Passive optics units (POUs)
Passive optics units
The Passive Optics Units (POUs) are a lower-cost solution to using DWDM for transmitting large amounts of traffic on one fiber. The shelf fits in a bay frame with Alcatel-Lucent 1665 DMX. If the POU is used in the same bay frame with Alcatel-Lucent 1665 DMX, then the number of Alcatel-Lucent 1665 DMX shelves in that bay frame is limited to three. The POUs do not need any power supply or management system.
POU shelves are available to support the following applications:
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Dual optical add-drop module (OADM): one 1310 nm port and four 1550 nm ports
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32 wavelengths using 16 unidirectional/bidirectional wavelengths (MUX or DMUX) with a wavelength interleaver used to add another 16 wavelengths: MUXINT or DMUXINT
The following figure shows the POU shelves.
Figure 4-3: POU shelves (DWDM filter units): MUX/DMUX
|
Height (mm/inches) |
Width (mm/inches) |
Depth (mm/inches) |
|---|---|---|
|
74/2.913 |
498/19.606 |
378.64/14.907 |
POU versions
As the variety of applications listed above suggests, there are various versions of the POU, each designed to maximize functionality in a variety of deployment scenarios. The bulleted list below details the various forms of POUs:
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16 Channel MUX or DMUX (odd numbered channels): This POU supports unidirectional and bidirectional transmission systems.
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16 Channel MUX or DMUX with Interleaver (even numbered channels): This POU supports unidirectional and bidirectional transmission systems, and includes an interleaver to support 16 additional channels.
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Dual 1-Channel Optical Add Drop: This POU supports unidirectional transmission systems and can add/drop one channel from a DWDM line carrying up to 32 different channels.
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Dual 2-Channel Optical Add Drop: This POU supports unidirectional transmission systems and can add/drop two channels from a DWDM line carrying up to 32 different channels.
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Dual 4-Channel Optical Add Drop: This POU supports unidirectional transmission systems and can add/drop four channels from a DWDM line carrying up to 32 different channels.
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Dual 1310 + 4x1550 MUX/DMUX: This POU provides one I/O port for 1310 nm signals and four I/O ports for 1550 nm signals. This POU supports unidirectional transmission systems and can MUX or DMUX a 1310 channel and four 1550 bands to/from a DWDM line.
Important!
The last four bulleted items in the list above describe the various OADMs and MUX/DMUX as "Dual". "Dual" is in reference to the fact that each of these specific POUs are comprised of two complete sets of OADMs or MUX/DMUX units. Thus, the dual 1-channel OADM POU contains 2 OADMs, enabling it to support 1 add/drop in each direction.
The following figure shows a diagram of transmission with up to 32 wavelengths (channels) being received and passed-through one of the Add/Drop units. Also, the diagram shows how 1, 2, or 4 wavelengths can be added and/or dropped from a passive DWDM OC-48/192 line using the Add/Drop Units.
Figure 4-4: Add/Drop unit
The following figure shows a diagram of transmission with 16 lines transmitting at one end of the fiber and 16 lines receiving at the other end. The 16 port units on each side of transmission may be a combination of OC-192 DWDM OLIUs and/or OC-48 DWDM OLIUs. Each OLIU is equipped with a bidirectional port (both transmit and receive). The fiber between the two POUs (DWDM Filter Units) on the upper portion of the figure is unidirectional in the east direction. The fiber between the two Passive Optics Shelves on the lower portion of the figure is unidirectional in the west direction. Another Passive Optics Shelf, with a wavelength interleaver, can be added to transport 32 wavelengths in each direction at the OC-192 or OC-48 rate on one fiber.
Figure 4-5: MUX/DMUX passive optics shelf (16 transmit at one end, 16 receive at the other end)
The following figure shows a diagram of bidirectional transmission with eight lines transmitting at one end of the fiber and eight lines receiving at the other end. This is the same POU pictured above, except that it is being used in a bidirectional application. The eight port units on each side of transmission may be a combination of OC-192 DWDM OLIUs and/or OC-48 DWDM OLIUs. Each OLIU is equipped with a bidirectional port (both transmit and receive). The fiber between the two POU shelves (DWDM filter unit box) is bidirectional (transmit and receive).
Figure 4-6: MUX/DMUX passive optics shelf (8 transmit and 8 receive at each end)
Important!
This figure assumes a full set of 8 bidirectional point-to-point cross-connections.