Monolithically integrated high power laser optical device
View Patent ↗An optical device, including a monolithically integrated diode laser and semiconductor optical amplifier, that has reduced linewidth and improved side mode suppression for a given output power target. In a preferred embodiment, the diode laser is detuned from a gain peak wavelength to an emission wavelength. The semiconductor optical amplifier has an active region that is bandgap shifted to move its gain peak towards the emission wavelength of the laser diode, thus reducing its linewidth enhancement factor. The diode laser is preferably either a gain-coupled or index-coupled distributed feedback laser. The bandgap shift can be effected by known bandgap shifting methods, such as ion implantation, dielectric cap disordering, and laser induced disordering.
1. An integrated optical device, comprising: a diode laser section; and a semiconductor optical amplifier section monolithically integrated with the laser section, one of the laser section and the semiconductor optical amplifier section having an active region that is bandgap shifted such that the gain peak wavelength of the semiconductor optical amplifier section is substantially aligned with an emission wavelength of the integrated optical device, and the gain peak wavelength of the laser section is detuned.
2. The integrated optical device of claim 1 , wherein the emission wavelength is a detuned gain peak wavelength of the diode laser section.
3. The integrated optical device of claim 1 , wherein the laser section is a distributed feedback laser.
4. The integrated optical device of claim 3 , wherein the distributed feedback laser is a gain-coupled distributed feedback laser.
5. The integrated optical device of claim 3 , wherein the distributed feedback laser is a index-coupled distributed feedback laser.
6. The integrated optical device of claim 1 , wherein the device is fabricated on an InP wafer.
7. The integrated optical device of claim 6 , wherein the active region is InGaAsP.
8. The integrated optical device of claim 1 , wherein the laser section is one of a plurality of diode laser sections having at least one semiconductor optical amplifier section monolithically integrated therewith.
9. The integrated optical device of claim 8 , wherein the plurality of lasers and the at least one semiconductor optical amplifier form a tunable laser.
10. The integrated optical device of claim 8 , wherein each of the at least one semiconductor optical amplifier sections has an active region that is bandgap shifted to shift its gain peak towards the emission wavelength of its respective laser section.
11. The integrated optical device of claim 1 , wherein the laser section is one of a plurality of diode laser sections, the output of each of the plurality of lasers being combined and amplified by a common semiconductor optical amplifier section monolithically integrated therewith.
12. The integrated optical device of claim 11 , wherein the plurality of laser sections and the common semiconductor optical amplifier section form a tunable laser.
13. The integrated optical device of claim 1 , wherein portions of the semiconductor optical amplifier section are differentially bandgap shifted.
14. A method of fabricating an integrated optical device, the integrated optical device having a diode laser section monolithically integrated with a semiconductor optical amplifier section, comprising: bandgap shifting an active region of one of the laser section and the semiconductor optical amplifier section such that the gain peak wavelength of the semiconductor optical amplifier section is substantially aligned with an emission wavelength of the integrated optical device, and the gain peak wavelength of the laser section is detuned.
15. The method of claim 14 , wherein the step of bandgap shifting includes ion implantation.
16. The method of claim 14 , wherein the step of bandgap shifting includes dielectric cap disordering.
17. The method of claim 14 , wherein the step of bandgap shifting includes laser induced disordering.
18. The method of claim 14 , wherein the step of bandgap shifting includes impurity induced disordering.