MATTHEW PEACH HI-REL COUPLERS
polishes its coupler manufacturing to ensure 100% performance Gooch & Housego
products G&H makes, in every undersea repeater there is an erbium-doped fibre amplifier (EDFA), which includes 980 nm pump lasers and an erbium-doped fibre. This has the critical function on the seabed, every 100 km or so, of boosting the signal inside the cable to separate it from the noise floor. In each repeater there are up to eight amplifiers. Several hundred repeaters are installed on a typical transatlantic undersea link. Wilson added, “To put this in perspective, Google’s Super-Fast Submarine Internet cable system, which uses six fibre pairs, each carrying 100 wavelengths at 100 Gbit/s, is enough to carry the content of 1600 DVDs per second.” The G&H HI REL components also feature: a 980 nm-1550 nm WDM system, which combines the 980 nm pump output with the 1550 nm signal to be ‘pumped’ up to strengthen and re- amplify the optical signal; there are also components to tap off signals; and the so-called “3dB components”, which split the signal by 50%. The repeater pods provide a dry, constant-temperature environment for our couplers, which are not hermetic. They are not overtly rugged; for example, the device is housed in a 3 mm diameter stainless 55 mm-long steel tube with two 250 µm buffered fibres coming out each end. It’s not built up with any
Significant market changes in intercontinental undersea cabling have had implications for the design and fabrication of high reliability fibre couplers, writes Matthew Peach, contributing editor.
MATTHEW PEACH
G ooch & Housego, the UK-based developer of advanced photonic systems, components and instrumentation, has refined the development and production of its HI REL (high reliability) fibre couplers to respond to increasing market demands from the communications providers seeking improved undersea links. The company’s Torquay facility has been making high-reliability (HI REL) fused couplers for the past 16 years, for deployment on the ocean floor. The company has been improving its manufacturing processes to ensure that these devices are completely reliable because once installed maintenance or replacement of parts on the sea floor is usually impossible – or prohibitively expensive. Over this period, there has also been a steady increase in the required bit- rate demanded by customers, which are the major international communications companies. Rates demanded are now up to 400 Gbit/s in some cases. 100,000 COUPLER SALES Fibre optic product manager Ian Wilson explains, “This year, we have shipped our 100,000th HI REL, high reliability fibre coupler to customers, who include all the
major service providers in the Americas, Europe and the Far East. These devices are installed in undersea intercontinental links. If you use the Internet, there is a greater than 50% chance that your data passes through G&H couplers.” The recent surge in demand for ultra- reliable undersea systems is due to the increased demands from the so-called “super-techs” – companies such as Apple, Facebook, Google, and Microsoft have created a significant market pull because they are directly involved in funding the networks they ultimately depend upon. Wilson commented, “We have also had to be responsive to this sudden growth in demand by rapidly recruiting a significant number of new staff and significantly expanding our manufacturing resources.” Considering the suite of
Gooch & Housego manufactures high- reliability erbium-doped fibre
amplifiers and erbium/ytterbium co-doped (EYDFA) fibre amplifier modules.
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| ISSUE 7 | Q3 2016
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