Difference frequency generation based on mass production laser by bgn16443

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									Difference frequency generation based
on mass production laser diodes

 M. Takahashi, S. Ohara*, T. Tezuka*, H. Ashizawa*,
            S . Yamaguchi* and E. Noda

                  Toshiba Corporation
                   *Tokai University
Contents


• Introduction
• Signal / Pump laser combination and
  characteristics
• Different Frequency Generation
• DFG laser characteristics
    Absorption measurement of N2O
• Conclusion
Introduction
   Background
Highly sensitive and selective gas sensing is required
                  • Environmental monitoring
                  • Industrial plant surveillance
                  • Industrial process control
                                ・
                               ・


           MIR absorption spectroscopy
Main advantage of MIR spectroscopy


    1. Sensitive

    2. Fast response

    3. Compact

    4. Cost effective
Purpose of the research


• Realize more compact and cheaper
  light source for MIR spectroscopy

Solution
    DFG laser based on mass production laser diodes
           980nm laser diode for fiber communication
           600-850nm band laser diode for optical storage
Signal / Pump laser combination and characteristics
Pump laser

    FBG stabilized 980nm LD for Eb fiber pumping
    Maximum output power : 100mW
               Pump laser oscillation spectrum

               0.06
Power (a.u.)
 相対強度(a.u.)




               0.04




               0.02




                 0
                  979       979.5         980         980.5   981
                                     波長(nm)
                                    Wavelength (nm)
Signal Laser

      788nm Fabry-Perot laser diode for CD-R
      Maximum output power from LD chip: 100mW
      Maximum output power from pigtailed fiber ~10mW
Signal laser oscillation spectrum


                1.4

                1.2
 Power (a.u.)




                 1
  相対強度(a.u.)




                0.8

                0.6

                0.4

                0.2

                 0
                  787   787.5        788          788.5   789
                                 波長(nm)
                                Wavelength (nm)
Oscillation Wavelength Control


• Temperature
     0.35 nm/K(5.6 cm−1/K).

        Select absorption line

• Operating current.
        Wavelength sweep in selected absorption line
operating current dependence of the oscillation
wavelength
                      788.2
 Wavelength (a.u.)




                                                                    0.16nm(77GHz)
                     788.15
    発振波長(nm)




                      788.1




                     788.05




                        788
                              90   100        110     120     130                   140
                                            動作電流(mA)
                                         Operating current (mA)
Different Frequency Generation
Difference Frequency Generation by PPMgLN




                                          PPMgLN
                                       L=21.3μm,L=20mm,
                                  s   t=0.5mm,T=40℃
           PMF
                   -W
                 PM DM Coupler                       i
                                                          4mm
                                  p
    Isolator


                                 DFG Wavelength;i = p - s
     Input-output characteristics of the DFG
                               Conversion efficiency=0.92mW/W2
                0.25
DFG power(μW)



                0.20

                0.15

                0.10

                0.05

                0.00
                       0          100              200           300
                           Poduct of signal/pump power(mW2)
DFG laser characteristics
    Absorption measurement of N2O
Schematic diagram of the DFG sensor
50 times averaged Doppler-broadened absorption
spectrum of N2O
Absorption spectrum of 1ppm N2O
Conclusion

   1. We proposed the Difference frequency
      generation laser based on mass production
      laser diodes.
   2. A mid-IR power of 0.23 μm and conversion
      efficiency of 0.92mW/W2 were obtained.
   3. A DFG linewidth of 161MHz was measured
      using absorption measurement of N2O
   4. We demonstrated 1ppm N2O detection by
      using the proposed DFG laser

								
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