Use of volume Bragg gratings for the conditioning of laser emission characteristics

• US 7,697,589 B2
• Filed: 04/26/2007
• Issued: 04/13/2010
• Est. Priority Date: 07/03/2003
• Status: Active Grant

• Current Assignee: Necsel Intellectual Property Inc. (Ushio Incorporated)
• Original Assignee: PD-LD Incorporated (Ushio Incorporated)
• Inventors: Volodin, Boris Leonidovich, Ban, Vladimir Sinisa
• Primary Examiner(s): Nguyen; Dung T
• Application Number:
  US11/740,459
• Publication Number:
  US 20080253424A1
• Time in Patent Office: 1,083 Days
• Field of Search: 372/102, 372/50.11
• US Class Current: 372/102
• CPC Class Codes: G02B 19/0014 at least one surface having optical power
• CPC Class Codes: G02B 19/0057 in the form of a laser diode array, e.g. laser diode bar semiconductor laser arrays with beam combining arrangement H01S5/4012
• CPC Class Codes: G02B 27/0944 Diffractive optical elements, e.g. gratings, holograms gratings per se G02B5/18; holograms used as optical elements per se G02B5/32
• CPC Class Codes: H01S 3/0057 Temporal shaping, e.g. pulse compression, frequency chirping soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108
• CPC Class Codes: H01S 3/08009 using a diffraction grating
• CPC Class Codes: H01S 3/08013 Resonator comprising a fibre, e.g. for modifying dispersion or repetition rate the active medium being a fibre H01S3/067
• CPC Class Codes: H01S 3/08031 Single-mode emission
• CPC Class Codes: H01S 3/109 Frequency multiplication, e.g. harmonic generation
• CPC Class Codes: H01S 5/005 Optical components external to the laser cavity, specially adapted therefor, e.g. for homogenisation or merging of the beams or for manipulating laser pulses, e.g. pulse shaping H01S5/026, H01S5/18388 take precedence
• CPC Class Codes: H01S 5/0654 Single longitudinal mode emission
• CPC Class Codes: H01S 5/0656 Seeding, i.e. an additional light input is provided for controlling the laser modes, for example by back-reflecting light from an external optical component H01S5/14, H01S5/4062 and H01S5/4006 take precedence
• CPC Class Codes: H01S 5/141 using a wavelength selective device, e.g. a grating or etalon H01S5/146 takes precedence
• CPC Class Codes: H01S 5/143 Littman-Metcalf configuration, e.g. laser - grating - mirror
• CPC Class Codes: H01S 5/4012 Beam combining, e.g. by the use of fibres, gratings, polarisers, prisms
• CPC Class Codes: H01S 5/405 Two-dimensional arrays
• CPC Class Codes: H01S 5/4062 with an external cavity or using internal filters, e.g. Talbot filters
• CPC Class Codes: H01S 5/4068 with lateral coupling by axially offset or by merging waveguides, e.g. Y-couplers
• CPC Class Codes: H01S 5/4087 emitting more than one wavelength

Abstract

Apparatus and methods for altering one or more spectral, spatial, or temporal characteristics of a light-emitting device are disclosed. Generally, such apparatus may include a volume Bragg grating (VBG) element that receives input light generated by a light-emitting device, conditions one or more characteristics of the input light, and causes the light-emitting device to generate light having the one or more characteristics of the conditioned light.

Claims

1. Apparatus for altering a characteristic of a light-emitting device, the apparatus comprising:

a light emitting device having an emission spectrum and defining a fast axis and a slow axis thereof; and

a three-dimensional reflective Bragg grating element that is adapted to receive light emitted from the light-emitting device, the emitted light having a first bandwidth, wherein the Bragg grating comprises a plurality of flat Bragg grating planes,

wherein the Bragg grating is adapted to redirect only a portion of the received light, the redirected portion having a second bandwidth that is narrower than the first bandwidth, such that the redirected portion is fed back directly into the light-emitting device as a narrow-wavelength seed that causes a narrowing of the emission spectrum of the light-emitting device, and

wherein the Bragg grating element is positioned to receive the light emitted from the light emitting device in the absence, between the light emitting device and the Bragg grating element, of any optics that collimates or reduces divergence along either the fast axis or the slow axis of the light emitting device.

2. Apparatus according to claim 1, wherein the Bragg grating element has a thickness in the range of about 0.1 mm to about 3.0 mm.

3. Apparatus according to claim 1, wherein the Bragg grating element is positioned at distance in front of the laser, the distance being in a range from about 0 mm to about 5 mm.