Laser module with sealed package containing limited optical components

1. A laser module comprising:

one or more semiconductor laser elements which emit one or more divergent laser beams;

one or more collimator lenses which collimate said one or more divergent laser beams to obtain one or more collimated laser beams;

a condensing lens which condenses said one or more collimated laser beams, and make the one or more collimated laser beams converge at a convergence position;

an optical fiber which has a light-entrance end face and is arranged in such a manner that said convergence position is located on the light-entrance end face;

a first package which contains said one or more semiconductor laser elements and said one or more collimator lenses, does not contain said condensing lens and said light-entrance end face, and is hermetically sealed;

a second package which contains said condensing lens, is hermetically sealed, and has lower sealing performance than said first package; and

a third package, provided outside said second package, wherein the third package contains the light entrance end face of said optical fiber and does not contain said condensing lens.

2. A laser module according to claim 1 , wherein said second package contains said first package.

3. A laser module according to claim 1 , wherein said first package is hermetically sealed by one of fusion, welding, soldering using a flux-free solder, and adhesion using an adhesive which does not contain a silicon-based organic material.

4. A laser module according to claim 1 , wherein said first package is filled with inert gas.

5. A laser module according to claim 4 , wherein said inert gas contains one or a mixture of oxygen gas, halogen gas, and halide gas at a concentration of 1 ppm or higher.

6. A laser module according to claim 1 , further comprising a second package which is separated from said first package, contains said light-entrance end face of said optical fiber, and is hermetically sealed.

7. A laser module according to claim 6 , wherein said second package is hermetically sealed by one of fusion, welding, soldering using a flux-free solder, and adhesion using an adhesive which does not contain a silicon-based organic material.

8. A laser module according to claim 1 , wherein said one or more semiconductor laser elements have an oscillation wavelength of 350 to 500 nm.

9. A laser module according to claim 1 , wherein said one or more semiconductor laser elements are realized by an array of single-cavity semiconductor laser elements, or a single multi-cavity semiconductor laser element, or an array of multi-cavity semiconductor laser elements, or a combination of at least one single-cavity semiconductor laser element and at least one multi-cavity semiconductor laser element.

10. A laser module according to claim 1 , wherein said one or more semiconductor laser elements emit a plurality of laser beams which are combined into a single laser beam in said optical fiber.

11. A laser module comprising:

one or more semiconductor laser elements which emit one or more divergent laser beams;

one or more magnifying condenser lenses which condense said one or more divergent laser beams so as to make the one or more divergent laser beams converge at a convergence position;

an optical fiber which has a light-entrance end face and is arranged in such a manner that said convergence position is located on the light-entrance end face;

a first package which contains said one or more semiconductor laser elements and said one or more magnifying condenser lenses, does not contain said light-entrance end face, and is hermetically sealed;

a second package having a front plate;

a ferrule into which the light-entrance end face of said optical fiber is inserted; and

a receptacle into which an end of said ferrule is inserted, wherein said receptacle is attached to the front plate of said second package such that the light entrance end face of said optical fiber within said ferrule abuts the light entrance face of said second package.

12. A laser module according to claim 11 , wherein said first package is hermetically sealed by one of fusion, welding, soldering using a flux-free solder, and adhesion using an adhesive which does not contain a silicon-based organic material.

13. A laser module according to claim 11 , wherein said first package is filled with inert gas.

14. A laser module according to claim 13 , wherein said inert gas contains one or a mixture of oxygen gas, halogen gas, and halide gas at a concentration of 1 ppm or higher.

15. A laser module according to claim 11 , wherein said second package is separated from said first package, and is hermetically sealed.

16. A laser module according to claim 15 , wherein said second package is hermetically sealed by one of fusion, welding, soldering using a flux-free solder, and adhesion using an adhesive which does not contain a silicon-based organic material.

17. A laser module according to claim 11 , wherein said one or more semiconductor laser elements have an oscillation wavelength of 350 to 500 nm.

18. A laser module according to claim 11 , wherein said one or more semiconductor laser elements are realized by an array of single-cavity semiconductor laser elements, or a single multi-cavity semiconductor laser element, or an array of multi-cavity semiconductor laser elements, or a combination of at least one single-cavity semiconductor laser element and at least one multi-cavity semiconductor laser element.

19. A laser module according to claim 11 , wherein said one or more semiconductor laser elements emit a plurality of laser beams which are combined into a single laser beam in said optical fiber.

20. A laser module according to claim 19 , wherein said one or more semiconductor laser elements have light-emission axes and are arranged so that said plurality of laser beams emitted from the one or more semiconductor laser elements are two-dimensionally arrayed along a plane perpendicular to the light-emission axes.