Device for generating or amplifying coherent electromagnetic radiation, and method of manufacturing the device
AssigneeU.S. Philips Corporation
InventorsGerard A. Acket, Peter J. de Waard, Giok D. Khoe, Gijsbrecht C. Wirtz, Tullio E. Rozzi
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Abstract
A semiconductor laser/amplifier is disclosed in which the radiation oscillates only in one longitudinal mode. According to the invention this is achieved by a strip-shaped active region which exhibits periodic variations in amplification (and preferably also in the amplification profile) in its longitudinal direction over at least a part of its length. The period of the amplification variation is at least ten times the wavelength of the radiation.
Claims12
A semiconductor device for operation with coherent electromagnetic radiation, which comprises:
- a semiconductor body having a major surface;
- a strip-shaped active region having a p-n junction extending substantially parallel to said major surface;
- a contact member on each side of said p-n junction to supply current to said junction, one of said contact members comprising an electrode layer which is located on said major surface above said strip-shaped active region, said electrode layer forming a current supply contact with a conductive part of said major surface within a strip-shaped contact region above said active region;
- and
- means for providing a spatially periodic amplification variation in portions of said active region in the wavelength range of said radiation over at least a part of its total length in the longitudinal direction, the period of said amplification variation being at least ten times the wavelength of said radiation within the semiconductor material and at most equal to one-fifth of the length of said active region, said portions of the active region having a common center line in the longitudinal direction.
A semiconductor device as claimed in claim 3, characterized in that the period of the amplification variations is at least equal to (.lambda..sup.2 o/2n'.LAMBDA.), where .lambda..sub.o is the free space wavelength for which the amplification is maximum, n' is the effective index of refraction and .LAMBDA. is the difference between the two wavelengths for which the amplification is half of that for the wavelength .lambda..sub.o.
Dependencies are inferred from the claim text.