Semiconductor laser with a tapered ridge
AssigneeADC Telecommunications, Inc.
InventorDevin Crawford
Life of this patent
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Abstract
A semiconductor ridge laser with a tapered ridge is disclosed. The tapered ridge is designed to provide for both gain-medium amplification and mode conversion amplification, the latter resulting in a higher kink power than is obtainable with gain medium amplification alone. The power and lateral mode content of the output beam is determined by the ridge parameters, which include length, width, number of sections and degree and type of taper for the tapered sections. The output beam can be made to have a profile that is more compatible with the lateral modes on an optical fiber than a conventional highly astigmatic output beam by including power in the higher-order lateral modes as well as in the fundamental lateral mode.
Claims33
A semiconductor ridge laser apparatus comprising:
- a first cladding layer, an active layer, and a second cladding layer formed on a substrate;
- a ridge formed in the second cladding layer, the ridge having a first section with a first width and an output end, and capable of supporting a fundamental lateral mode;
- a second section having a second width different than the first width and capable of supporting the fundamental and higher-order lateral modes;
- and
- a third section connecting the first and second sections, the third section designed to facilitate mode conversion amplification, wherein at least a portion of energy in the higher-order lateral modes is converted to energy in the fundamental mode.
A semiconductor ridge laser apparatus, comprising:
- a first active ridge section having a first width formed at an output end of the laser and capable of supporting a fundamental lateral mode and one higher-order lateral mode;
- a second active ridge section having a second width and capable of supporting the fundamental lateral mode and a first number of higher-order lateral modes;
- and
- a third active ridge section connecting the first and second active ridge sections and designed to facilitate mode conversion amplification of the fundamental and one higher-order lateral mode in the first active ridge section;
- and
- wherein the fundamental lateral mode and the one higher-order lateral mode form an output beam having a profile that is less astigmatic than a purely fundamental lateral mode output beam profile.
The apparatus of claim 25, wherein the one higher-order lateral mode is a second-order mode.
A method of providing a high-power output beam in a semiconductor ridge laser, comprising:
- propagating a fundamental lateral mode and at least one higher-order lateral mode in a ridge waveguiding structure so as to amplify the fundamental lateral mode and the at least one higher-order lateral mode by gain medium amplification;
- tailoring the ridge waveguiding structure to perform mode conversion amplification of the fundamental lateral mode;
- and
- outputting the energy in the fundamental lateral mode to form the output beam.
A method of forming a output beam, comprising:
- in a semiconductor ridge laser, forming an active waveguiding structure with an upper cladding layer, the waveguiding structure being capable of amplifying light propagating therein;
- forming a tapered ridge in the upper cladding layer by forming:
- a first section that enables the waveguiding structure to support a fundamental lateral mode and higher-order lateral modes;
- a second section having an output end and that enables the waveguide structure to support the fundamental lateral mode;
- a tapered section connecting the first and second sections;
- performing mode conversion amplification of the fundamental mode by channeling the higher-order lateral modes through the tapered section;
- and
- outputting the energy in the fundamental mode at the output end of the second section to form the output beam.
Dependencies are inferred from the claim text.