JP4598382B2 - Optical logic unit - Google Patents

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JP4598382B2
JP4598382B2 JP2003359226A JP2003359226A JP4598382B2 JP 4598382 B2 JP4598382 B2 JP 4598382B2 JP 2003359226 A JP2003359226 A JP 2003359226A JP 2003359226 A JP2003359226 A JP 2003359226A JP 4598382 B2 JP4598382 B2 JP 4598382B2
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JP2005122031A (en
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浩 福田
浩治 山田
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Nippon Telegraph and Telephone Corp
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本発明は、光反転器として用いることができる光論理演算のための光論理演算器に関するものである。   The present invention relates to an optical logic unit for optical logic operation that can be used as an optical inverter.

近年の光エレクトロニクス技術の進歩はめざましいものがあり、この技術の範囲は、光通信を中心にセンシングやコンピューティングにまでおよんでいる。光エレクトロニクスを応用した光コンピュータの実現にあたっては、電気回路が介在することが無く、信号光を制御光で制御する光−光制御による方法が注目され、これまでも、光−光制御の高度化のための検討が進められている。   Recent advances in optoelectronic technology are remarkable, and the scope of this technology extends to sensing and computing, centering on optical communications. In the realization of optical computers that apply optoelectronics, light-light control methods that control signal light with control light without any electrical circuit have been attracting attention. Consideration is underway.

光−光制御の方法の代表としては、吸収飽和型半導体素子を用いる方法や側面入射双安定レーザダイオードを用いる方法(非特許文献1参照)がある。また、偏光面の異なる2つの光でセットリセット(set-reset)を行う方法(非特許文献2参照),エルビウムイオンの非線形負性吸収を用いる方法(非特許文献3参照)などがある。これら方法による光論理素子の動作も報告されている。しかしながら、これらの技術では、素子サイズが大きくなり、高密度集積化には不向きである。   Typical examples of the light-light control method include a method using an absorption saturation type semiconductor element and a method using a side-incident bistable laser diode (see Non-Patent Document 1). In addition, there are a method of performing set-reset with two lights having different polarization planes (see Non-Patent Document 2), a method using nonlinear negative absorption of erbium ions (see Non-Patent Document 3), and the like. The operation of optical logic devices by these methods has also been reported. However, these technologies increase the element size and are not suitable for high-density integration.

また、光−光制御の方法として、非線形光学素子を用いた方法も多く検討されている。非線形光学素子を用いた方法では、光の強度に対する屈折率や吸収係数の変化により、光−光制御を可能としている。しかしながら、これらの効果は、物質の3次の分極により生じるため、非線形定数の大きな非線形光学結晶と同時に、尖頭値の高い高出力パルスレーザ光源を必要とするので、実用的な光集積デバイスを実現するためには、さらなる高効率化が必要となる。   In addition, many methods using nonlinear optical elements have been studied as light-light control methods. In the method using a non-linear optical element, light-light control is enabled by a change in refractive index and absorption coefficient with respect to light intensity. However, since these effects are caused by the third-order polarization of the material, a high-power pulsed laser light source with a high peak value is required simultaneously with a nonlinear optical crystal having a large nonlinear constant. In order to realize this, further high efficiency is required.

また、基礎的な検討として、化合物半導体光導波路の二光子吸収を利用した光スイッチ(非特許文献4参照)などが報告されており、これらの検討を元に、シリコンフォトダイオードの二光子吸収を利用したオートコリレータ(非特許文献5参照)、シリコンCCDカメラを用いたオートコリレータ(非特許文献6参照)、シリコンフォトダイオードの二光子吸収を利用したリフレクトメータ(非特許文献7参照)などの実用的なデバイスや装置の報告もある。しかしながら、これらは、大がかりな装置群が必要であると同時に、素子サイズが大きいため、光集積回路への適応報告はまだ無い。
なお、出願人は、本明細書に記載した先行技術文献情報で特定される先行技術文献以外には、本発明に関連する先行技術文献を出願時までに発見するには至らなかった。
K.Nonaka, H.Tsuda, H.Uenofara, H.Iwamura, and T.Kurokawa "Optical Nonlinear Characteristics of a Side-injection Light-controlled Laser Diode with a Multiple-quantum-well Saturable Absorption Region",IEEE PHOTONICS TECHNOLOGY LETTERS, VOL.5, NO.2, pp139-141, FEBRUARY 1993. H.Kawaguchi and T.Irie "OPTICALLY TRIGGERED POLARISATION BISTABLE SWITCHING IN LASER DIODES WITH EXTERNAL CAVITIES", ELECTRONICS LETTERS, Vol.28, No.17, pp1645-1647, 13th August 1992. Y.Maeda "All-optical NAND logic device operating at 1.51-1.55μm in Er-doped aluminosilicate glass", ELECTRONICS LETTERS, Vol.35, No.7, pp582-584, 1st April 1999. H.K.TSANG, R.S.GRANT, R.V.PENTY, I.H.WHITE, J.B.D.SOOLE, E.COLAS, H.P.LEBLANC, N.C.ANDREADAKIS, M.S.KIM, W.SIBBETT, "GaAs/GaAlAs MULTIQUANTUM WELL WAVEGUIDES FOR ALL-OPTICAL SWITCHING AT 1.55μm" , ELECTRONICS LETTERS, Vol.27, No.22, pp1993-1994, 24th October 1991. C.Xu, J.M.Roth, W.H.Knox and K.Bergman, "Ultra-sensitive autocorrelation of 1.5μm light with single photon counting silicon avalanche photodiode", ELECTRONICS LETTERS, Vol.38, No.2, pp86-88, 17th January 2002. Dmitriy Panasenko and Yeshaiahu Fainman, "Interferometric correlation of infrared femtosecond pulses with two-photon conductivity in a silicon CCD", APPLIED OPTICS,Vol.41,No.18,pp3748-3752,20 June 2002. Y Tanaka,N Sako, T Kurokawa, H Tsuda, and M Takeda, "Profilometry based on two-photon absorption in a silicon avalanche photodiode",OPTICS LETTERS, Vol.28, No.6, pp402-404, 15 March 2003.
In addition, as a basic study, optical switches using two-photon absorption of compound semiconductor optical waveguides (see Non-Patent Document 4) have been reported. Based on these studies, two-photon absorption of silicon photodiodes has been reported. Practical use of an autocorrelator used (see Non-Patent Document 5), an autocorrelator using a silicon CCD camera (see Non-Patent Document 6), a reflectometer using two-photon absorption of a silicon photodiode (see Non-Patent Document 7), etc. There are also reports of typical devices and equipment. However, these require a large group of devices and at the same time have a large element size, so there are no reports of adaptation to optical integrated circuits.
The applicant has not yet found prior art documents related to the present invention by the time of filing other than the prior art documents specified by the prior art document information described in this specification.
K. Nonaka, H. Tsuda, H. Uenofara, H. Iwamura, and T. Kurokawa "Optical Nonlinear Characteristics of a Side-injection Light-controlled Laser Diode with a Multiple-quantum-well Saturable Absorption Region", IEEE PHOTONICS TECHNOLOGY LETTERS , VOL.5, NO.2, pp139-141, FEBRUARY 1993. H. Kawaguchi and T. Irie "OPTICALLY TRIGGERED POLARISATION BISTABLE SWITCHING IN LASER DIODES WITH EXTERNAL CAVITIES", ELECTRONICS LETTERS, Vol.28, No.17, pp1645-1647, 13th August 1992. Y.Maeda "All-optical NAND logic device operating at 1.51-1.55μm in Er-doped aluminosilicate glass", ELECTRONICS LETTERS, Vol.35, No.7, pp582-584, 1st April 1999. HKTSANG, RSGRANT, RVPENTY, IHWHITE, JBDSOOLE, E.COLAS, HPLEBLANC, NCANDREADAKIS, MSKIM, W.SIBBETT, "GaAs / GaAlAs MULTIQUANTUM WELLGUIDE FOR ALL-OPTICAL SWITCHING AT 1.55μm", ELECTRONICS LETTERS, Vol. 22, pp1993-1994, 24th October 1991. C.Xu, JMRoth, WHKnox and K. Bergman, "Ultra-sensitive autocorrelation of 1.5μm light with single photon counting silicon avalanche photodiode", ELECTRONICS LETTERS, Vol.38, No.2, pp86-88, 17th January 2002. Dmitriy Panasenko and Yeshaiahu Fainman, "Interferometric correlation of infrared femtosecond pulses with two-photon conductivity in a silicon CCD", APPLIED OPTICS, Vol.41, No.18, pp3748-3752,20 June 2002. Y Tanaka, N Sako, T Kurokawa, H Tsuda, and M Takeda, "Profilometry based on two-photon absorption in a silicon avalanche photodiode", OPTICS LETTERS, Vol.28, No.6, pp402-404, 15 March 2003.

以上に説明したように、従来の光−光制御による光論理素子は、素子サイズが大きいことや効率があまり高くないために高出力の光源が必要となるなど、高集積化された光論理集積回路へ適用しにくいという問題があった。
本発明は、以上のような問題点を解消するためになされたものであり、素子サイズが小さく高密度集積が可能で、また、高い出力の光源を必要としない光論理演算器を提供することを目的とする。
As described above, the conventional optical logic device based on light-light control is highly integrated, such as a large-sized optical logic device that requires a high-output light source due to its large size and low efficiency. There was a problem that it was difficult to apply to circuits.
The present invention has been made to solve the above-described problems, and provides an optical logic unit that has a small element size and can be integrated at high density, and does not require a high-output light source. With the goal.

本発明に係る光論理演算器は、異なる光強度のオン状態とオフ状態とから構成されたビットパターンの波長が各々異なる複数の制御光と、これら制御光とは異なる波長の第2波長の信号光とを合波する合波回路と、シリコンからなるコアとこのコアより低い屈折率のクラッドとから構成され、合波回路で合波された光を導波する光導波路と、合波回路で合波されて光導波路を導波した光より、第2波長の光を取り出すろ波回路とを少なくとも備え、ビットパターンは、光導波路において二光子吸収が起こる光強度を境とした異なる光強度のオン状態とオフ状態とから構成されているものである。
この光論理演算器では、光導波路を導波する制御光が一方の光強度の状態では光導波路において多光子吸収が起こり、オン状態とオフ状態との2つの状態に変化する制御光で、光導波路を同時に導波する信号光が変調される。
The optical logic unit according to the present invention includes a plurality of control lights each having a different bit pattern wavelength composed of an on state and an off state having different light intensities, and a second wavelength signal having a wavelength different from these control lights. An optical waveguide configured to combine light, a core made of silicon, and a clad having a refractive index lower than that of the core. At least a filtering circuit that extracts light of the second wavelength from the light that has been combined and guided through the optical waveguide, and the bit pattern has different light intensities at the light intensity at which two-photon absorption occurs in the optical waveguide. a it shall consist of an oN state and an oFF state.
In this optical logic unit, multi-photon absorption occurs in the optical waveguide when the control light guided through the optical waveguide is in one light intensity, and the control light changes into two states, an on state and an off state. The signal light that is simultaneously guided through the waveguide is modulated.

上記光論理演算器において、合波回路の前段に設けられ、信号光及び制御光の光強度を減衰する減衰器を備えるようにしてもよい。 In the optical logic unit, provided before the multiplexer multiplexing circuit may be provided with an attenuator that attenuates the optical intensity of the signal light and control light.

また、本発明に係る他の光論理演算器は、異なる光強度のオン状態とオフ状態とから構成されたビットパターンの第1波長の第1制御光と、この第1制御光と異なる波長の第2波長の第2制御光と、第1制御光および第2制御光のいずれとも波長が異なる第3波長の信号光とを合波する合波回路と、シリコンからなるコアとこのコアより低い屈折率のクラッドとから構成され、合波回路で合波された光を導波する光導路と、合波回路で合波されて光導波路を導波した光より、第3波長の光を取り出すろ波回路とを少なくとも備え、ビットパターンは、光導波路において二光子吸収が起こる光強度を境とした異なる光強度のオン状態とオフ状態とから構成されているものである。 In addition, another optical logic unit according to the present invention includes a first control light having a first wavelength of a bit pattern composed of an on state and an off state having different light intensities, and a wavelength different from that of the first control light. A multiplexing circuit that multiplexes the second control light of the second wavelength and the signal light of the third wavelength different in wavelength from both the first control light and the second control light, a core made of silicon, and lower than this core A third wavelength light is extracted from an optical path configured by a clad having a refractive index and guiding light combined by the multiplexing circuit and light guided by the multiplexing circuit and guided through the optical waveguide. comprising at least a filtering circuit, the bit pattern is shall consist of a boundary of light intensity occurring two-photon absorption is different between on and off states of the light intensity in the optical waveguide.

以上説明したように、本発明によれば、シリコンコアからなる光導波路を用いるようにしたので、高密度集積化が容易であり、また、光導波路における光強度密度を高めることが容易であるので安価でハイブリッド実装が容易な、低出力半導体CWレーザなどを光源として用いることができるという優れた効果が得られる。   As described above, according to the present invention, since an optical waveguide made of a silicon core is used, high-density integration is easy, and it is easy to increase the light intensity density in the optical waveguide. An excellent effect is obtained in that a low-power semiconductor CW laser or the like that is inexpensive and easy to perform hybrid mounting can be used as a light source.

以下、本発明の実施の形態について図を参照して説明する。
図1は、本発明の実施の形態における光論理演算器である光反転器100の構成例を示す構成図である。この光反転器100は、シリコンのコアとこれより低屈折率のクラッドとから構成された光導波路101と、例えば方向性結合器(3dBカプラ)などの合波回路104と、例えばバンドパスフィルタなどのろ波回路105とから構成されたものである。
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram showing a configuration example of an optical inverter 100 that is an optical logic unit in the embodiment of the present invention. The optical inverter 100 includes an optical waveguide 101 composed of a silicon core and a clad having a lower refractive index, a multiplexing circuit 104 such as a directional coupler (3 dB coupler), and a bandpass filter. And the filtering circuit 105.

例えば、パタンジェネレータ102及び光変調器103によってビットパターンに変調した波長λ1(1.1μm<λ1<2.2μm)の制御光と、波長λ2(1.1μm<λ2<2.2μm)の連続光である信号光とが、合波回路104の入力側より入力され、合波回路104で合波されて出力する。出力した合波光は、光導波路101に入力される。 For example, the control light having the wavelength λ 1 (1.1 μm <λ 1 <2.2 μm) modulated into the bit pattern by the pattern generator 102 and the optical modulator 103 and the wavelength λ 2 (1.1 μm <λ 2 <2.2 μm). ) Is input from the input side of the multiplexing circuit 104, and is multiplexed by the multiplexing circuit 104 and output. The output combined light is input to the optical waveguide 101.

光導波路101に制御光もしくは信号光のいずれか一方のみを入力した場合、これら各々の波長がシリコンのバンドギャップより長いため、光の強度が低い場合は、光導波路101を透過(導波)して出力(出射)される。光導波路101を出射した光は、ろ波回路105を通ることで、信号光だけが取り出される。ろ波回路105により取り出された信号光の状態は、O/Eサンプリングオシロスコープ106により測定可能である。O/Eサンプリングオシロスコープ106は、ビットパターンの反転した光信号を測定する。   When only one of the control light and the signal light is input to the optical waveguide 101, each of these wavelengths is longer than the band gap of silicon, so that when the light intensity is low, the light is transmitted (guided) through the optical waveguide 101. Is output (emitted). The light emitted from the optical waveguide 101 passes through the filtering circuit 105, so that only the signal light is extracted. The state of the signal light extracted by the filtering circuit 105 can be measured by the O / E sampling oscilloscope 106. The O / E sampling oscilloscope 106 measures an optical signal having an inverted bit pattern.

ここで、シリコンコアの光導波路101は、波長1.1〜2.2μmの光であれば、コアの径を500nm以下としても導波させることが可能であり、この構成の光導波路101を導波する波長1.1〜2.2の光は、コア内で光強度が著しく大きくなる。この構造において、光導波路101を導波する制御光の強度を大きくし、この強度が所定値を超えると二光子吸収が起こり、キャリア(電子正孔対)が生成されて光吸収が起きる。なお、より強い光強度の光により、光導波路101においては、三光子吸収,四光子吸収・・と多光子吸収が起こる。   Here, the silicon core optical waveguide 101 can guide light even when the core diameter is 500 nm or less as long as the light has a wavelength of 1.1 to 2.2 μm. The light having a wavelength of 1.1 to 2.2 is remarkably increased in light intensity in the core. In this structure, the intensity of the control light guided through the optical waveguide 101 is increased, and when the intensity exceeds a predetermined value, two-photon absorption occurs, carriers (electron-hole pairs) are generated, and light absorption occurs. It should be noted that multi-photon absorption occurs in the optical waveguide 101 by three-photon absorption, four-photon absorption,...

従って、二光子吸収が起こる光強度を境に、これより小さい光強度をオフレベルとし、これより大きい光強度をオンレベルとしたビットパターンの制御光を光導波路101に入射させると、オンレベルでは二光子吸収が起きる状態となる。二光子吸収により生成されたキャリアは、信号光も吸収するため、制御光がオンレベルの際には、合波回路104で合波されて同時に入射した信号光も、光導波路101において吸収を受ける。   Therefore, when the control light of the bit pattern in which the light intensity lower than this is set to the off level and the light intensity higher than this is turned on at the light intensity where the two-photon absorption occurs is incident on the optical waveguide 101, Two-photon absorption occurs. Since the carrier generated by the two-photon absorption also absorbs the signal light, when the control light is on level, the signal light that is combined and incident at the same time by the combining circuit 104 is also absorbed by the optical waveguide 101. .

また、二光子吸収により生成された電子正孔対が再結合する場合、制御光の2倍のエネルギーの光を放出するが、光導波路101のコアを構成しているシリコンのバンドギャップよりエネルギーが大きいため、再結合により放出された光は、光導波路101を伝播することができない。従って、図1に示した光反転器100によれば、合波回路104によって信号光に合波させた制御光により、信号光を変調することができる。   In addition, when electron-hole pairs generated by two-photon absorption recombine, light having twice the energy of the control light is emitted, but the energy is larger than the band gap of silicon forming the core of the optical waveguide 101. Since it is large, the light emitted by recombination cannot propagate through the optical waveguide 101. Therefore, according to the optical inverter 100 illustrated in FIG. 1, the signal light can be modulated by the control light combined with the signal light by the multiplexing circuit 104.

図2は、制御光の波形を示した特性図である。図3は、制御光のみを入射したときにO/Eサンプリングオシロスコープ106で測定された制御光の波形を示した特性図である。また、図4は、制御光の入力ピーク強度を変化させた場合の、図3のB/Aの値をプロットした特性図である。なお、これら場合、光導波路101を出射した光を、ろ波回路105を介さずにO/Eサンプリングオシロスコープ106で測定した結果を示している。   FIG. 2 is a characteristic diagram showing the waveform of the control light. FIG. 3 is a characteristic diagram showing the waveform of the control light measured by the O / E sampling oscilloscope 106 when only the control light is incident. FIG. 4 is a characteristic diagram in which the values of B / A in FIG. 3 are plotted when the input peak intensity of the control light is changed. In these cases, the result of measuring the light emitted from the optical waveguide 101 with the O / E sampling oscilloscope 106 without passing through the filtering circuit 105 is shown.

図4より判るように、制御光の入力ピーク強度と透過率の逆数が比例関係にあり、図3に示す制御光の減衰が、光導波路101における二光子吸収であることを示している(文献:J.H.Bechtel and W.L.Smith,"Two-photon absorption in semiconductors with picosecond laser pulses", PHYSICAL REVIEW B, Vo.13, No.8, pp3515-3522, 15th APRIL 1976.)。   As can be seen from FIG. 4, the input peak intensity of the control light and the reciprocal of the transmittance are in a proportional relationship, indicating that the attenuation of the control light shown in FIG. 3 is two-photon absorption in the optical waveguide 101 (references). : JHBechtel and WLSmith, "Two-photon absorption in semiconductors with picosecond laser pulses", PHYSICAL REVIEW B, Vo.13, No.8, pp3515-3522, 15th APRIL 1976.).

制御光の減衰が起こる光ピーク強度の条件下では、二光子吸収によるキャリア(電子正孔対)の生成が生じており、電子正孔対が生成されている導波路に信号光が入射すると、信号光も減衰を受け、信号光は制御光によって反転変調を受ける。
図5は、制御光と信号光とを合波して光導波路101に入射したときに、O/Eサンプリングオシロスコープ106で測定された出力光信号(信号光)の波形を示したものである。また、図6は、図5における反転変調率(D/C)をプロットしたものである。
これらより明らかなように、入力ピーク強度が20mW程度(位置E)では、ほとんど反転動作を示さないが、入力ピーク強度が50mW程度(位置F)では、50%近くの変調を受けることが判る。
Under the condition of the light peak intensity where the control light is attenuated, the generation of carriers (electron-hole pairs) by two-photon absorption occurs, and when signal light enters the waveguide where the electron-hole pairs are generated, The signal light is also attenuated, and the signal light is subjected to inversion modulation by the control light.
FIG. 5 shows the waveform of the output optical signal (signal light) measured by the O / E sampling oscilloscope 106 when the control light and the signal light are combined and incident on the optical waveguide 101. FIG. 6 is a plot of the inversion modulation rate (D / C) in FIG.
As is apparent from these figures, when the input peak intensity is about 20 mW (position E), almost no reversal operation is shown, but when the input peak intensity is about 50 mW (position F), it can be seen that the modulation is about 50%.

次に、図1に示した光反転器100を構成する合波回路,ろ波回路の他の例について、図7を用いて説明する。
まず、図7(a)に示すように、光導波路101を出射した光より、光ラティスフィルタからなるろ波回路115で信号光を取り出すようにしてもよい。また、図7(b)に示すように、光導波路101を出射した光より、リング共振器よりなるろ波回路125で信号光を取り出すようにしてもよい。
Next, another example of the multiplexing circuit and the filtering circuit constituting the optical inverter 100 shown in FIG. 1 will be described with reference to FIG.
First, as shown in FIG. 7A, signal light may be extracted from light emitted from the optical waveguide 101 by a filtering circuit 115 including an optical lattice filter. Further, as shown in FIG. 7B, signal light may be extracted from the light emitted from the optical waveguide 101 by a filtering circuit 125 formed of a ring resonator.

また、図7(c)に示すように、光ラティスフィルタよりなる合波回路114で信号光と制御光とを合波し、光導波路101を出射した光より、ろ波回路115で信号光を取り出すようにしてもよい。また、図7(d)に示すように、合波回路114で信号光と制御光とを合波し、光導波路101を出射した光より、ろ波回路125で信号光を取り出すようにしてもよい。   Further, as shown in FIG. 7C, the signal light and the control light are multiplexed by the multiplexing circuit 114 formed of an optical lattice filter, and the signal light is output by the filtering circuit 115 from the light emitted from the optical waveguide 101. You may make it take out. Further, as shown in FIG. 7D, the signal light and the control light are multiplexed by the multiplexing circuit 114, and the signal light is extracted by the filtering circuit 125 from the light emitted from the optical waveguide 101. Good.

また、図7(e)に示すように、リング共振器よりなる合波回路124で信号光と制御光とを合波し、光導波路101を出射した光より、ろ波回路115で信号光を取り出すようにしてもよい。また、図7(f)に示すように、合波回路124で信号光と制御光とを合波し、光導波路101を出射した光より、ろ波回路125で信号光を取り出すようにしてもよい。   Further, as shown in FIG. 7E, the signal light and the control light are combined by the multiplexing circuit 124 formed of a ring resonator, and the signal light is output by the filtering circuit 115 from the light emitted from the optical waveguide 101. You may make it take out. Further, as shown in FIG. 7F, the signal light and the control light are multiplexed by the multiplexing circuit 124, and the signal light is extracted by the filtering circuit 125 from the light emitted from the optical waveguide 101. Good.

また、図7(g)に示すように、反射形回折格子よりなる合波回路134で信号光と制御光とを合波し、光導波路101を出射した光より、反射形回折格子よりなるろ波回路135で信号光を取り出すようにしてもよい。また、図7(h)に示すように、透過形回折光値よりなる合波回路144で信号光と制御光とを合波し、光導波路101を出射した光より、透過形回折光値よりなるろ波回路145で信号光を取り出すようにしてもよい。また、図7(i)に示すように、アレイ導波路回折格子よりなる合波回路154で信号光と制御光とを合波し、光導波路101を出射した光より、アレイ導波路回折格子よりなるろ波回路155で信号光を取り出すようにしてもよい。   Further, as shown in FIG. 7G, the signal light and the control light are combined by a multiplexing circuit 134 made of a reflective diffraction grating, and the light emitted from the optical waveguide 101 is made of a reflective diffraction grating. The signal light may be extracted by the wave circuit 135. Further, as shown in FIG. 7 (h), the signal light and the control light are multiplexed by the multiplexing circuit 144 composed of the transmissive diffracted light value, and the light emitted from the optical waveguide 101 is obtained from the transmissive diffracted light value. The signal light may be extracted by the filtering circuit 145. Further, as shown in FIG. 7 (i), signal light and control light are multiplexed by a multiplexing circuit 154 composed of an arrayed waveguide diffraction grating, and light emitted from the optical waveguide 101 is transmitted from the arrayed waveguide diffraction grating. The signal light may be extracted by the filtering circuit 155.

次に、上述した本実施の形態における光反転器を用いた光回路の構成例について説明する。
図8は、2つの光反転器100a,100bを直列2段に配置して構成した光波長変換回路を示す構成図である。前段となる光反転器100aに、ビットパターンに変調された制御光と、制御光とは波長が異なる連続光からなる1次信号光を入力し、後段となる光反転器100bに、光反転器100aからの出力光と、1次信号光とは波長が異なる2次信号光とを入力し、光反転器100bより2次信号光を出力する。
Next, a configuration example of an optical circuit using the optical inverter in the above-described embodiment will be described.
FIG. 8 is a configuration diagram showing an optical wavelength conversion circuit configured by arranging two optical inverters 100a and 100b in two stages in series. The control light modulated into the bit pattern and the primary signal light composed of continuous light having a wavelength different from that of the control light are input to the optical inverter 100a at the previous stage, and the optical inverter is input to the optical inverter 100b at the subsequent stage. The output light from 100a and the secondary signal light having different wavelengths from the primary signal light are input, and the secondary signal light is output from the optical inverter 100b.

図8に示す光波長変換回路によれば、光反転器100bより出力される2次信号光は、制御光の変調パターンが複写された状態、すなわち、制御光により変調された状態となる。従って、 図8に示す光波長変換回路により、入力された1次信号光は、異なる波長で制御光に変調された2次信号光として出力されることになる。ここで、2次信号光は、1次信号光と異なる波長であれば良く、制御光と同じ波長であってもよい。   According to the optical wavelength conversion circuit shown in FIG. 8, the secondary signal light output from the optical inverter 100b is in a state where the modulation pattern of the control light is copied, that is, a state modulated by the control light. Therefore, the input primary signal light is output as the secondary signal light modulated by the control light at a different wavelength by the optical wavelength conversion circuit shown in FIG. Here, the secondary signal light may have a wavelength different from that of the primary signal light, and may be the same wavelength as the control light.

なお、光反転器100bは、光反転器100aに比較して感度が高い構造とした方がよい。光反転器100bを光反転器100aと同様に構成した場合、図9に示すように、光反転器100aより出力された1次信号光を、光増幅器200により増幅してから光反転器100bに入力するようにすればよい。   Note that the optical inverter 100b should have a higher sensitivity than the optical inverter 100a. When the optical inverter 100b is configured in the same manner as the optical inverter 100a, as shown in FIG. 9, the primary signal light output from the optical inverter 100a is amplified by the optical amplifier 200 and then transmitted to the optical inverter 100b. Just input.

ところで、上述では、光反転器に1つの制御光を入力するようにしたが、これに限るものではなく、図10に示すように、2つの異なる制御光を入力して信号光を変調するようにしてもよい。図10に示す光論理演算器は、制御光A,制御光B及び信号光を合波する合波回路104aを用いるようにしたものである。   In the above description, one control light is input to the optical inverter. However, the present invention is not limited to this. As shown in FIG. 10, two different control lights are input to modulate the signal light. It may be. The optical logic unit shown in FIG. 10 uses a multiplexing circuit 104a that combines the control light A, the control light B, and the signal light.

図10に示す光論理演算器によれば、制御光Aと、これとは波長及びビットパターンが異なる制御光Bと、これら制御光とは波長が異なる連続光である信号光を入力し、制御光Aと制御光Bの否定論理積が、信号光としてろ波回路105より出力される。
この光論理演算器では、制御光A,制御光Bの少なくとも一方がオフレベルの場合、図6に示した位置E以下の入力ピーク強度になる。また、制御光A,制御光Bの両方がオンレベルのとき、図6に示した位置Fの入力ピーク強度となる。
According to the optical logic unit shown in FIG. 10, the control light A, the control light B having a wavelength and a bit pattern different from the control light A, and the signal light which is a continuous light having a wavelength different from the control light are input and controlled. The NAND of the light A and the control light B is output from the filtering circuit 105 as signal light.
In this optical logic unit, when at least one of the control light A and the control light B is at the off level, the input peak intensity is equal to or lower than the position E shown in FIG. Further, when both the control light A and the control light B are on level, the input peak intensity at the position F shown in FIG. 6 is obtained.

従って、制御光Aと制御光Bが合波された光が、光導波路101に入射(入力)すると、制御光Aと制御光Bの両方がオンレベルのときのみ反転操作を受けるので、光導波路101の出力光をろ波回路105でろ波して信号光を取り出すことで、否定論理積回路として動作することになる。   Accordingly, when the combined light of the control light A and the control light B enters (inputs) the optical waveguide 101, the optical waveguide undergoes an inversion operation only when both the control light A and the control light B are on level. By filtering the output light 101 by the filtering circuit 105 and taking out the signal light, it operates as a NAND circuit.

図10に示した光論理演算器の合波回路104aは、例えば、図11(a)に示すように、2つの光ラティスフィルタ114a,114bから構成すればよい。このとき、光導波路101を出力した光より、光ラティスフィルタからなるろ波回路115で信号光を取り出すようにしてもよい。また、図11(b)に示すように、光導波路101を出力した光より、リング共振器よりなるろ波回路125で信号光を取り出すようにしてもよい。   The multiplexing circuit 104a of the optical logic unit shown in FIG. 10 may be configured by two optical lattice filters 114a and 114b, for example, as shown in FIG. At this time, signal light may be extracted from the light output from the optical waveguide 101 by the filtering circuit 115 including an optical lattice filter. Further, as shown in FIG. 11B, signal light may be extracted from the light output from the optical waveguide 101 by a filtering circuit 125 formed of a ring resonator.

なお、合波回路104aは、2つの方向性結合器より構成しても良く、2つのリング共振器より構成してもよい。また、合波回路104aは、3つ以上の入力チャネルをもつ反射型回折格子から構成しても良く、3つ以上の入力チャネルをもつ透過形回折格子から構成しても良く、また、3つ以上の入力チャネルをもつアレイ導波路回折格子から構成してもよい。また、ろ波回路は、光ラティスフィルタやリング共振器に限るものではなく、反射型回折光子,透過形回折格子,またアレイ導波路回折格子から構成してもよい。   The multiplexing circuit 104a may be constituted by two directional couplers or may be constituted by two ring resonators. The multiplexing circuit 104a may be composed of a reflection type diffraction grating having three or more input channels, may be composed of a transmission type diffraction grating having three or more input channels, You may comprise from the array waveguide diffraction grating which has the above input channels. Further, the filtering circuit is not limited to the optical lattice filter or the ring resonator, but may be composed of a reflection type diffractive photon, a transmission type diffraction grating, or an arrayed waveguide diffraction grating.

次に、3つ以上の各々異なる複数の制御光を入力して信号光を変調する光回路例について説明する。図12は、n個(n>2)の制御光A,制御光B,制御光C,・・・,及び信号光を、各々可変光減衰器110を通して合波回路164に入力し、合波回路164で合波された光を導波回路101に入力する光論理演算器の構成を示す構成図である。合波回路164、n+1個の光を合波する。   Next, an example of an optical circuit that modulates signal light by inputting three or more different control lights will be described. In FIG. 12, n (n> 2) control light A, control light B, control light C,..., And signal light are respectively input to the multiplexing circuit 164 through the variable optical attenuator 110 and multiplexed. 3 is a configuration diagram showing a configuration of an optical logic unit that inputs light combined by a circuit 164 to a waveguide circuit 101. FIG. A multiplexing circuit 164 multiplexes n + 1 lights.

図12の光論理演算器では、各々個別のビットパターンで個別の波長のn個の制御光と、これら制御光とは異なる波長の連続光である信号光を入力し、n個の制御光の光強度の和によって信号光の出力をスイッチングする。合波回路164の前段には各制御光及び信号光毎に可変光減衰器110が設けられ、各々の入力光強度が調整可能とされている。   In the optical logic unit shown in FIG. 12, n control lights having individual wavelengths are input in individual bit patterns, and signal light that is continuous light having a wavelength different from these control lights is input, and the n control lights The output of the signal light is switched by the sum of the light intensities. A variable optical attenuator 110 is provided for each control light and signal light in the preceding stage of the multiplexing circuit 164 so that the input light intensity can be adjusted.

例えば、制御光チャネルパターンに対する出力ビットが予め判明している場合には、誤差逆伝搬アルゴリズムを用い、各可変光減衰器110の減衰量を設定しておけば、任意の制御光チャネルパターンに応じた出力を得るニューロコンピュータ用の光論理演算器として用いることができる。この例では、教師パターンとなる制御チャネルパターンが予め判明していない場合、学習過程においてパターン分類アルゴリズムを用いて各可変光減衰器110の減衰量を設定すればよい。   For example, when the output bits for the control optical channel pattern are known in advance, an error back-propagation algorithm is used, and the attenuation amount of each variable optical attenuator 110 is set. It can be used as an optical logic unit for a neurocomputer that obtains a high output. In this example, when the control channel pattern to be a teacher pattern is not known in advance, the attenuation amount of each variable optical attenuator 110 may be set using a pattern classification algorithm in the learning process.

なお、可変光減衰器110には、例えばPIN型光減衰器を用いるようにすればよい。また、可変光減衰器110として、NDフィルタ型光減衰器を用いるようにしても良く、また、磁気光学効果を用いた光減衰器や、マッハツェンダ干渉計を用いた光減衰器などを用いるようにしてもよい。また、予め各入力チャネル毎の光減衰量を決めておくことができる場合、可変光減衰器の代わりに固定光減衰器を用いてもよい。   The variable optical attenuator 110 may be a PIN type optical attenuator, for example. Further, as the variable optical attenuator 110, an ND filter type optical attenuator may be used, and an optical attenuator using a magneto-optical effect, an optical attenuator using a Mach-Zehnder interferometer, or the like may be used. May be. If the optical attenuation amount for each input channel can be determined in advance, a fixed optical attenuator may be used instead of the variable optical attenuator.

以上に説明した本発明の光論理演算器は、シリコンコアからなる光導波路を用いるようにした。シリコンは、微細なパターンの形成が容易であり、素子の微細化が容易であるので、本発明の光論理演算器によれば、高密度集積化が容易である。また、コアの断面寸法を500nm程度とすることも容易であり、このような微小領域に光を閉じ込めることができるので、光導波路における光強度密度を高めることが容易である。この結果、本発明の光論理演算器によれば、安価でハイブリッド実装が容易な、低出力半導体CWレーザなどを光源として用いることができる。   The optical logic unit of the present invention described above uses an optical waveguide composed of a silicon core. Silicon is easy to form a fine pattern and can be easily miniaturized. Therefore, according to the optical logic unit of the present invention, high-density integration is easy. In addition, the cross-sectional dimension of the core can be easily set to about 500 nm, and light can be confined in such a minute region, so that it is easy to increase the light intensity density in the optical waveguide. As a result, according to the optical logic unit of the present invention, it is possible to use a low-power semiconductor CW laser or the like as a light source that is inexpensive and easy to perform hybrid mounting.

本発明の実施の形態における光論理演算器である光反転器100の構成例を示す構成図である。It is a block diagram which shows the structural example of the optical inverter 100 which is an optical logic unit in embodiment of this invention. 制御光の波形を示した特性図である。It is the characteristic view which showed the waveform of control light. 信号光がオフの状態で制御光を入射したときにO/Eサンプリングオシロスコープ106で測定された制御光の波形を示した特性図である。It is a characteristic view showing a waveform of the control light measured by the O / E sampling oscilloscope 106 when the control light is incident with the signal light turned off. 制御光の入力ピーク強度を変化させた場合の、図3のB/Aの値をプロットした特性図である。FIG. 4 is a characteristic diagram in which values of B / A in FIG. 3 are plotted when the input peak intensity of control light is changed. 制御光と信号光とを合波して光導波路101に入射したときに、O/Eサンプリングオシロスコープ106で測定された出力光信号(信号光)の波形を示したものである。The waveform of the output optical signal (signal light) measured by the O / E sampling oscilloscope 106 when the control light and the signal light are combined and incident on the optical waveguide 101 is shown. 図5における反転変調率(D/C)をプロットしたものである。FIG. 6 is a plot of the inversion modulation rate (D / C) in FIG. 5. 図1に示した光反転器100を構成する合波回路,ろ波回路の他の構成例を示す構成図である。It is a block diagram which shows the other structural example of the multiplexing circuit and the filtering circuit which comprise the optical inverter 100 shown in FIG. 2つの光反転器100a,100bを直列2段に配置して構成した光波長変換回路を示す構成図である。It is a block diagram which shows the optical wavelength conversion circuit comprised by arrange | positioning two optical inverters 100a and 100b in two steps in series. 2つの光反転器100a,100bを直列2段に配置して構成した光波長変換回路を示す構成図である。It is a block diagram which shows the optical wavelength conversion circuit comprised by arrange | positioning two optical inverters 100a and 100b in two steps in series. 本発明の実施の形態における光論理演算器の他の構成例を示す構成図である。It is a block diagram which shows the other structural example of the optical logic unit in embodiment of this invention. 本発明の実施の形態における光論理演算器の他の構成例を示す構成図である。It is a block diagram which shows the other structural example of the optical logic unit in embodiment of this invention. 本発明の実施の形態における光論理演算器の他の構成例を示す構成図である。It is a block diagram which shows the other structural example of the optical logic unit in embodiment of this invention.

符号の説明Explanation of symbols

100…光反転器、101…光導波路、102…パタンジェネレータ、103…光変調器、104…合波回路、105…ろ波回路、106…O/Eサンプリングオシロスコープ。   DESCRIPTION OF SYMBOLS 100 ... Optical inverter, 101 ... Optical waveguide, 102 ... Pattern generator, 103 ... Optical modulator, 104 ... Multiplexing circuit, 105 ... Filter circuit, 106 ... O / E sampling oscilloscope.

Claims (3)

異なる光強度のオン状態とオフ状態とから構成されたビットパターンの波長が各々異なる複数の制御光と、これら制御光とは異なる波長の第2波長の信号光とを合波する合波回路と、
シリコンからなるコアとこのコアより低い屈折率のクラッドとから構成され、前記合波回路で合波された光を導波する光導波路と、
前記合波回路で合波されて前記光導波路を導波した光より、前記第2波長の光を取り出すろ波回路と
を少なくとも備え
前記ビットパターンは、前記光導波路において二光子吸収が起こる光強度を境とした異なる光強度のオン状態とオフ状態とから構成されていることを特徴とする光論理演算器。
A multiplexing circuit that multiplexes a plurality of control lights having different wavelengths of bit patterns composed of an on state and an off state having different light intensities, and signal light having a second wavelength different from these control lights; ,
An optical waveguide configured of a core made of silicon and a clad having a refractive index lower than that of the core, and guides light combined by the multiplexing circuit;
From light guided through the optical waveguide are multiplexed by the multiplexing circuit, comprising at least a filtering circuit for taking out the light of the second wavelength,
The bit pattern, an optical logic unit, characterized that you have been composed of a border of light intensity occurring two-photon absorption is different between on and off states of the light intensity in the optical waveguide.
請求項1記載の光論理演算器において、
前記合波回路の前段に設けられ、前記信号光及び前記制御光の光強度を減衰する減衰器を備えることを特徴とする光論理演算器。
The optical logic unit according to claim 1,
An optical logic unit comprising an attenuator provided in a preceding stage of the multiplexing circuit and configured to attenuate the light intensity of the signal light and the control light.
異なる光強度のオン状態とオフ状態とから構成されたビットパターンの第1波長の第1制御光と、この第1制御光と異なる波長の第2波長の第2制御光と、前記第1制御光および前記第2制御光のいずれとも波長が異なる第3波長の信号光とを合波する合波回路と、
シリコンからなるコアとこのコアより低い屈折率のクラッドとから構成され、前記合波回路で合波された光を導波する光導波路と、
前記合波回路で合波されて前記光導波路を導波した光より、第3波長の光を取り出すろ波回路と
を少なくとも備え
前記ビットパターンは、前記光導波路において二光子吸収が起こる光強度を境とした異なる光強度のオン状態とオフ状態とから構成されていることを特徴とする光論理演算器。
A first control light having a first wavelength of a bit pattern composed of an ON state and an OFF state having different light intensities, a second control light having a second wavelength different from the first control light, and the first control light A multiplexing circuit that multiplexes a third wavelength signal light having a wavelength different from that of both the light and the second control light;
An optical waveguide configured of a core made of silicon and a clad having a refractive index lower than that of the core, and guides light combined by the multiplexing circuit;
A filtering circuit that extracts light of a third wavelength from the light that has been multiplexed by the multiplexing circuit and guided through the optical waveguide ;
The bit pattern, an optical logic unit, characterized that you have been composed of a border of light intensity occurring two-photon absorption is different between on and off states of the light intensity in the optical waveguide.
JP2003359226A 2003-10-20 2003-10-20 Optical logic unit Expired - Fee Related JP4598382B2 (en)

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