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公开(公告)号：JPH0818026A
公开(公告)日：1996-01-19
申请号：JP14689494
申请日：1994-06-29
Applicant: NEC CORP
Inventor： TAKEUCHI TAKESHI , TAGUCHI KENSHIN , KOMATSU YOSHIRO , YAMAMOTO MASAKO , HAMAMOTO KIICHI
IPC: H01L31/10 , G02B6/122 , G02B6/42 , H01L27/14 , H01L27/15 , H01L31/0352 , H01L31/109
Abstract: PURPOSE:To improve the combination efficiency between a light waveguide path and a photodiode by continuously forming the light waveguide path of the connection part between a passive waveguide path and a waveguide path type light reception element and reducing a band gap wavelength as compared with that of a light reception element part. CONSTITUTION:A photodiode part 19 has a wide mask width and is narrow at a light waveguide path part 20. A selective growth mask pattern according to SiO2 film 18 is formed on n-type InP substrate 17. Then, n -InP lower clad layer 21, n -InGaAsP layer 22, and P -InP upper clad layer 23 are formed. Then, P -InP upper clad layer 23 being present on the interlocked region between the photodiode part 19 and the light waveguide path part 20 is eliminated and element separation is made, thus forming an electrode. At the light waveguide path part 20, a refractive index increases and an absorption edge wavelength decreases and the absorption edge wavelength at the photodiode part becomes longer, thus collectively forming the photodiode and light waveguide path and preventing a re-growth interface from being generated.
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公开(公告)号：JPH04268765A
公开(公告)日：1992-09-24
申请号：JP2899491
申请日：1991-02-25
Applicant: NEC CORP
Inventor： KOMATSU YOSHIRO , SASAKI TATSUYA , KATO TOMOAKI , MITO IKUO
IPC: G02B6/12 , G02B6/124 , G02B6/125 , G02B6/13 , G02F1/025 , H01L27/15 , H01S5/00 , H01S5/026 , H01S5/0625 , H01S5/227 , H01S5/40
Abstract: PURPOSE:To enable an optical integrated circuit where various waveguide type devices are integrated and easily connected together low in loss or custom IC type optical integrated circuits similar in constitution but different in connection to be efficiently manufactured. CONSTITUTION:An optical integrated circuit is composed of ridge type active optical devices formed of a variable wavelength laser 1 and an optical modulator 2 and the ridge type passive optical waveguide of a Y-type optical branching devices 4 which connect the ridge type active optical devices together or the ridge type active optical device and an outgoing light waveguide, where the ridge type active optical device and the ridge of the ridge type passive optical waveguide are formed through a selective crystal growth method.
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公开(公告)号：JPH03263388A
公开(公告)日：1991-11-22
申请号：JP6298190
申请日：1990-03-13
Applicant: NEC CORP
Inventor： TERAKADO TOMOJI , AJISAWA AKIRA , YAMAGUCHI MASAYUKI , KOMATSU YOSHIRO
Abstract: PURPOSE:To lower an element capacity and to execute an ultrahigh-speed operation by a method wherein a high-resistance substrate is used, a semiconductor multilayer structure including an active layer is provided on it, and a wiring which connects an electrode formed at the upper part of the semiconductor multilayer structure to a bonding pad formed on the high-resistance semiconductor substrate is formed into an air-bridge structure. CONSTITUTION:An optical modulator is formed so as to have a structure in which both sides of a mesa stripe 6 composed of a multilayer structure by an InP buffer layer 2, an undoped InGaAsP waveguide layer 3, a p-InP clad layer 4 and a p-InGaAs cap layer 5 are filled into Fe-doped InP high-resistance layers 7. Bonding pads 15 composed of a metal are formed selectively on one main face of a high-resistance semiconductor substrate 1 composed of Fe-doped InP; an interconnection 14 which connects the optical modulator to the bonding pad 15 has an air-bridge structure on a semiconductor layer of the optical modulator.
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公开(公告)号：JPH025027A
公开(公告)日：1990-01-09
申请号：JP15750288
申请日：1988-06-24
Applicant: NEC CORP
Inventor： KOMATSU YOSHIRO
Abstract: PURPOSE:To improve switching characteristic by forming a groove having a width narrower than the space between two optical wave guides and having a depth which reaches a clad layer on a substrate side or a substrate between two optical wave guides along them. CONSTITUTION:An AlGaAs buffer layer 101 and an AlGaAs clad layer 102 are grown on a GaAs substrate 100. Between the two optical wave guides 110a and 110b on an incident side formed just under the edge of an Au strip 301 for impressing stress, the groove 109 (air gap) having the width which is much narrower than the space between the optical wave guides and having the depth which reaches the AlGaAs buffer layer 101 is formed along a light propagation direction in the almost middle of the optical wave guides 110a and 110b. There fore, free carrier generated in one optical wave guide 110a does not diffuse to the other optical wave guide 110b. Thus, the mismatching quantity of phase which is larger than in the case that the groove 109 is not formed can be obtained and the switching characteristic can be improved.
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公开(公告)号：JPH01134433A
公开(公告)日：1989-05-26
申请号：JP29332787
申请日：1987-11-20
Applicant: NEC CORP
Inventor： KOMATSU YOSHIRO , AJISAWA AKIRA , FUJIWARA MASAHIKO
Abstract: PURPOSE:To enable optical control and optical modulation, optical logical arithmetic operation, etc., by utilizing nonlinear variation in the refractive index of a multiple quantum well MQW which is caused by absorbing light nearby the exciton peak wavelength of the MQW. CONSTITUTION:This element consists of 1st and 2nd optical waveguides 13a and 13b which cross each other and a reflection part 6 which is arranged on the center line of the intersection part, and the reflection part 6 has MQW structure wherein quantum wells are multiplied in the layer thickness direction. Then when control light 10 is not incident on an optical waveguide 13b, signal light 12 entering an optical waveguide 13a travels as it is and is projected. When control light 10 with the same wavelength as the exciton peak wavelength of this MQW is entered into the optical waveguide 13b, the control light 10 reaches an MQW reflection part 6 and is absorbed by the MQW to eliminate the exciton peak of the MQW, thereby causing a decrease in refractive index. The signal light 12 is therefore reflected totally by the MQW reflection part 6 and outputted from the optical waveguide 13b. Consequently, various waveguide optical logic element, waveguide type optical control and optical modulating element, optical control wavelength converting element, etc., which have low loss and small crosstalk are obtained.
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Patent Agency Ranking
公开(公告)号：JPS6239825A
公开(公告)日：1987-02-20
申请号：JP17960885
申请日：1985-08-14
Applicant: NEC CORP
Inventor： KOMATSU YOSHIRO
Abstract: PURPOSE:To obtain the titled modulator capable of operating at a low voltage and in a broad-band by forming the optical modulator in a thin ferroelectric body through an epitaxial film composed of a MgAl2O4 film or a laminated film composed of said film and MgO film. CONSTITUTION:The LiNbO3 film 4 is formed on a high resistance Si substrate through the epitaxial film of MgAl2O4 2 and and that of MgO 3. Ti diffusion optical waveguides 5 and 6, and a directional coupler 7 using said waveguides are formed in the film 4. A planar type electrodes 8 facing with a minute gap are formed on the optical waveguides of the directional coupler 7 through a buffer film 9 composed of SiO2. Thus, the film thickness of the film 4 is selected so as to be
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公开(公告)号：JPS61156209A
公开(公告)日：1986-07-15
申请号：JP27748384
申请日：1984-12-28
Applicant: NEC CORP
Inventor： KOMATSU YOSHIRO
Abstract: PURPOSE:To reduce the coupling loss of optical signals, by changing the waveguide spot size of a wave guiding type light controlling element which outputs optical signals prepared by adding various kinds of control to the output light of a luminous element to an optical fiber between its luminous element side end face and optical fiber side end face. CONSTITUTION:The waveguide 105 spot size at the end face 107 at the side to be coupled wit a luminous element 101 having a smaller spot size is made smaller and the spot size at the end face 108 at the side to be coupled with an optical fiber 110 having a larger spot size is made larger so that the spot size can be made coincident with the spot size of the optical fiber 110. Then the module of a light controlling element, in which the luminous element 101, wave guiding type optical element 109, and optical fiber 110 are united in one body is constituted, by directly terminal-couplling between the luminous element 101 and waveguiding type light controlling element 109 and between the wave guiding type light controlling element 109 and optical fiber 110, respectively. Therefore, the module of a light controlling element which is low in loss and light in weight can be obtained and this module can be used for high-speed optical communication system.
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公开(公告)号：JPH07202316A
公开(公告)日：1995-08-04
申请号：JP33792993
申请日：1993-12-28
Applicant: NEC CORP
Inventor： KOMATSU YOSHIRO , KITAMURA MITSUHIRO , YAMAGUCHI MASAYUKI
Abstract: PURPOSE:To obtain a waveguide optical control element with low capacitance and high speed by making such a structure of the waveguide optical control element that can utilize selective growth and by inserting a semiconductor buffer layer with low carrier concentration between a conductive semiconductor substrate and an inversely conductive semiconductor second clad layer. CONSTITUTION:A lightly doped n-InP buffer layer 102 with low carrier concentration is formed on an n-InP substrate 101 using organic metal vapor phase growth technique or the like. A SiO2 film is formed on this substrate to be patterned onto a pair of selectively growing SiO2 masks in a striped shape which are opposite to each other across a stripe-like gap. Then an n-InGaAsP optical waveguide layer 502, an n-InP spacer layer 503 or the like are sequentially stacked selectively only on the gap to form a mesa of a double hetero structure. As a result, no failure such as an increase in series resistance of an element occurs, coupling loss with a single mode fiber is small, speed is high and a yield in manufacture can be improved.
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公开(公告)号：JPH04243216A
公开(公告)日：1992-08-31
申请号：JP1941191
申请日：1991-01-17
Applicant: NEC CORP
Inventor： KATO TOMOAKI , KOMATSU YOSHIRO , SASAKI TATSUYA
IPC: G02B6/122 , G02B6/13 , G02F1/025 , G02F1/35 , H01L27/15 , H01S5/00 , H01S5/026 , H01S5/12 , H01S5/20 , H01S5/323
Abstract: PURPOSE:To integrate optical elements onto the same substrate by forming a slab optical waveguide which provides an effect of confining light only in the layer thickness direction on a semiconductor substrate and forming a dielectric film thereon. CONSTITUTION:A lower clad layer 102, an optical waveguide layer 103 and an upper clad layer 104 are successively formed on the substrate 101 to constitute the slab optical waveguide. An SiO2 film 105 having a striped aperture is formed thereon. The light is confined by the optical waveguide layer 103 having the refractive index larger than the refractive index of the clad layers 102, 104 and is further confined in a transverse direction into the lower part of an undoed InP ridge layer 106 as the effective refractive index in the lower part of the ridge layer 106 is larger than the refractive index at both end parts and, therefore, this element acts as three-dimensional optical waveguides.
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公开(公告)号：JPH0496025A
公开(公告)日：1992-03-27
申请号：JP21388790
申请日：1990-08-13
Applicant: NEC CORP
Inventor： KOMATSU YOSHIRO
Abstract: PURPOSE:To reduce the size of the element by specifying the element length about lengths to a TE mode and a TM mode which are required for the complete movement of waveguide light power from one of two close three- dimensional optical waveguides to the other optical waveguide. CONSTITUTION:On a (100) azimuth semiconductor substrate, a 1st semiconductor clad layer, a semiconductor waveguide layer, and a 2nd semiconductor clad layer are laminated, a directional coupler is composed of the two nearby three- dimensional optical waveguides which are formed on the semiconductor substrate, and a means which applies electric fields to them independently is provided. Denoting the lengths to the TE and TM modes which are required for the complete movement of the waveguide light power from one of the two nearby three-dimensional optical waveguides to the other optical waveguide as LTE and LTM, the element length L of the directional coupler is nearly equalized to LTE and LTM. Consequently, element size of
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