Back to results
US 7,627,012 B2Granted
Distributed feedback semiconductor laser including wavelength monitoring section
AssigneeApplied Optoelectronics, Inc.
InventorToshihiko Makino
Life of this patent
Estimating the term…
Abstract
In general, a complex-coupled distributed feedback (DFB) semiconductor laser includes a grating formed by grooves through at least a part of an active region of a laser cavity. The complex-coupled DFB laser may be configured with a wavelength monitoring section and may be configured to provide facet power asymmetry. The wavelength monitoring section may include a second-order grating section configured to emit radiation (e.g., vertical radiation) from a side of the DFB laser for monitoring.
Claims25
A distributed feedback (DFB) semiconductor laser device, comprising:
- a laser cavity extending from a front facet to a rear facet and between first and second sides, the laser cavity including at least first and second main cavity sections and a wavelength monitoring section;
- an active region located in the laser cavity, the active region comprising a plurality of quantum-well layers and barrier layers between the quantum-well layers, the bandgap energy of the barrier layers being greater than the bandgap energy of the quantum-well layers;
- and
- a grating formed by grooves extending at least partially through the active region and spaced along at least a portion of the laser cavity, wherein the grating comprises first and second grating sections in the first and second main cavity sections, respectively, and a second-order grating section in the wavelength monitoring section of the cavity, wherein the second grating section is longer than the first grating section and provides a main feedback mechanism for lasing, wherein the first grating section is configured to reflect the lasing wavelength such that laser radiation is emitted from the front facet, and wherein the second-order grating section in the wavelength monitoring section is configured to emit laser radiation from the first side.
1 more element
A laser transmitter comprising:
- a laser drive circuit configured to provide at least a modulation current;
- and
- a directly modulated distributed feedback semiconductor laser configured to receive the modulation current and configured to generate a modulated light output in response to the modulation current, the directly modulated distributed feedback semiconductor laser comprising:
- a laser cavity extending from a front facet to a rear facet and between first and second sides, the laser cavity including at least first and second main cavity sections and a wavelength monitoring section;
- an active region located in the laser cavity, the active region comprising a plurality of quantum-well layers and barrier layers between the quantum-well layers, the bandgap energy of the barrier layers being greater than the bandgap energy of the quantum-well layers;
- and
- a grating formed by grooves extending at least partially through the active region and spaced along at least a portion of the laser cavity, wherein the grating comprises first and second grating sections in the first and second main cavity sections, respectively, and a second-order grating section in the wavelength monitoring section of the cavity, wherein the second grating section is longer than the first grating section and provides a main feedback mechanism for lasing, wherein the first grating section is configured to reflect the lasing wavelength such that laser radiation is emitted from the front facet, and wherein the second-order grating section in the wavelength monitoring section is configured to emit laser radiation from the first side.
4 more elements
Dependencies are inferred from the claim text.