JPH02201989A - Self-oscillation semiconductor laser device - Google Patents

Abstract

PURPOSE:To eliminate the need for providing elements with the exception of semiconductor laser diodes and as a result, dispense with peripheral connection circuits by connecting electrodes of different polarities of separated semiconductor laser diodes to each other. CONSTITUTION:As left side diodes are biased in the forward direction and an electric current flows in an active layer 103, laser oscillations take place and its layer 103 acts as a light amplification (generation) region. On the other hand, right side diodes are applied by inverse bias and act as a photodetector. Then a part of laser beams transmitting the active layer of the right side diodes is absorbed to generate a photoelectric current. Its current flows in a direction which decreases the forward direction current of the left side diodes and then, once the laser beams are produced, self-excited pulse oscillations are operated. Such a movement eliminates the need for providing elements with the exception of semiconductor laser diodes and then dispenses with peripheral connection circuits.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor laser that performs pulsed self-oscillation operation.

[Conventional technology]

Conventionally, the pulse self-excited oscillation circuit in a semiconductor laser and the circuit shown in Figure 2 (SOVIBT PHYSIC3-
3BMICONDIICTORYS, Yol, 2.
No, 8. p, 1012. February
, 1969) is known.

In FIG. 2, an element 200 on the left side is a tandem electrode type laser diode, and an element 201 on the right side is a photodiode. In this circuit, a pulse generator 202 supplies current in a pulsed manner, an optical amplification section 200a generates laser oscillation, and a photodiode 201 detects the laser beam.
Tandem electrode type laser diode 20 instead of electric signal
Self-sustained oscillation is generated based on the principle of suppressing laser oscillation by applying feedback to the zero light absorption section 200b.

[Problem to be solved by the invention]

However, the self-excited oscillation circuit shown in FIG. 2 requires a photodiode for detecting light in addition to the laser diode, and there is a problem in that the peripheral connection circuit for this also becomes complicated.

The present invention is intended to solve the above-mentioned problems, and aims to provide a self-oscillation semiconductor laser device that does not require any other elements other than a semiconductor laser diode, and as a result does not require peripheral connection circuits. .

[Means to solve the problem]

FIG. 1 is a diagram showing a self-oscillation semiconductor laser device of the present invention, where FIG. 1(a) is a top view, and FIG. 1(b) is a top view.
It is an AA sectional view of. In the figure, 100 is a self-oscillation semiconductor laser device, 101 is a high-resistance GaAs substrate, ], 02
is a high resistance AlGaAs layer, 103 is a GaAs active layer, 1
04 is an undoped AAGaAs cladding layer, 105a is a p-AflGaΔS cladding layer, 105b is an n-, A
12 Ga As cladding layer, 106a is p-G
aAs key? The whelk layer, 106b is n-Ga A S
camp layer, 107a is an n-electrode, 107b is an n-electrode, 1
．． 10 is an undoped AfGaAs cladding layer.

In FIG. 1(b), a high resistance AlGaAs layer 102 is formed on a high resistance GaAs substrate 101, and a GaAs layer 102 is formed on the high resistance GaAs substrate 101.
After forming the s active layer 103 and the undoped Al1GaAs cladding layer 104, p A/GaA is formed on the left and right sides of the active layer.
s cladding layer 105a.

n-Aj! A GaAs cladding@to5b is buried and formed, and a gate is formed on each of the cladding layers on the left and right sides of the active layer.
Tube layer p-GaAs 106 a%n-GaAs106
b, I) It has a structure in which an electrode 107a and an n-electrode 107b are formed. Then, as shown in FIG. 1(a), the electrodes of the semiconductor laser are separated by a high resistance layer 110 to form a light amplification region and a light detection region.
A self-oscillation optical circuit is constructed by connecting the n electrode and the n and n electrodes of the photodetection region in reverse, respectively.

[Effect]

The present invention will be described in detail.

In FIG. 1(a), the diode on the left side is biased in the forward direction, and current flows into the active layer 103, thereby generating laser oscillation and operating as a light amplification (generation) region.

On the other hand, when the diode on the right is connected as shown in FIG. 1(a), it is reverse biased and operates as a photodetector.

That is, a portion of the laser light propagating through the active layer of the right diode is absorbed, generating a photocurrent. The current flows in a direction that reduces the forward current of the left diode.

Therefore, when laser light is generated, a reverse current flows from the right diode to the left diode, reducing the laser light. Therefore, the laser diode shown in FIG. 1 performs self-excited pulse oscillation operation.

〔Example〕

The present invention will be explained in detail below.

The method shown in FIG. 1 was implemented using a material system of GaAs and AlGaAs. In the optical amplification region, holes are injected from the p-cladding layer on the left side and electrons from the n-cladding layer on the right side are injected into the GaAs active layer 103, thereby recombining light emission and optical amplification, resulting in laser oscillation. occurs. The laser light propagates through the GaAs active layer of the optical amplification region and the optical detection region. Then, a part of the laser oscillation light is absorbed in the photodetection region, and pairs of electrons and holes are generated, which flow through the n-cladding layer and the p-cladding layer, respectively, and become current. Since the current flows in a direction that reduces the current flowing through the optical amplification region, the amount of carrier injection decreases and the laser oscillation in the optical amplification region is stopped. When laser oscillation stops, no current flows from the photodetection region to the optical amplification region, so the amount of carrier injection increases again in the optical amplification region, causing laser oscillation, and self-sustained oscillation continues in this way. become. Such a self-oscillating semiconductor laser is effective in eliminating laser mode hopping noise.

Although the above description uses GaAs and AlGaAs as examples, it is clear that the present invention can also be implemented in semiconductor lasers using other materials such as InGaAsP.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to realize an integrated self-oscillating semiconductor laser, which was previously impossible, and does not require any other elements other than the semiconductor laser diode, resulting in the need for peripheral wiring circuits. It can be done.

[Brief explanation of the drawing]

FIG. 1 shows a self-oscillation semiconductor laser device of the present invention, in which FIG. 1(a) is a top view, and FIG. 1(b) is a top view of FIG. 1(a).
FIG. 2 is a sectional view taken along line A-A of FIG. 2, and is a diagram showing a pulse self-oscillation circuit in a semiconductor laser. 100... Self-oscillation semiconductor laser device, 101...
High resistance GaAs substrate, 102...High resistance Aj! GaA
S layer, 103... GaAs active layer, 104... undoped ΔI! GaΔS cladding layer, 105 a-p-A
AGaAs cladding layer, 105 bn-Aj! GaA
s cladding layer, 107a...p electrode, 107b...
n electrode, ■10... undoped AβGaAs cladding layer;

Claims (1)

[Claims] (1) A tandem electrode type semiconductor laser device in which electrodes are separated by providing a high resistance layer between carrier injection cladding layers of a horizontal junction type buried semiconductor laser device, in which electrodes of different polarities of separated semiconductor laser diodes are connected to each other. A self-oscillation semiconductor laser device characterized by: