KR20010073734A - Waveguide-type optical thyristor - Google Patents

Abstract

PURPOSE: A waveguide-type optical thyristor is provided to enable a fast switching, maximize characteristic of a unitary device and increase optical absorption efficiency and lasing effect. CONSTITUTION: An N+ layer having a larger energy band gap is connected to a grounding metal. A p layer having a smaller energy band gap is grown in a stacked structure on an upper part of an electrode semiconductor layer. An n layer having a smaller energy band gap is grown in a stacked structure on an upper part of the p layer. A P+ layer having a larger energy band gap is grown in a stacked structure on an upper part of the n layer. The N+ layer is connected to the earth and includes a substrate. The first thyristor is structured in a waveguide form which has four layers of P+-n-p-N+ on a left side of the substrate. The second thyristor is structured in a waveguide form which has four layers of P+-n-p-N+ on a right side of the substrate. A metal film is connected to a load resistance which is connected to a battery to receive a predetermined voltage, and is installed on the P+ layers of the second thyristor and the first thyristor.

Description

Waveguide Optical Thyristors {Waveguide-type optical thyristor}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveguide optical thyristor, and more particularly to a waveguide optical thyristor which is a high speed optical switching device capable of operating a laser diode (LD) in the development of an optical communication device.

In general, an optical thyristor is a P + -np-N + device having a vertical surface radiation structure having four layers as shown in FIG. 1, and an optical thyristor is shown in FIG. It is a bipolar element having nonlinear current-voltage characteristics. This satisfies the switching device's ability to achieve dual stability with increasing or decreasing voltage.

In the operation method of the optical thyristor, when the forward voltage is applied, the reverse voltage of the center region is applied to maintain a kind of off state in which the current is extremely fine compared to the applied voltage. When a predetermined voltage or more is applied thereto, the current rapidly increases due to voltage breakdown and transitions to the on state, thereby emitting light in the on state. In addition, when light is applied to the intermediate region for switching, it acts as a photocurrent and contributes to voltage breakdown.

When the optical thyristor element is implemented as a circuit, the connection point with the load line becomes the operating point (A, B) of the circuit. However, until recently, the problem with this device was that the switching time was very long (a few ms) by recombination of excess transmitters trapped in the middle region. As a solution to this problem, a fully depleted optical thyristor has been proposed that removes excess transmitters by applying a reverse voltage pulse. In addition, a differential structure has been proposed for faster switching operation. The advantage of this structure is that it can be switched even with a small amount of light. Another advantage of the light thyristor is that light emission and light reception can be realized as one device. The operation of the optical thyristor receives light when no voltage pulse is applied as shown in FIG. At this time, even if a slight light enters a voltage pulse, a winner-takes-all operation that emits light occurs. The improved optical thyristor proposed up to now has been developed into a reverse voltage and differential structure, and an easy light receiving and emitting structure. These optical thyristors have been recognized as suitable devices for structures such as parallel optical interconnection using optical switching because of the advantages that they can be integrated and can be switched by using a small amount of light.

Most of the currently proposed optical thyristors are used for parallel optical connection of short wavelength (800 nm) using GaAs-based materials as vertical surface emission structures. In the case of the above vertical surface optical thyristor, the LED is generally operated in an on state.

However, for high speed switching, a structure that enables the operation of a laser diode having a good frequency characteristic is essential. At present, the optical switching device capable of LD operation is absolutely necessary in the development of the optical communication device, which is rapidly expanding.

The present invention has been proposed to solve the above problems of the prior art, and an object of the present invention is to provide an optical thyristor structure in order to enable fast switching used in optical communication. It is necessary to enable lasing and maximize the characteristics as a single device by converting it into a waveguide form, so that the intermediate layer serving as the active layer region uses bulk material and multiple quantum wells (MQW). In two cases, the degree of doping and thickness of each layer should be adjusted for optimum performance in consideration of the increase of the characteristics and light absorption efficiency and the lasing effect. One-dimensional multi-array light by integrating optical thyristors to meet various conditions to enable lasing Provided is a waveguide optical thyristor considering the fabrication degree of a switching device.

1 is a structure of a conventional basic optical thyristor.

2 is a current-voltage characteristic curve of a typical optical thyristor.

3 is an example of a switching cycle timing diagram of a differential composition optical thyristor.

4 is a structure of a waveguide optical thyristor of a differential structure according to the present invention.

5 is an example of an epilayer structure according to the present invention.

Explanation of symbols on the main parts of the drawings

V: Voltage RL: Load Resistance

PMMA: polymide

In order to achieve the above object, the present invention provides an optical switching device system for optical communication, comprising: an N + layer connected to ground and composed of a conductor; A first thyristor configured in the form of a waveguide formed of four layers of P + -n-p-N + on the left side of the conductor; A second thyristor configured in the form of a waveguide having four layers of P + -n-p-N + on the right side of the conductor; The first thyristor and the first thyristor, which are connected to the load resistor RL connected to the battery V to be provided with a constant voltage, are commonly connected to each other, and are differentially applied in a double heterojunction structure of P + -np-N +. A metal film installed in H type on the P + layer of 2 thyristor; And a polyamide (PMMA) that guides light to prevent light from leaking from the left and right sides of the first and second thyristors.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 is a structure of a waveguide optical thyristor according to the present invention. Referring to FIG. 4, the optical thyristor proposed in the present invention is an edge-emitting structure having four layers. P + -n-n-N + is a double heterojunction structure and differential method is applied. In this case, each single thyristor is configured in the form of a waveguide, and electrodes are connected in common.

It shows nonlinear voltage-current characteristics like conventional thyristors, and its operation is the same as that of conventional thyristors. A fully depleted light thyristor is realized by using a reverse voltage pulse, and as a differential structure, the winner takes the higher intensity of light by the intensity of light incident on both sides. all)

As a dual heterojunction structure, efficiency improvement due to optical confinement and carrier confinement can be expected. At this time, waveguide such as Fabry-Perot of conventional LED and laser diode (LD) The structure of the waveguide type has the advantage of easy lasing due to the relatively long active layer as well as reflectance due to the dielectric constant difference from the outside on both sides.

Both P + and N + have a large energy bandgap, which allows the transmitters to diffuse into the middle layer to help the population inversion occur. This results in lasing which improves the frequency characteristics and thus the switching speed.

The Fabry-Perot type can induce high light absorption and greatly improve light reception efficiency and light output efficiency. In addition, when the intermediate layer is used as a multi-quantum well, the absorption rate is increased due to the exciton effect, thereby achieving higher efficiency.

5 shows an example of an epilayer structure according to the present invention.

The waveguide optical thyrister according to the present invention is applied in a differential manner with a double heterojunction structure, and a second thyristor is provided on the right side of the first thyristor on the left side of the conductor of the N + layer. Form.

The first thyristor is a high density doped InP layer connected to ground with the conductor, an N + layer doped with 1e18N + -InP (500nm) on the InP layer, and 2e17P-InP (300nm) on the N + layer. P layer doped with) and doped with 1e17p-InGaAsP (200 nm) thereon, N layer doped with 1e17n-InGaAsP (200 nm) over the P layer and 2e17N-InP (300 nm) thereon, 1e18P + over the N layer A P + layer doped with InP (500 nm), and a P + -InGaAs (100 nm) layer doped over the P + layer and bonded to the metal film.

The second thyristor may include a highly doped InP layer connected to the ground through the conductor; An N + layer doped with 1e18N + -InP (500nm) over the InP layer, 2e17P-InP (300nm) over the N + layer and a multiple quantum well (MQW) of 1e17p-InGaAsP / InP MQW thereon Doped P layer, doped with multiple quantum wells (MQW) of 1e17n-InGaAsP / InP MQW on the P layer and doped with 2e17N-InP (300nm) thereon, 1e18P + -InP (500nm) on the N layer And a P + -InGaAs (100 nm) layer bonded to the metal film and bonded to the P + layer.

Accordingly, the waveguide optical thyrister can provide a high speed optical switching function capable of laser diode (LD) operation in the development of optical communication devices.

As described above, the waveguide optical thyristor according to the present invention presents a waveguide type optical thyristor capable of high speed lasing to improve the frequency characteristics to improve switching speed. Optical hard-limiter, ATM packet header processing that induces high optical absorption, greatly improving optical reception efficiency and optical output efficiency, and maintains constant amplitude by providing high speed optical switching device in optical communication It can be applied to many optical communication applications such as optical ATM packet switching.

While the foregoing has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

Claims (2)

In a thyristor semiconductor device having a multilayer structure, An N + layer having a large energy band gap connected to the ground metal; A p layer having a small energy band gap grown in a stacked structure on the electrode semiconductor layer; An n-layer having a small energy band gap grown in a stacked structure on the p-layer; And a P + layer having a large energy band gap grown in a stacked structure on the n-layer. The method of claim 1, wherein the high speed optical switching device system An N + layer connected to ground and composed of a conductor; A first thyristor configured in the form of a waveguide formed of four layers of P + -n-p-N + on the left side of the conductor; A second thyristor configured in the form of a waveguide having four layers of P + -n-p-N + on the right side of the conductor; The first thyristor and the first thyristor, which are connected to the load resistor RL connected to the battery V to be provided with a constant voltage, are commonly connected to each other, and are differentially applied in a double heterojunction structure of P + -np-N +. A metal film placed on the P + layer of the two thyristors; And Waveguide light having a differential structure, characterized in that the optical refractive index of air or polyamide (PMMA) that guides light on the left and right sides of the first and second thyristors is smaller than the refractive index of the semiconductor. Thyristor.