Optical alignment systems and methods for wavelength beam combining laser systems

Patent metadata

Field	Value
Publication number	US-2017219835-A1
Application number	US-201715485742-A
Country	US
Kind code	A1
Filing date	Apr 12, 2017
Priority date	Jun 13, 2014
Publication date	Aug 3, 2017
Grant date	—

Abstract

In various embodiments, wavelength beam combining laser systems incorporate fast-axis collimation lenses and slow-axis collimation lenses (either separately or as portions of a single hybrid lens) optically upstream of an optical rotation system to thereby reduce or minimize cross-talk in the combined output beam.

First claim

What is claimed is:

1 .- 22 . (canceled)

23 . A laser apparatus comprising:
an array of beam emitters each emitting a beam of a different wavelength, each emitted beam having a fast diverging axis and a slow diverging axis; a hybrid lens disposed optically downstream of the array of beam emitters, the hybrid lens having (i) a first surface for collimating the beams along the fast diverging axis, and (ii) a second surface for reducing divergence of the beams along the slow diverging axis; disposed optically downstream of the hybrid lens, an optical rotator for rotating the beams; disposed optically downstream of the optical rotator, focusing optics for focusing the rotated beams toward a dispersive element; disposed optically downstream of the focusing optics, the dispersive element for receiving and dispersing the focused beams; and disposed optically downstream of the dispersive element, a partially reflective output coupler for receiving the dispersed beams, reflecting a first portion thereof back toward the dispersive element, and transmitting a second portion thereof as a multi-wavelength output beam.

24 . The laser apparatus of claim 23 , wherein a distance between the hybrid lens and the array of beam emitters is selected to incompletely collimate the beams along the slow diverging axis and thereby introduce cross-talk between the fast diverging axis and slow diverging axis of each of the beams.

25 . The laser apparatus of claim 23 , wherein the hybrid lens comprises a fast-axis collimating lens optically bonded, at an interface, to one or more slow-axis collimating lenses.

26 . The laser apparatus of claim 25 , wherein at least one of the slow-axis collimating lenses comprises a cylindrical Fresnel lens.

27 . The laser apparatus of claim 23 , wherein the hybrid lens comprises a fast-axis collimating lens optically bonded, at an interface, to a plurality of slow-axis collimating lenses.

28 . The laser apparatus of claim 27 , wherein at least one of the slow-axis collimating lenses comprises a cylindrical Fresnel lens.

29 . The laser apparatus of claim 23 , wherein the hybrid lens consists essentially of a unitary optical component having shaped first and second surfaces.

30 . The laser apparatus of claim 23 , wherein the second surface of the hybrid lens is shaped as a plurality of cylindrical Fresnel lenses.

31 . The laser apparatus of claim 30 , wherein a spacing of the cylindrical Fresnel lenses is substantially equal to a spacing of the array of beam emitters.

32 . The laser apparatus of claim 23 , wherein the dispersive element comprises a diffraction grating.

33 . The laser apparatus of claim 23 , wherein the focusing optics comprises at least one of a cylindrical lens or a cylindrical mirror.

34 . The laser apparatus of claim 23 , wherein the optical rotator comprises two spaced-apart cylindrical lenses.

35 . The laser apparatus of claim 34 , wherein a spacing between the two spaced-apart cylindrical lenses is less than approximately 2 mm.

36 . The laser apparatus of claim 23 , wherein an index of refraction of the optical rotator is greater than approximately 1.5.

37 . The laser apparatus of claim 23 , wherein a focal length of the optical rotator is less than approximately 2 mm.

38 . The laser apparatus of claim 23 , further comprising an optical fiber into which the multi-wavelength output beam is coupled.

39 . The laser apparatus of claim 23 , wherein the array of beam emitters comprises a diode bar, each of the beam emitters comprising a diode emitter within the diode bar.

40 . The laser apparatus of claim 23 , wherein the first surface is disposed optically downstream of the second surface.

41 . The laser apparatus of claim 23 , wherein the second surface is disposed optically downstream of the first surface.

42 . A laser apparatus comprising:
an array of beam emitters each emitting a beam of a different wavelength, each emitted beam having a fast diverging axis and a slow diverging axis; disposed optically downstream of the array of beam emitters, a fast-axis collimating lens for collimating the beams along the fast diverging axis; disposed optically upstream of the fast-axis collimating lens, a slow-axis collimating lens for reducing divergence of the beams along the slow diverging axis, wherein a distance between the slow-axis collimating lens and the array of beam emitters is selected to incompletely collimate the beams along the slow diverging axis and thereby introduce cross-talk between the fast diverging axis and slow diverging axis of each of the beams; disposed optically downstream of the slow-axis collimating lens, an optical rotator for rotating the beams, wherein a focal length of the optical rotator is selected to reduce the cross-talk arising from the incomplete collimation of the beams along the slow diverging axis; disposed optically downstream of the optical rotator, focusing optics for focusing the rotated beams toward a dispersive element; disposed optically downstream of the focusing optics, the dispersive element for receiving and dispersing the focused beams; and disposed optically downstream of the dispersive element, a partially reflective output coupler for receiving the dispersed beams, reflecting a first portion thereof back toward the dispersive element, and transmitting a second portion thereof as a multi-wavelength output beam.

Assignees

• Zambuto James
• Tayebati Parviz
• Chann Bien
• Deutsch Michael
• Wang Daqing
• Lochman Bryan

Inventors

• Zambuto James
• Tayebati Parviz
• Chann Bien
• Deutsch Michael
• Wang Daqing
• Lochman Bryan

Classifications

• G02B19/0057

  in the form of a laser diode array, e.g. laser diode bar (semiconductor laser arrays with beam combining arrangement H01S5/4012) · CPC title

• G02B3/08

  with discontinuous faces, e.g. Fresnel lens {(diffractive Fresnel lenses G02B5/1876)} · CPC title

• H01S3/2383

  Parallel arrangements · CPC title

• G02B27/286

  for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another (G02B5/3083 takes precedence; light guide coupling means utilising polarising elements G02B6/34) · CPC title

• H01S5/4087

  emitting more than one wavelength · CPC title