Understanding the Integrated Photonic Line Card Architecture
This topic provides an architectural and functional overview of the IPLC and includes the following sections:
You can use the integrated photonic line system to transport
100 Gbps coherent DWDM optics located in either the same or different
PTX3000 chassis, a PTX5000 chassis, or an MX Series chassis—simply
make the proper physical connections between the
DROP ports on the IPLC module and the interface
in the chassis. All connections between the DWDM optics and the IPLC
are made through the front panel. The IPLC base module accepts and
then multiplexes 32 individual wavelengths (connected through the
DROP ports on the front panel)
into a single fiber pair. If you require more than 32 channels, you
can connect the optional IPLC expansion module to the IPLC base module
to increase the port capacity of the node to 64 ports.
The wavelengths from the
DROP ports are then amplified, monitored, and controlled
and then transmitted towards the optical network over the
Line OUT port on front panel of the IPLC base module.
In the reverse direction, the received signals from the optical network
Line IN port are amplified to overcome
for loss in the optical fiber and then demultiplexed into individual
wavelengths and sent to the configured
DROP ports on the front panel.
The 32 channels provided by the IPLC base module are known as the odd channels. The 32 channels provided by the optional IPLC expansion module are known as the even channels. This odd and even designation reflects the default wavelengths the channels support.
In the multiplexing-add path, the 32 even channels from the IPLC expansion module are interleaved with the 32 odd channels from the IPLC base module. In the demultiplexing-drop path, the 32 even channels are separated from the odd channels using a deinterleaver. All 64 channels go through the main common components used for amplification and equalization. All 32 channels on the IPLC base module are 100 GHz spaced, per the ITU-T Grid Specifications (G.694.1). The 32 channels on the IPLC expansion module are offset from the IPLC base module channels by 50 GHz.
For ring topologies and other network topologies that require
a two-degree node for east-and west communications, you can connect
two IPLC base modules together through the
PT OUT ports on the front panel and enter a
few CLI commands to form a two-degree node. Two-degree nodes enable
you to route wavelengths in both directions.
Functional Component Overview
The high-level optical functional block diagram of the combined functions of both the IPLC base module and the IPLC expansion module are shown in Figure 1.
IPLC Base Module Functional Components
The main building blocks of the IPLC base module architecture are as follows:
A 2x1 wavelength selective switch (WSS) on the add path selects wavelengths from among all channels presented from the 32
Addports of the IPLC base module (shown in blue in Figure 1) and from the 32
Addports on the IPLC expansion module (shown in gray in Figure 1).
A booster erbium-doped fiber amplifier (EDFA) (E1) followed by a variable optical attenuator (VOA) compensate for the loss of the WSS, multiplexer, and 3 dB coupler.
A variable gain preamplifier EDFA (E2) to compensate for the loss of the preceding fiber span.
An optical channel monitor (OCM) with three points of observation including the following:
Booster EDFA (E1) output
Preamplifier EDFA (E2) output
The combined channels of the local add function at the input of the WSS, which indicates which channels (both odd and even channels) are being added locally
An optical supervisory channel (OSC) communicates inband with the remote IPLC modules, as well as the optical ILA and is used for the analysis of the fiber span characteristics, performance monitoring, and IPLC fault handing.
An optical splitter is used to broadcast the received signal from the output of the preamplifier (E2) toward both
Four power monitors:
AWG Add—Monitors the input of the WSS measuring the total input power of the combined channels of the local add function
Express In—Monitors the input of the WSS measuring the total input power at the input to the WSS coming from the
PT OUTexpress ports
Line IN—Monitors the input at the
Line INport, for detection of the incoming line signal optical power
Line OUT—Monitors the output at the
Line OUTport, for detection of the outgoing line signal optical power
OSC ADD—Monitors OSC power at
OSC DROP—Monitors OSC power at
IPLC Expansion Module Functional Components
The IPLC expansion module is a passive multiplexer/demultiplexer
that interfaces only with the IPLC base module. The IPLC expansion
module receives its sole input from and delivers its sole output to
the IPLC base module through the
XPN IN and
XPN OUT ports. As such, it does not interface directly
with the network or the high-speed backplane of the PTX3000 Series
router. Figure 1 shows
the main building blocks for both the IPLC base module and expansion
module, which include:
Add filter capable of multiplexing 32 DWDM channels of certain wavelengths
Drop filter capable of demultiplexing 32 DWDM channels having the same certain wavelengths
Demultiplexing filter whose input (which is also the sole input to the expansion module) is monitored through a power detector. The power detector determines whether light is present. If light is present, the power detector determines whether the light has reached the expansion module through the patch cord between the IPLC base module and the IPLC expansion module.