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New Member

Erbium-doped fiber amplifiers

I am reading about the EDFA and I know that there is a laser source as the pump. I am just curious for those long-haul submarine cable under the sea, where is the energy of the laser coming from?

And before DWDM is avaliable, what is the fiber type used in those submarine cable, is it Dispersion-shifed fiber(DSF), Zero dispersion fiber (DSF), or Nonzero dispersion fiber(NDF)? What fiber type are required for DWDM? and if the fiber type don't support by DWDM, do they have to relay new cable?

Thanks you for your attention.

1 ACCEPTED SOLUTION

Accepted Solutions
New Member

Re: Erbium-doped fiber amplifiers

In case of overseas cables EDFA pump is coming from the landed system over the same fiber.

Since wavelength is different, pump source can be of relatively high power (where fiber nonlinearities permit) and therefore reach further distance.

In some cases pump can come on a separate fiber, in some cases there can be an autonomous (nuclear) power supply burried in the sea.

As for the fiber type - the optimal fiber type for next generation optics is considered to be Non Zero Dispersion Shifted Fiber, where dispersion optimum is shifted to C-band artificially introducing a little dispersion of ~ 4ps/nm/km to avoid non-linear affects such as FWM.

This fiber is expensive that slows its wide usage.

6 REPLIES
noc
New Member

Re: Erbium-doped fiber amplifiers

energy is 10,000 Volts run along the cable from the ends.. it is used to perform Re-amp and re-generation. But cable systems are being deployed which can make it from NYC to London without electo-optical conversion.

All legacy cables can be made to support DWDM from filters at the ends

New Member

Re: Erbium-doped fiber amplifiers

In case of overseas cables EDFA pump is coming from the landed system over the same fiber.

Since wavelength is different, pump source can be of relatively high power (where fiber nonlinearities permit) and therefore reach further distance.

In some cases pump can come on a separate fiber, in some cases there can be an autonomous (nuclear) power supply burried in the sea.

As for the fiber type - the optimal fiber type for next generation optics is considered to be Non Zero Dispersion Shifted Fiber, where dispersion optimum is shifted to C-band artificially introducing a little dispersion of ~ 4ps/nm/km to avoid non-linear affects such as FWM.

This fiber is expensive that slows its wide usage.

New Member

Re: Erbium-doped fiber amplifiers

In case of overseas cables EDFA pump is coming from the landed system over the same fiber.

Since wavelength is different, pump source can be of relatively high power (where fiber nonlinearities permit) and therefore reach further distance.

In some cases pump can come on a separate fiber, in some cases there can be an autonomous (nuclear) power supply burried in the sea.

As for the fiber type - the optimal fiber type for next generation optics is considered to be Non Zero Dispersion Shifted Fiber, where dispersion optimum is shifted to C-band artificially introducing a little dispersion of ~ 4ps/nm/km to avoid non-linear affects such as FWM.

This fiber is expensive that slows its wide usage.

New Member

Re: Erbium-doped fiber amplifiers

In case of overseas cables EDFA pump is coming from the landed system over the same fiber.

Since wavelength is different, pump source can be of relatively high power (where fiber nonlinearities permit) and therefore reach further distance.

In some cases pump can come on a separate fiber, in some cases there can be an autonomous (nuclear) power supply burried in the sea.

As for the fiber type - the optimal fiber type for next generation optics is considered to be Non Zero Dispersion Shifted Fiber, where dispersion optimum is shifted to C-band artificially introducing a little dispersion of ~ 4ps/nm/km to avoid non-linear affects such as FWM.

This fiber is expensive that slows its wide usage.

New Member

Re: Erbium-doped fiber amplifiers

In case of overseas cables EDFA pump is coming from the landed system over the same fiber.

Since wavelength is different, pump source can be of relatively high power (where fiber nonlinearities permit) and therefore reach further distance.

In some cases pump can come on a separate fiber, in some cases there can be an autonomous (nuclear) power supply burried in the sea.

As for the fiber type - the optimal fiber type for next generation optics is considered to be Non Zero Dispersion Shifted Fiber, where dispersion optimum is shifted to C-band artificially introducing a little dispersion of ~ 4ps/nm/km to avoid non-linear affects such as FWM.

This fiber is expensive that slows its wide usage.

New Member

Re: Erbium-doped fiber amplifiers

In case of overseas cables EDFA pump is coming from the landed system over the same fiber.

Since wavelength is different, pump source can be of relatively high power (where fiber nonlinearities permit) and therefore reach further distance.

In some cases pump can come on a separate fiber, in some cases there can be an autonomous (nuclear) power supply burried in the sea.

As for the fiber type - the optimal fiber type for next generation optics is considered to be Non Zero Dispersion Shifted Fiber, where dispersion optimum is shifted to C-band artificially introducing a little dispersion of ~ 4ps/nm/km to avoid non-linear affects such as FWM.

This fiber is expensive that slows its wide usage.

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