1-5
Cisco ONS 15501 User Guide
78-14134-02, Release 2.0
Chapter1 Product Overview
Cisco ONS 15501 Applications

Low Noise Figure

The low noise characteristics of the Cisco ONS 15501 allow over six amplifiers to be cascaded and still
achieve an excellent OSNR at input powers as low as –21 dBm per channel. This enables seamless
migration to higher speeds beyon d OC-48 and to a larger number of channels.

High Maximum Output Power

The high maximum optical power of the Cisco ONS 15501 increases the number of wavelengths that can
potentially be routed to it. The higher input power range available can be used to increase the number of
wavelengths to 128 from 32, without having any spectral gain tilt effect s.

Network Management

The CiscoONS 15501 supports SNMP, and it has a console port to facilitate setup and monitoring. With
a customer-supplied network monitor and the provided MIB file, all monitorable and settable parameters
are available remotely.
Cisco ONS 15501 Applications
The CiscoONS 15501 supports the following applications:
•Point-to-point topologies
•Ring topologies
•Adding or dropping wavelengths
•Adjusting to span loss changes

Point-to-Point Topologies

In a metropolitan point-to-point DWDM network, the CiscoONS 15501 can function as a pre-, post-,
and/or inline amplifier. Most metropolit an point-to-point DWDM networks require post-amplifiers, but
if a given span length exceeds the unit gain (>17 d B), a preamplifier may also be required to ha ndle the
optical link loss budget. When the sp an length greatly exceeds 17 dB, an inli ne amplifier might also be
required.
Because of the wide input power range (-29 to 0 dBm) of the CiscoONS 15501, trunk attenuation is
typically also necessary, especially when the unit is used as a post-am plifier. For instance, when the per
channel output power from the node is -5 dBm in a 32-channel system, the total output power from the
node is +10 dBm. Thus, at least 10 dB of trunk attenuation is required directly preceding the amplifier.
The CiscoONS 15501 can also be tuned to meet post- or inline amplification input power requirements.
Assuming that the typical per channel power levels in a point-to-point network are id entical at the source
node, and that there are fewer than four amplifiers between source and destination nodes, it is not
necessary to maintain per channel power equalization to satisfy each amplifier’s total input power
requirement and maintain ac ceptable OSNR for each chann el.