Coherent light generators – Particular active media – Semiconductor
Reexamination Certificate
2000-04-11
2003-08-26
Davie, James (Department: 2828)
Coherent light generators
Particular active media
Semiconductor
C372S096000
Reexamination Certificate
active
06611544
ABSTRACT:
FIELD OF THE INVENTION
The invention relates generally to semiconductor lasers. More particularly, the invention relates to semiconductor lasers having a narrow bandwidth distributed Bragg reflector (DBR).
The present invention relates generally to semiconductor lasers. More particularly, the present invention relates to folded cavity surface emitting lasers (FCSELs) and edge emitting semiconductor lasers.
BACKGROUND OF THE INVENTION
Semiconductor lasers have become more important. One of the most important applications of semiconductor lasers is in communication systems where fiber optic communication media is employed. With growth in electronic communication, communication speed has become more important in order to increase data bandwidth in electronic communication systems. Improved semiconductor lasers can play a vital roll in increasing data bandwidth in communication systems using fiber optic communication media such as local area networks (LANs), metropolitan area networks (MANs) and wide area networks (WANs). A preferred component for optical interconnection of electronic components and systems via optical fibers is a semiconductor laser. Semiconductor lasers are generally lower in cost, consume less power and typically require a fraction of the space than other types of lasers. Due to optical properties of optical fibers, photons emitted at longer wavelengths from a laser tend to propagate longer distances and are less disturbed by optical noise sources. Thus, forming a semiconductor laser that can operate at longer wavelengths, such as a wavelength greater than 1.25 microns (um) or 1250 nanometers (nm), is desirable.
Additionally, single mode operation of a semiconductor laser is required for optical communications relying on a single mode fiber as a transmission medium. A semiconductor laser using distributed feedback, oftentimes referred to as a distributed feedback laser (DFB), is one commonly used technology to achieve single narrow line-width operation at either 1.3 um or 1.55 um wavelength range. However, DFB laser fabrication requires re-growth and cleaving. It is therefore intrinsically a low volume, low yield and high cost manufacturing technology.
A vertical cavity surface emitting laser (VCSEL) is a low cost approach to achieve DFB-like single mode operation and is a mature technology for lasing at a 850 nm wavelength. However, long wavelength VCSELs in the range of 1.3 um to 1.55 um have not yet reached performances needed in commercial applications for a number of reasons.
It is desirable to overcome the limitations of the prior art.
BRIEF SUMMARY OF THE INVENTION
Briefly, the present invention includes a method, apparatus and system as described in the claims.
Semiconductor lasers are disclosed having a narrow bandwidth distributed Bragg reflector (DBR). The narrow bandwidth distributed Bragg reflector reflects photons over a narrow wavelength range and does not reflect photons outside the narrow wavelength range back into the laser cavity for amplification. The narrow bandwidth distributed Bragg reflector can be formed of semiconductor materials or dielectric materials. The narrow bandwidth distributed Bragg reflector is included as part of folded cavity surface emitting lasers and edge emitting lasers. Photons within the narrow wavelength range of the narrow bandwidth distributed Bragg reflector reflects are of a relatively long wavelength to improve efficiency of communication over fiber optic cables.
A number of embodiments are disclosed.
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Dapkus Dan
Jiang Wenbin
Lee Hsing-Chung
Blakely & Sokoloff, Taylor & Zafman
Davie James
E20 Communications Inc.
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