Coherent light generators – Particular resonant cavity – Distributed feedback
Reexamination Certificate
1998-07-13
2001-09-04
Font, Frank G. (Department: 2877)
Coherent light generators
Particular resonant cavity
Distributed feedback
C372S096000, C372S069000, C372S075000, C372S044010, C372S050121
Reexamination Certificate
active
06285704
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to the field of laser diodes, and more particularly to a field modulated vertical cavity surface-emitting laser with an internal optical pumping.
BRIEF DESCRIPTION OF PRIOR ART
VCSELs or vertical cavity surface-emitting laser diodes are known in the art. While 850 nm current modulated VCSEL laser diodes are commercially available, it is hard to realize a 1300 nm VCSEL due to technical difficulties. In a VCSEL, the optical cavity needs to be defined by mirrors having high reflectivity and low loss to create laser action at room temperature. In addition, the mirrors need to be electrically conductive in order to allow current injection.
Up to the present time, it has not been possible to grow mirrors of the desired quality on substrates made of indium phosphide, emitting at 1300 nm.
It has been demonstrated that it is possible to fuse mirrors made of aluminum gallium arsenide and its alloys onto an active layer of if indium gallium arsenide phosphide, emitting at 1300 nm. However, this procedure is complicated. The active layer is only about 100 nm thick and it needs to be separated from the substrate on which it was grown and transported to a substrate containing the first mirror, then the stack consisting of the active layer and the first mirror again need to be transported to a substrate containing the second mirror. Obviously, no significant yield can be expected using this method. Also, three wafers are consumed for each functional device fabricated.
It has been proposed that one of the mirrors be replaced by a dielectric mirror using silicon and low refractive index materials such as oxides, nitrides or even an airgap. The problem is that the mirror is then no longer conductive so that carrier injection pumping is not possible.
An object of the invention is to overcome this problem.
SUMMARY OF INVENTION
According to the present invention there is provided a laser diode structure, comprising top and bottom mirrors defining a first laser cavity containing a laser medium and designed to resonate at a first wavelength, at least one of said mirrors being electrically non-conductive; and a second laser cavity designed to resonate at a second wavelength less than said first wavelength, said second laser cavity being optically coupled to said first laser cavity so as to optically pump said laser medium and create laser action in said first laser cavity.
The laser diode is preferably a VCSEL, (vertical cavity surface emitting laser) diode.
The problems of the prior art are overcome by optically pumping the VCSEL operating at the longer wavelength with a VCSEL operating at a shorter wavelength that can be pumped by other means, such as carrier injection. The optical pumping is preferably carried out with the aid of a second VCSEL, which since it operates at a shorter wavelength can be fabricated on the same substrate in a conventional manner using conductive mirrors and carrier injection pumping. Typically, the main VCSEL operates at 1300 nm and the VCSEL that provides the optical pumping operates at 980 nm.
REFERENCES:
patent: 5513204 (1996-04-01), Jayaraman
patent: 473982 (1992-03-01), None
patent: 549853 (1993-07-01), None
patent: WO 98/31080 (1998-07-01), None
“Vertical Cavity Laser with Two Air-Gap Reflectors”, Electronics Letters, Jul. 18, 1996, vol. 32 No. 15, pp. 1369-1370.
“Lasing Oscillation of Vertical Microcavity Quantum Dot Lasers”, Extended/Abstracts of the 1996 International Conference on Solid State Devices and Materials, Yokohama, 1996, pp. 199-201.
Kullander-Sjoberg Anna
Widman Michael
Flores Ruiz Delma R.
Font Frank G.
Laubscher, Jr. Lawrence E.
Mitel Semiconductor AB
LandOfFree
Field modulated vertical cavity surface-emitting laser with... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Field modulated vertical cavity surface-emitting laser with..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Field modulated vertical cavity surface-emitting laser with... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2498557