KR100345449B1 - A semiconductor laser including doped polymer waveguide - Google Patents

Abstract

An object of the present invention is to stabilize wavelength selection of a semiconductor laser device by applying a laser beam transition which is not affected by an external temperature change to a semiconductor laser device. In order to achieve the above object, the semiconductor laser device of the present invention comprises a waveguide 5 made of a polymer doped with iodine, niobium, erbium, prandium or the like, a gain waveguide region 3 made of a semiconductor, (6) and (7) between the region portions (4). The gain waveguide region 3 and the wavelength selection grating region 4 which are in contact with the waveguide 5 made of polymer are provided between the resonator mirrors 1 and 2. The power supply electrodes 8 and 9 are brought into contact with the gain waveguide region 3 and the wavelength selection grating region 4, respectively.

Description

[0001] The present invention relates to a semiconductor laser device including a doped polymer waveguide,

Relates to wavelength stabilization of a semiconductor laser device, and more particularly relates to stabilizing a wavelength of a semiconductor laser device by using a doping technique of a polymer waveguide and an atomic beam transition material.

Conventionally, DFB type and DBR type laser diodes for inserting a grating under a gain medium for wavelength selection of a semiconductor laser device have been studied for a long time. Further, technologies for monitoring the output wavelength and injecting current feedback to the outside of the laser device have been developed, and techniques such as passive mode locking and active mode locking are known.

In addition, a polymer layer having different refractive indexes is stacked to form an optical waveguide, and a light splitter, an optical switch, a one-to-many waveguide system, and the like have been studied. Recently, a material capable of being transferred to a polyimide waveguide (Nd ³⁺ ) Is doped to achieve light emission and gain.

However, since the wavelength selection is changed according to the injection current or the external temperature, the conventional semiconductor laser device has a disadvantage that the wavelength selection is not stable when the wavelength selection is used for a long time.

Accordingly, an object of the present invention is to stabilize wavelength selection of a semiconductor laser device by applying a laser beam transition which is not influenced by an external temperature change to a semiconductor laser device.

1 is a cross-sectional view showing an embodiment of a semiconductor laser device enhanced in longitudinal mode selectivity of the present invention,

FIG. 2 is a sectional view showing the arrangement of electrodes for current injection into the laser device of FIG. 1,

3A to 3C are diagrams for explaining the distribution of the saturated absorption along the longitudinal direction in the polymer waveguide included in the semiconductor laser device with enhanced longitudinal mode selectivity of the present invention,

Fig. 4 is a diagram for explaining the absorption spectrum of the gain medium in the waveguide doped with the atomic-line-transition material and the gain spectrum (gain-loss) of the gain region engraved with the lattice.

According to an aspect of the present invention, there is provided a semiconductor laser for stabilizing an output wavelength, comprising: a polymer waveguide doped with a material having a circular transition; A first semiconductor waveguide for imparting a gain connected to one end of the polymer waveguide at a Brewster's angle; A second semiconductor waveguide in which a grating for wavelength selection is connected to the other side of the polymer waveguide by a Brewster's angle; A resonator mirror coupled to the first and second semiconductor waveguides; And an electrode for injecting a current into the first and second semiconductor waveguides.

Wherein the polymer waveguide comprises a core polymer doped with a material having the atomic transition and a clad polymer covering the core polymer.

The material having the arc transition may be any one selected from iodine, nioium, erbium, and prismium.

And an antireflection coating is applied to the resonator mirror connected to the second semiconductor waveguide.

As described above, the present invention uses a material capable of being atomic-line-shifted by doping into a polymer, and applies a stable transition wavelength of these atoms to wavelength stabilization of a semiconductor laser. By using the material capable of the atomic beam transition, it is possible to stabilize the output wavelength of the semiconductor laser by the light emission of the narrow line width of the densely inverted atoms in the region where the light intensity in the resonator is high by the passive mode selection in the region where the light intensity in the resonator is low have. Iodine, Neodimium, Erbium, Praseodymium, and the like are available as the materials capable of being transferred to the polymer, and the materials are respectively 1.31 μm, 1.06 μm, 1.53 μm, It mainly transits near 1.6 ㎛ wavelength and shows gain. One of these materials is operated by connecting the doped polymer waveguide to the inside of the resonator waveguide of the semiconductor laser device of each wavelength band by a Brewster angle so as to obtain wavelength stabilization that is not affected by the external environment at the level of the semiconductor laser device .

Hereinafter, the present invention will be described in detail with reference to Figs. 1 to 4. Fig.

The semiconductor laser device having enhanced longitudinal mode selectivity of the present invention includes a polymer waveguide 5 doped with a material having a circular arc transition and a resonator mirror 1, 2, InP, InGaAs, InGaAsP, InAlGaAs, GaInNAs And a grating-engraved region 4 made of a semiconductor such as InP, InGaAs, InGaAsP, InAlGaAs, GaInNAs or the like for wavelength selection. The polymer waveguide 5 such as polyimide is connected to the semiconductor waveguide 3 and the semiconductor waveguide 4 by Brewster's angles 6 and 7 so as to minimize the reflection loss of the connection part . Further, an electrode 8 for supplying a current to the gain region and an electrode 9 for supplying current to the wavelength selection region are formed.

As can be seen from the structures of FIGS. 1 and 2, the waveguide of the fabricated semiconductor laser device is etched deeply with a Brewster angle through pattern etching, then the portion is filled with a core and a clad polymer Thereby forming a waveguide. In order to obtain a polymer waveguide, a material capable of forming a circular arc is mixed with a polymer corresponding to a core so as to have an appropriate ion density, and a polymer for forming a clad is coated thereon. Then, a pattern is formed and connected to the waveguide of the semiconductor laser device.

Since the solubility of the solvent containing a material capable of converting the atomic energy into the solvent affects ion density and polymer waveguide formation, it is necessary to select an appropriate solvent and solvent. In some cases, the solubility of the semiconductor waveguide (3) An adhesion promoter may be used to improve the adhesion between the polymer dopes 5.

When the current is injected through the electrodes 8 and 9 of the gain region and the wavelength selection region, the semiconductor laser device having the above-described longitudinal mode selectivity enhanced has a low current, that is, The wavelength selection is made by the distribution of saturated absorption along the lengthwise direction (see FIG. 3). As can be seen from FIG. 3, the longitudinal mode within the resonator of the laser device is a standing wave having a constant light intensity distribution with time, and there is a standing wave distribution also in the doped polymer waveguide 5 inside the resonator. As described above, the laser operation starts at the longitudinal mode wavelength at which the (gain-loss) becomes the maximum among the standing wave modes. Once the selected longitudinal mode 10 has already been saturated and absorbed through the doped polymer waveguide 5, it does not undergo absorption, but neighboring longitudinal modes 11 and 12 will undergo absorption, . The device must be in the vicinity of the absorption linewidth of the polymer waveguide in which the longitudinal mode (gain-loss) in the remaining semiconductor laser structures other than the initially doped polymer waveguide is maximized. 4, the gain line width 13 in the laser structure is much wider than the absorption line width 15 of the polymer waveguide. However, the gain wavelength and line width 14 of the gain region in which the lattice is plotted, (Gain-loss) maximum longitudinal mode wavelength can be precisely taken away.

An appropriate current injection is performed in consideration of the change of the center wavelength of the wavelength selection region in accordance with the current injection amount of the wavelength selection region. Since the absorption wavelength of the polymer waveguide doped with a material capable of being converted into a circular arc does not change according to the external temperature or the injection current, the output wavelength can be fixed for a long time. In addition, when the intensity of light is increased inside the resonator, that is, when a highly reflective reflector is provided on the end face and the injection current is increased, the oscillation of the oscillation wavelength can be enhanced by injecting the circularly polarized light emission from the polymer waveguide into the laser resonator .

The semiconductor laser device according to the present invention has an output wavelength stabilized by the wavelength of the atomic beam transition, so that the semiconductor laser device is not affected by the temperature change of the external and can act as a reference wavelength. The above-mentioned light source is advantageous in that it can be effectively applied in a large-capacity optical communication system in which DWDM is required, since a long-term wavelength stability is required when a semiconductor laser device is used.

Claims (5)

In a semiconductor laser for stabilizing an output wavelength, A material doped polymer waveguide having a circular arc transition; A first semiconductor waveguide for imparting a gain connected to one end of the polymer waveguide at a Brewster's angle; A second semiconductor waveguide in which a grating for wavelength selection is connected to the other side of the polymer waveguide by a Brewster's angle; A resonator mirror coupled to the first and second semiconductor waveguides; And And an electrode for current injection into the first and second semiconductor waveguides . The method according to claim 1, The polymer waveguide includes: Wherein the material having the atomic transition is doped with a core polymer and a clad polymer covering the core polymer. 3. The method according to claim 1 or 2, Wherein the material having the atomic transition is selected from iodine, nioium, erbium, and prussiate. 3. The method according to claim 1 or 2, Wherein the semiconductor is made of any one selected from the group consisting of InP, InGaAs, InGaAsP, InAlGaAs, and GaInNAs, or a combination thereof . The method according to claim 1, Wherein an antireflection coating is applied to the resonator mirror connected to the second semiconductor waveguide.