Transmitting optical module implementing optical waveguide device

Patent metadata

Field	Value
Publication number	US-2016170146-A1
Application number	US-201514965466-A
Country	US
Kind code	A1
Filing date	Dec 10, 2015
Priority date	Dec 11, 2014
Publication date	Jun 16, 2016
Grant date	—

Abstract

A transmitting optical module that includes multi-laser diode (LDs) and a planar lightwave circuit (PLC) to multiplex optical beams each output from the optical sources is disclosed. The PLC is mounted on a carrier through a WG carrier in upside down arrangement. The LDs are also mounted on the carrier through an LD carrier. The LDs and the PLC are optical coupled with two lenses each having respective optical axes offset from the other such that the optical coupling of the optical beam inputting the PLC becomes a maximum.

First claim

What is claimed is:

1 . An optical module, comprising:
a laser diode (LD) that outputs an optical beam; a waveguide device including an optical waveguide in a primary surface thereof, optical waveguide optically coupling with the LD; and a carrier that mounts the waveguide device as interposing a waveguide (WG) carrier and the LD as interposing laser diode (LD) carrier, wherein the waveguide device is mounted on the WG carrier as a surface thereof providing the optical waveguide faces the WG carrier.

2 . The optical module of claim 1 ,
wherein the WG carrier has a mark aligned with the optical waveguide of the waveguide device, the mark being provided in a bottom surface of the carrier, the bottom surface being opposite to a surface facing and in contact to the primary surface of the waveguide device.

3 . The optical module of claim 2 ,
wherein the LD is optically coupled with the waveguide device through a first lens and a second lens, the first lens being disposed closer to the LD and the second lens being disposed closer to the waveguide device, and wherein the first lens has an optical axis vertically offset from an optical axis of the second lens.

4 . The optical module of claim 3 ,
wherein the waveguide device has an input surface inclined by an angle θ with respect to a surface perpendicular to the optical axis of the second lens, and wherein the offset d 1 between the optical axis of the first lens and the optical axis of the second lens is given by:
d 1=( f /α)·{√(1+α· n )−√(1+α/ n )},

where α is given by:
α=1/( n ·tan 2 θ)− n,

where f and n are a focal length of the second lens in a side of the waveguide device and refractive index of the optical waveguide of the waveguide device, respectively.

5 . The optical module of claim 3 ,
wherein the first lens makes a gap against the carrier equal to a gap between the second lens and the carrier.

6 . The optical module of claim 3 ,
wherein the first lens is a collimating lens that collimates an optical beam output from the LD and the second lens is a concentrating lens that concentrates the collimated beam output from the first lens on the optical waveguide of the waveguide device.

7 . The optical module of claim 2 ,
wherein the carrier provides a mark aligned with corners of the WG carrier.

8 . The optical module of claim 7 ,
wherein the WG carrier has a lateral width perpendicular to the optical waveguide greater than a lateral width of the waveguide device.

9 . The optical module of claim 1 ,
wherein the WG carrier has a front edge facing the LD retreated from a front edge of the waveguide device facing the LD.

10 . A method to assemble an optical module that comprises a semiconductor laser diode (LD) as an optical source, a waveguide device including an optical waveguide optically coupled with the LD, a lens system for coupling the LD with the waveguide device, the lens system including a first lens and a second lens, and a carrier that mounts the LD, the waveguide device as interposing a waveguide (WG) carrier, and the lens system thereon, the WG carrier and the carrier providing respective marks, the method comprising steps of:
mounting the waveguide device on the WG carrier as aligning the optical waveguide of the waveguide device with the mark of the WG carrier; and mounting the WG carrier on the carrier as aligning outer shape of the WG carrier with the mark of the carrier.

11 . The method of claim 10 ,
wherein the step of mounting the waveguide device includes a step of mounting the waveguide as facing a primary surface thereof providing the optical waveguide to a surface of the WG carrier opposite to a surface providing the mark providing in the WG carrier.

12 . The method of claim 10 ,
wherein the step of mount ing the WG carrier includes a step of mounting the WG carrier as aligning outer shapes of the WG carrier with the mark provided in the carrier.

13 . The method of claim 10 ,
wherein the optical module further includes a first lens and a second lens that couples the LD optically with the optical waveguide, and wherein the method further comprising steps of, after the step of mounting the WG carrier, mounting the first lens on the carrier such that the first lens collimates an optical beam output from the LD, and mounting the second lens on the carrier such that the second lens maximizes power of the optical beam collimated by the first lens, concentrated on the optical waveguide of the waveguide device by the second lens, and output from the waveguide device.

14 . The method of claim 13 ,
wherein the step of mounting the first lens includes a step of mounting the first lens as monitoring the optical beam passing through the first lens at a position apart from the optical module.

15 . The method of claim 13 ,
wherein the step of mounting the second lens including a step of mounting the second lens as offsetting an optical axis thereof from an optical axis of the first lens by an amount d 1 determined by a relation of:
d 1=( f /α)·{√(1 +α·n )−√(1+α/ n )},

where α is given by:
α=1/( n ·tan 2 θ)− n,

wherein θ, f, and n are an inclined angle of a front surface of the waveguide device facing the second lens with respect to a surface perpendicular to the optical axis of the second lens, a focal length of the second lens in a side of the waveguide device, and refractive index of the optical waveguide of the waveguide device.

Assignees

• Sumitomo Electric Industries

Inventors

• Kurokawa Munetaka
• Sato Shunsuke
• Saeki Tomoya
• Fujimura Yasushi

Classifications

• G02B6/4244

  Mounting of the optical elements · CPC title

• G02B6/425

  Optical features (semiconductor laser arrays H01S5/40; hybrid LED arrays H10W90/00) · CPC title

• G02B6/4206 Primary

  Optical features (G02B6/4207, G02B6/421 take precedence) · CPC title

• G02B6/4257

  having a supporting carrier or a mounting substrate or a mounting plate (G02B6/3648 takes precedence) · CPC title

• G02B6/4224

  using visual alignment markings, e.g. index methods · CPC title