Product category:
Lasers
News Release from: Oki Electric | Subject: Gain-coupled DFB laser
Edited by the Electronicstalk Editorial
Team on 28 March 2007
Laser promises isolator-free optical
transmission
A gain-coupled DFB laser that is tolerant of optical reflection enables the development of isolator-free optical transmitter modules for practical applications in long-distance fibre networks.
Oki Electric has developed a gain-coupled DFB laser that is tolerant of optical reflection By employing the GC-DFB laser, Oki is able to develop isolator-free optical transmitter modules for practical applications, enabling lower cost, smaller size optical modules for use in long distance networks such as fibre to the home ( FTTH)
This article was originally published on Electronicstalk on 10 Apr 2002 at 8.00am (UK)
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"The results we obtained from this technology confirm that it will contribute to achieving lower cost, isolator-free optical subassembly modules", says Harushige Sugimoto, Senior Vice President and Chief Technology Officer at Oki Electric.
"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".
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"In our long-term plan, we are aiming to commercialise small and low-cost components for optical communication using Oki's original silicon lens technology".
For a normal FTTH light source, Fabry-Perot lasers that emit multiple modes are used for short-distance transmission (up to 10km), and 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 is necessary to shut out reflection.
However, optical isolators are costly components and require space of 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 when impacted by reflected light.
With this advance, Oki conducted 25km transmission experiments over the temperature range where optical modules normally operate (0 to 70C) 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 at the Optical Fiber Communication Conference and the National Fiber Optic Engineers Conference (OFC/NFOEC2007) in Anaheim, California.
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