JPH0715086A - Semiconductor laser element - Google Patents

Abstract

PURPOSE:To enhance workability in the optical coupling work of a semiconductor laser element and an optical fiber by providing a reference surface for positioning on the plane where an active layer is present. CONSTITUTION:An active layer 3 is formed in flush with the top surfaces 21a, 21b on the opposite sides. In other words, the active layer 3 of an optical fiber 22 is positioned in the vertical direction with reference to the top surfaces 21a, 21b on the opposite sides. An emission part is then positioned in X direction by conducting the scanning in parallel with the top surfaces 21a, 21b from a groove 15a to a groove 15b. Subsequently, the optical fiber 22 is shifted perpendicularly to the emission edge 23 of an element thus determining a position where the intensity of light entering the optical fiber 22 increases. Since the optical fiber is positioned by monitoring the output from the optical fiber only in two axial directions in three-dimensional space, workability is enhanced in the optical coupling work of the semiconductor laser element and the optical fiber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device which serves as a light source for optical communication.

[0002]

2. Description of the Related Art In a semiconductor laser device used for optical communication, it is necessary to position a light emitting portion with high precision in order to efficiently couple it with an optical fiber. The light emitting portion of the semiconductor laser element usually uses a cleavage plane of a crystal. Therefore, when performing optical coupling between the optical fiber and the semiconductor laser element,
Since it is not possible to determine with naked eyes where the active layer is located on the cleaved surface, the following method is used. That is, 1) First, the semiconductor laser device is oscillated. 2) Next, monitor the light emitted from the end of the optical fiber opposite to the semiconductor laser device, and adjust the relative position of the semiconductor laser device and the optical fiber in a three-dimensional space to maximize the light intensity. Adjust and fix each.

[0003]

However, the above method has the following problems. That is, 1) In particular, in the case of a single mode optical fiber, the allowable range of the coupling position of the optical fiber is as small as several μm. Therefore, although it is necessary to first enter a little light into the optical fiber, it is difficult to position the light emitting portion because the light emitting portion is not visible to the naked eye. 2) In the case of a tapered spherical optical fiber, it is necessary to bring them closer to each other so that the distance between the element end face and the optical fiber is 10 μm or less. However, since there is a vertical distance from the top surface of the device to the light emitting part, it is difficult to see the device and the optical fiber at the same time with a CCD camera because the focus is out of focus. It cannot be measured accurately. 3) When the output of the optical fiber is monitored, if the relative displacement between the optical fiber and the element is large, the peak search takes time. 4) When fixing an optical fiber for the purpose of manufacturing a module or the like, when the optical fiber is deviated from the optimum position, it is difficult to correct it because the deviation direction is unknown.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a semiconductor laser device that solves the above-mentioned problems. In a semiconductor laser device having an active layer formed on a semiconductor substrate, positioning is performed within a plane having the active layer. Is provided with a reference surface for

[0005]

As described above, when the reference plane for positioning is provided in the plane in which the active layer is located, the optical fiber is moved along this reference plane when the optical fiber is coupled, whereby the active layer of the active layer is moved. The optical fiber can be positioned in the light emitting part.
Therefore, since the relative position can be adjusted in a two-dimensional space, the number of positions can be reduced by one dimension compared with the conventional method, and the optical fiber can be positioned efficiently.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings. 1 (a), (b) and (c)
FIG. 3A is a top view, a front view and a side view, respectively, of an embodiment of a semiconductor laser device according to the present invention. As shown in FIG. 2, the device of this example was manufactured by the following steps. That is, 1) First, the p-InP clad layer 2, the InGaAsP active layer 3, and the n-InP clad layer 4 are grown on the p-InP substrate 1. Next, after forming the dielectric mask 5, a groove having a width of 20 μm is formed by etching so as to leave a mesa stripe having a width of 2 μm (FIG. 2A). 2) Next, p-I which becomes a current confinement layer by selective growth
The nP layer 6, the n-InP layer 7, and the p-InP layer 8 are grown (FIG. 2B). 3) Next, the dielectric mask 5 is removed, and n-In is further removed.
P clad layer 9, n ⁺ -InGaAsP cap layer 10
Are sequentially laminated (FIG. 2C). 4) Next, after forming the dielectric mask 11 having a width of 20 μm, selective etching is performed as indicated by the dotted line. When an HCl-based etching solution is used, the InGaAsP active layer 3 that is a quaternary layer is not etched, and only the InP layer is etched, resulting in the shape shown in FIG. 2 (d). 5) Next, a dielectric layer 12 is formed on the entire surface, a stripe-shaped window is opened in a portion above the active layer 3, and an n-electrode 13 is formed. Finally, the p-electrode 14 is formed (see FIG. 2).
(E)).

A method of coupling the semiconductor laser device and the optical fiber of this embodiment will be described with reference to FIG. The active layer 3 is flush with the upper surfaces 21a and 21b on both sides. Therefore, the height direction (Z direction) of the active layer 3 of the optical fiber 22 can be easily set by using the upper surfaces 21a and 21b on both sides as reference planes for positioning. Next, the upper surface 21a,
21b to the groove 15b in the direction parallel to 21b (X direction).
By scanning to, the position of the light emitting portion in the X direction is determined. Next, the optical fiber 22 is moved in a direction (Y direction) perpendicular to the light emitting end face 23 of the device to determine the position where the intensity of light entering the optical fiber 22 is increased. In this way, the Z direction can be easily positioned with the naked eye using a camera or the like, and only the Y and X directions are positioned by monitoring the optical fiber output. The positioning reference plane of the present invention is not limited to the one arranged on both sides of the active layer as in the above-mentioned embodiment.

[0008]

As described above, according to the present invention, in a semiconductor laser device in which a planar active layer is formed on a semiconductor substrate, a reference plane for positioning is provided in the plane in which the active layer is formed. When performing optical coupling with the optical fiber, it is sufficient to position the optical fiber by monitoring the optical fiber output in only two axial directions of the three-dimensional space. There is an excellent effect that workability can be improved.

[Brief description of drawings]

1A, 1B, and 1C are a top view, a front view, and a side view, respectively, of an embodiment of a semiconductor laser device according to the present invention.

2 (a) to 2 (e) are explanatory views of a manufacturing process of the above embodiment.

FIG. 3 is an explanatory diagram of an optical coupling work between the element of the above embodiment and an optical fiber.

[Explanation of symbols]

 1 p-InP substrate 1 2 p-InP clad layer 3 active layer 4 n-InP clad layer 5, 11 dielectric mask 6, 8 p-InP layer 7 n-InP layer 9 n-InP clad layer 10 cap layer 12 dielectric Body layer 13 n electrode 14 p electrode 15a, 15b Grooves 21a, 21b Upper surface 22 Optical fiber 23 Light emitting end surface

Claims (1)

[Claims] 1. A semiconductor laser device having an active layer formed on a semiconductor substrate, wherein a reference plane for positioning is provided in a plane having the active layer.