Chromatic dispersion compensator
1,400 ps/nm | OTS 4520
OpNext
* Dispersion tuning range > 1,400ps/nm
* Broadband operation, can be used over multiple DWDM channels
* Automated optimization during 40Gbps channel turn-up
* Increases 40Gbps optical reach
* Managed in a standard OTS-4000 shelf
* Compatible with all OTS-4000 line cards
Applications
As a design goal, 40Gbps transponders should be deployable using 10Gbps DWDM rules. This is achieved to a large extent by using spectrally efficient modulation formats such as Phase Shaped Binary Transmission (PSBT). The use of PSBT increases the CD tolerance from 50ps/nm (for 40Gbps NRZ or CS-RZ) to around 300ps/nm. This alleviates the requirement for a closed-loop Tunable Dispersion Compensator (TDC) to obtain a practical dispersion tolerance window. For some 10Gbps DWDM systems, it is possible that the required chromatic dispersion tolerance will actually exceed 300ps/nm. This could be due to several reasons, such as:
1. Use of DCMs with poor dispersion slope compensation;
2. Heavily under-compensated SMF-28 metro/regional networks, where DCMs have been minimized to reduce upfront cost;
3. Use of pre-chirp on the 10Gbps channels which offsets the required dispersion compensation window;
4. Coarse granularity DCMs;
5. Unknown transmission fiber dispersion characteristics.
