Laser diode
AssigneeThe Provost, Fellows and Scholars of the College of the Holy and Undivided Trinity of Queen Elizabeth Near Dublin
InventorsJames Christopher O'Gorman, Frederick Paul Logue
Life of this patent
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Abstract
A laser diode (1) for outputting light of a single mode comprises a substrate layer (5), a cladding layer (6) and a compound light propagating layer (7) comprising first, second, third and fourth layers (9 to 12). A wave guiding region (15) of refractive index lower than its adjacent regions is defined by the third layer (11) by two quantum wells (16) positioned at the anti-node of light of a single mode which is propagating in the third layer (11) for propagating and amplifying the single mode light. A central ridge (17) locates the wave guiding region transversely of the direction of light propagation. The wave guiding region (15) can also be defined by shaping the top cladding layer (6) by forming an elongated central channel through the central ridge (17).
Claims40
A laser diode for outputting light of a single spatial mode, the laser diode (1, 30) comprising a substrate layer (5, 32), a cladding layer (6, 33), and a light propagating layer (7, 35) located between the substrate layer (5, 32) and the cladding layer (6, 33), characterised in that a means (16, 37) is provided for defining a wave guiding region (15, 36) in the light propagating layer (7, 35), the defined wave guiding region (15, 36) being of refractive index lower than an adjacent region in the light propagating layer (7, 35) and being defined in the light propagating layer (7, 35) in a region in which light of the single mode propagates, so that when the defined wave guiding region (15, 36) is pumped the intensity of the light of the single mode is amplified above light of other modes propagated in the light propagating layer (7, 35).
A laser diode as claimed in any preceding claim characterised in that the wave guiding region (15, 36) is defined in the light propagating layer (7, 35) during growing of the layers of the laser diode (1).
A laser diode as claimed in any preceding claim characterised in that a locating means is provided for locating the wave guiding region (15, 36) in a direction transversely of the direction of light propagation.
A method for outputting light of a single spatial mode from a laser diode, wherein the laser diode (1, 30) comprises a substrate layer (5, 32), a cladding layer (6, 33), and a light propagating layer (7, 35) located between the substrate layer (5, 32) and the cladding layer (6, 33), characterised in that the method comprises defining a wave guiding region (15, 36) in the light propagating layer (7, 35), the defined wave guiding region (15, 36) being of refractive index lower than an adjacent region in the light propagating layer (7, 35) and being defined in the light propagating layer (7, 35) in a region in which light of the single mode propagates, and pumping a current through the defined wave guiding region (15, 36) so that the intensity of the light of the single mode is amplified above light of other modes propagated in the light propagating layer (7, 35).
Dependencies are inferred from the claim text.