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US 6,665,457 B2Granted
Tunable electro-absorption modulator and tunable laser
AssigneeAltitun AB
InventorLennart P. O. Lundqvist
Life of this patent
Estimating the term…
Abstract
An electro-absorption modulator is tunable along with the laser. Tuning the electro-absorption modulator permits optimum detuning to be maintained, even though the laser is tuned over several tens of nm. One approach to tuning the electro-absorption modulator is to heat the electro-absorption modulator. A semiconductor laser device includes a semiconductor laser positioned on a substrate. The semiconductor laser produces output light that is tunable over a tuning range between a first wavelength and a second wavelength. An electro-absorption modulator is disposed to modulate the light produced by the semiconductor laser. The operating temperature of the electro-absorption modulator is tunable so as to maintain constant detuning over at least a portion of the tuning range.
Claims50
A semiconductor laser device comprising:
- a substrate;
- a semiconductor laser positioned on the substrate and producing output light tunable over a tuning range between a first wavelength and a second wavelength;
- an electro-absorption modulator disposed to modulate the output light produced by the semiconductor laser, an operating temperature of the electro-absorption modulator being tunable to maintain constant detuning over at least a portion of the tuning range;
- and
- a thermal resistor positioned between the electro-absorption modulator and an output end of the semiconductor laser so as to reduce conductive transfer of heat energy between the electro-absorption modulator and the semiconductor laser.
2 more elements
An optical communications system, comprising:
- an optical transmitter, the optical transmitter including at least one laser operable at a plurality of wavelengths, the laser including
- a substrate;
- a semiconductor laser positioned on the substrate and producing output light tunable over a tuning range between a first wavelength and a second wavelength;
- and
- an electro-absorption modulator disposed to modulate the output light produced by the semiconductor laser, an operating temperature of the electro-absorption modulator being tunable to maintain approximately constant detuning between the first and second wavelengths;
- an optical receiver;
- and
- an optical communication link coupled between the optical transmitter and the optical receiver.
5 more elements
A method of operating a semiconductor laser modulated by an electro-absorption modulator, the method comprising:
- tuning output light from the semiconductor laser to a desired wavelength between first and second wavelengths;
- directing the output light through an electro-absorption modulator;
- and
- adjusting an operating temperature of the electro-absorption modulator so as to achieve a preselected extinction level in the electro-absorption modulator;
- wherein a voltage applied to the modulator to achieve the preselected extinction level when the semiconductor laser is operating at the first wavelength is approximately equal to the applied voltage required to achieve the preselected extinction level when the semiconductor laser is operating at the second wavelength.
2 more elements
A laser device, comprising:
- means for tuning output light from a semiconductor laser to a desired wavelength between first and second wavelengths;
- means for directing the output light through an electro-absorption modulator;
- and
- means for adjusting an operating temperature of the electro-absorption modulator so as to achieve a preselected extinction level in the electro-absorption modulator;
- wherein a voltage applied to the modulator to achieve the preselected extinction level when the semiconductor laser is operating at the first wavelength is approximately equal to the applied voltage required to achieve the preselected extinction level when the semiconductor laser is operating at the second wavelength.
2 more elements
A semiconductor laser device, comprising:
- a substrate;
- a semiconductor laser positioned on the substrate and producing output light tunable over a tuning range between a first wavelength and a second wavelength;
- an electro-absorption modulator disposed to modulate the output light produced by the semiconductor laser, an operating temperature of the electro-absorption modulator being tunable to maintain constant detuning between the first and second wavelengths;
- and
- a thermal resistor positioned between the electro-absorption modulator and an output end of the semiconductor laser so as to reduce conductive transfer of heat energy between the electro-absorption modulator and the semiconductor laser.
2 more elements
A semiconductor laser device, comprising:
- a substrate;
- a semiconductor laser positioned on the substrate and producing output light tunable over a tuning range between a first wavelength and a second wavelength;
- and
- an electro-absorption modulator disposed to modulate the output light produced by the semiconductor laser, an operating temperature of the electro-absorption modulator being tunable to maintain constant detuning over at least a portion of the tuning range;
- wherein voltage applied to the electro-absorption modulator is substantially independent of operating wavelength and the detuning is approximately constant between the first and second wavelengths.
2 more elements
A semiconductor laser device, comprising:
- a substrate;
- a semiconductor laser positioned on the substrate and producing output light tunable over a tuning range between a first wavelength and a second wavelength;
- an electro-absorption modulator disposed to modulate the output light produced by the semiconductor laser, an operating temperature of the electro-absorption modulator being tunable to maintain constant detuning over at least a portion of the tuning range;
- and
- a heatsink, a side of the substrate containing the laser is mounted to a mounting face of the heatsink, the mounting face of the heatsink including a groove, the electro-absorption modulator being disposed in the groove.
2 more elements
A method of operating a semiconductor laser modulated by an electro-absorption modulator, the method comprising, comprising:
- tuning output light from the semiconductor laser to a desired wavelength between first and second wavelengths;
- directing the output light through an electro-absorption modulator;
- and
- adjusting an operating temperature of the electro-absorption modulator so as to achieve a preselected extinction level in the electro-absorption modulator, adjusting the operating temperature including maintaining a substantially constant detuning;
- wherein a voltage applied to the modulator to achieve the preselected extinction level when the semiconductor laser is operating at the first wavelength is approximately equal to the applied voltage required to achieve the preselected extinction level when the semiconductor laser is operating at the second wavelength.
2 more elements
Dependencies are inferred from the claim text.