JP2005191074A - Rare earth element-added semiconductor optical amplifier and optical switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rare earth element-added semiconductor optical amplifier which can be used to amplify a femtosecond laser and which can amplify an ultrashort pulse. <P>SOLUTION: The rare earth element-added semiconductor optical amplifier includes a rare earth element-added semiconductor optical waveguide 1, and electrodes 2, 2 for applying a voltage to the semiconductor optical waveguide 1, thereby moving the charge injected in the semiconductor waveguide 1 by applying the voltage to the rare earth element to excite to amplify a signal light propagating through the semiconductor waveguide 1. Since an amplifying band width is determined according to the energy level of the rare earth element, the amplifying band width is wide and the optical amplifier can amplify even the femtosecond laser beam having wide spectral band width. Since the waveguide can be thickened, the ultrashort pulse can be amplified. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  Lasers are applied in a wide range of technical fields such as information communication, measurement, medical care, and processing. In that case, it is necessary to amplify or switch laser light generated from the laser. As optical amplifiers, rare earth element doped fiber amplifiers and semiconductor amplifiers are known. As an optical switch, one using a nonlinear optical crystal or a semiconductor is known. The present invention relates to a semiconductor optical amplifier and a semiconductor optical switch.

As semiconductor optical amplifiers, amplifiers using various semiconductors are known. For example, as a 1.5 μm band amplifier, an amplifier using a compound semiconductor (InGaAsP) is known (for example, see Patent Document 1). Further, in the conventional semiconductor amplifier, the active layer (waveguide portion) through which the signal light pulse propagates is thin (˜1 μm), and the power of the signal light pulse is limited because it is destroyed when the ultrashort pulse light is amplified. Furthermore, the conventional semiconductor optical amplifier has a very short carrier lifetime of several nanoseconds and is not suitable for the amplification of repetitive pulses from a pulse laser. That is, since the carrier lifetime is short, spontaneous emission occurs before the next pulse (signal light pulse) arrives, and ASE (Amplified Stimulated Emission) occurs. When ASE occurs, the signal light pulse spreads to the short wavelength side, and the spectrum of the signal light pulse deteriorates. When trying to amplify a femtosecond laser with a relatively wide spectral bandwidth,
There was a problem that the pulse width widened due to material dispersion.

On the other hand, it is known that when a voltage is applied to a semiconductor active layer to which Er is added, charge transfer occurs and Er emits light (for example, see Non-Patent Document 1).
JP 2002-372691 A Xinwei Zhao, et.al., Fabrication and stimulated emission of Er-doped nanocrystalline Si waveguides formed on Si substrates by laser ablation, Applied Physics letters, January 4, 1999, Vol. 74, No. 1, pp. 120- 122

  As mentioned in the background art above, conventional semiconductor optical amplifiers have a narrow amplification bandwidth and cannot be used for amplification of femtosecond lasers. There were problems that the spectrum was short and the pulse width was widened due to material dispersion.

  The present invention has been created to solve such problems. That is, an object of the present invention is to provide a rare earth element-doped semiconductor optical amplifier which can be used for amplification of a femtosecond laser and can amplify an ultrashort pulse. Another object of the present invention is to provide a rare earth element-doped semiconductor optical amplifier that compensates for the spread of the pulse width without degradation of the spectrum. Still another object of the present invention is to provide an optical switch using a rare earth element doped semiconductor optical amplifier.

  The invention according to claim 1 made to solve this problem includes a rare earth element-doped semiconductor optical waveguide (active layer) and an electrode for applying a voltage to the semiconductor optical waveguide. It is characterized in that the electric charge injected into the semiconductor waveguide by application is moved to the rare earth element and excited to amplify the signal light propagating through the semiconductor waveguide.

  The rare earth element-doped semiconductor optical amplifier of the present invention having such characteristics is wide because the amplification bandwidth is determined by the energy level of the rare earth element, and can be amplified even by femtosecond laser light having a wide spectrum bandwidth. Further, since the waveguide portion can be made thick, it is possible to amplify ultrashort pulses.

  The invention according to claim 2 is the rare earth element-doped semiconductor optical amplifier according to claim 1, wherein the rare earth element is at least one of Er, Yb, and Nd.

  At least one of abundant 1.5 μm band laser, 1.0 μm band laser, and 1.06 μm band laser can be amplified.

  The invention according to claim 3 is the rare earth element-doped semiconductor optical amplifier according to claim 1 or 2, wherein the semiconductor optical waveguide section has a chirped Bragg grating that compensates for chromatic dispersion. .

  Even if the signal light is pulse light having a wide spectrum width, it is possible to prevent the pulse width from widening.

  The invention according to claim 4 is the rare-earth-element-doped semiconductor optical amplifier according to claims 1 to 3, wherein the semiconductor optical waveguide section is a pair of end faces orthogonal to the direction in which the signal light propagates. And at least one of the pair of end faces has a transmittance control layer for controlling the transmittance of light.

  By making the transmittance control layer an antireflection film, reflection loss at the end face can be reduced. The transmittance control layer on one end face is an antireflection film, and the transmittance control layer on the other end face is a high reflection film, so that signal light is incident from one end face and the semiconductor waveguide is double-passed to be larger. The amplified signal light can be emitted.

  The invention according to claim 5 is the rare earth element-doped semiconductor optical amplifier according to claim 4, wherein the end face of the pair of end faces from which the signal light is emitted has a wavelength filter layer. It is said. In particular, the wavelength filter layer cuts light having a shorter wavelength than the signal light incident on the semiconductor optical waveguide.

  The short wavelength side that has spread due to the generation of ASE can be cut.

  The invention according to claim 6 is the rare earth element-doped semiconductor optical amplifier according to claim 4 or 5, wherein one of the pair of end faces has a chirped mirror or a chirped Bragg grating that compensates for chromatic dispersion. It is characterized by.

  Signal light can be incident from the other end face, and the semiconductor waveguide can be double-passed to emit more amplified signal light, and the pulse width can be widened by dispersion even if the signal light is pulse light with a wide spectral width. Can be prevented.

  The invention according to claim 7 is the rare-earth-element-doped semiconductor optical amplifier according to claim 4 or 5, wherein the signal light is incident at a predetermined angle from one of the pair of end faces, and the signal light is The semiconductor waveguide portion is configured to be multi-reflected between the end faces of the semiconductor and to be multipathed.

  Since the signal light multipaths in the waveguide section, the amplification factor can be increased.

  The invention according to claim 8 is the rare earth element-doped semiconductor optical amplifier according to any one of claims 4 to 7, wherein an end face of the pair of end faces on which the signal light is incident has a pulse width of the incident signal light. It is characterized by having a stretcher that stretches.

  Since the pulse width of the signal light pulse is expanded, the amplifier is not damaged even if the power is increased by amplification in the waveguide section.

  The invention according to claim 9 is the rare earth element-doped semiconductor optical amplifier according to any one of claims 4 to 8, wherein an end face of the pair of end faces from which the signal light is emitted has a pulse width of the emitted signal light. It has the compressor which compresses.

  Since the emitted signal light pulse is compressed, the pulse width spread by the material dispersion of the waveguide can be restored. Further, since the pulse width of the emitted signal light is compressed, the pulse width of the incident signal light can be extended in order to prevent damage due to the signal light power.

  A tenth aspect of the present invention is the rare earth element-doped semiconductor optical amplifier according to the eighth or ninth aspect, wherein the stretcher and the compressor are chirp Bragg gratings, and at least one of them is a chirp amount variable type chirp Bragg grating. It is characterized by being.

  The pulse width of the signal light can be arbitrarily changed by changing the chirp amount.

  The invention according to claim 11 is a rare earth element-added semiconductor optical switch, a rare earth element-added semiconductor optical waveguide section, an electrode for applying a voltage to the semiconductor optical waveguide section, and a voltage control for ON-OFF controlling the voltage. And amplifying the signal light propagating through the semiconductor optical waveguide by moving the electric charge injected into the semiconductor optical waveguide by the voltage control means ON to the rare earth element, and controlling the voltage. The signal light propagating through the waveguide is absorbed by the means OFF.

  The signal light can be turned on and off by turning on and off the voltage control means.

  The semiconductor optical amplifier of the present invention is wide because the amplification bandwidth is determined by the energy level of the rare earth element, and can be amplified even by femtosecond laser light having a wide spectrum bandwidth.

  Further, the waveguide portion of the semiconductor optical amplifier of the present invention has a chirped Bragg grating that compensates for chromatic dispersion, thereby preventing the pulse width from being widened even if the signal light is pulsed light.

  Furthermore, the optical waveguide part of the semiconductor optical amplifier of the present invention has a pair of end faces orthogonal to the direction in which the signal light propagates, and at least one end face has a transmittance control layer for controlling the light transmittance, By making the transmittance control layer an antireflection film, reflection loss at the end face can be reduced. By setting the transmittance control layer on one end face as an antireflection film and the other end face as a highly reflective film, signal light can be incident from one end face and emitted amplified signal light can be emitted. Can be doubled.

  The semiconductor optical waveguide of the semiconductor optical amplifier of the present invention has a wavelength filter layer shorter than the signal light incident on the semiconductor optical waveguide by making the end face from which the signal light is emitted have a wavelength filter layer. Therefore, it is possible to cut the short wavelength side of the signal light pulse spread by the generation of ASE.

  In addition, the semiconductor optical amplifier of the present invention has one end face having a chirp mirror or chirp Bragg grating that compensates for chromatic dispersion, so that signal light is incident from the other end face and emitted amplified signal light is emitted. In addition, even if the signal light is pulsed light, it is possible to prevent the pulse width from spreading due to dispersion.

  Furthermore, in the semiconductor optical amplifier of the present invention, components are arranged so that signal light is incident at a predetermined angle from one end face, and the signal light is multi-reflected between the pair of end faces and multipaths in the semiconductor waveguide. By doing so, the amplification factor can be further increased.

  In the semiconductor optical amplifier according to the present invention, the end face on which the signal light is incident has an expansion element so that the pulse width of the signal light pulse is expanded. Will not be damaged.

  In the semiconductor optical amplifier of the present invention, since the signal light pulse to be emitted is compressed by making the end face from which the signal light is emitted have a compression element, the pulse width spread by the material dispersion of the waveguide portion is used. Can be returned. Further, since the pulse width of the emitted signal light is compressed, the pulse width of the incident signal light can be extended in order to prevent damage due to the signal light power.

  In the semiconductor optical amplifier of the present invention, the pulse width of the signal light can be arbitrarily changed by using the chirped Bragg grating as the expansion element and the compressing element and the chirped Bragg grating having at least one chirp amount.

  Furthermore, the semiconductor optical switch of the present invention can turn on / off the signal light by turning on / off the voltage control means.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a schematic cross-sectional view of a rare earth element-doped semiconductor optical amplifier showing an embodiment of the present invention. As shown in this figure, in the optical amplifier, a rare earth element-doped semiconductor optical waveguide portion 1 (hereinafter abbreviated as waveguide portion 1) as a core is sandwiched between a p-type semiconductor clad layer 10 and an n-type semiconductor clad layer 10 ′. Further, a p-type electrode 2 having an electrode pad 21 and an n-type electrode 2 ′ having an electrode pad 21 ′ are laminated on the outer side. The waveguide section 1 has a chirped Bragg grating 3 in which the grating interval gradually increases in the propagation direction of the signal light, and has end faces 4 and 4 ′ that are orthogonal to the propagation direction of the signal light at both ends of the waveguide section 1. Each end face 4, 4 ′ is provided with a transmittance control layer 5, 5 ′.

  The rare earth element and the semiconductor of the rare earth element-doped semiconductor waveguide 1 are related to the wavelength band of signal light. For example, Er is transmitted in the 1.5 μm band, Yb is transmitted in the 1.0 μm band, and the signal light wavelength is transmitted. It may be added to a semiconductor having a band gap. As the semiconductor having a band gap that transmits signal light having a wavelength longer than the 1.0 μm band, GaAs, InGaAsP, or the like can be used. When the addition concentration of the rare earth element is increased, the amplification gain is increased. However, when the addition concentration is increased, concentration quenching occurs. In order to suppress concentration quenching and add a rare earth element at a high concentration, oxygen may be added together.

  As will be described later, since the semiconductor optical amplifier is made by growing a semiconductor crystal, the semiconductor of the cladding layers 10 and 10 ′ needs to be selected according to the semiconductor of the waveguide section 1. That is, for the cladding layers 10 and 10 ', p-type GaAs, n-type GaAs, p-type GaInP, n-type GaInP, or the like may be used when the waveguide 1 is GaAs. When the waveguide 1 is InGaAsP, the cladding layers 10 and 10 'may be p-type InP and n-type InP, respectively. When the signal light is collimated light, the confinement of the signal light in the waveguide section 1 may be weak, so the cladding layers 10 and 10 'may be omitted.

  The transmittance control layers 5 and 5 ′ in FIG. 1 are antireflection films, and can reduce reflection loss when signal light is incident on the end surface 4 and emitted from the end surface 4 ′ to a negligible level. The antireflection film can be formed by alternately laminating substances having different refractive indexes, for example, SiO 2 and TiO 2 with a predetermined film thickness.

  A method for manufacturing a semiconductor optical amplifier in the case where the waveguide portion 1 is Er-doped GaAs will be described below. First, a chirped Bragg grating 3 is manufactured by exposing a diffraction grating photomask on the p-type GaAs clad layer 10 for close exposure and etching. Next, GaAs is grown on the p-type GaAs cladding layer 10 on which the chirped Bragg lattice 3 is formed by a predetermined film thickness by MOCVD (metal organic chemical vapor deposition), MBE (molecular beam crystal growth) or the like. Next, Er and O are added onto the GaAs by a predetermined amount by ion plantation, laser ablation, or the like, thereby producing an Er-doped GaAs waveguide 1. Next, an n-type GaAs clad layer 10 ′ is formed on the Er-doped GaAs waveguide 1 with a predetermined film thickness by MOCVD or the like. Next, the p-type electrode 2 is formed on the p-type GaAs cladding layer 10 side, the n-type electrode 2 'is formed on the n-type GaAs cladding layer 10' side, and Au electrode pads 21, 21 'are formed by sputtering or the like. .

  The end surfaces 4 and 4 ′ are formed by cleaving the end portion of the waveguide portion 1 or polishing the end portion. The antireflection films 5, 5 'are formed by sputtering SiO2 and TiO2 alternately on the end faces 4, 4' so as to have the same film thickness.

  FIG. 1 described above is a schematic cross-sectional view of the rare earth element-doped semiconductor optical amplifier according to the first embodiment of the present invention. That is, the rare earth element-doped semiconductor waveguide 1 as a core is sandwiched between a p-type semiconductor clad layer 10 and an n-type semiconductor clad layer 10 ′, and further has a p-type electrode 10 and an electrode pad 21 ′ having an electrode pad 21 on the outer side. Are stacked. The waveguide section 1 has a chirped Bragg grating 3 whose grating spacing gradually increases in the propagation direction of signal light designed to compensate for material dispersion of the waveguide section 1, and propagation of signal light at both ends of the waveguide section 1. It has end faces 4, 4 'perpendicular to the direction. Each end face 4, 4 ′ is provided with an antireflection film 5, 5 ′ as a transmittance control layer.

The semiconductor waveguide 1 is a GaAs active layer to which Er is added at 10 ²⁰ co / cm ³ , and the cladding layers 10 and 10 ′ are p-type GaInP and n-type GaInP, respectively. The electrodes 2 and 2 'are p-type GaAs and n-type GaAs, respectively, and the electrode pads 21 and 21' are Au. The antireflection films 5 and 5 ′ are multilayer films of SiO2 and TiO2.

  When signal light having a wavelength of 1.5 μm, a spectral width of 10 nm, a pulse width of 300 fs, and a peak power of 2 KW is incident with a predetermined DC voltage applied to the electrode pads 21 and 21 ′, an output with a pulse width of 300 fs and a peak power of 3 KW is made. Signal light was obtained. Note that the spectrum width of the outgoing signal light was 12 nm with an extension to the short wavelength side seen according to ASE.

  FIG. 2 is a schematic cross-sectional view of a rare earth element-doped semiconductor optical amplifier according to the second embodiment. The optical amplifier of the second embodiment is characterized in that the antireflection film 5 of the optical amplifier of the first embodiment is a chirp mirror 7 and the chirped grating 3 is eliminated, and the wavelength filter 6 is mounted on the antireflection film 5 ′. Except for the difference, the optical amplifier is the same as that of the first embodiment.

  The chirp mirror 7 is a multilayer film of SiO2 and TiO2 whose film thickness gradually increases in the direction away from the end face 4, and the film thickness is designed so as to increase the reflection diffraction efficiency. The wavelength filter 6 is a normal interference filter type optical filter, and is a long-pass filter with a cutoff wavelength of 1.495 μm. As the wavelength filter 6, a Fabry-Perot etalon or a semiconductor can be used. Since the semiconductor cuts light having a wavelength shorter than the wavelength corresponding to the band gap energy, a semiconductor having a cutoff wavelength of 1.495 μm may be formed on the antireflection film 5 ′ to form the wavelength filter 6. For example, the cutoff wavelength can be controlled by controlling the composition of GaAs and InP of InGaAsP.

  When signal light having a wavelength of 1.5 μm, a spectral width of 10 nm, a pulse width of 300 fs, and a peak power of 2 KW is incident on the electrode pads 21 and 21 ′ from the end face 4 ′ side, a pulse width of 300 fs, Outgoing signal light having a peak power of 4.5 KW was obtained from the same end face 4 ′ side. The spectrum width of the obtained signal light was 10 nm which is the same as the incident signal light.

  FIG. 3 is a schematic cross-sectional view of the rare earth element-doped semiconductor optical amplifier according to the third embodiment, and FIG. 4 is a cross-sectional view taken along line AA of FIG. In the optical amplifier of the third embodiment, the antireflection film 5 of the optical amplifier of the first embodiment is changed to a chirp amount variable negative chirp Bragg grating (extension element) 8, and the antireflection film 5 'is changed to a chirp amount variable positive chirp Bragg grating (compression element). ) 9 and the point that the chirp Bragg grating 3 is eliminated and as can be seen from FIG. This is the same as the optical amplifier of the first embodiment except that the diffracted light due to is subjected to multiple reflection at the end faces 4 and 4 '. When the antireflection films 5 and 5 'are used instead of the expansion element 8 and the compression element 9 as in the first embodiment (FIG. 1), the signal light needs to be incident in the direction of the dotted arrow.

  The chirp variable negative chirp Bragg grating 8 includes a multilayer film 81 of SiO2 and TiO2 whose thickness gradually decreases in the direction in which the signal light propagates, and a platinum resistance heater 82, and the film thickness of the multilayer film 81 has a transmission diffraction efficiency. Is designed to be high. The chirp amount variable positive chirp Bragg grating 9 includes a multilayer film 91 of SiO2 and TiO2 and a platinum resistance heating body 92 whose film thickness gradually increases in the direction in which signal light propagates. Is designed to be high. By adjusting the current flowing through the platinum resistance heaters 82 and 92 to adjust the temperature of the multilayer films 8 and 9, the lattice spacing can be changed.

  As the chirp amount variable chirp Bragg grating, in addition to the above, a chirp Bragg grating may be formed in the semiconductor waveguide, and an electric field may be applied to change the chirp amount. Alternatively, periodic polarization that chirps by poling or the like may be formed in an electro-optic crystal such as LiNbO3, and the period may be electrically changed.

  In this embodiment, the expander and the compressor are chirped Bragg gratings, but ordinary prism pairs and diffraction grating pairs may be used.

  Platinum is applied so that a predetermined DC voltage is applied to the electrode pads 21, 21 ′, the pulse width of the signal light is doubled by the negative chirp Bragg grating 8, and the original pulse width is compressed by the positive chirp Bragg grating 9. When the current flowing through the resistance heating elements 82 and 92 is adjusted, signal light having a wavelength of 1.5 μm, a spectral width of 10 nm, a pulse width of 300 fs, and a peak power of 2 KW is incident from the negative chirp Bragg grating 8 side. An outgoing signal light having a peak power of 6.75 KW was obtained. Although a peak power twice as high as that of Example 1 was obtained, the pulse width of the signal light propagating through the semiconductor waveguide 1 was extended twice, so that it was not damaged.

  This example is an example of the rare earth element-doped semiconductor optical switch of the present invention, and a schematic cross-sectional view is shown in FIG. The configuration of the optical switch of this embodiment is almost the same as that of the semiconductor amplifier of the first embodiment (FIG. 1), but the semiconductor optical waveguide section 1 does not have the chirped Bragg grating 3, and the voltage control means 11 Is different. That is, the rare earth element-doped semiconductor waveguide 1 as the core is sandwiched between the p-type semiconductor clad layer 10 and the n-type semiconductor clad layer 10 ′, and the p-type electrode 2 and electrode pad 21 ′ having the electrode pad 21 on the outer side thereof. Are stacked. Then, both ends of the waveguide section 1 have end faces 4, 4 ′ orthogonal to the propagation direction of the signal light, and each end face 4, 4 ′ is provided with an antireflection film 5, 5 ′ as a transmittance control layer. .

The semiconductor waveguide 1 is a GaAs active layer to which Er is added at 10 ²⁰ co / cm ³ , and the cladding layers 10 and 10 ′ are p-type GaInP and n-type GaInP, respectively. The electrodes 2 and 2 'are p-type GaAs and n-type GaAs, respectively, and the electrode pads 21 and 21' are Au. The antireflection films 5 and 5 ′ are multilayer films of SiO2 and TiO2.

  When the voltage applied to the electrode pads 21 and 21 'was turned on / off by the voltage control means 11 in a state where signal light having a wavelength of 1.5 μm was incident, emission of the signal light was observed only when the voltage was on. .

It is a schematic sectional drawing of the rare earth element addition semiconductor optical amplifier which shows one Embodiment of this invention. 6 is a schematic cross-sectional view of a rare earth element-doped semiconductor optical amplifier according to Example 2. FIG. 6 is a schematic cross-sectional view of a rare earth element-doped semiconductor optical amplifier according to Example 3. FIG. FIG. 4 is a cross-sectional view taken along line AA in FIG. 3. 6 is a schematic cross-sectional view of a rare earth element-doped semiconductor optical switch according to Example 4. FIG.

Explanation of symbols

1 Rare earth element-doped semiconductor optical waveguide (active layer)
2, 2 'electrode 3 chirp Bragg grating 4, 4' end face 5, 5 'transmittance control layer 6 wavelength filter layer 7 chirp mirror 8 stretching element (chirp amount variable type chirp Bragg grating)
9 Compression element (variable chirp amount type chirp Bragg grating)
11 Voltage control means

Claims (11)

A rare earth element-doped semiconductor optical waveguide,
An electrode for applying a voltage to the semiconductor optical waveguide;
Have
A rare earth element-added semiconductor optical amplifier, which amplifies signal light propagating through the semiconductor optical waveguide by exciting the charge injected into the semiconductor optical waveguide by applying the voltage to the rare earth element. 2. The rare earth element-doped semiconductor optical amplifier according to claim 1, wherein the rare earth element is at least one of Er, Yb, and Nd. 3. The rare earth element-doped semiconductor optical amplifier according to claim 1, wherein the semiconductor optical waveguide section has a chirped Bragg grating that compensates for chromatic dispersion. The semiconductor optical waveguide section has a pair of end faces orthogonal to the direction in which the signal light propagates, and at least one of the pair of end faces has a transmittance control layer for controlling the light transmittance. 4. A rare earth element-doped semiconductor optical amplifier according to claim 1. 5. The rare earth element-doped semiconductor optical amplifier according to claim 4, wherein one of the pair of end faces from which the signal light is emitted has a wavelength filter layer. 6. The rare earth element-doped semiconductor optical amplifier according to claim 4, wherein one of the pair of end faces includes a chirped mirror or a chirped Bragg grating that compensates for chromatic dispersion. Arranging components such that signal light is incident at a predetermined angle from one of the pair of end faces, and the signal light is multi-reflected between the pair of end faces and multipaths in the semiconductor optical waveguide. 6. The rare earth element-doped semiconductor optical amplifier according to claim 4 or 5. 8. The rare earth element-doped semiconductor optical amplifier according to claim 4, wherein an end face of the pair of end faces on which the signal light is incident has a stretching element that stretches a pulse width of the incident signal light. . 9. The rare earth element-doped semiconductor optical amplifier according to claim 4, wherein an end face of the pair of end faces from which the signal light is emitted has a compression element that compresses a pulse width of the emitted signal light. . 10. The rare earth element-doped semiconductor optical amplifier according to claim 8, wherein the extension element and the compression element are chirp Bragg gratings, and at least one of them is a chirp amount variable type chirp Bragg grating. A rare earth element-doped semiconductor optical waveguide,
An electrode for applying a voltage to the semiconductor optical waveguide;
Voltage control means for on-off control of the voltage;
Have
When the voltage control means is turned on, the electric charge injected into the semiconductor optical waveguide is moved to the rare earth element to excite and amplify the signal light propagating through the semiconductor optical waveguide, and when the voltage control means is turned off, the waveguide A rare earth element-added semiconductor optical switch characterized by absorbing signal light propagating through the substrate.

Images