JPH0697579A - Semiconductor laser array - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a semiconductor laser array capable of arbitrarily driving a microcavity laser integrated on a semiconductor substrate and having flexible functions and easy integration. In a semiconductor laser array in which a microcavity laser is integrated on a semiconductor substrate, a semiconductor substrate 1
A channel 13 for two-dimensional electron gas is formed in 0, an electron emitter 17 and a direction control electrode 18 are formed,
It is characterized in that current injection into each microcavity laser 20, common ground, and switching control are performed through the channel 13 of the two-dimensional electron gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser used for optical communication, optical interconnection, optical information processing, etc., and particularly to a semiconductor laser using a low threshold microcavity laser suitable for integration. For arrays.

[0002]

2. Description of the Related Art A microcavity laser realizes a laser without a threshold in principle by efficiently coupling spontaneous emission light from an active layer into an oscillation resonator mode. Distributed reflection film (DBR)
It is sandwiched between. Conventionally, when integrating such a laser, as shown in FIG. 5, a plurality of microcavity lasers are installed on a semiconductor substrate, and a common electrode is provided above and below the microcavity laser to supply power to each element.

In the figure, 50 is an n-GaAs substrate, 51
Is D in which n-AlAs and n-AlGaAs are alternately laminated.
A BR reflector, 52 is a single quantum well active layer made of GaAs, 53 is a DBR reflector in which p-AlAs and p-AlGaAs are alternately stacked, 54 is a high resistance layer by ion implantation, and 55 is p- by Zn diffusion. A GaAs layer, 56 is an Au-Ge electrode deposited on the lower surface of the substrate, and 57 is an Au-Cr electrode deposited on the upper surface of the substrate and having an optical output window.

However, this type of device has the following problems. That is, since power is supplied to each laser which is two-dimensionally arrayed on the semiconductor substrate by a normal metal wiring, all the lasers can be driven at the same time, but it is difficult to selectively oscillate a specific laser. And, there is little development of the function. In addition, selective driving is possible by separating one of the electrodes for each laser.
In this case, a large number of wirings for taking out electrodes are required on the surface of the substrate, and a large number of bonding pads for connecting to an external circuit are also required. Then, as the number of integrated microcavity lasers increases and the distance between these becomes shorter, it becomes substantially difficult to form the above-mentioned wirings and bonding pads.

[0005]

As described above, in the conventional semiconductor laser array in which microcavity lasers are integrated, a specific laser is selectively driven with respect to each laser which is two-dimensionally arranged on a semiconductor substrate. It is difficult to do so, and there is a problem that the developability of the function is low.

The present invention has been made in consideration of the above circumstances, and an object thereof is to be able to selectively drive a microcavity laser integrated on a substrate, and to provide a flexible function. An object is to provide a semiconductor laser array that can be easily integrated.

[0007]

The essence of the present invention is to drive a microcavity laser using a channel of a two-dimensional electron gas. That is, the present invention is, in a semiconductor laser array in which a microcavity laser is integrated on a semiconductor substrate, forms a channel of a two-dimensional electron gas in the semiconductor substrate and connects each microcavity laser to the channel of the two-dimensional electron gas. It is characterized in that the current injection is performed.

[0008]

According to the present invention, two-dimensional electron gas (2DEG)
By forming the microcavity laser on the semiconductor substrate containing the channels of the following, the following effects occur. (1) 2DE the ground electrode of each microcavity laser
Each ground can be formed inside the semiconductor substrate by ohmic connection to the G channel. In this case, the microcavity lasers can be simultaneously driven. (2) By providing an input terminal (source), a control terminal (gate) and an output terminal (drain) on the 2DEG channel, the injection current to each microcavity laser can be turned on and off.
Off control is possible. In this case, the microcavity laser can be selectively driven. (3) Flexible quantum wiring (controlling the wave nature / particle nature of electrons to control the propagation direction of electrons) using the 2DEG channel as a wiring space enables selective excitation of the microcavity laser.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is for explaining the schematic configuration of a semiconductor laser array according to the first embodiment of the present invention.
Is a perspective sectional view, and (b) is a plan view. In the figure, 10 is Ga
An As substrate, and undoped GaAs on this substrate 10.
A layer 11 and an n-AlGaAs layer 12 are formed. Then, the 2DEG channel 13 is formed in the region sandwiched by the GaAs layer 11 and the AlGaAs layer 12.

A plurality of microcavity lasers 20 are formed on the AlGaAs layer 12. In the microcavity laser 20, a GaAs active layer 21 is sandwiched between an n-type clad layer 22 and a p-type clad layer 23, and this double hetero structure is further provided with an n-type distributed Bragg reflection film (DBR).
It is sandwiched between a reflection mirror 24 and a p-type DBR reflection mirror 25, and is formed in a columnar shape standing upright with respect to the substrate 10.

A dielectric layer 15 is embedded between the microcavity lasers 20. A metal electrode 16 is formed on these, and a light extraction window 16a for extracting light from the microcavity laser 20 is formed in a part of the electrode 16. Also, the substrate 10
An electron emitter 17 that emits electrons and a direction control electrode 18 that controls the direction of the emitted electrons are formed in the upper part. The region of the n-AlGaAs layer 12 in contact with the microcavity laser 20 is an n ⁺ layer due to impurity diffusion or the like.

The positional relationship between the cylinder of the microcavity laser 20 and the electron emitter 17 is as shown in FIG. 1B, and the direction control electrode 18 is laterally arranged on the electron emitter 17. The trajectory of the electrons emitted from the electron emitter 17 is controlled by the direction control electrode 18, and any one of the microcavity lasers 20 is selectively driven as shown by the broken line in the figure.

To make the above structure, first, GaAs is used.
An undoped GaAs layer 11 and an n-AlGaAs layer 12 are grown on the substrate 10 by molecular beam epitaxy (MBE) or metal organic chemical vapor deposition (MOCVD) to obtain 2
The DEG channel 13 is formed. On top of this, n-type DBR
Reflector 24 (AlAs / AlGaAs), n-type cladding layer 22 (barrier layer), active layer 21 (GaAs single quantum well: SQW), p-type cladding layer 23 (barrier layer) and p
A type DBR reflecting mirror 25 ((AlAs / AlGaAs) is sequentially grown and formed.

Next, the layers 25, 23, 21, 22, and 24 are patterned using a circular pattern mask to form an array structure of microcavities. Furthermore, a dielectric layer 1 such as SiO ₂ is provided between the microcavities.
5 is embedded to flatten the surface. Then, a metal electrode 16 is formed on the surface, and a window 16a for extracting light is formed in a portion of the electrode 16 on the microcavity laser 20 to obtain the structure shown in FIG.

As described above, according to this embodiment, the 2DEG channel 13 is formed on the GaAs substrate 10, the electron emitter 17 and the direction control electrode 18 are formed, and a plurality of microcavity lasers 20 are integrated on the electron emitter 17 and the direction control electrode 18. Therefore, by emitting electrons from the electron emitter 17 and controlling the direction of the electrons by the direction control electrode 18, the substrate 1
A plurality of microcavity lasers 20 integrated on
Can be selectively oscillated. And in this case
Since it is not necessary to provide an independent electrode for each laser, it is effective for integration. Further, there is an advantage that the laser to be driven can be sequentially switched only by changing the voltage applied to the direction control electrode 18.

FIGS. 2A and 2B are for explaining the construction of the main part of the second embodiment of the present invention, wherein FIG. 2A is a plan view and FIG. 2B is a sectional view. In this example, the substrate surface or n-AlGa is used.
The control electrode 19 is formed on the As layer 12. In this case, by applying a negative bias to the control electrode 19, a depletion layer 13a is formed in the 2DEG channel 13,
This depletion layer 13a becomes an electron reflecting mirror. Then, the orbit of the electrons emitted from the electron emitter 17 can be changed by using this electron reflecting mirror. Therefore, the control electrode 1
It is also possible to switch the microcavity laser 20 to be driven as shown in the figure by turning the bias of 9 on and off. Further, various paths can be selected from the electron emitter 17 to the microcavity laser 20, which has an advantage of increasing the degree of freedom of arrangement of the electron emitter 17.

FIG. 3 is a sectional view showing the structure of the main part of the third embodiment of the present invention. In this embodiment, in addition to the structure of FIG. 1, an n ⁺ type GaA is provided between the substrate 10 and the GaAs layer 11.
The s layer 31 is formed. In addition, the n-AlGaAs layer 1
An undoped AlGaAs layer 32 is formed under the layer 2.

With such a structure, the electron emitter 1
During selective excitation by 7, the electrons from the electron emitter 17 are supplied to the microcavity laser 20 through the 2DEG channel 13 as shown in the band diagram of FIG. Therefore, the same effect as the first embodiment can be obtained. Further, by providing the n ⁺ -GaAs layer 31 and strongly applying a negative bias thereto, the resistance of the entire 2DEG channel 13 is lowered as shown in the band diagram of FIG. 4B. In this case, all the microcavity lasers 20 can be driven simultaneously.

The present invention is not limited to the above embodiments. The number and arrangement relationship of the microcavity lasers installed on the substrate are not limited to those shown in FIG. 1 and can be appropriately changed according to the specifications. Also, 2D
It is also possible to control the switching of the microcavity lasers by using the EG channel to establish a common ground or by forming a transistor such as HEMT in each microcavity laser. In addition, various modifications can be made without departing from the scope of the present invention.

[0020]

As described in detail above, according to the present invention, by forming a channel of a two-dimensional electron gas in a semiconductor substrate for integrating a microcavity laser,
It is possible to realize a semiconductor laser array which is easy to selectively oscillate a specific laser, modulates light intensity, etc. and has a possibility of developing a function with respect to microcavity lasers which are two-dimensionally arranged on a semiconductor substrate.

[Brief description of drawings]

FIG. 1 is a perspective view and a plan view showing a schematic configuration of a semiconductor laser array according to a first embodiment.

2A and 2B are a plan view and a cross-sectional view showing a main part configuration of a second embodiment.

FIG. 3 is a cross-sectional view showing the structure of a main part of a third embodiment.

FIG. 4 is a schematic diagram for explaining the operation of the third embodiment.

FIG. 5 is a perspective view showing a schematic configuration of a conventional semiconductor laser array.

[Explanation of symbols]

 10 ... GaAs substrate, 11 ... GaAs layer, 12 ... n-AlGaAs layer, 13 ... 2DEG channel, 15 ... Dielectric layer, 16 ... Metal electrode, 16a ... Light extraction window, 17 ... Electron emitter, 18 ... Direction control electrode, 20 ... Microcavity laser, 21 ... SQW active layer, 22, 23 ... Clad layer, 24, 25 ... DBR reflector.

Claims (1)

[Claims] 1. A semiconductor substrate having a two-dimensional electron gas channel, and a plurality of microcavity lasers formed on the substrate, wherein each microcavity laser is provided via the two-dimensional electron gas channel. A semiconductor laser array characterized in that current is injected into the semiconductor laser array.