itu launches a new four-year study period

By WILLIAM B. GARDNER

Last year marked the first year of a new four-year study period for the International Telecommunication Union (itu). At the beginning of each study period, a set of questions is approved for each study group. These questions divide up the work that will be pursued for the next four years. A "rapporteur" assigned to each question is responsible for coordinating the work on that question. Although lightwave issues are spread over several itu study groups, the greatest concentration of work occurs in Study Group 15`s Working Party 4, chaired by Gastone Bonaventura of Telecom Italia. In the 1997 to 2000 Study Period, this working party is responsible for six questions.

Question 15 encompasses four singlemode fiber recommendations (G.652 through G.655), one on multimode fiber (G.651), and one on singlemode definitions and test methods (G.650). Current issues include polarization-mode dispersion (see Lightwave, September 1996, page 36) and fiber with non-zero dispersion (see Lightwave, December 1996, page 62). The rapporteur is William Gardner of Lucent Technologies ([email protected]).

Under Question 16, there are three recommendations on optical equipment interfaces and digital line systems for use on optical-fiber cables (G.955, G.957, and G.958). These three pre-date the commercial use of the optical amplifier (OA). They were followed by Recommendations G.681 on the functional characteristics of systems using OAs, and G.692 on optical interfaces for multichannel systems with OAs (for a description of the latter, see Lightwave, August 1997, page 22). Recommendation G.691 on optical interfaces for single-channel Synchronous Digital Hierarchy systems with OAs awaits approval, while work is just beginning on G.onp on the physical layer aspects of optical networks. The rapporteur for Question 16 is John Eaves of at&t ([email protected]).

Three recommendations on OAs are included in Question 17: G.661 on definitions and test methods, G.662 on generic characteristics, and G.663 on application-related aspects of OA devices and subsystems. Recommendation G.671 covers transmission characteristics of passive optical components. Yet to be approved is Recommendation G.onc on optical network components and subsystems. The rapporteur is H. Okamura of Nippon Telegraph & Telephone (ntt) ([email protected]).

Question 18 has a series of recommendations dealing with fiber-optic submarine cable systems: G.971 on the general features of such systems, G.972 on definitions of terms, G.973 on repeaterless systems, G.974 on systems with regenerators, G.975 on forward error correction, and G.976 on test methods. Yet to be approved is G.OASS on submarine cable systems with optical amplifiers. This question has two rapporteurs: M. Ohashi of ntt ([email protected]) and J.J. Thiennot of France Telecom ([email protected]).

Question 19 covers Recommendation G.911 on the parameters and calculation methodologies for reliability and availability of optical systems, and the yet-to-be- approved Recommendation G.mda on methodology for deriving fiber-optic system reliability objectives. The rapporteur is James Spencer of Bell Communications Research ([email protected]).

Question 20, a new question in this study period, addresses optical-networking issues. The rapporteur is Pietro DiVita of cselt of Italy ([email protected]). The work that is planned was described by recommendations editor Paul Bonenfant of Lucent Technologies ([email protected]) in Lightwave, November 1997, page 36. q

William B. Gardner represents Lucent Technologies, Norcross, GA, on several fiber standards committees. He can be contacted at tel: (770) 798-2674; fax: (770) 798-4654; e-mail: [email protected].