JPS59103394A - Laser diode with detector - Google Patents

Abstract

PURPOSE:To prevent the useless optical interaction between a light detector and a laser by a method wherein the light input end surface of the light detecting part is not arranged to the light output end surface of the laser part in parallel. CONSTITUTION:The laser diode with a detector is provided with a laser part 1 and a light detecting part 2. This laser diode with a detector is manufactured with a groove part 9 in such a manner that the light output end surface 7 of the laser part and the light input end surface 8 of the light detecting part are not arranged each other in parallel, that is, in such a manner that an angle 11, which the end surface 7 makes with the end surface 8, can be taken the values of 10-30 deg., for example. As a result, the useless interaction between the laser part 1 and the detecting part 2 can be dispensed with less interaction.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a laser diode with a detector in which a photodetector and a laser are formed on the same substrate, and particularly relates to a laser diode with a detector in which a photodetector and a laser are formed on the same substrate. The present invention relates to a laser diode with a detector that can prevent (cross) - ri).

[Prior art]

An example of a conventional laser diode with a detector of this type is I
A striped metal electrode attached to a double heterostructure compound semiconductor crystal using nP/InGaAsP? An etched groove is formed in the center of the crystal by chemical or physical etching in a direction perpendicular to the electrode, and one side of the groove is used as a laser and the other side is used for optical detection. It is used as a vessel. Although the photodetector and the laser have the same cross-sectional shape, they are electrically used by applying bias voltages in opposite directions (as described in Abride by B.I. Mira and K. Iga).
Physics Letters (B, I.

Miller and K, Iga, Appl, Ph.
Lett, Vol. 37, No. 4, p. 339 (1980
Year).

However, in conventional laser diodes with detectors in which a compound semiconductor laser and a photodetector are monolithically formed on the same substrate (chip) as exemplified above, the optical Due to the interaction, the photodetector and laser often form a double cavity, causing unwanted laser oscillation.

[Purpose of the invention]

The present invention has been made in view of the actual state of the prior art, and its purpose is to eliminate unnecessary optical interaction between a photodetector and a laser when they are formed on the same substrate. The object of the present invention is to provide a laser diode with a detector that can prevent the above problems.

[Summary of the invention]

In order to achieve this object, the present invention devises the shape of the groove that separates the photodetector and the laser section, so that the light of the photodetector, which is installed close to and opposite to the light output end face of the laser section, is devised. It is characterized in that the input end face is not arranged parallel to the light output end face of the laser section. Further, desirably, the angle formed by the light output end face of the laser section and the light input end face of the photodetector section is within the range of 10° to 30°. More preferably, the distance between the end faces of both (the length of the line segment connecting the midpoint in the width direction of the active layer on each end face of both) is 500 μm.
It's getting narrower than m.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described based on the drawings. FIG. 1 is a perspective view of a laser diode with a detector according to an embodiment of the present invention. The laser diode with detector of this embodiment shown in FIG. 1 is InP/InGaAsp or G
Etched grooves as shown in the figure are formed by wet chemical etching on the double heterostructure crystal produced by aA,s/Gakths. In this figure, 1 is a laser (laser section), 2 is a photodetector (photodetection section), 3 is a laser section stripe electrode, 4 is a photodetection section stripe electrode, and 5 is GaAtAs or InGaAs.
Laser part active layer such as P, 6 is the same < G a A lk
s or an active layer of the photodetection section such as InGaAsP, 7 is the laser section light output end face, 8 is the light input end face of the photodetection section, 9 is the groove, 11 is the laser section light output end surface 7 and the photodetection section The angle 12 formed with the light input end surface 8 is the distance between the laser section light output end surface 7 and the photodetector section light input end surface 8, that is, the distance between the widthwise midpoint of the laser section active layer 50 on the laser section light output end surface 7 and the light This is the length of a line segment connecting the light input end face 8 of the detection section to the midpoint in the width direction of the active layer 6 of the photodetection section. The laser diode with a detector of the present invention is arranged such that the laser section light output end surface 7 and the photodetector section light input end surface 8 are not arranged in parallel; The 64 portions 9 are created so that the angle 11 formed by the angle 11 takes a value of, for example, 15°, 20°, 30°, etc. This etching of the groove portion 9 is a striped electric pattern! After forming (4, 5), use a photoresist to form a pattern of each end face (7°8) in which the angle 11 has a predetermined value, and then apply an appropriate etching solution or
This was done by reactive ion beam etching using Cl3. As the above-mentioned etching solution, I n P / I n
In the case of G a A s P crystal, HCl-CH5
Using a solution of COOH: H2C) + (1:2:1), in the case of GaAs/GaAtAs crystal,
N H40H or H3P04 (pH adjusted H202 aqueous solution, or B r 2- CH3
0H solution, or H3po.

: H2O2: A solution of HOCH2CH20H (ethylene glycol) (1:1:3) was used.

As a result of the inventor's experiments, laser oscillation with stable output and mode was obtained compared to a laser diode with a detector, which has both end faces parallel to each other.

Note that when the angle 11 formed by both end surfaces <7.8) is 10° or more, the light incident on the photodetector 2 is reflected inside the photodetector 2, and then the light is directed toward the laser 1 and becomes ff. It is derived from Plenel's law regarding reflection that it rarely occurs. Also, the angle 11 is not very large, for example 4
When the angle is 5° or less, it is derived from Schiffrenel's law that the amount of light from the laser 1 that enters the inside of the photodetector 2 without being reflected by the light input end face 8 of the photodetector section increases. That is, in the present invention, light is detected most efficiently especially when the angle is within the range of 10° to 30°, and at the same time unnecessary mutual interaction between the laser 1 and the photodetector 2 is avoided. It has less effect.

Furthermore, although the distance 12 has a good detection efficiency for short culms, the inventor has confirmed that it is practical if the distance is smaller than 500 μrn.

As mentioned above, the laser diode with detector of the present invention has the following features:
Since the light input end face of the light production section is not arranged parallel to the light output end face of the laser section, the output and mode of the laser diode are stabilized, and there is an effect that performance comparable to that of a single laser can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a laser diode with a detector according to an embodiment of the present invention. 1...Laser, 2...Photodetector, 3...Laser part strut 1st eye 479

Claims (1)

[Claims] 1. A photodetecting section and a laser section separated by a groove formed in a portion of a layered crystal of a compound semiconductor are provided on the same substrate, and a laser section is provided on the laser section side in the depth direction of the groove. In a laser diode with a detector, in which a wall is a light output end face of the laser section, and a wall on the side of the photodetector that is close to and opposite to the end face is a light input end face of the photodetector, the light input end face of the photodetector section is connected to the light output end face of the laser section. A laser diode with a detector characterized in that the laser diode is not arranged parallel to the detector. 2. The laser diode with a detector according to claim 1, wherein the angle formed by the light output end face of the laser section and the light input end face of the photodetector section is within the range of 106 to 30'. 3. The first aspect of the present invention is characterized in that the length of the line segment connecting the midpoints in the width direction of the active layers of the laser part light output end face and the photodetector part light input end face is smaller than 500 μm. A laser diode with a detector according to item 1 or 2.