40 Gbit/s signal has been successfully transmitted for a distance of 1,000 km during a test for Rostelecom OJSC – Компания «Т8». DWDM-системы

40 Gbit/s signal has been successfully transmitted for a distance of 1,000 km during a test for Rostelecom OJSC

A 43 Gbit/s (OUT-3) signal has been successfully transmitted for 1,000 km without electrical reclaiming at October 6th in the T8 laboratory together with Rostelecom representatives. The new aggregating transponder AТP-40-4-B6-XFP, which is a part of the PUSK DWDM system, has been used for this test.

I.V. Bogdanov, the chief specialist of the «Planning and development of transport networks» department, and A.V. Semenov, the chief specialist of the «Technical maintenance of digital data transfer networks» department, which is a part of the “Maintenance and industrial management of communication networks” department, have been participating on the Rostelecom behalf.

The first half of the meeting has been devoted to a presentation on the “Differential phase shift keying in 40 Gbit/s networks (DPSK)” theme read by Naniy O.E., the MSU professor, Doctor of Physical and Mathematical Sciences, the T8 consultant. The presentation has minutely explained modulation formats for transmitting channels at the 40G speed, features of DPSK formats, comparisons between DPSK and ASKS formats for transmitting channels at the 40G speed and results of our company researches on these questions. Proof of choosing the NRZ-DPSK modulation format for the AТP-40-4-B6-XFP transponder has been given, great technical features of the equipment have been demonstrated: a reconfigurable in the С-range laser with a step of 50 GHz and, use of the SuperFec algorithm. Also specialists have discussed questions on implementation of transponders with the 100 Gbit/s transmission speed and perspectives of using such speeds in Rostelecom networks.

The second part of the meeting has been conducted by employees of the «Т8» company: M.A. Sleptsov, the leader of the project implementation department, and Sachalin Е.А., the engineer, have conducted hand-over tests of the AТP-40-4-B6-XFP unit in a 1,000 km line. Measurements have been done at the laboratory stand of our company according to the program agreed by Rostelecom OJSC. There were no errors on the loop test through 1,000 km of the G652 optical fiber (10 sections 100 km each).

The testing has been conducted according to programs agreed by Rostelecom with a glance to the results of the PUSK DWDM test area: local and section tests of the equipment have been done. The results have shown that the unit for transmitting 43 Gbit/s satisfies the stated requirements and the technical requirements of Rostelecom OJSC. It’s been protocolled that «Tests have been accomplished successfully without any reprimands. There have been three client interfaces available – OTU-2, 10GE, STM-64 – and tests have been conducted using OTU-2».

The successful testing of transmitting 40 Gbit/s for 1,000 km via a single DWDM channel proves the high quality of the PUSK DWDM equipment and opens possibilities for a broad implementation of the PUSK equipment within Rostelecom networks.