Optical assembly and method for assembling the same, and optical module implemented with optical assembly

Patent metadata

Field	Value
Publication number	US-9243761-B2
Application number	US-201414192385-A
Country	US
Kind code	B2
Filing date	Feb 27, 2014
Priority date	Feb 28, 2013
Publication date	Jan 26, 2016
Grant date	Jan 26, 2016

Abstract

An optical assembly that installs red, green, blue laser diodes (LDs) within a single package is disclosed. The LDs are mounted on a base via respective sub-mounts. Light emitted from the LDs is collimated by collimating lenses and multiplexed by two wavelength filters so as to align optical axes of the light. The multiplexed light has an axis substantially leveled with the axes of the red, green, and blue light measured from the top of the base.

First claim

What is claimed is:

1. A method to assemble an optical assembly having a red laser diode (LD), a green LD, a blue LD, a first lens, a second lens, a third lens, and a base to mount the red, green and blue LDs, and the first to third lenses, the optical assembly outputting multiplexed light containing red light emitted from the red LD, green light emitted from the green LD, and blue light emitted from the blue LD, the method comprising steps of:
mounting a first LD among the red, green and blue LDs on a top surface of the base such that the first LD emits first light projecting on a first point on a virtual plane after transmitted through the first lens, the virtual plane being placed apart by at least one meter from the base, the first point being positioned on a line corresponding to the top surface of the base;
mounting a second LD among the red, green and blue LDs except for the first LD on the top surface of the base such that the second LD emits second light projecting on a second point on the virtual plane after transmitted through the second lens, the second point being positioned on the line;
mounting a third LD among the red, green and blue LDs except for the first and second LDs on the top surface of the base such that the third LD emits third light projecting on a third point on the virtual plane after transmitted through the third lens, the third point being positioned on the line;
after mounting the second LD, mounting a first wavelength selective filter (WSF) on the top surface of the base, wherein the first WSF transmits one of the first light transmitted through the first lens and the second light transmitted through the second lens but reflects another of the first light transmitted through the first lens and the second light transmitted through the second lens, such that one of the first light and the second light reflected by the first WSF projects on a point on the virtual plane on which another of the first light transmitted through the first lens and the second light transmitted through the second lens projects, the first WSF outputting a mid-multiplexed light containing the first light and the second light; and
mounting a second WSF on the top surface of the base, wherein the second WSF transmits one of the mid-multiplexed light and the third light transmitted through the third lens but reflects another of the mid-multiplexed light and the third light transmitted through the third lens, such that one of the mid-multiplexed light and the third light reflected by the second WSF projects on a point on which another of the mid-multiplexed light and the third light transmitted through the second WSF projects, the second WSF outputting the multiplexed light.

2. The method of claim 1 ,
wherein the mounting the first WSF is carried out before the mounting the third LD on the base.

3. The method of claim 1 ,
wherein the mounting the second WSF is carried out such that the second WSF becomes substantially parallel to the first WSF.

4. The method of claim 3 ,
wherein the mounting the third LD on the base is carried out such that the third point locates in a side same as a side of the second point with respect to the first point.

5. The method of claim 1 ,
wherein the mounting the third LD on the base is carried out such that the third point locates in a position opposite to the second point with respect to the first point.

6. The method of claim 5 ,
wherein the mounting the second WSF is carried out such that the second WSF makes a right angle with respect to the first WSF.

7. An optical module that outputs multiplexed light containing red light, green light, and blue light, comprising:
a first laser diode (LD) to emit the red light;
a second LD to emit the green light;
a third LD to emit the blue light;
a first lens to collimate the red light emitted from the first LD to generate collimated red light;
a second lens to collimate the green light emitted from the second LD to generate collimated green light;
a third lens to collimate the blue light emitted from the third LD to generate collimated blue light;
a package enclosing the first to third LDs and the first to third lenses;
a first wavelength selective filter (WSF) that reflects one of the collimated red light and the collimated green light but transmits another of the collimated red light and the collimated green light to generate mid-multiplexed light containing the collimated red light and the collimated green light whose optical axes are aligned to each other;
a second WSF that reflects one of the mid-multiplexed light and the collimated blue light but transmits another of the mid-multiplexed light and the collimated blue light, wherein the second WSF outputs the multiplexed light containing the collimated red light, the collimated green light, and the collimated blue light whose optical axes are aligned to each other; and
a mirror,
wherein the collimated red light, the collimated green light, and the collimated blue light are aligned with an optical axis of the optical module to be generated as the multiplexed light,
wherein the first to third lenses, the first and second WSFs, and the mirror are mounted on a base, and
wherein the mirror reflects the multiplexed light in a direction perpendicular to the base.

8. The optical module of claim 7 ,
wherein each of the red light, the green light, and the blue light has an ellipsoidal far-field pattern, and
wherein the mirror provides a restricted area to reflect the multiplexed light, the multiplexed light reflected at the restricted area having a circular far-field pattern.

9. The optical module of claim 7 ,
wherein the package is a CAN package.

10. The optical module of claim 9 ,
wherein the CAN package includes a cap and a stem with a block protruding therefrom, the cap and the stem enclosing the first to third LDs, the first to third lenses, and the first and second WSFs therein air-tightly, the base being mounted in a side of the block, and
wherein the multiplexed light is output in a direction perpendicular to the stem.

11. The optical module of claim 10 ,
wherein the first to third LDs are mounted on the base.

12. The optical module of claim 10 ,
wherein the first to third LDs are mounted on the side of the block.

13. The optical module of claim 10 ,
wherein the block provides a pocket in the side thereof, the base being mounted within the pocket.

14. The optical module of claim 7 ,
wherein the first to third lenses and the first and second WSFs are mounted on the base via respective sub-bases.

15. An optical module that outputs multiplexed light containing red light, green light, and blue light, comprising:
a first laser diode (LD) to emit the red light;
a second LD to emit the green light;
a third LD to emit the blue light;
a first lens to collimate the red light emitted from the first LD to generate collimated red light;
a second lens to collimate the green light emitted from the second LD to generate collimated green light;
a third lens to collimate the blue light emitted from the third LD to generate collimated blue light;
a package enclosing the first to third LDs and the first to third lenses;
a first wavelength selective filter (WSF) that reflects one of the collimated red light and the collimated green light but transmits another of the collimated red light and the collimated green light to generate mid-multiplexed light containing the collimated red light and the collimated green light whose optical axes are aligned to each other;
a second WSF that reflects one of the mid-multiplexed light and the collimated blue light but

Assignees

• Sumitomo Electric Industries

Inventors

• Nakanishi Hiromi
• Okada Takeshi

Classifications

• F21K9/90 Primary

  Methods of manufacture · CPC title

• H01S5/02292

  Electricity · mapped topic

• H01S5/02248

  Electricity · mapped topic

• H01S5/02288

  Electricity · mapped topic

• H01S5/4093

  Red, green and blue [RGB] generated directly by laser action or by a combination of laser action with nonlinear frequency conversion · CPC title