Optical coupling apparatus

1. An optical coupling apparatus comprising:

a temperature control element on which a semiconductor light emitting element, a substrate and a lens are mounted, the semiconductor light emitting element being mounted on the substrate, and rays of light from the semiconductor light emitting element being introduced into the lens;

a base on which the temperature control element is disposed;

a through-hole portion formed in a housing wall portion installed on the base, penetrating through the housing wall portion and having a wall surface portion longer than a thickness of the housing wall portion; and

an optical fiber communicated with the through-hole portion and receiving converted light from the lens introduced thereto;

wherein a length of the substrate in a direction connecting the light emitting element to the optical fiber is within a range from 0.1 to 0.25 with respect to a length of the base sandwiched by the housing walls of the substrate.

2. The optical coupling apparatus according to claim 1 , further comprising an optical isolator which communicates with the through-hole portion and into which the converged light is introduced on a side of the lens from an end portion of the optical fiber;

wherein the optical isolator and at least a part of the optical fiber are arranged inside a region of the through-hole portion encompassed by the housing walls; and

wherein the end portion of the optical fiber is arranged at a position within three times the thickness of the housing wall from an outer or inner side surface of the housing wall in a direction connecting the light emitting element and the optical fiber.

3. The optical coupling apparatus according to claim 1 , wherein the end portion of the optical fiber is formed at a position within a range from 3.5 to 12.5 times a thickness of the lens from the light emitting element.

4. The optical coupling apparatus according to claim 1 , wherein a distance from an inner side wall of the housing wall to the temperature control element in a direction connecting the light emitting element and the optical fiber is arranged within a range of 0.51 with respect to a length of a side surface of the base of the temperature control element.

5. The optical coupling apparatus according to claim 4 , wherein the temperature control element is arranged within a range of 6.0 mm from the inner side wall of the housing wall in the direction of the temperature control element connecting the light emitting element to the optical fiber.

6. The optical coupling apparatus according to claim 1 , wherein seven lead terminals for electrically connecting an inside and an outside of a housing are provided with a gap of 2.54 mm on each of housing side wall portions installed on the base, and a length of the base sandwiched by housing end wall portions installed on the base is 18.8 mm as an inner distance between the housing end wall portions in a direction of optically connecting the light emitting diode and the optical fiber.

7. The optical coupling apparatus according to claim 2 , wherein seven lead terminals for electrically connecting an inside and an outside of a housing are provided with a gap of 2.54 mm on each of housing side wall portions installed on the base, and a length of the base sandwiched by housing end wall portions installed on the base is of 1.8. mm as an inner distance between the housing end wall portions in a direction of optically connecting the light emitting diode and the optical fiber.

8. The optical coupling apparatus according to claim 3 , wherein seven lead terminals for electrically connecting an inside of an outside of a housing are provided with a gap of 2.54 mm on each of housing side wall portions installed on the base, and a length of the base sandwiched by housing end wall portions installed on the base is 18.8 mm as an inner distance between the housing end wall portions in a direction of optically connecting the light emitting diode and the optical fiber.

9. The optical coupling apparatus according to claim 4 , wherein seven lead terminals for electrically connecting an inside and an outside of a housing are provided with a gap of 2.54 mm on each of housing side wall portions installed on the base, and a length of the base sandwiched by housing end wall portions installed on the base is 18.8 mm as an inner distance between the housing end wall portions in a direction of optically connecting the light emitting diode and the optical fiber.

10. The optical coupling apparatus according to claim 5 , wherein seven lead terminals for electrically connecting an inside and an outside of a housing are provided with a gap of 2.54 mm on each of housing side wall portions installed on the base, and a length of the base sandwiched by housing end wall portions installed on the base is 18.8 mm as an inner distance between the housing end wall portions in a direction of optically connecting the light emitting diode and the optical fiber.

11. The optical coupling apparatus according to claim 1 , wherein a housing installed on the base has an outer length of 20.8 mm, an outer width of 12.7 mm, an inner length of 18.8 mm and an inner width of 10.7 mm.

12. The optical coupling apparatus according to claim 2 , wherein a housing installed on the base has an outer length of 20.8 mm, an outer width of 12.7 mm, an inner length of 18.8 mm and an inner width of 10.7 mm.

13. The optical coupling apparatus according to claim 3 , wherein a housing installed on the base has an outer length of 20.8 mm, an outer width of 12.7 mm, an inner length of 18.8 mm and an inner width of 10.7 mm.

14. The optical coupling apparatus according to claim 4 , wherein a housing installed on the base has an outer length of 20.8 mm, an outer width of 12.7 mm, an inner length of 18.8 mm and an inner width of 10.7 mm.

15. The optical coupling apparatus according to claim 5 , wherein a housing installed on the base has an outer length of 20.8 mm, an outer width of 12.7 mm, an inner length of 18.8 mm and an inner width of 10.7 mm.