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Cut-off wavelength in PCF

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(joined March 2015)
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How can man extract cut-off wavelength for a photonic crystal fibers? which product oft optiwave is proper for this aim?

Responses (6):

    • #18303
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      Bijan goudarzi
      Participant

      How can man extract cut-off wavelength for a photonic crystal fibers? which product oft optiwave is proper for this aim?

    • #18314
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      Bijan goudarzi
      Participant

      Dear Sethi,
      Is it possible to design a photonic crystal fiber in OptiFiber?

    • #18325
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      Damian Marek
      Participant

      You would need OptiFDTD for this application. Not necessarily the OptiFDTD simulation engine but the additional software that comes with it, OptiMode. In OptiMode you can construct photonic crystal fibers and simulate the modes that exist. You can also run a parameter sweep to find which wavelength corresponds to cutoff.

      Regards

    • #18326
      Dr Rk Sethi
      Participant

      OptiFiber uses numerical mode solvers and other models specialized to fibers for calculating dispersion, losses, birefringence, and PMD.
      KEY APPLICATIONS of OptiFiber
      :
      ◦Assess parameters, sensitivities, and tolerances
      ◦Fiber mode solving of LP or Vector modes by Finite Difference or by Transfer Matrix Methods
      ◦Analysis of measured fiber profiles from instruments such as the EXFO NR-9200
      ◦Single mode fiber designs such as Corning SMF-28, dispersion flattened or shifted fibers.
      ◦Multimode fiber design, such as 50/125 m and 62.5/125 m silica fibers.
      ◦Visualization of multimode interference patterns with propagation
      ◦Automatic parameter scanning
      ◦Fiber Sensor design
      ◦Calculation of birefringence and PMD from intrinsic or extrinsic perturbations

      Please have a look at the post of Damian Marek :
      Home » Topics » KNOWLEDGE » Photonic Crystal Fiber [FDTD]
      Damian Marek
      Question:
      I want to simulate the transparency of a photonic crystal fiber. For example, I am trying to design a fiber so that there is a small range of wavelengths that will be able to propagate. Is this an OptiFDTD application?
      Answer:
      OptiFDTD is, as you suggested, the most suitable software for this purpose. You can define a small section of fiber within the software and calculate the transmission and reflection spectra. You can then define geometrical parameters in your design and perform parameter sweeps to fine tune the fiber spectrum.

      +1
    • #18342
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      Bijan goudarzi
      Participant

      Dear Marek,
      Follow your tip, I went to design my PCF with optiMODE. I was going to do it base on OptiMode_User_Reference pdf file (section: OptiMode Tutorial 5- Photonic Crystal Fiber and VB script). but the script given by the tutorial return error and cant made the PCF structure. here is the exact script of the tutorial and at the end is the returned error,

      ‘ Make the hexagonal crystal lattice fibre of
      ‘ Optics Letters Vol.22 No. 13 p961 (1997)
      Option Explicit
      WGMgr.DeleteAll
      Dim X0,Y0,Nperiods,i,j,YLevel,Pitch,HoleDiameter,x_coord
      Dim wg_object, Xdefect, Ydefect, windowsz

      windowsz = ParamMgr.EvaluateExpr(“window”)

      Nperiods = 9
      Pitch = 2.3
      X0 = – (Nperiods/2 – 0.5) * Pitch
      Y0 = – (Nperiods – 1) * (3)^(0.5) * Pitch / 2.0
      HoleDiameter = 0.45 * Pitch

      Xdefect = Nperiods
      Ydefect = Nperiods

      WGMgr.OutputMSG(” Periods = ” & Nperiods & ” Pitch = ” & Pitch & _
      ” Hole Diameter = ” & HoleDiameter)
      ‘ Create the lower half of the photonic crysal.
      ‘ Don’t put a waveguide at i = j = Nperiods
      For j = 1 To Nperiods
      YLevel = Y0 + (j-1) * (3)^(0.5) * Pitch / 2.0
      If YLevel > – windowsz / 2 Then
      For i = 1 To Nperiods + j – 1
      x_coord = X0 + (i – 1) * Pitch – (j – 1) * Pitch / 2.0
      If( (i<>Xdefect Or j<>Ydefect) And x_coord < windowsz / 2 _
      And x_coord > – windowsz / 2 ) Then
      Set wg_object = WGMgr.CreateObj(“WGLinearXS”, “Hole_”& _
      CStr(j)&”_”&CStr(i) )
      wg_object.SetStart x_coord, YLevel
      wg_object.SetAttr “WidthExpr”, CStr(HoleDiameter)
      wg_object.SetProfileName “Hole”
      End If
      Next
      End If
      Next

      ‘ Create the upper half of the photonic crystal
      For j = Nperiods + 1 To 2 * Nperiods – 1
      YLevel = Y0 + (j-1) * (3)^(0.5) * Pitch / 2.0
      If YLevel < windowsz / 2 Then
      For i = 1 To 3 * Nperiods – j – 1
      x_coord = X0 + (i – 1) * Pitch + (j – 2 * Nperiods + 1) _
      * Pitch / 2.0
      If x_coord < windowsz / 2 And x_coord > – windowsz / 2 Then
      Set wg_object = WGMgr.CreateObj(“WGLinearXS”, “Hole_” _
      &CStr(j) &”_”&CStr(i) )

      wg_object.SetStart x_coord, YLevel
      wg_object.SetAttr “WidthExpr”, CStr(HoleDiameter)
      wg_object.SetProfileName “Hole”
      End If
      Next
      End If
      Next

      VB scripting: ‘Microsoft VBScript runtime error’ Line:25,char:4, ‘Type mismatch: ‘[string: “Error: Unknown varia”]”

      *Line 25 is refered to: If YLevel > – windowsz / 2 Then

      what is wrong with it?

      • #18384
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        Damian Marek
        Participant

        The error is because you are trying to access a parameter that might not exist in your Functions and Variables, Before running the script go to Solving tab -> Edit Parameters and add the parameters “window” = 25 and “ScanWavelength” = 1.00 the tutorial file has them as well.

        Regards

    • #18361
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      Ravil
      Participant

      Agree with Damian, sweep option should give you a cut-off wavelength.

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