JPS62106686A - Semiconductor laser - Google Patents

Abstract

PURPOSE:To facilitate convergence of a laser beam without using a lens by providing monolithic integration of concave mirrors in a DFB laser. CONSTITUTION:A grating 2 for distributed reflection is formed on an N-type InP substrate 1 and an N-type InGaAsP waveguide layer 2, a P-type InGaAsP active layer 3, a P-type InP cladding layer 4 and a P-type InGaAsP cap layer 5 are formed successively on the grating 2 to form a material wafer. A BH laser wafer is composed of this material wafer. Holes 6, which have partially circular cross sections and side walls vertical to the wafer surface, are formed in the wafer and, at the same time, electrodes 8 and 9 are provided on the top and bottom surfaces of the wafer to form a DFB laser. With this constitution, as a laser beam 10 emitted from the laser 15 is focused on one point, alignment can be achieved easily by providing the end surface 12 of an optical fiber 11 at that point.

Description

[Detailed description of the invention] Industrial applications The present invention relates to semiconductor lasers.

2. Description of the Related Art Conventionally, laser light emitted from a semiconductor laser has been made to enter an optical fiber using a lens as shown in FIG. In Figure 3, SELFOC lens 20
is used, but in addition to this, a ball lens, a flat microlens, etc. can also be used. 21 is an optical fiber, and 22 is a semiconductor laser. Furthermore, in order to prevent light returning from the optical fiber to the semiconductor laser, an optical isolator made of YIG or the like may be incorporated.

Problems to be Solved by the Invention However, since such a configuration requires at least three components: a semiconductor laser, a lens, and an optical fiber, it is necessary to develop a fixing method that aligns the optical axes of each component and achieves long-term stability. A lot of time and effort is spent on.

Means for Solving the Problems The present invention solves the above problems by monolithically integrating a concave mirror into a DFB laser, thereby making it possible to converge laser light without using a lens.

Effects According to the present invention, the number of parts can be reduced, and alignment of optical axes and long-term stability can be easily ensured.

Embodiment FIG. 1 is a sectional view of the embodiment according to the present invention combined with an optical fiber, and FIG. 2 is a top view of the embodiment of FIG. 1.

After forming a grating 2 for distributed reflection on an n-type InP substrate 1 whose main surface is the (110) plane, the n-type nGaAgP waveguide layer, the p-type InGaAsP active layer 3, the p-type InGaAsP active layer 3,
A mold part nP cladding layer 4 and a p type part nGaAsP cap layer 5 are formed to form a base wafer. Thereafter, the original wafer is chemically etched leaving a portion with a width of about 2 μm in the <111> direction, and a current blocking layer is formed in the second crystal growth to produce a normal BH laser wafer. Thereafter, as shown in FIG. 2, a semicircular etching hole 6 is formed by chemical etching.

As shown in FIG. 1, a cross-sectional view at this time, a portion of the hole 6 is circular and the remaining portion is perpendicular to the surface of the wafer.

For example, a 2 weight percent bromine methanol solution is used for chemical etching at this time.

Thereafter, electrodes 8.9 are provided on the top and bottom surfaces of the wafer.

The laser beam 10 output from the DFB laser 15 created in this way is focused at one point as shown in FIG. Therefore, by bringing the end face 12 of the optical fiber 11 to this position, alignment can be easily performed. Also, the partial score is 2
Because there are only two, it is easier to fix than the conventional three or more. 13
is the cladding of the fiber, and 14 is the core.

Note that there is no problem even if the etched hole 6 is filled with a dielectric material for planarization.

Furthermore, as is clear from FIG. 1, the other end face 16 of the DFB laser is not perpendicular to the active layer, so the Fabry-Perot mode appears ((), improving the characteristics of the DFB laser.

Effects of the Invention According to the present invention, it is possible to condense the light of a semiconductor laser without passing through a lens, and the number of parts can be reduced for coupling with an optical 7-eyeper, etc., and improvements in optical axis alignment, long-term stability, etc. It has excellent efficacy in many aspects.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a laser according to an embodiment of the present invention coupled with an optical 7-eyeper, Fig. 2 is a top view of the embodiment of Fig. 1, and Fig. 3 is a conventional laser and an optical FIG. 3 is a diagram showing a state of fiber coupling. 2... Grating, 3... Active layer, e... Hole, 1Q... Laser light, 11
...Optical fiber, 15...DFB laser. Name of agent: Patent attorney Toshio Nakao and 1 other person Yoshio 1
figure? Glenite Pugu

Claims (1)

[Claims] An active layer formed on an InP substrate having a (110) plane as a main surface, a cladding layer sandwiching the active layer, and a distributed reflection resonator provided near the active layer so as to resonate in the <111> direction. and at least one hole reaching at least the active layer from the surface, and the hole has a concave shape such that the laser beam emitted from the active layer is focused at one point. Features of the semiconductor laser device.