OKI Develops World's First Gain-coupled DFB Lasers for Practical Use.- Company Aims to Promote Long Distance Communication Using Optical Isolator-Free Technology for Optical Subassembly sub·as·sem·bly n. pl. sub·as·sem·blies An assembled unit forming a component to be incorporated into a larger assembly. Modules - ANAHEIM, Calif. -- Oki Electric Industry Co., Ltd. (TOKYO:6703) today announced it has developed a gain-coupled (1) (GC-) DFB DFB acronym for dark, firm, dry meat. Called also dark cutting beef. laser (2) that is tolerant of optical reflection. By employing the GC-DFB laser, OKI succeeded in becoming the world's first to develop optical isolator-free optical transmitter modules for practical applications, enabling lower cost, smaller size optical modules for use in long distance networks, such as FTTH (Fiber To The Home) See FTTP. . "The results we obtained from this technology confirm that it will contribute to achieving lower cost, isolator free optical subassembly modules. Because the manufacturing process of the GC-DFB laser is approximately equivalent to that of conventional index-coupled (IC-) DFB lasers, chip manufacturing costs are expected to be the same as well. We are developing samples for evaluation, planning to provide them to the market by June this year," said Harushige Sugimoto, Senior Vice President and Chief Technology Officer at Oki Electric Industry. "In our long term plan, we are aiming to commercialize small and low cost components for optical communication using OKI's original silicon lens technology (3)." For a normal FTTH light source, Fabry-Perot (4) lasers that emit multiple modes are used for short distance transmission (up to 10km), while IC-DFB lasers that emit a single mode are used for long distance transmission (up to 20km). In long distance transmission, IC-DFB lasers contribute to increased degradation in receiver sensitivity after sending data as the noise from unwanted optical reflection increases. Because of this, an optical isolator A device used to prevent lightwaves from reflecting backwards (the optical counterpart to an electrical diode). It is a one-way filter for a range of light frequencies. Optical isolator is necessary to shut out reflection. However, optical isolators are costly components and require space on the order of several millimeters. Thus, for optical sources, the market has been requesting semiconductor lasers which do not require optical isolators. OKI achieved optical isolator free capability through a GC-DFB laser with improved tolerance of optical reflection and reduced degradation from relative intensity noise Relative intensity noise (RIN), describes the instability in the power level of a laser. The noise term is important to describe lasers used in fiber-optic communication and LIDAR remote sensing. when impacted by reflected light. With this advance, OKI conducted 25km transmission experiments over the temperature range where optical modules normally operate (0 ~ 70ae C) and found that in a state where reflected light (-14dB) was forcefully applied, there was almost no degradation of reception sensitivity. This confirmed a marked improvement in tolerance to reflected light, compared to conventional IC DFB lasers. OKI introduced this technology today at the Optical Fiber Communication Conference and the National Fiber Optic Engineers Conference (OFC/NFOEC 2007) in Anaheim, California “Anaheim” redirects here. For Annaheim, see Annaheim, Saskatchewan. Anaheim is a city in Orange County, California, located 28 miles southeast of Los Angeles. . [Glossary] (1) Gain-coupled: To oscillate To swing back and forth between the minimum and maximum values. An oscillation is one cycle, typically one complete wave in an alternating frequency. in a single mode by periodically gain (or loss) in the waveguide waveguide, device that controls the propagation of an electromagnetic wave so that the wave is forced to follow a path defined by the physical structure of the guide. layer in the laser. (2) DFB (Distributed Feedback) laser: The whole cavity contains active layers and thus creates a periodic structure which acts as a distributed reflector reflector: see telescope. in the wavelength range of laser operation. Therefore, single-frequency operation is easily achieved. (3) Silicon Lens: OKI's ultra small lens for optical communication developed in 2002. This lens can be manufactured in volume with LSI LSI: see integrated circuit. (Large Scale Integration) Between 3,000 and 100,000 transistors on a chip. See SSI, MSI, VLSI and ULSI. manufacturing technology. (4) Fabry-Perot lasers: Fabry-Perot Diode Lasers are the most common type of diode lasers. Laser oscillation is demonstrated in multiple modes as the light in the active layer is amplified when it goes back and forth in the resonator resonator /res·o·na·tor/ (rez´o-na?ter) 1. an instrument used to intensify sounds. 2. an electric circuit in which oscillations of a certain frequency are set up by oscillations of the same frequency in another . About Oki Electric Industry Co., Ltd. Founded in 1881, Oki Electric Industry Co., Ltd. is Japan's first telecommunications manufacturer, with its headquarters in Tokyo, Japan. OKI provides top-quality products, technologies and solutions to its customers through its info-telecom system business, semiconductor business and printer business. All three businesses function as a collective force to create exciting new products and technologies that satisfy a spectrum of customer needs in various markets. Visit OKI's global web site at http://www.oki.com/. Notes: * Names of companies and products are trademarks or registered trademarks of the respective companies and organizations. |
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