Photonic crystal lasers

Abstract

The present disclosure provides a photonic crystal laser, which relates to the field of semiconductor lasers and includes a substrate, an N-type confinement layer, an N-type waveguide layer, an active layer, a P-type waveguide layer, a P-type confinement layer, an insulating layer, an ohmic contact layer, and a P-surface electrode layer stacked sequentially on the substrate; wherein a first film layer and a second film layer, both with a reflectivity of 0%, are respectively provided on two sides along the cavity length direction to suppress the light wave mode from oscillating in the cavity length direction; and a third film layer with a reflectivity of 0%-10% is provided on one side of two adjacent side surfaces along the cavity length direction, and a fourth film layer with a reflectivity of 90%-100% is provided on the other side to prevent the light wave mode from oscillating in the side direction. The present disclosure can avoid the longitudinal hole burning effect while ensuring high-power output of the optical signal.

Description

Technical Field

[0001] The present disclosure relates to the technical field of semiconductor lasers, and in particular to a photonic crystal laser. Background Art

[0002] Semiconductor lasers offer numerous advantages, including high power, strong reliability, long life, compact size, and low cost, making them widely used in fields such as pumping, medical treatment, and communications. Output power is a key metric for measuring semiconductor lasers. Laser output power can typically be increased by increasing the laser's bar width or cavity length. However, larger bar widths can cause spontaneous emission, while longer cavity lengths can lead to severe longitudinal hole burning. Furthermore, the laser's output power is limited by the laser's luminous area. These factors affect the laser's maximum output power. Summary of the Invention

[0003] In view of the above problems, the present disclosure provides a photonic crystal laser to improve the problems of spontaneous emission effect and longitudinal hole burning effect caused by outputting high-power optical signals.

[0004] One aspect of the present disclosure provides a photonic crystal laser, comprising: a substrate, and an N-type confinement layer, an N-type waveguide layer, an active layer, a P-type waveguide layer, a P-type confinement layer, an insulating layer, an ohmic contact layer, and a P-side electrode layer sequentially stacked on the substrate; wherein a first film layer and a second film layer, both having a reflectivity of 0%, are respectively provided on two sides along the cavity length direction to suppress the oscillation of light wave modes in the cavity length direction; and, on two adjacent side surfaces along the cavity length direction, a third film layer having a reflectivity of 0%-10% is provided on one side surface, and a fourth film layer having a reflectivity of 90%-100% is provided on the other side surface to prevent the light wave mode from oscillating on the side surfaces.

[0005] According to an embodiment of the present disclosure, a portion of the P-type confinement layer is corroded to form a ridge, and an insulating layer is stacked on both sides of the ridge; a portion of the ohmic contact layer is corroded to cover the surface of the ridge.

[0006] According to an embodiment of the present disclosure, the width of the ridge is 5 μm-300 μm.

[0007] According to an embodiment of the present disclosure, the ridges are arranged periodically, wherein the number of periods is greater than 2 and the period spacing is greater than 100 μm.

[0008] According to an embodiment of the present disclosure, the cavity length of the photonic crystal laser is 0.5 mm-6 mm, and the lateral length is 0.5 mm-1 mm; wherein the length in the cavity length direction is set to be greater than the lateral length.

[0009] According to an embodiment of the present disclosure, an N-side electrode layer is further provided on a side of the substrate away from the N-type confinement layer; the N-side electrode layer and the P-side electrode layer are prepared by thermal evaporation or magnetron sputtering technology.

[0010] According to an embodiment of the present disclosure, the materials of the first film layer, the second film layer, the third film layer and the fourth film layer can be any one of TiO2, SiO2, Ta2O5, SiO2 and Al2O3.

[0011] According to an embodiment of the present disclosure, a passivation layer is provided on the third film layer to increase the threshold damage power of the anti-reflection film cavity surface of the photonic crystal laser; wherein the material of the passivation layer can be any one of AlN and GaAs.

[0012] According to the embodiments of the present disclosure, the material of the substrate can be any one of GaAs, InP, GaN, and GaSb; the material of the N-side electrode layer can be any one of AuGeNiAu; and the material of the P-side electrode layer can be any one of TiPtAu, AuZnAu, and CrAu.

[0013] At least one of the above-mentioned technical solutions adopted in the embodiments of the present disclosure includes at least the following beneficial effects: (1) The length of the cavity length direction is set to be greater than the lateral length, and at the same time, by respectively setting a film layer with a reflectivity of 0% on both sides along the cavity length direction, on two adjacent side surfaces along the cavity length direction, one side surface does not have a film layer with a reflectivity of 0%-10%, and the other side surface is set with a film layer with a reflectivity of 90%-100%, thereby suppressing the oscillation of the light wave mode in the cavity length direction, and the light wave mode oscillates on the side surface, which can effectively alleviate the longitudinal hole burning effect. (2) By etching and setting an insulating layer to form multiple light-emitting units with periodic refractive index changes, it can not only solve the problem of lateral light emission quality, but also avoid the problem of cavity surface disaster caused by a single light-emitting unit carrying too high power, thereby greatly improving the performance of the laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] For a more complete understanding of the present disclosure and its advantages, reference will now be made to the following description taken in conjunction with the accompanying drawings, in which:

[0015] Figure 1A The overall structural diagram of the photonic crystal laser provided in Example 1 of the present disclosure is schematically shown;

[0016] Figure 1B The current injection diagram of the photonic crystal laser provided in Example 1 of the present disclosure is schematically shown;

[0017] Figure 2A The overall structural diagram of the photonic crystal laser provided in Example 2 of the present disclosure is schematically shown;

[0018] Figure 2BThe current injection diagram of the photonic crystal laser provided by Example 2 of the present disclosure is schematically shown.

[0019] [Description of Reference Numerals]

[0020] 1. N-side electrode layer; 2. Substrate; 3. N-type confinement layer; 4. N-type waveguide layer; 5. Active layer; 6. P-type waveguide layer; 7. P-type confinement layer; 8. Insulation layer; 9. Ohmic contact layer; 10. P-side electrode layer; 101. Current blocking region; 102. Current injection region. DETAILED DESCRIPTION

[0021] To make the objectives, technical solutions, and advantages of the present disclosure more clearly understood, the present disclosure is further described below in conjunction with specific embodiments and with reference to the accompanying drawings. It is apparent that the embodiments described are only a portion of the embodiments of the present disclosure, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present disclosure without inventive effort are intended to fall within the scope of protection of the present disclosure.

[0022] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise," "include," etc. used herein indicate the presence of the features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0023] In this disclosure, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections, electrical connections, or communication; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of these terms in this disclosure based on specific circumstances.

[0024] In the description of the present disclosure, it should be understood that the terms "longitudinal", "length", "circumferential", "front", "rear", "left", "right", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the subsystem or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present disclosure.

[0025] Throughout the drawings, identical elements are denoted by identical or similar reference numerals. Conventional structures or configurations are omitted where they may obscure the understanding of this disclosure. The shapes, sizes, and positional relationships of components in the drawings do not reflect actual size, proportion, or positional relationships. In addition, in the claims, any reference signs placed between parentheses should not be construed as limitations of the claims.

[0026] Similarly, in order to streamline the present disclosure and aid in understanding one or more of the various disclosed aspects, in the above description of exemplary embodiments of the present disclosure, the various features of the present disclosure are sometimes grouped together into a single embodiment, figure, or description thereof. Descriptions with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples" and the like mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in an appropriate manner.

[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the present disclosure, "plurality" means at least two, such as two or three, unless otherwise specifically defined.

[0028] The output power of a laser can usually be increased by increasing the laser's stripe width or cavity length. However, a larger stripe width can cause spontaneous emission, and a longer cavity length can cause severe longitudinal hole burning. Furthermore, the laser's output power is limited by the laser's luminous area. These factors affect the maximum power that the laser can output.

[0029] To solve the above problems, an embodiment of the present disclosure provides a photonic crystal laser.

[0030] Example 1

[0031] Figure 1A The overall structure of the photonic crystal laser provided by Example 1 of the present disclosure is schematically shown. Referring to Figure 1, the photonic crystal laser provided by the present disclosure comprises: a substrate 2, an N-type confinement layer 3, an N-type waveguide layer 4, an active layer 5, a P-type waveguide layer 6, a P-type confinement layer 7, an insulating layer 8, an ohmic contact layer 9, and a P-side electrode layer 10 sequentially stacked on the substrate 2; wherein a first film layer and a second film layer are respectively provided on both sides along the cavity length direction to suppress the oscillation of the light wave mode in the cavity length direction.

[0032] Specifically, a first film layer and a second film layer, both with a reflectivity of 0%, are placed on both sides along the cavity length to suppress oscillation of the light mode along the cavity length. Simultaneously, on two adjacent side surfaces along the cavity length, a third film layer with a reflectivity of 0%-10% is placed on one side, and a fourth film layer with a reflectivity of 90%-100% is placed on the other side to prevent oscillation of the light mode in the lateral direction. This suppresses oscillation of the light mode along the cavity length, while allowing the light mode to oscillate in the lateral direction, thereby achieving sideways light emission.

[0033] The materials of the first, second, third, and fourth film layers can be any one of TiO2, SiO2, Ta2O5, SiO2, and Al2O3. A passivation layer is provided on the third film layer to increase the threshold damage power of the anti-reflection film cavity surface of the photonic crystal laser. The passivation layer can be made of any one of AlN and GaAs.

[0034] In the disclosed embodiment, the ridges are arranged in a periodic structure and arranged along the length of the cavity, wherein the number of periods is greater than 2 and the period spacing is greater than 100 μm. Figure 1B Schematically shows a current injection diagram of a photonic crystal laser provided by another embodiment of the present disclosure. Figure 1B As shown, the corroded area is the current blocking region 101, through which current cannot be injected into the active layer 5. The ridge is the current injection region 102, through which current can be injected into the active layer 5. The length of the current injection region 102 is the lateral length of the laser, and the width of the current injection region 102 is 5μm-300μm. By etching and providing an insulating layer 8 to form multiple light-emitting units with a periodic refractive index variation, it can not only improve the lateral emission quality, but also avoid the problem of cavity surface catastrophic damage caused by excessive power carrying by a single light-emitting unit, greatly improving the performance of the laser.

[0035] The side of the substrate 2 facing away from the N-type confinement layer 3 is also provided with an N-side electrode layer 1. The N-side electrode layer 1 and the P-side electrode layer 10 are fabricated using thermal evaporation or magnetron sputtering techniques. In the disclosed embodiment, the substrate 2 can be made of any of GaAs, InP, GaN, or GaSb; the N-side electrode layer 1 is made of AuGeNiAu; and the P-side electrode layer 7 can be made of any of TiPtAu, AuZnAu, or CrAu.

[0036] The cavity length of the photonic crystal laser is 0.5 mm to 6 mm, and the lateral length is 0.5 mm to 1 mm. The cavity length is set to be greater than the lateral length. Specifically, the cavity length can be selected from 0.5 mm, 1 mm, 2 mm, 3 mm, and 4 mm, and the lateral length can be selected from 0.5 mm to 0.8 mm.

[0037] Example 2

[0038] The structure of this embodiment is basically the same as that of embodiment 1, except that:

[0039] Figure 2A The overall structure of a photonic crystal laser provided by another embodiment of the present disclosure is schematically shown. The length of the ridges formed by etching is extended inward by 5-10 μm to improve the heat distribution of the photonic crystal laser.

[0040] Figure 2B Schematically shows a current injection diagram of a photonic crystal laser provided by another embodiment of the present disclosure. Figure 2B As shown, the corroded area is the current blocking area 101, through which current cannot be injected into the active layer 5, and the ridge is the current injection area 102, through which current can be injected into the active layer 5. The length of the current injection area 102 is 5-10 μm shorter than the lateral length of the photonic crystal laser, and is used to reduce the power density on the lateral cavity surface of the laser.

[0041] It should be noted that some specific implementation details and technical effects not mentioned in Example 2 are similar to or the same as those in Example 1 and will not be repeated here.

[0042] The specific embodiments described above further illustrate the technical solutions of the present disclosure in detail. It should be understood that the above description is merely a specific embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the scope of protection of the present disclosure.

Claims

1. A photonic crystal laser, characterized in that: include: A substrate (2), an N-type confinement layer (3), an N-type waveguide layer (4), an active layer (5), a P-type waveguide layer (6), a P-type confinement layer (7), an insulating layer (8), an ohmic contact layer (9), and a P-surface electrode layer (10) sequentially stacked on the substrate (2); Among them, a first film layer and a second film layer with a reflectivity of 0% are respectively set on the two sides along the length direction of the cavity to suppress the oscillation of the light wave mode in the length direction of the cavity; on the two adjacent side surfaces along the length direction of the cavity, a third film layer with a reflectivity of 0%-10% is set on one side, and a fourth film layer with a reflectivity of 90%-100% is set on the other side to prevent the light wave mode from oscillating in the side direction.

2. The photonic crystal laser according to claim 1, wherein The P-type restriction layer (7) is partially corroded to form ridges, and the insulating layer (8) is stacked on both sides of the ridges; the ohmic contact layer (9) is partially corroded to cover the surface of the ridges.

3. The photonic crystal laser according to claim 2, characterized in that The width of the ridges is 5 μm-300 μm.

4. The photonic crystal laser according to claim 2, characterized in that The ridges are arranged periodically, wherein the number of periods is greater than 2 and the period spacing is greater than 100 μm.

5. The photonic crystal laser according to claim 1, wherein The cavity length of the photonic crystal laser is 0.5mm-6mm, and the lateral length is 0.5mm-1mm; wherein the length in the cavity length direction is set to be greater than the lateral length.

6. The photonic crystal laser according to claim 1, characterized in that An N-side electrode layer (1) is further provided on a side of the substrate (2) away from the N-type confinement layer (3); the N-side electrode layer (1) and the P-side electrode layer (10) are prepared by thermal evaporation or magnetron sputtering technology.

7. The photonic crystal laser according to claim 1, wherein The materials of the first film layer, the second film layer, the third film layer and the fourth film layer can be any one of TiO2, SiO2, Ta2O5, SiO2 and Al2O3.

8. The photonic crystal laser according to claim 1, wherein: A passivation layer is provided on the third film layer to increase the threshold damage power of the anti-reflection film cavity surface of the photonic crystal laser; wherein the material of the passivation layer can be any one of AlN and GaAs.

9. The photonic crystal laser according to claim 1, wherein: The material of the substrate (2) can be any one of GaAs, InP, GaN, and GaSb.

10. The photonic crystal laser according to claim 6, characterized in that The material of the N-side electrode layer is AuGeNiAu; the material of the P-side electrode layer can be any one of TiPtAu, AuZnAu, and CrAu.

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