System and method for passively aligning and coupling optical devices

• US 6,760,520 B1
• Filed: 05/09/2001
• Issued: 07/06/2004
• Est. Priority Date: 05/09/2000
• Status: Active Grant

• Current Assignee: Cirrex Systems, LLC
• Original Assignee: Teralux Corporation
• Inventors: Medin, Michael W., Marple, Eric T.
• Primary Examiner(s): Ullah, Akm Enayet
• Application Number:
  US09/851,602
• Time in Patent Office: 1,154 Days
• Field of Search: 385/39, 385/42-25, 385/88-92, 385/147
• US Class Current: 385/43
• CPC Class Codes: G02B 6/305 and having an integrated mode-size expanding section, e.g. tapered waveguide
• CPC Class Codes: G02B 6/4206 Optical features G02B6/4207, G02B6/421 take precedence
• CPC Class Codes: G02B 6/423 using guiding surfaces for the alignment

Abstract

An external mode size transformer includes a waveguide having an input section, an output section, and a tapered section disposed between the input and output sections. The cross sections between the input and output sections of the waveguide can vary smoothly throughout the length of the waveguide, similar to a waveguide shaped like a boat hull. By positioning the external mode size transformer between optical devices, coupling between optical devices is substantially improved compared to that of direct coupling. For example, by positioning the external mode size transformer between a laser and an optical fiber, laser to fiber coupling is significantly improved compared to that of direct coupling between these optical devices. The present invention can include a manufacturing method that employs multiple masks with predetermined shapes to fabricate the sections of the waveguide within a planar substrate via an exemplary ion exchange process.

Claims

1. A method for passively aligning two optical devices for transferring light energy therebetween, comprising the steps of:

positioning a mode size transformer on a submount with a groove;

positioning a first optical device having a first modal profile on the submount having a groove;

aligning the first optical device with the transformer by sliding one of the first optical device and transformer along the groove, the transformer comprising a tapered waveguide section having a smoothly varying cross sectional area;

positioning a second optical device having a second modal profile on the submount; and

aligning the second optical device with the transformer by sliding one of the second optical device and transformer along the groove.

2. The method of claim 1, further comprising the steps of:

receiving light energy from the first optical device with the transformer;

transforming the light energy from the first modal profile to the second modal profile; and

propagating the light energy to the second optical device.

3. The method of claim 2, wherein the step of transforming the light energy, further comprises the steps of:

receiving the light energy at a first end of a tapered waveguide section having a first cross sectional area;

propagating the light energy along the tapered waveguide section having a variable cross section;

sending the light energy through a second end of the tapered waveguide section having a second cross sectional area substantially greater than the first cross sectional area.

4. The method of claim 1, further comprising the step of propagating light energy from the first optical device through a waveguide of the transformer to the second optical device.

5. The method of claim 1, wherein the step of aligning the first optical device with the transformer further comprises the step of positioning a longitudinal centerline marker of the first optical device over the groove.

6. The method of claim 1, wherein the step of aligning the first optical device with the transformer further comprises the step of positioning a clad stripe within the groove.

7. The method of claim 1, wherein the step of aligning the first optical device with the transformer further comprises the step of aligning a fiducial mark on the first optical device with a fiducial mark on the submount.

8. The method of claim 1, wherein the step of positioning the first optical device having a first modal profile on the submount further comprises the step of positioning a laser diode to the submount.

9. The method of claim 1, wherein the step of positioning the second optical device having a second modal profile on the submount further comprises the step of positioning an optical fiber within the groove of the submount.