EDGE-EMITTING SEMICONDUCTOR LASER WITH HIGH THERMAL CONDUCTIVITY AND LOW REFLECTION FRONT MIRROR SURFACE

Abstract

An edge-emitting semiconductor laser with high thermal conductivity and low reflection front mirror surface, comprising: an edge-emitting semiconductor laser die having a rear mirror surface and a front mirror surface on the lateral side, and the electromagnetic radiation generated by the edge-emitting semiconductor laser die is in the wavelength range of 635 nm to 1550 nm; a rear mirror surface coating; and a front mirror surface e, and a passivation layer, an affinity layer, a high thermal conductivity layer and a protective layer. Whereby, providing an edge-emitting semiconductor laser with high thermal conductivity and low reflection front mirror surface, and the front mirror surface coating is made of high thermal conductivity insulating materials to form a multi-layer coating structure, so that the front mirror surface coating has the effect of high thermal conductivity and low reflection.

Claims

1. An edge-emitting semiconductor laser with high thermal conductivity and low reflection front mirror surface, comprising: an edge-emitting semiconductor laser die 10 having a rear mirror surface 11 and a front mirror surface 12 on the lateral side, and the electromagnetic radiation generated by the edge-emitting semiconductor laser die 10 is in the wavelength range of 635 nm to 1550 nm; a rear mirror surface coating 20 is formed on the rear mirror surface 11; and a front mirror surface coating 30 is formed on the front mirror surface 12, and a passivation layer 31, an affinity layer 32, a high thermal conductivity layer 33 and a protective layer 34 are sequentially formed from the inside to the outside.

2. The edge-emitting semiconductor laser with high thermal conductivity and low reflection front mirror surface as claimed in claim 1, wherein the material selected for the passivation layer 31 is aluminum (Al), the material selected for the affinity layer 32 is aluminum oxide (Al.sub.2O.sub.3), the material selected for the high thermal conductivity layer 33 is aluminum nitride (AlN), and the material selected for the protective layer 34 is aluminum oxide (Al.sub.2O.sub.3).

3. The edge-emitting semiconductor laser with high thermal conductivity and low reflection front mirror surface as claimed in claim 2, wherein the reflectivity of the high thermal conductivity multilayer film formed by combining the affinity layer 32, the high thermal conductivity layer 33 and the protective layer 34 is less than 0.5%.

4. The edge-emitting semiconductor laser with high thermal conductivity and low reflection front mirror surface as claimed in claim 3, wherein the relation between the thickness (d1) and the wavelength (λ) of the affinity layer 32 whose material is aluminum oxide and the protective layer 34 whose material is aluminum oxide is: d1=(0.3±0.01)*λ/4/n1, n1 is the refractive index of aluminum oxide; the relation between the thickness (d2) and the wavelength (λ) of the high thermal conductivity layer 33 whose material is aluminum nitride is: d2=(0.4±0.01)*λ/4/n2, n2 is the refractive index of aluminum nitride; therefore, the material thickness range of the passivation layer 31 is 1.5˜4 nm, the material thickness range of the affinity layer 32 is 26˜72 nm, the material thickness range of the high thermal conductivity layer 33 is 28˜78 nm, the material thickness range of this protective layer 34 is 26˜72 nm.

5. The edge-emitting semiconductor laser with high thermal conductivity and low reflection front mirror surface as claimed in claim 4, wherein the preferred material thickness of the passivation layer 31 is 3 nm, the preferred material thickness of the affinity layer 32 is 44 nm, the preferred material thickness of the high thermal conductivity layer 33 is 47.6 nm, and the preferred material thickness of the protective layer 34 is 44 nm.

6. The edge-emitting semiconductor laser with high thermal conductivity and low reflection front mirror surface as claimed in claim 5, wherein the front mirror surface coating 30 is fabricated using an electron cyclotron resonance-chemical vapor deposition (ECR-CVD) machine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The FIGURE is a schematic diagram showing the structure of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0013] Referring to the FIGURE, the present invention, comprising: an edge-emitting semiconductor laser die 10 having a rear mirror surface 11 and a front mirror surface 12 on the lateral side, and the electromagnetic radiation generated by the edge-emitting semiconductor laser die 10 is in the wavelength range of 635 nm to 1550 nm; a rear mirror surface coating 20 is formed on the rear mirror surface 11; and a front mirror surface coating 30 is formed on the front mirror surface 12, and a passivation layer 31, an affinity layer 32, a high thermal conductivity layer 33 and a protective layer 34 are sequentially formed from the inside to the outside; the material selected for the passivation layer 31 is aluminum (Al), the material selected for the affinity layer 32 is aluminum oxide (Al.sub.2O.sub.3), the material selected for the high thermal conductivity layer 33 is aluminum nitride (AlN), and the material selected for the protective layer 34 is aluminum oxide (Al.sub.2O.sub.3); and the reflectivity of the high thermal conductivity multilayer film formed by combining the affinity layer 32, the high thermal conductivity layer 33 and the protective layer 34 is less than 0.5%.

[0014] Moreover, the material thickness range of the passivation layer 31 is 1.5˜4 nm (preferred 3 nm), the material thickness range of the affinity layer 32 is 26˜72 nm (preferred 44 nm), the material thickness range of the high thermal conductivity layer 33 is 28˜78 nm (preferred 47.6 nm), the material thickness range of this protective layer 34 is 26˜72 nm (preferred 44 nm); wherein the relation between the thickness (d1) and the wavelength (λ) of the affinity layer 32 whose material is aluminum oxide and the protective layer 34 whose material is aluminum oxide is: d1=(0.3±0.01)*λ/4/n1, n1 is the refractive index of aluminum oxide; the relation between the thickness (d2) and the wavelength (λ) of the high thermal conductivity layer 33 whose material is aluminum nitride is: d2=(0.4±0.01)*λ/4/n2, n2 is the refractive index of aluminum nitride.

[0015] With the feature disclosed above, the mirror floating bond and high temperature heat dissipation is the main problem of the edge-emitting semiconductor laser during operation; therefore, the present invention provide a four-layer structure of the front mirror surface coating 30. The first layer is the passivation layer 31, and the material is aluminum. First, make the floating bonds on the split surface of the edge-emitting semiconductor laser die 10 bond with aluminum; the second layer is the affinity layer 32, and the material is Al.sub.2O.sub.3 has high affinity with GaAs substrate and has a similar expansion coefficient. The third layer is a high thermal conductivity layer 33, and the material is AlN. However, since AlN itself is deliquescent by water vapor, it will be equipped with a fourth layer of protective layer 34, which material is Al.sub.2O.sub.3; according to this design, the front mirror surface coating 30 selects high thermal conductivity insulating materials to form a multi-layer coating structure, so that the front mirror surface coating 30 has the effect of high thermal conductivity and low reflection; however, the front mirror surface coating 30 can be fabricated by using an electron cyclotron resonance-chemical vapor deposition (ECR-CVD) machine, because production process with coating uses aluminum targets, it can be continuously completed in the same cavity; in addition, the affinity layer 32, the high thermal conductivity layer 33 and the protective layer 34 can be adjusted according to different laser wavelength products to form a high thermal conductivity multilayer film.