To repeat, or not repeat, that is the question
Are you familiar with unrepeatered submarine cables? As Ciena’s Brian Lavallée often gets asked about this lesser-known technology, he took some time to explain what they are, when to use them, and why they’re important.
By Brian Lavallée – Many new submarine cables have been announced by major Internet Content Providers, such as Google, Facebook, and Amazon, to interconnect data centers. These high-capacity submarine cables traverse oceans by leveraging the latest in wet plant and Submarine Line Terminating Equipment (SLTE) coherent modem technology… but what about the lesser known counterpart of these submarine cable designs, the unamplified submarine cables? I often get asked about unamplified submarine cable networks, so I thought I’d share some of my thoughts in this blog.
Due to the distances and capacities associated with transoceanic submarine cables, optical amplifiers are spaced at regular intervals along the cable to amplify information-carrying wavelengths. Undersea optical amplifiers are similar to their terrestrial counterparts, at least from an optoelectronic perspective, but are installed in one of the harshest telecom operating environments on Earth – the ocean floors, and sometimes several kilometers deep. Amplified submarine cables are more commonly referred to as “repeatered” cables, but this is actually a misnomer.
A traditional optical communications “repeater” regenerates a received optical signal by performing 3Rs – Reamplify, Reshape, and Retime – to restore the quality of received optical signals, which involves OEO (Optical-Electrical-Optical) conversion. Repeaters, also referred to as “regenerators, or “regens” for short, were expensive and power-hungry devices, but were absolutely necessary for the proper transmission of information across great distances. more>
- Disruptive Innovation Possible Even in the Most Mature Economies, Rick Seeto
- Breaking Down the Barriers Between IT & Network, James Crawshaw