WO2013070484A2 - Multi-wavelength dbr laser - Google Patents

Multi-wavelength dbr laser Download PDF

Info

Publication number
WO2013070484A2
WO2013070484A2 PCT/US2012/063000 US2012063000W WO2013070484A2 WO 2013070484 A2 WO2013070484 A2 WO 2013070484A2 US 2012063000 W US2012063000 W US 2012063000W WO 2013070484 A2 WO2013070484 A2 WO 2013070484A2
Authority
WO
WIPO (PCT)
Prior art keywords
laser diode
bragg wavelengths
distinct
gain
dbr
Prior art date
Application number
PCT/US2012/063000
Other languages
French (fr)
Other versions
WO2013070484A3 (en
Inventor
Catherine G. Caneau
Feng Xie
Chung-En Zah
Original Assignee
Corning Incorporated
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Corning Incorporated filed Critical Corning Incorporated
Priority to EP12791908.2A priority Critical patent/EP2777107A2/en
Priority to KR1020147013167A priority patent/KR20140089548A/en
Publication of WO2013070484A2 publication Critical patent/WO2013070484A2/en
Publication of WO2013070484A3 publication Critical patent/WO2013070484A3/en

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
    • H01S5/062—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes
    • H01S5/0625—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes in multi-section lasers
    • H01S5/06255—Controlling the frequency of the radiation
    • H01S5/06256—Controlling the frequency of the radiation with DBR-structure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
    • H01S5/0607—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying physical parameters other than the potential of the electrodes, e.g. by an electric or magnetic field, mechanical deformation, pressure, light, temperature
    • H01S5/0612—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying physical parameters other than the potential of the electrodes, e.g. by an electric or magnetic field, mechanical deformation, pressure, light, temperature controlled by temperature
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
    • H01S5/12—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers
    • H01S5/1206—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers having a non constant or multiplicity of periods
    • H01S5/1215—Multiplicity of periods
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/30—Structure or shape of the active region; Materials used for the active region
    • H01S5/34—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers
    • H01S5/3401—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers having no PN junction, e.g. unipolar lasers, intersubband lasers, quantum cascade lasers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/30—Structure or shape of the active region; Materials used for the active region
    • H01S5/34—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers
    • H01S5/3401—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers having no PN junction, e.g. unipolar lasers, intersubband lasers, quantum cascade lasers
    • H01S5/3402—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers having no PN junction, e.g. unipolar lasers, intersubband lasers, quantum cascade lasers intersubband lasers, e.g. transitions within the conduction or valence bands

Definitions

  • the present disclosure relates to laser diodes characterized by multi-wavelength emission and, more particularly, to distributed Bragg reflector (DBR) quantum cascade (QCL) laser diodes.
  • DBR distributed Bragg reflector
  • QCL quantum cascade
  • the present disclosure also relates to the use of such lasers as a mid-IR tunable source in the identification of molecular compositions in, for example, gas sensing and medical diagnostics, although the concepts of the present disclosure will enjoy broad applicability in a variety of fields.
  • the present disclosure is directed to multi-wavelength DBR QCL products that can be operated to generate several wavelengths sequentially in time.
  • the resulting emission can be used, for example, to sample a broad absorption line.
  • Particular embodiments of the present disclosure are limited to uni-polar QCLs, which use inter-sub-band transitions to produce photons, but it is also contemplated that the concepts of the present disclosure can be adapted for use with bi-polar lasers, which use inter-band transitions to produce photons.
  • a multi-wavelength distributed Bragg reflector (DBR) laser diode comprising front and rear DBR sections and a plurality of dedicated tuning signal control nodes.
  • the front DBR section comprises a plurality of front wavelength selective grating sections defining a plurality of distinct grating periodicities ⁇ *, ⁇ 2 *... corresponding to distinct Bragg wavelengths ⁇ ⁇ ⁇ *, s2* ....
  • the rear DBR section comprises a plurality of rear wavelength selective grating sections defining a plurality of distinct grating periodicities ⁇ , ⁇ 2 ... corresponding to distinct Bragg wavelengths ⁇ ⁇ ⁇ , ⁇ ⁇ 2 ....
  • the plurality of dedicated tuning signal control nodes are associated with individual ones of the front wavelength selective grating sections, individual ones of the rear wavelength selective grating sections, or both, and are constructed such that one or more tuning signals applied to one or more of the dedicated tuning signal control nodes spectrally aligns distinct Bragg wavelengths a selected one of the distinct Bragg wavelengths si*, s 2 *. chorus of the front DBR section with a selected one of the distinct Bragg wavelengths $ ⁇ , s 2 ... of the rear DBR section.
  • Fig. 1 is a schematic illustration of a multi-wavelength distributed Bragg reflector (DBR) quantum cascade laser diode according to the present disclosure
  • Fig. 2 illustrates the characteristics of the front and rear grating portions of an untuned multi-wavelength DBR according to the present disclosure
  • FIG. 3 illustrates a method of tuning a multi- wavelength DBR according to one embodiment of the present disclosure
  • Fig. 4 illustrates a method of tuning a multi-wavelength DBR according to an alternative embodiment of the present disclosure.
  • the DBR 10 comprises front and rear DBR sections 20, 30, a plurality of dedicated tuning signal control nodes 25, 35, a gain section 40, a phase section 50, and a waveguide core 45 extending between the front and rear facets 12, 14 of the laser diode 10.
  • the gain section 40 may comprise a quantum cascade active region and is positioned between the front and rear DBR sections 20, 30 along an optical propagation axis defined by the waveguide core 45 of the laser diode 10.
  • a DBR section of a DBR laser comprises Bragg gratings, i.e., a light-reflecting device based on Bragg reflection by a periodic structure.
  • the periodic structure of the DBR section defines the Bragg wavelength ⁇ of the laser.
  • the front and rear DBR sections 20, 30 of the present disclosure do not rely upon periodic or aperiodic shifts in the grating phase ⁇ or chirped grating periodicities to generate multiple wavelength selection capabilities.
  • the respective reflectivity peaks of the front and rear DBR sections 20, 30 are spaced such that they do not overlap each other, although individual reflectivity peaks of the front DBR section 20 can be tuned to match a selected reflectivity peak of the rear DBR section 30, as will be explained in detail below.
  • the present disclosure is directed to the particulars of the front and rear DBR sections 20, 30.
  • the respective structures of the waveguide core 45, the associated waveguide layers, the gain and phase sections 40, 50, and the anti-reflection coatings can be gleaned from readily available teachings in the art.
  • the front DBR section 20 comprises a plurality of front wavelength selective grating sections defining a plurality of distinct grating periodicities ⁇ *, ⁇ 2 *... corresponding to distinct Bragg wavelengths ⁇ ⁇ ⁇ *, s2* ...
  • the rear DBR section 30 comprises a plurality of rear wavelength selective grating sections defining a plurality of distinct grating periodicities Ai, ⁇ 2 ... corresponding to distinct Bragg wavelengths ⁇ ⁇ ⁇ , ⁇ ⁇ 2 ... distinct Bragg wavelengths
  • each of the distinct Bragg wavelengths si*, s 2 *. is spectrally misaligned with respect to the distinct Bragg wavelengths ⁇ ⁇ ⁇ , ⁇ ⁇ 2 ...
  • the wavelength selective grating sections comprise dedicated tuning signal control nodes 25, 35 that are associated with individual ones of the front wavelength selective grating sections, individual ones of the rear wavelength selective grating sections, or both. In operation, as is illustrated in Fig.
  • a tuning signal is applied to one of the dedicated tuning signal control nodes 25, 35 to alter a selected one of the distinct Bragg wavelengths, i.e., s3*, and place it into spectral alignment with a selected one of the distinct Bragg wavelengths, i.e., s 3 , to generate emission at the selected emission wavelength - ⁇ $3 in the illustrated example.
  • Successive tuning signals can be tailored for emission at successive emission wavelengths ⁇ ⁇ ⁇ , ⁇ ⁇ 2 ... [0014] Although, in the embodiment illustrated in Figs. 2 and 3, each of the distinct Bragg wavelengths ⁇ ⁇ ⁇ *, ⁇ ⁇ 2 * ...
  • the distinct Bragg wavelengths ⁇ ⁇ ⁇ *, ⁇ ⁇ 2 * ... could be shorter and/or longer than the corresponding distinct Bragg wavelengths ⁇ ⁇ ⁇ , ⁇ ⁇ 2 ...
  • long wavelength grating sections will be aligned with the a corresponding shorter Bragg wavelength grating sections in the opposite DBR section of the laser diode by activating the tuning signal control nodes, e.g., micro- heaters or direct current injection electrodes, in the short wavelength grating section, although a variety of control node configurations are contemplated.
  • the tuning signal control nodes e.g., micro- heaters or direct current injection electrodes
  • one or more of the distinct Bragg wavelengths ⁇ ⁇ ⁇ *, ⁇ ⁇ 2 * ... could be spectrally aligned with respect to the distinct Bragg wavelengths $ ⁇ , ⁇ $2 ... in the "un-tuned” state.
  • one or more tuning signals could be applied to the dedicated front tuning signal control nodes 25 or rear tuning signal control nodes 30 to alter selected ones of the distinct Bragg wavelengths si * , such that all but one of the distinct Bragg wavelengths si * , s2* ⁇ ⁇ ⁇ are spectrally misaligned with respect to the distinct Bragg wavelengths $ ⁇ , s 2 ...
  • each of the distinct Bragg wavelengths si * , s 2 * jointly. are spectrally misaligned with respect to the distinct Bragg wavelengths ⁇ $ ⁇ , ⁇ ... by approximately 4.1 cm "1 or more (wave number) for a DBR length of 0.5 mm.
  • the spectral separation should be increased with reduced DBR length.
  • the rear wavelength selective grating sections of the rear DBR section 30 may also be provided with a control mechanism.
  • This control mechanism may take the form of a laser diode heat sink or the illustrated rear tuning signal control nodes 35, which can be associated with individual ones of the rear wavelength selective grating sections of the rear DBR section 30.
  • the laser diode is provided with a heat sink or some other temperature control mechanism that is common to both the front and rear DBR sections 20, 30, it is contemplated that thermal control of the front and rear DBR sections 20, 30 can be executed by either tuning the heat sink temperature, tuning the tuning signal control nodes 25, 35, or both.
  • the front and rear tuning signal control nodes 25, 35 comprise thermal tuning nodes, e.g., micro-heater elements, it will typically be advantageous to ensure that each of the distinct Bragg wavelengths si*, s 2 * architect. are shorter than the distinct Bragg wavelengths $ ⁇ , « 2 ... so that a temperature increase initiated by one of the front thermal tuning nodes will increase the corresponding tuning wavelength to bring it into alignment with the target emission wavelength. It is also contemplated that the front and rear tuning signal control nodes 25, 35 may comprise electrical contacts for direct current injection to the front and rear wavelength selective grating sections. Finally, it is contemplated that individual ones of the tuning signal control nodes 25, 35 could be operated together, as a single control node, depending upon the operational demands of the particular application.
  • the front and rear wavelength selective grating sections of the front and rear DBR sections 20, 30 may be arranged such that grating sections corresponding to reflectance peaks in relatively low gain portions of the optical gain spectrum are positioned relatively close to the gain section 40 of the laser diode 10, while grating sections corresponding to reflectance peaks in relatively high gain portions of the optical gain spectrum are positioned relatively far from the gain section 40 of the laser diode 10.
  • the waveguide core 45 of the laser diode 10 may comprise a stack of quantum cascade cores and each quantum cascade core may be configured to define a gain peak approximating one of the distinct Bragg wavelengths $ ⁇ , ⁇ $ 2 ... of the rear wavelength selective grating sections.
  • the waveguide core 45 of the laser diode 10 may comprise a single quantum cascade core with a gain spectrum that is broad enough to encompass the distinct Bragg wavelengths $ ⁇ , « 2 ... of the rear wavelength selective grating sections.
  • the gain section 40 of the laser diode 10 will be characterized by a wavelength-dependent optical gain spectrum.
  • quantum cascade cores with relatively low optical gains can be placed relatively close to the center of the optical mode of propagation of the laser diode 10, while quantum cascade cores with relatively high optical gains can be placed relatively far from the center of the optical mode of propagation of the laser diode 10.
  • cores with relatively low optical gain can be constructed with a greater number of stages or higher confinement factors, and cores with relatively high optical gain can be constructed with a fewer number of stages or lower confinement factors.
  • shorter wavelength cores can be placed near the center of the waveguide core 45, with longer wavelength cores outside, because optical mode size at longer wavelengths is larger than at relatively short wavelengths.
  • the waveguide core 45 of the laser diode 10 comprises a unipolar QCL using inter-sub-band transitions to produce photons.
  • the waveguide core 45 of the laser diode 10 may comprise a bi-polar laser using inter-band transitions to produce photons.
  • the distinct Bragg wavelengths ⁇ ⁇ ⁇ , ⁇ ⁇ 2 ... are selected to be the sampling wavelengths of a relatively broad absorption line, i.e., approximately 150 cm "1 spectral width.
  • Figs. 2 and 3 show five reflection peaks that can be generated using five 0.75 mm long rear wavelength selective grating sections selected to match the five absorption peaks of glucose.
  • the front wavelength selective grating sections are shorter than the rear sections to allow higher output power.
  • the spectral distance between the Bragg wavelength of a selected grating section and the 1 st null of the DBR is about 4.1 cm "1
  • the front reflectivity peaks should be set at approximately 4.1 cm "1 shorter than one of the rear sampling wavelengths such that each can be tuned to match the nearby sampling wavelength by heating using a micro-heater or direct current injection.
  • Thermal tuning efficiencies determined from a 4.57 ⁇ DBR QCL are approximately 1 1 cm ' Vmm and 15 cm ' Vmm, using a micro heater or current injection, respectively.
  • the heating power required to align the Bragg wavelength of a 0.5 mm long front grating to one of the sampling wavelengths is estimated to be 186 mW and 137 mW using a micro-heater or current injection, respectively.

Landscapes

  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Nanotechnology (AREA)
  • Chemical & Material Sciences (AREA)
  • Biophysics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Semiconductor Lasers (AREA)
  • Optical Communication System (AREA)

Abstract

A multi-wavelength distributed Bragg reflector (DBR) laser diode is provided including front and rear DBR sections and a plurality of dedicated tuning signal control nodes. The front DBR section includes a plurality of front wavelength selective grating sections defining a plurality of distinct grating periodicities λ1*, λ2*... corresponding to distinct Bragg wavelengths λS1*, λS2*.... The rear DBR section comprises a plurality of rear wavelength selective grating sections defining a plurality of distinct grating periodicities λ1, λ2... corresponding to distinct Bragg wavelengths λS1, λS2.... The tuning signal control nodes are associated with corresponding front wavelength selective grating sections, rear wavelength selective grating sections, or both, such that tuning signals applied to one or more of the dedicated tuning signal control nodes spectrally aligns select Bragg wavelengths λS1*, λS2*... of the front DBR section with a selected distinct Bragg wavelengths λS1, λS2... of the rear DBR section.

Description

MULTI- WAVELENGTH DBR LASER
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority to US Provisional Application Serial No. 61/556,434 filed on November 7, 2011 and US Application Serial No. 13/570,719 filed on August 9, 2012 the contents of which are relied upon and incorporated herein by references in its entirety.
BACKGROUND
[0002] The present disclosure relates to laser diodes characterized by multi-wavelength emission and, more particularly, to distributed Bragg reflector (DBR) quantum cascade (QCL) laser diodes. The present disclosure also relates to the use of such lasers as a mid-IR tunable source in the identification of molecular compositions in, for example, gas sensing and medical diagnostics, although the concepts of the present disclosure will enjoy broad applicability in a variety of fields.
BRIEF SUMMARY
[0003] The present disclosure is directed to multi-wavelength DBR QCL products that can be operated to generate several wavelengths sequentially in time. The resulting emission can be used, for example, to sample a broad absorption line. Particular embodiments of the present disclosure are limited to uni-polar QCLs, which use inter-sub-band transitions to produce photons, but it is also contemplated that the concepts of the present disclosure can be adapted for use with bi-polar lasers, which use inter-band transitions to produce photons.
[0004] In accordance with one embodiment of the present disclosure, a multi-wavelength distributed Bragg reflector (DBR) laser diode is provided comprising front and rear DBR sections and a plurality of dedicated tuning signal control nodes. The front DBR section comprises a plurality of front wavelength selective grating sections defining a plurality of distinct grating periodicities Λι*, Λ2*... corresponding to distinct Bragg wavelengths λδι*, s2* .... The rear DBR section comprises a plurality of rear wavelength selective grating sections defining a plurality of distinct grating periodicities Λι, Λ2... corresponding to distinct Bragg wavelengths λδι, λδ2.... The plurality of dedicated tuning signal control nodes are associated with individual ones of the front wavelength selective grating sections, individual ones of the rear wavelength selective grating sections, or both, and are constructed such that one or more tuning signals applied to one or more of the dedicated tuning signal control nodes spectrally aligns distinct Bragg wavelengths a selected one of the distinct Bragg wavelengths si*, s2*.„ of the front DBR section with a selected one of the distinct Bragg wavelengths $ι, s2... of the rear DBR section.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0005] The following detailed description of specific embodiments of the present disclosure can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:
[0006] Fig. 1 is a schematic illustration of a multi-wavelength distributed Bragg reflector (DBR) quantum cascade laser diode according to the present disclosure;
[0007] Fig. 2 illustrates the characteristics of the front and rear grating portions of an untuned multi-wavelength DBR according to the present disclosure;
[0008] Fig. 3 illustrates a method of tuning a multi- wavelength DBR according to one embodiment of the present disclosure; and
[0009] Fig. 4 illustrates a method of tuning a multi-wavelength DBR according to an alternative embodiment of the present disclosure.
DETAILED DESCRIPTION
[0010] The general structure of a multi-wavelength DBR laser diode 10 according to the present disclosure is illustrated in Fig. 1. In Fig. 1, the DBR 10 comprises front and rear DBR sections 20, 30, a plurality of dedicated tuning signal control nodes 25, 35, a gain section 40, a phase section 50, and a waveguide core 45 extending between the front and rear facets 12, 14 of the laser diode 10. The gain section 40 may comprise a quantum cascade active region and is positioned between the front and rear DBR sections 20, 30 along an optical propagation axis defined by the waveguide core 45 of the laser diode 10. [0011] As will be appreciated by those familiar with DBR lasers, a DBR section of a DBR laser comprises Bragg gratings, i.e., a light-reflecting device based on Bragg reflection by a periodic structure. The periodic structure of the DBR section defines the Bragg wavelength λβ of the laser. The front and rear DBR sections 20, 30 of the present disclosure do not rely upon periodic or aperiodic shifts in the grating phase Φ or chirped grating periodicities to generate multiple wavelength selection capabilities. Further, the respective reflectivity peaks of the front and rear DBR sections 20, 30 are spaced such that they do not overlap each other, although individual reflectivity peaks of the front DBR section 20 can be tuned to match a selected reflectivity peak of the rear DBR section 30, as will be explained in detail below.
[0012] The present disclosure is directed to the particulars of the front and rear DBR sections 20, 30. The respective structures of the waveguide core 45, the associated waveguide layers, the gain and phase sections 40, 50, and the anti-reflection coatings can be gleaned from readily available teachings in the art. As is illustrated in Figs. 1 and 2, the front DBR section 20 comprises a plurality of front wavelength selective grating sections defining a plurality of distinct grating periodicities Λι*, Λ2*... corresponding to distinct Bragg wavelengths λδι*, s2* ... distinct Bragg wavelengths Similarly, the rear DBR section 30 comprises a plurality of rear wavelength selective grating sections defining a plurality of distinct grating periodicities Ai, Λ2... corresponding to distinct Bragg wavelengths λδι, λδ2... distinct Bragg wavelengths
[0013] As is illustrated schematically in Fig. 2, in one embodiment of the present disclosure, each of the distinct Bragg wavelengths si*, s2*.„ is spectrally misaligned with respect to the distinct Bragg wavelengths λδι, λδ2... However, the wavelength selective grating sections comprise dedicated tuning signal control nodes 25, 35 that are associated with individual ones of the front wavelength selective grating sections, individual ones of the rear wavelength selective grating sections, or both. In operation, as is illustrated in Fig. 3, a tuning signal is applied to one of the dedicated tuning signal control nodes 25, 35 to alter a selected one of the distinct Bragg wavelengths, i.e., s3*, and place it into spectral alignment with a selected one of the distinct Bragg wavelengths, i.e., s3, to generate emission at the selected emission wavelength - λ$3 in the illustrated example. Successive tuning signals can be tailored for emission at successive emission wavelengths λδι, λδ2... [0014] Although, in the embodiment illustrated in Figs. 2 and 3, each of the distinct Bragg wavelengths λδι*, λδ2* ... are shorter than the corresponding distinct Bragg wavelengths λδι, $2 - .■ it is noted that a variety of "un-tuned" states are contemplated according to the present disclosure. For example, the distinct Bragg wavelengths λδι*, λδ2* ... could be shorter and/or longer than the corresponding distinct Bragg wavelengths λδι, λδ2... Typically, long wavelength grating sections will be aligned with the a corresponding shorter Bragg wavelength grating sections in the opposite DBR section of the laser diode by activating the tuning signal control nodes, e.g., micro- heaters or direct current injection electrodes, in the short wavelength grating section, although a variety of control node configurations are contemplated.
[0015] As a further example, it is contemplated that one or more of the distinct Bragg wavelengths λδι*, λδ2* ... could be spectrally aligned with respect to the distinct Bragg wavelengths $ι, λ$2 ... in the "un-tuned" state. In which case, in a "tuned" state, one or more tuning signals could be applied to the dedicated front tuning signal control nodes 25 or rear tuning signal control nodes 30 to alter selected ones of the distinct Bragg wavelengths si * , such that all but one of the distinct Bragg wavelengths si * , s2* · · · are spectrally misaligned with respect to the distinct Bragg wavelengths $ι, s2... This configuration and procedure is illustrated in Fig. 4. In practice, it may be beneficial to ensure that each of the distinct Bragg wavelengths si * , s2*„. are spectrally misaligned with respect to the distinct Bragg wavelengths λ$ι, λ^... by approximately 4.1 cm"1 or more (wave number) for a DBR length of 0.5 mm. The spectral separation should be increased with reduced DBR length.
[0016] As is further illustrated in Fig. 1, the rear wavelength selective grating sections of the rear DBR section 30 may also be provided with a control mechanism. This control mechanism may take the form of a laser diode heat sink or the illustrated rear tuning signal control nodes 35, which can be associated with individual ones of the rear wavelength selective grating sections of the rear DBR section 30. Where the laser diode is provided with a heat sink or some other temperature control mechanism that is common to both the front and rear DBR sections 20, 30, it is contemplated that thermal control of the front and rear DBR sections 20, 30 can be executed by either tuning the heat sink temperature, tuning the tuning signal control nodes 25, 35, or both. [0017] In cases where the front and rear tuning signal control nodes 25, 35 comprise thermal tuning nodes, e.g., micro-heater elements, it will typically be advantageous to ensure that each of the distinct Bragg wavelengths si*, s2*„. are shorter than the distinct Bragg wavelengths $ι, «2... so that a temperature increase initiated by one of the front thermal tuning nodes will increase the corresponding tuning wavelength to bring it into alignment with the target emission wavelength. It is also contemplated that the front and rear tuning signal control nodes 25, 35 may comprise electrical contacts for direct current injection to the front and rear wavelength selective grating sections. Finally, it is contemplated that individual ones of the tuning signal control nodes 25, 35 could be operated together, as a single control node, depending upon the operational demands of the particular application.
[0018] In cases where the gain section 40 of the laser diode 10 is characterized by a wavelength-dependent optical gain the front and rear wavelength selective grating sections of the front and rear DBR sections 20, 30 may be arranged such that grating sections corresponding to reflectance peaks in relatively low gain portions of the optical gain spectrum are positioned relatively close to the gain section 40 of the laser diode 10, while grating sections corresponding to reflectance peaks in relatively high gain portions of the optical gain spectrum are positioned relatively far from the gain section 40 of the laser diode 10.
[0019] The waveguide core 45 of the laser diode 10 may comprise a stack of quantum cascade cores and each quantum cascade core may be configured to define a gain peak approximating one of the distinct Bragg wavelengths $ι, λ$2 ... of the rear wavelength selective grating sections. Alternatively, the waveguide core 45 of the laser diode 10 may comprise a single quantum cascade core with a gain spectrum that is broad enough to encompass the distinct Bragg wavelengths $ι, «2... of the rear wavelength selective grating sections. In many cases, the gain section 40 of the laser diode 10 will be characterized by a wavelength-dependent optical gain spectrum. To account for this, it is contemplated that quantum cascade cores with relatively low optical gains can be placed relatively close to the center of the optical mode of propagation of the laser diode 10, while quantum cascade cores with relatively high optical gains can be placed relatively far from the center of the optical mode of propagation of the laser diode 10. Alternatively, or additionally, cores with relatively low optical gain can be constructed with a greater number of stages or higher confinement factors, and cores with relatively high optical gain can be constructed with a fewer number of stages or lower confinement factors. As a further alternative, it is contemplated that shorter wavelength cores can be placed near the center of the waveguide core 45, with longer wavelength cores outside, because optical mode size at longer wavelengths is larger than at relatively short wavelengths.
[0020] In some ombodiments the waveguide core 45 of the laser diode 10 comprises a unipolar QCL using inter-sub-band transitions to produce photons. However, it is also contemplated that the waveguide core 45 of the laser diode 10 may comprise a bi-polar laser using inter-band transitions to produce photons.
[0021] For example, and not by way of limitation, in one implementation of the concepts of the present disclosure, the distinct Bragg wavelengths λδι, λδ2... are selected to be the sampling wavelengths of a relatively broad absorption line, i.e., approximately 150 cm"1 spectral width. To this end, Figs. 2 and 3 show five reflection peaks that can be generated using five 0.75 mm long rear wavelength selective grating sections selected to match the five absorption peaks of glucose. Noting that the power needed to thermally tune the wavelength is less for shorter DBR sections than longer DBR sections, generally, the front wavelength selective grating sections are shorter than the rear sections to allow higher output power. In a more specific implementation, the spectral distance between the Bragg wavelength of a selected grating section and the 1st null of the DBR is about 4.1 cm"1
Figure imgf000007_0001
assuming a grating length of 0.5 mm. For sampling wavelengths to be outside the grating bandwidth of sampling wavelengths in the rear DBR sections, the front reflectivity peaks should be set at approximately 4.1 cm"1 shorter than one of the rear sampling wavelengths such that each can be tuned to match the nearby sampling wavelength by heating using a micro-heater or direct current injection. Thermal tuning efficiencies determined from a 4.57 μηι DBR QCL are approximately 1 1 cm'Vmm and 15 cm'Vmm, using a micro heater or current injection, respectively. The heating power required to align the Bragg wavelength of a 0.5 mm long front grating to one of the sampling wavelengths is estimated to be 186 mW and 137 mW using a micro-heater or current injection, respectively. [0022] It is noted that terms like "preferably," "commonly," and "typically," when utilized herein, are not utilized to limit the scope of the claimed invention or to imply that certain features are critical, essential, or even important to the structure or function of the claimed invention. Rather, these terms are merely intended to identify particular aspects of an embodiment of the present disclosure or to emphasize alternative or additional features that may or may not be utilized in a particular embodiment of the present disclosure.
[0023] For the purposes of describing and defining the present invention it is noted that the terms "substantially" and "approximately" are utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. The terms "substantially" and "approximately" are also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.
[0024] Having described the subject matter of the present disclosure in detail and by reference to specific embodiments thereof, it is noted that the various details disclosed herein should not be taken to imply that these details relate to elements that are essential
components of the various embodiments described herein, even in cases where a particular element is illustrated in each of the drawings that accompany the present description. Rather, the claims appended hereto should be taken as the sole representation of the breadth of the present disclosure and the corresponding scope of the various inventions described herein. Further, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims. More specifically, although some aspects of the present disclosure may be identified herein as preferred or particularly advantageous, it is contemplated that the present disclosure is not necessarily limited to these aspects.
[0025] It is noted that one or more of the following claims utilize the term "wherein" as a transitional phrase. For the purposes of defining the present invention, it is noted that this term is introduced in the claims as an open-ended transitional phrase that is used to introduce a recitation of a series of characteristics of the structure and should be interpreted in like manner as the more commonly used open-ended preamble term "comprising."

Claims

CLAIMS What is claimed is:
1. A multi-wavelength distributed Bragg reflector (DBR) laser diode comprising front and rear DBR sections, a plurality of dedicated tuning signal control nodes, a gain section, and a waveguide core extending between front and rear facets of the laser diode, characterized by: the gain section comprises an active region and is positioned between the front and rear DBR sections along an optical propagation axis defined by the waveguide core of the laser diode;
the front DBR section comprises a plurality of front wavelength selective grating sections defining a plurality of distinct grating periodicities Λι*, Λ2*... corresponding to distinct Bragg wavelengths λδι*, λδ2*...;
the rear DBR section comprises a plurality of rear wavelength selective grating sections defining a plurality of distinct grating periodicities Λι, Λ2... corresponding to distinct Bragg wavelengths λδι,
the plurality of dedicated tuning signal control nodes are associated with individual ones of the front wavelength selective grating sections, individual ones of the rear wavelength selective grating sections, or both, and are constructed such that one or more tuning signals applied to one or more of the dedicated tuning signal control nodes spectrally aligns distinct Bragg wavelengths a selected one of the distinct Bragg wavelengths si*, s2*„. of the front DBR section with a selected one of the distinct Bragg wavelengths $ι, s2... of the rear DBR section.
2. A laser diode as claimed in claim 1 wherein:
the front or rear wavelength selective grating sections and the dedicated front or rear tuning signal control nodes are constructed such that a tuning signal applied to one of the dedicated front or rear tuning signal control nodes will place a selected one of the distinct Bragg wavelengths si*, s2*... into spectral alignment with a selected one of the distinct Bragg wavelengths λδι, λδ2; and
the distinct Bragg wavelengths si*, s2*.„ are shorter or longer than the distinct Bragg wavelengths λδι, λδ2.
3. A laser diode as claimed in claim 2 wherein the front and rear wavelength selective grating sections and the dedicated front and rear tuning signal control nodes are constructed such that a tuning signal applied to a dedicated front or rear tuning signal control node associated with a shorter wavelength places a selected one of the distinct Bragg wavelengths λβι *, λ«2* ... into spectral alignment with a selected one of the distinct Bragg wavelengths $ι,
4. A laser diode as claimed in claim 2 wherein each of the distinct Bragg wavelengths si *, s2* ... are spectrally misaligned with respect to the corresponding distinct Bragg wavelengths βι, A«2... by approximately 4.1 cm_1or more for a DBR length of 0.5 mm.
5. A laser diode as claimed in one of the preceding claims wherein:
one or more of the distinct Bragg wavelengths si *, s2*... are spectrally aligned with respect to the distinct Bragg wavelengths λδι, λδ2...; and
the front wavelength selective grating sections and the dedicated front tuning signal control nodes are constructed such that tuning signals applied to the dedicated front tuning signal control nodes will alter selected ones of the distinct Bragg wavelengths λδι *, λδ2*... such that all but one of the distinct Bragg wavelengths si *, s2* ... are spectrally misaligned with respect to the distinct Bragg wavelengths λδι, λδ2...
6. A laser diode as claimed in one of the preceding claims wherein:
the front tuning signal control nodes comprise thermal tuning nodes; and
each of the distinct Bragg wavelengths si *, s2*„. are shorter than the distinct Bragg wavelengths $ι, s2... such that a temperature increase initiated by one or more of the front thermal tuning nodes will increase the distinct Bragg wavelengths si *, s2*.„
7. A laser diode as claimed in one of the preceding claims wherein the front tuning signal control nodes comprise electrical contacts for direct current injection to the front wavelength selective grating sections.
8. A laser diode as claimed in one of the preceding claims wherein:
the rear wavelength selective grating sections comprise one or more rear tuning signal control nodes associated with the rear wavelength selective grating sections; and
the rear tuning signal control nodes are constructed such that one or more tuning signals applied to one or more of the rear tuning signal control nodes will alter one or more of the distinct Bragg wavelengths λδι, λδ2...
9. A laser diode as claimed in one of the preceding claims wherein a dedicated front control node comprises a single control node associated with a single front wavelength selective grating section or a plurality of tuning signal control nodes associated with a single front wavelength selective grating section.
10. A laser diode as claimed in one of the preceding claims wherein:
the waveguide core of the laser diode comprises a stack of quantum cascade cores; and
each quantum cascade core comprises a gain peak approximating one of the distinct Bragg wavelengths λδι, λδ2... of the rear wavelength selective grating sections.
11. A laser diode as claimed in claim 10 wherein:
the gain section of the laser diode is characterized by a wavelength-dependent optical gain spectrum; and
the quantum cascade cores with relatively low optical gains are placed relatively close to the center of the optical mode of propagation of the laser diode, while the quantum cascade cores with relatively high optical gains are placed relatively far from the center of the optical mode of propagation of the laser diode.
12. A laser diode as claimed in claim 10 wherein:
the gain section of the laser diode is characterized by a wavelength-dependent optical gain spectrum; and
the quantum cascade cores with relatively low optical gains are constructed with a relatively high number of stages or relatively high confinement factors, while the quantum cascade cores with relatively high optical gains are constructed with a relatively low number of stages or relatively low confinement factors.
13. A laser diode as claimed in claim 10 wherein:
relatively short wavelength quantum cascade cores are placed relatively close to the center of the optical mode of propagation of the laser diode, while relatively long wavelength quantum cascade cores are placed relatively far from the center of the optical mode of propagation of the laser diode.
14. A laser diode as claimed in one of the preceding claims wherein the waveguide core of the laser diode comprises a single quantum cascade core with a gain spectrum that is broad enough to encompass the distinct Bragg wavelengths λδι, λδ2... of the rear wavelength selective grating sections.
15. A laser diode as claimed in one of the preceding claims wherein the waveguide core of the laser diode comprises a uni-polar QCL using inter-sub-band transitions to produce photons.
16. A laser diode as claimed in one of the preceding claims 1 - 14 wherein the waveguide core of the laser diode comprises a bi-polar laser using inter-band transitions to produce photons.
17. A laser diode as claimed in one of the preceding claims wherein:
the gain section of the laser diode is characterized by a wavelength-dependent optical gain spectrum; and
the front and rear wavelength selective grating sections are arranged along the optical propagation axis of the laser diode such that grating sections corresponding to reflectance peaks in relatively low gain portions of the optical gain spectrum are positioned relatively close to the gain section of the laser diode, while grating sections corresponding to reflectance peaks in relatively high gain portions of the optical gain spectrum are positioned relatively far from the gain section of the laser diode.
18. A laser diode as claimed in one of the preceding claims wherein:
the gain section of the laser diode is characterized by a wavelength-dependent optical gain spectrum; and
the front grating section corresponding to a reflectance peak in the lowest gain portion of the optical gain spectrum is positioned closest to the gain section along a front portion of the optical propagation axis of the laser diode.
19. A laser diode as claimed in one of the preceding claims wherein:
the gain section of the laser diode is characterized by a wavelength-dependent optical gain spectrum; and
the rear grating section corresponding to a reflectance peak in the lowest gain portion of the optical gain spectrum is positioned closest to the gain section along a rear portion of the optical propagation axis of the laser diode.
20. A multi-wavelength distributed Bragg reflector (DBR) laser diode comprising front and rear DBR sections, a plurality of dedicated tuning signal control nodes, a gain section, and a waveguide core extending between front and rear facets of the laser diode, wherein:
the gain section comprises an active region and is positioned between the front and rear DBR sections along an optical propagation axis defined by the waveguide core of the laser diode;
the front DBR section comprises a plurality of front wavelength selective grating sections defining a plurality of distinct grating periodicities Λι *, Λ2*.„ corresponding to distinct Bragg wavelengths λδι *, λδ2*...;
the rear DBR section comprises a plurality of rear wavelength selective grating sections defining a plurality of distinct grating periodicities Ai, A2... corresponding to distinct Bragg wavelengths λδι,
each of the distinct Bragg wavelengths si *, s2*„. are shorter than and spectrally misaligned with respect to the distinct Bragg wavelengths λδι, λδ2...; the plurality of dedicated tuning signal control nodes are associated with individual ones of the front wavelength selective grating sections and are constructed such that one or more tuning signals applied to one or more of the front dedicated tuning signal control nodes spectrally aligns distinct Bragg wavelengths a selected one of the distinct Bragg wavelengths λβι*, λ«2*... of the front DBR section with a selected one of the distinct Bragg wavelengths βι, A«2... of the rear DBR section;
the waveguide core of the laser diode comprises a stack of quantum cascade cores; each quantum cascade core comprises a gain peak approximating one of the distinct Bragg wavelengths λδι, λδ2... of the rear wavelength selective grating sections;
the gain section of the laser diode is characterized by a wavelength-dependent optical gain spectrum;
the quantum cascade cores with relatively low optical gains are placed relatively close to the center of the optical mode of propagation of the laser diode, while the quantum cascade cores with relatively high optical gains are placed relatively far from the center of the optical mode of propagation of the laser diode; and
the front grating section corresponding to a reflectance peak in the lowest gain portion of the optical gain spectrum is positioned closest to the gain section along a front portion of the optical propagation axis of the laser diode.
PCT/US2012/063000 2011-11-07 2012-11-01 Multi-wavelength dbr laser WO2013070484A2 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP12791908.2A EP2777107A2 (en) 2011-11-07 2012-11-01 Multi-wavelength dbr laser
KR1020147013167A KR20140089548A (en) 2011-11-07 2012-11-01 Multi-wavelength DBR Laser

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US201161556434P 2011-11-07 2011-11-07
US61/556,434 2011-11-07
US13/570,719 US20130114628A1 (en) 2011-11-07 2012-08-09 Multi-wavelength dbr laser
US13/570,719 2012-08-09

Publications (2)

Publication Number Publication Date
WO2013070484A2 true WO2013070484A2 (en) 2013-05-16
WO2013070484A3 WO2013070484A3 (en) 2013-07-04

Family

ID=48223655

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2012/063000 WO2013070484A2 (en) 2011-11-07 2012-11-01 Multi-wavelength dbr laser

Country Status (5)

Country Link
US (1) US20130114628A1 (en)
EP (1) EP2777107A2 (en)
KR (1) KR20140089548A (en)
TW (1) TW201328091A (en)
WO (1) WO2013070484A2 (en)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2926420A1 (en) * 2012-11-30 2015-10-07 Thorlabs Quantum Electronics, Inc. Monolithic wide wavelength tunable mid-ir laser sources
US9660417B2 (en) 2014-01-31 2017-05-23 Photodigm, Inc. Light emitting device with extended mode-hop-free spectral tuning ranges and method of manufacture
US20150311665A1 (en) * 2014-04-29 2015-10-29 Board Of Regents, The University Of Texas System External cavity system generating broadly tunable terahertz radiation in mid-infrared quantum cascade lasers
CN105895775B (en) * 2015-02-17 2019-09-17 新世纪光电股份有限公司 Light emitting diode
US11539190B2 (en) 2016-09-02 2022-12-27 Kyushu University, National University Corporation Continuous-wave organic thin-film distributed feedback laser and electrically driven organic semiconductor laser diode
JP7162306B2 (en) * 2017-02-07 2022-10-28 国立大学法人九州大学 CURRENT INJECTION ORGANIC SEMICONDUCTOR LASER DIODE, PRODUCTION METHOD AND PROGRAM
CN107482477B (en) * 2017-07-28 2019-09-10 长春理工大学 The high-power distributed feedback semiconductor laser on surface and the modulation of side dielectric grating
CN114094442A (en) * 2021-11-10 2022-02-25 海南师范大学 Dual-wavelength quantum cascade semiconductor laser chip

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5379318A (en) * 1994-01-31 1995-01-03 Telefonaktiebolaget L M Ericsson Alternating grating tunable DBR laser
WO2002075867A2 (en) * 2001-03-19 2002-09-26 Bookham Technology Tuneable laser
GB2377545A (en) * 2001-07-14 2003-01-15 Marconi Caswell Ltd Tuneable Laser
DE10143956A1 (en) * 2001-09-07 2003-04-03 Fraunhofer Ges Forschung Quantum Cascade Lasers
US7403552B2 (en) * 2006-03-10 2008-07-22 Wisconsin Alumni Research Foundation High efficiency intersubband semiconductor lasers

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None

Also Published As

Publication number Publication date
WO2013070484A3 (en) 2013-07-04
TW201328091A (en) 2013-07-01
US20130114628A1 (en) 2013-05-09
EP2777107A2 (en) 2014-09-17
KR20140089548A (en) 2014-07-15

Similar Documents

Publication Publication Date Title
WO2013070484A2 (en) Multi-wavelength dbr laser
US6822982B2 (en) Device and method for providing a tunable semiconductor laser
US6819702B2 (en) Pump laser diode with improved wavelength stability
EP2820727B1 (en) Surface emitting multiwavelength distributed-feedback concentric ring lasers
US20090022186A1 (en) Method of controlling semiconductor laser
GB2493988A (en) Monolithically integrated tunable semiconductor laser
EP2803122B1 (en) Mid-ir multiwavelength concatenated distributed-feedback laser with an active core made of cascaded stages
US20130089115A1 (en) High Power Semiconductor Laser with Phase-Matching Optical Element
EP2777105A1 (en) Heating elements for multi-wavelength dbr laser
JP2016500472A (en) Monolithic mid-infrared laser source with wide wavelength tuning range
JP2009044024A (en) Semiconductor laser device, and control method of semiconductor laser
US8681826B2 (en) Method for tuning semiconductor laser
Rauter et al. Single-mode tapered quantum cascade lasers
GB2493989A (en) Tunable multi-mode laser
Crump et al. Efficiency-optimized monolithic frequency stabilization of high-power diode lasers
Debrégeas-Sillard et al. DBR module with 20-mW constant coupled output power, over 16 nm (40 x 50-GHz spaced channels)
US20150117482A1 (en) Method for controlling wavelength tunable laser
Diba et al. Wavelength tuning of sampled-grating DBR quantum cascade lasers
US9331455B1 (en) Frequency locked diode laser devices exhibiting low power penalty
Crump et al. 10-W reliable 90-µm-wide broad area lasers with internal grating stabilization
Elarde et al. Curved waveguide array diode lasers for high-brightness applications
EP1283573A2 (en) A distributed bragg reflector semiconductor laser
Lucas-Leclin et al. External-cavity designs for phase-coupled laser diode arrays
Gubenko et al. Quantum dot comb laser with the integrated DBR section for DWDM optical interconnects
Crump et al. Monolithically wavelength-stabilized high power diode lasers

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12791908

Country of ref document: EP

Kind code of ref document: A2

ENP Entry into the national phase

Ref document number: 2014541106

Country of ref document: JP

Kind code of ref document: A

ENP Entry into the national phase

Ref document number: 20147013167

Country of ref document: KR

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 2012791908

Country of ref document: EP

NENP Non-entry into the national phase

Ref country code: JP