelength newly formed when the wave number changes changes the lower DBR mirror layer 11 and the upper DBR mirror layer. By entering 15 high reflection bands W (see FIGS. 7A and 8A), it becomes possible to oscillate at a new wavelength (see FIGS. 7B and 8B). Because. 7A and 7B show the reflectance, gain, and transmitted light intensity of the surface emitting semiconductor laser of this embodiment when the number of modes is 1, respectively. (A) and (B) show the reflectivity, gain, and transmitted light intensity of the surface emitting semiconductor laser according to the present embodiment when the number of modes is 2, respectively.

  Although the present invention has been described with reference to one embodiment, the present invention is not limited to the above embodiment and can be variously modified.

  For example, in the above embodiment, the longitudinal mode adjustment layer 11-2 is provided in the lower DBR mirror layer 11 near the active layer 13, but the lower DBR mirror layer 11 near the active layer 13 is provided. Other portions (for example, a portion near the substrate 10), the upper DBR mirror layer 15, and both the lower DBR mirror layer 11 and the upper DBR mirror layer 15 may be provided. Further, a portion other than the lower DBR mirror layer 11 and the upper DBR mirror layer 15, for example, between the lower DBR mirror layer 11 and the substrate 10 may be provided. The function of the lower DBR mirror layer 11 and the upper DBR mirror layer 15 is not impaired by the portion where the longitudinal mode adjustment layer 11-2 is disposed, and the effect of the longitudinal mode adjustment layer 11-2 is lost. Because there is no.

  However, as the longitudinal mode adjustment layer 11-2 approaches the resonator 40, the intensity of the light emitted from the active layer 13 increases, so that at least one of the upper DBR mirror layer 15 and the lower DBR mirror layer 11 It is preferable to be provided at a site near the active layer 13. Further, since the longitudinal mode adjustment layer 11-2 is thicker than the low refractive index layer 11A and the high refractive index layer 11B, it is not necessary to increase the height of the mesa portion 30, for example, the lower DBR mirror layer. 11 is more preferable to be provided only at a site near the active layer 13.

  In the above embodiment, the n-side electrode 19 is provided on the back side of the substrate 10, but as shown in FIG. 9, it is provided so as to be in contact with a part of the longitudinal mode adjustment layer 11-2. May be. However, in that case, it is necessary to make ohmic contact between the longitudinal mode adjustment layer 11-2 and the n-side electrode layer 20, and therefore it is preferable that the value of the Al composition of the longitudinal mode adjustment layer 11-2 is large. More preferably, it is the same value as that of the high refractive index layer 11B in the vicinity of the longitudinal mode adjusting layer 11-2. At this time, the upper layer of the first lower DBR mirror layer 11-1 and the lower layer of the second lower DBR mirror layer 11-1, that is, the first lower DBR mirror layer 11-1 and the second lower DBR mirror layer 11 are used. Each of the layers in contact with the longitudinal mode adjusting layer 11-2 in −1 is a low refractive index layer 11A. Thereby, the longitudinal mode adjustment layer 11-2 can be provided inside the lower DBR mirror layer 11 without impairing the function as the lower DBR mirror layer 11.

1 is a cross-sectional configuration diagram of a surface emitting semiconductor laser according to an embodiment of the present invention. It is a cross-sectional block diagram of the principal part of the laser of FIG. It is sectional drawing for demonstrating the manufacturing process of the laser shown in FIG. It is sectional drawing for demonstrating the process following FIG. It is a conceptual diagram for demonstrating the change of the number of modes. It is a conceptual diagram for demonstrating the transition of an oscillation wavelength. It is a conceptual diagram for demonstrating a reflectance, a gain, and the transmitted light intensity in a single longitudinal mode. It is a conceptual diagram for demonstrating a reflectance, a gain, and transmitted light intensity in multimode. It is a cross-sectional block diagram of the modification of the laser of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Board | substrate, 11 ... Lower DBR mirror layer, 11-1 ... 1st lower DBR mirror layer, 11-2 ... Longitudinal mode adjustment layer, 11-3 ... 2nd lower DBR mirror layer, 11A, 15A ... Low refractive index layer 11B, 15B ... high refractive index layer, 12 ... lower cladding layer, 13 ... active layer, 14 ... upper cladding layer, 15 ... upper DBR mirror layer, 15C ... current confinement layer, 15C-1 ... current injection region, 15C- 2 ... current confinement region, 15D ... AlAs layer, 16 ... p-side contact layer, 17 ... protective film, 18 ... p-side electrode, 19 ... n-side electrode, 30 ... mesa portion, 40 ... resonator.

Claims (9)

A first resonator including an active layer, and a first cladding layer and a second cladding layer provided with the active layer interposed therebetween, and configured to resonate at a first wavelength;
A surface-emitting type semiconductor laser comprising: a second resonator whose film thickness is adjusted so as to resonate at a wavelength different from the first wavelength. When the optical film thickness of the second resonator is L and a is an integer of 1 to less than 10, L is set so as to satisfy the following formula (1) or formula (2). Item 2. The surface emitting semiconductor laser according to Item 1.
_{λ 0/4 <L <2λ} 0/4 ... (1)
_{(2a + 1) λ 0/} 4 ≦ L <2 (a + 1) λ 0/4 ... (2) 2. The surface emitting according to claim 1, wherein L is set to satisfy the following expression (3), where L is an optical film thickness of the second resonator, and a is an integer of 10 or more. Type semiconductor laser.
_{(2a + 1) λ 0/} 4 ≦ L <2 (a + 1) λ 0/4 ... (3) 2. The surface emitting according to claim 1, wherein L is set so as to satisfy the following expression (4), where L is an optical film thickness of the second resonator, and a is an integer of 1 or more. Type semiconductor laser.
_{(2a) λ 0/4 ≦} L <(2a + 1) λ 0/4 ... (4) The first provided between the resonator comprises a pair of multilayer mirror optical thickness is respectively configured to include multiple layers lambda _0/4 of the low refractive index layer and the high refractive index layer, respectively,
The surface emitting semiconductor laser according to claim 1, wherein the second resonator is provided in at least one of the pair of multilayer film reflecting mirrors. The surface emitting semiconductor laser according to claim 5, wherein the second resonator is provided so as to be in contact with the two low refractive index layers or the two high refractive index layers. The surface according to claim 6, wherein the second resonator provided between the two low-refractive index layers has the same composition as the high-refractive index layer in the vicinity of the low-refractive index layers. Light emitting semiconductor laser. The surface according to claim 6, wherein the second resonator provided between the two high refractive index layers has the same composition as the low refractive index layer in the vicinity of the high refractive index layers. Light emitting semiconductor laser. The surface emitting semiconductor laser according to claim 8, wherein the electrode layer is provided so as to be in contact with a part of the second resonator.

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