2010 Update on Photonics for Optical Communications - Photonics is the Key to Broadband Access

Background
Early use of the Internet depended on “dial-up access” using telephone lines, which was limited to a bit rate less than 56 kbit/second. This allowed computers to “talk to each other” and exchange and access text information. But shortly, computers were developed that could process information faster; higher-speed transmission lines were needed.

In the 1990’s broadband Internet access, using co-ax cable and twisted pair wires, expanded the bit rate up to 256 kbit/second, and served the business community well by speeding up transmission times and enabling higher data rates and larger data files, like pictures and video transmission.

To expand the use of the Internet to more users, and to allow rapid transmission over longer (intercontinental) distances, fiber optics cabling has been installed for transoceanic Internet cables, across large land distances and in urban areas where business use is very dense. The use of fiber optics means that we are transmitting information over optical (laser diode) beams where the carrier frequencies are many orders of magnitude greater than the radio frequencies sent over copper wire. Over the last decade, the use of laser transmitters, optical receivers and fiber optics transmission cables ushered in photonics technology to enhance Internet and telecommunications services.

Cell phones required wireless transmission over radio and microwave frequencies. Their wide-spread use required transmission towers positioned every 10-50 miles apart throughout the land; the cell phone towers “talked to each other” around the world by connecting through synchronous, orbiting satellites. Computers also began communicating “wirelessly” by tying into the communication towers and satellites.

Digital Communications has become more complex and more crowded: We’re outgrowing our infrastructure
Smart phones (such as iPhones and BlackBerries) combine cell phones with computer access to the Internet, requiring broadband access. Today, according to the International Telecommunications Union, 60 out of every 100 people in the world own and/or are using cell phones and smart phones; and more than 85 percent of the world’s online population has used the Internet to make a purchase.

Over the last 3 years, the surge of computer and smart phone use for social networking (e.g. Facebook and Twitter), as well as video streaming and video conferencing, has placed an enormous demand on broadband access that can only be met by greatly increasing the bit rates to 1-10 megabit/second. This can be accomplished by changing our entire digital infrastructure for distance transmission as well as local area networks (LANs).

Note: Distance transmission provides Internet service to a building or communication tower, and LANs distributes the Internet service to users within the facility. In a home or small office LANs are relatively simple, but still must be fast. In large corporations, college/universities, and Internet businesses, such as Google, LANs support the use of huge megaservers.

Photonics technologies will provide the tools and techniques to reconfigure our digital infrastructure
Fiber optics networks, carrying optical signals generated by laser diodes, are the technology tools that will allow us to reconfigure the digital network. In 2009, the US Federal Communications Commission (FCC) defined "Basic Broadband" as data transmission speeds exceeding 768 kilobits per second (Kbps), in at least one direction: downstream (from the Internet to the user’s computer) or upstream (from the user’s computer to the Internet). The trend is to raise the threshold of the broadband definition as the marketplace rolls out faster services. Broadband penetration is now treated as a key economic indicator.

As the bandwidth delivered to end users increases, the market expects that video on-demand services streamed over the Internet will become more popular, though at the present time such services generally require specialized networks. The data rates on most broadband services still do not suffice to provide good quality video, as MPEG-2 video requires about 6 Mbit/s for good results. Adequate video for some purposes becomes possible at lower data rates, with rates of 768 kbit/s and 384 kbit/s used for some video conferencing applications, and rates as low as 100 kbit/s used for videophones using H.264/MPEG-4 AVC. The MPEG-4 format delivers high-quality video at 2 Mbit/s, at the low end of cable modem performance.

Technology applications change the landscape
Because of falling costs to acquire the equipment, businesses may have dozens or even hundreds of video cameras on their premises, carrying video on the LAN. The combination of lower prices and technology advancements enhances security and enables fewer people to keep track of assets that may be scattered far and wide.

Telepresence, the latest generation of video conferencing that uses large flat screens and high-definition video to replicate face-to-face meetings, is gaining traction.

As these trends grow, new bandwidth-hungry applications appear. Enterprise bandwidth demand escalates month after month and requires upgrades in electronic apparatus and larger copper cables. Information technology (IT) managers scratch their heads wondering how to accommodate these requirements. It won’t be done with copper. We need massive shifts to fiber delivery systems, using laser diode transmitters and other photonics components, especially in outlying rural areas.

Verizon Conducts World's First 10 Gigabit-per-Second Fiber-to-the-Premises Field Test Waltham, Mass. – December 16, 2009
Last month, Verizon became the first telecommunications company in the world to successfully field-test a passive optical network system known as XG-PON that can transmit data at 10 gigabits per second (Gbps) downstream and 2.4 Gbps upstream, four times as fast as the current top transmission speeds supporting the company's all-fiber FiOS network. Additional demonstrations of this nature are expected by Verizon and other companies in early 2010.

Photonics is the key to the future in broadband access
A few weeks ago, the Federal government announced that it will hand out the first $182 million of a $7.2 billion pot of stimulus money that will go toward building high-speed Internet networks and encouraging more Americans to use them.

The money is being targeted for "last-mile" connections that link homes, businesses and other end users to the Internet; "middle-mile" connections that link communities to the Internet backbone; computing centers in libraries, colleges and other public facilities; and adoption programs that teach people how to use the Internet and encourage them to sign up for broadband services. By March 2010, additional stimulus funds will be released to build our country’s broadband access.

The need is evident, the technology has been proven and stimulus funds are being applied. It is quite possible - even likely - that 2010 will be the year of massive development for broadband infrastructure. And photonics components will pave the way.

What’s your perspective on this? Am I too optimistic? Have I understated the case? Will U.S. photonics suppliers be the main beneficiaries in this market? Are we ready? Will we need even more photonics techs? How about retraining needs?

Leave your comments here or contact me by e-mail!

What would life be like without lasers? Part B - Lasers and Fiber Optics in High-Speed Internet & Smart Phones

The Internet, fax machines, smart phones, and other mobile devices are a way of life in modern society. All these technologies rely on lasers and fiber optics.

The properties of laser beams that allow them to be excellent carriers of high-data-rate signals (like high-speed Internet) are: 1) they are extremely high-frequency (0.3 GHz) carriers; and, 2) they have the coherence properties of radio or microwave radiation. These properties allow laser beams to carry many concurrent high-frequency signals.

Laser beams travel through the air in straight lines except when they are bent by lenses or prisms or reflected by mirrors. Optical fibers permit the transmission, or “piping,” of laser beams in flexible cables that can be wrapped around corners or laid on the ocean floor. An optical fiber is a fine glass or plastic strand that carries light internally along its length. Fiber-optic cables, which consist of bundles of optical fibers, are used to transmit laser beams in high-data-rate (high-bandwidth) optical communication. Optical fibers prevent the laser signals from being blocked or scattered by clouds or other particles in the atmosphere or by electromagnetic interference. This means that laser beams can travel over long distances without significant distortion or attenuation.

Fiber-optic cables can support Internet systems with up to 3 trillion bits per second at transfer rates as high as 111 gigabits per second (Gb/s), although 10 or 40 Gb/s is typical. The fibers used in long-distance telecommunication applications are always glass because glass causes only minimal attenuation. Both multi-mode and single-mode fibers are used, with multi-mode fiber used mostly for short distances (up to 600 yards) and single-mode fiber used for longer distances.

The process of communicating using fiber optics involves five basic steps: Creating the optical signal by modulating the laser output beam, relaying the modulated laser signal along the fiber, ensuring that the signal does not become too distorted or weak, receiving the optical signal, and converting the signal into an electrical signal.

Optical fibers are widely used to transmit telephone signals, Internet communication, and cable television signals. Due to much lower attenuation and interference, optical fiber has significant advantages over electrical transmission in long-distance and high-demand applications. Because of these advantages, optical fibers have largely replaced copper wire in core communication networks in the developed world. For example, many landline cell tower connections are made over optical fiber.

As one of the most talked about technological breakthroughs of the last few decades, laser/fiber-optic Internet carries a big name and responsibility in today’s world. Through the use of lasers and fiber optics, the computer and the Internet have evolved into realities that not too long ago were considered purely imaginary. Computers that used to take up entire rooms can now fit in a person’s back pocket. The Internet, which was created to help secure U.S. military networks, has now united the world with information.

With lasers and fiber optics, the frustrating days of slow Internet connections are forever in the past. Some people argue that wireless Internet is still faster than fiber-optic Internet, but that is not true. Laser/fiber-optic Internet is nearly a million times faster than wireless. A fiber-optic Internet cable can carry up to around three trillion bits per second. At that rate, the Library of Congress could be downloaded to your computer within a minute, compared to about eighty years for a dial-up connection (Fiberoptics VP).

The first transatlantic fiber-optic cable was installed in 1988, using glass fibers so transparent that repeaters (to regenerate and recondition the signal) were needed only about every 40 miles. In 1997, the Fiber Optics Link Around the World (FLAG) became the longest single-cable network in the world, providing infrastructure for the next-generation Internet. The 17,500-mile cable begins in England and runs through the Strait of Gibraltar to Palermo, Sicily, before crossing the Mediterranean to Egypt. It then goes to Dubai and UAR before crossing the Indian Ocean, Bay of Bengal, and Andaman Sea, through Thailand, and across the China Sea to Hong Kong and Japan (National Academy of Engineering).

Transistors get a lot of attention in the digital world, but the backstage heroes are lasers. Red lasers brought us compact discs and cheap long-distance communication. Blue lasers, which cram even more data into a small spot, became a hit around 1999 and have made possible Blu-ray DVDs (Elizabeth Corcoran, Forbes Magazine, June 08, 2009).

Gordon Snyder, Director of the NSF/ATE ICT Center, says, “The entire landline infrastructure is being replaced with fiber.” More valuable comments about this from Gordon can be found at the following blogspots:
http://ictcenter.blogspot.com/2009/09/why-verizon-is-sunsetting-public.html
http://ictcenter.blogspot.com/2009/09/verizon-no-longer-concerned-with-tele.html

Questions or comments? Post your comments here or e-mail me!