专利快速检索-快速检索全球专利，免费商用专利数据库-IPRDB

1. 发明专利

JP2000147580A OPTICAL SWITCH 失效
公开(公告)号：JP2000147580A
公开(公告)日：2000-05-26
申请号：JP32521298
申请日：1998-11-16
申请人： NEC CORP
发明人： NAKAMURA SHIGERU , TAJIMA KAZUTO
IPC分类号： G02F1/35
摘要： PROBLEM TO BE SOLVED: To realize high extinction ratio optical switch operation by a control beam pulse of low energy in an optical switch using a signal beam frequency shift accompanying a resonance excitation nonlinear optical effect in a semiconductor. SOLUTION: A signal beam pulse of a frequency ω1 and the control beam pulse of the frequency ω0 are inputted to a nonlinear optical waveguide 1. At this time, control beam pulse width is set in a value smaller than signal beam pulse width. The optical waveguide part of the nonlinear optical waveguide 1 consists of a nonlinear optical medium showing a nonlinear refractive index change by the absorption or the amplification of the control beam. The frequency ω1 of the signal beam is set in the transparent area of the nonlinear optical waveguide 1. When the frequency ω0 of the control beam is set in the absorption area of the nonlinear optical waveguide 1, a frequency shift to a high frequency side occurs in a part of the signal beam pulse made incident together with the control beam. An optical frequency filter 2 outputs only a component that the frequency is shifted. Thus, the optical switch operation by the control beam pulse of the low energy is realized.

2. 发明专利

JPH08179385A FULL OPTICAL SWITCH 失效
公开(公告)号：JPH08179385A
公开(公告)日：1996-07-12
申请号：JP32080194
申请日：1994-12-22
申请人： NEC CORP
发明人： TAJIMA KAZUTO
IPC分类号： G02B6/12 , G02F1/21 , G02F1/225 , G02F1/313 , G02F1/35 , G02F3/00
摘要： PURPOSE: To provide a full optical switch capable of performing a low power operation and super high speed switching and excellent in stability for a long term. CONSTITUTION: This switch is provided with a polarized beam splitter 1 splitting signal light into two polarized components, the polarized beam splitter 2 multiplexing the polarized components after imparting a specified propagation delay time difference to t he split polarized components, a semiconductor waveguide 6 imparting phase modulation to the signal light by propagating the signal light after multiplexion through material generated with a refractive index change by control light, the polarized beam splitter 7 splitting the signal light passing through the semiconductor waveguide 6 into two polarized components again and a half mirror 13 imparting the propagation delay time difference opposite to the former to the split polarized components and making the polarized components interfere with each other after the polarization are arranged.

3. 发明专利

JPH07333660A NONLINEAR OPTICAL ELEMENT 失效
公开(公告)号：JPH07333660A
公开(公告)日：1995-12-22
申请号：JP13151294
申请日：1994-06-14
申请人： NEC CORP
发明人： NAKAMURA SHIGERU , TAJIMA KAZUTO
IPC分类号： G02B6/12 , G02F1/025 , G02F1/35 , G02F1/365
摘要： PURPOSE:To decrease control light energy of a nonlinear optical element of a waveguide type which executes high-speed photo-photo control by utilizing a band filling effect by absorption of control light. CONSTITUTION:This nonlinear optical element has an InGaAs/InGaAsP multiplex quantum well structure 2 which is an optical waveguide part to develop a nonlinear change in refractive index on an InP substrate 1. The band gap energy of the optical waveguide part in regions 4 to 6 decreases stepwise and monotonously along the propagation direction from an incident side. Both of the control light and the signal light are made incident on the element from the region 4 side. The control light is absorbed in the optical waveguide part of the element and carriers are formed, by which the change in the refractive index is induced in the optical waveguide part. A phase shift of the signal light propagating in the optical waveguide part is then induced. The coefft. of absorption to the control light is larger in order of the regions 4 to 6. The concentration of the carriers near to the incident port is thus averted and the carriers are more uniformly distributed over the entire length of the waveguide. The nonlinear change in the refractive index is not satd. over the entire length of the waveguide and the efficient signal light phase shift is obtd.

4. 发明专利

JPH0720510A FULLY OPTICAL ELEMENT 失效
公开(公告)号：JPH0720510A
公开(公告)日：1995-01-24
申请号：JP16445593
申请日：1993-07-02
申请人： NEC CORP
发明人： TAJIMA KAZUTO
IPC分类号： G02F1/21 , G02F1/225 , G02F1/313 , G02F1/35 , G02F3/00
摘要： PURPOSE:To provide the Mach-Zehnder type fully optical element with which the switch off time does not depend on the relaxation time of a nonlinear effect by introducing control light into respective optical nonlinearity developing parts of both arms of a Mach-Zehnder system. CONSTITUTION:This fully optical element has control light input ports A, B at both arms A, B of the Mach-Zehnder system. The control light B changes the refractive index of the nonlinear waveguide B by photoexciting the nonlinear waveguide B of the arm B. The control light A excites the arm A 50ps after excitation by the control light B. The pulse energy of the control light A is the extent of exiting the carriers remaining in the nonlinear waveguide B at the moment the control light A excites the nonlinear waveguide A and is weaker than the control light B. The effective lengths of both arms A, B are, therefore, made into the same at the moment the control light A excites the nonlinear waveguide A. Then, the output light thereof rapidly rises (switch on) at the excitation of the control light B and rapidly restores the original state (switch off) at the moment of the excitation of the control light A.

5. 发明专利

JPH0293626A OPTICAL LOGICAL ELEMENT 失效
公开(公告)号：JPH0293626A
公开(公告)日：1990-04-04
申请号：JP24721188
申请日：1988-09-30
申请人： NEC CORP
发明人： TAJIMA KAZUTO
IPC分类号： G02F1/225 , G02F1/35 , G02F3/00
摘要： PURPOSE:To obtain the element which has high performance and allows easy cascade connection by providing a means of multiplexing light to a common optical path and a means of demultiplexing part of the light of the common optical path to two Mach-Zehnder interference system. CONSTITUTION:A GaAlAs buffer layer 2, a GaAlAs clad layer 3 are formed on a GaAs substrate 1 and further, a GaAlAs/GaAs superlattice layer 4 are formed thereon. The layer 4 is etched about 1mum and waveguide parts 11 to 13, etc., are formed to about 1.2 to 1.4mum wavelength and about 4.0mum width. Directional coupling parts 9, 10 are formed to 1 coefft. at 1.27mum wavelength and about 0 coefft. at 1.33mum wavelength. The input light 5 of 1.27mum wave length is branched to two in a branching part 14 and is multiplexed in the multiplexing part. The lengths of the waveguides 11 and 12 are shifted by a half wavelength. Input light 5 is, therefore, converted to a radiation mode in the multiplexing part 16 and output light 7 is not obtd. The same holds true of the input light 6 of 1.33mum wavelength. On the other hand, output light 7 and 8 are obtd. by a mutual phase modulating effect when the input light 5 and the input light 6 are simultaneously made incident.

6. 发明专利

JPS62139502A OPTICAL TRANSMISSION LINE 失效
公开(公告)号：JPS62139502A
公开(公告)日：1987-06-23
申请号：JP28037085
申请日：1985-12-13
申请人： NEC CORP
发明人： TAJIMA KAZUTO
IPC分类号： G02F1/35 , G02B6/02 , G02B6/10 , H04B10/2507 , H04B10/2513
摘要： PURPOSE:To propagate an optical soliton by long distance without using any optical amplifier by providing an optical fiber which varies in optical loss coefficient and group speed dispersion so that a specific equation holds in a light propagation direction. CONSTITUTION:The optical fiber which has the optical loss coefficient Y(1/cm) of the optical transmission line and varies in group speed dispersion K2 so that the equation [where K2 is group speed dispersion (s/cm ), Z the transmission-directional distance (cm) of the optical fiber, F(K2) the core diameter (cm) of the optical fiber expressed as a function of K2, and alpha the constant determined by K2 when Z=0) is satisfied in the optical propagation direction is provided. Thus, a decrease in the nonlinearity of the optical fiber due to the propagation of the optical soliton is corrected by varying the group speed dispersion according to the propagation distance, so the optical soliton is propagated by long distance without using any optical amplifier.

7. 发明专利

JPH1152440A OPTICAL SWITCH 失效
公开(公告)号：JPH1152440A
公开(公告)日：1999-02-26
申请号：JP21153497
申请日：1997-08-06
申请人： NEC CORP
发明人： NAKAMURA SHIGERU , TAJIMA KAZUTO
IPC分类号： G02F1/313 , G02F1/35
摘要： PROBLEM TO BE SOLVED: To embody an increase of signal light output ports, an improvement in jigger resistance, relaxation of band limitation and an improvement in the fiber transmission characteristic of output signal light in an optical switch utilizing the signal light frequency shift associated with the resonance excitation nonlinear optical effect in a semiconductor. SOLUTION: The nonlinear optical waveguide 1 has a signal light/control light input port 11 to which a signal light pulse of a central frequency ω1, pulse energy E1, a first control light pulse of a central frequency ω0, pulse energy E2, and a second control light pulse of a central frequency ω0 are inputted. The optical waveguide part of the nonlinear optical waveguide 1 consists of a nonlinear optical medium which indicates a nonlinear refractive index change by the absorption or amplification of the control light. The central frequency ω1 is set at the transparent region of the nonlinear optical waveguide 1. When the central frequency ω0 of the control light is set at the absorption region of the nonlinear optical waveguide 1, the refractive index change occurs in accompaniment with carrier excitation. As a result, the optical switch of the one input and three output type is embodied.

8. 发明专利

JPH0472786A SEMICONDUCTOR LASER ELEMENT 失效
公开(公告)号：JPH0472786A
公开(公告)日：1992-03-06
申请号：JP18633290
申请日：1990-07-13
申请人： NEC CORP
发明人： NANBU YOSHIHIRO , TAJIMA KAZUTO
IPC分类号： H01S5/00
摘要： PURPOSE:To obtain a semiconductor laser element which is low in power consumption and high in efficiency by a method wherein a means which injects carriers modulating them in density at an optical wavelength period of half the emission wavelength in a direction in which light is guided is provided. CONSTITUTION:An N-Ga1-zAlzAs barrier 5, a GaAs active layer 6, a P-GaAs barrier 6, and a P-Ga1-uAluAs stripe-like barrier 7 are made to grow on an N doped GaAs substrate 1, stripe-like barrier layers 5 and 7 and an active layer 6 are provided through etching, a side part is filled with an N-Ga1-xAlxAs 2 to constitute a current constriction structure. Then, an SiO2 insulating layer 3 is provided. The SiO2 insulating layer 3 formed on the stripe is removed through etching, an upper and a lower electrode 4 are provided through sputtering or the like, current block layers 8 are provided between the electrode and the active layer in a periodic manner in a direction in which the stripe extends. When the current block layers 8 are laid just above the active layer, the active layer is modulated in equivalent refractive index owing to the block layers, so that a distributed feedback effect (DFB) is induced to affect an electric field distribution in a standing wave mode.

9. 发明专利

JPH0434421A NONLINEAR OPTICAL ELEMENT 失效
公开(公告)号：JPH0434421A
公开(公告)日：1992-02-05
申请号：JP14069290
申请日：1990-05-30
申请人： NEC CORP
发明人： TAJIMA KAZUTO
IPC分类号： G02F1/35
摘要： PURPOSE:To speed up the optical element which utilizes a change in refractive index by providing grooves of a specific width in the part where the carriers of a semiconductor are excited or near this part. CONSTITUTION:The grooves 75 having lambda0/(4n) width in the part where the carriers of the semiconductor are excited or near this part, lambda0 is the light wave length in a vacuum; n is the linear refractive index of the semiconductor. Name ly, the response speed of a change in the refractive index of the semiconductor by the actual excitation by the light of electrons is determined by the time (carrier time) when the electrons make recombination. The extremely thin but deep grooves 75 are dug in the optical element down to the part where the electrons are excited in this case. The formed carriers are then recombined in a short period of time by the surface of the formed grooves 75. The response speed is improved in this way.

10. 发明专利

JPS63228830A OPTICAL RECEIVER 失效
公开(公告)号：JPS63228830A
公开(公告)日：1988-09-22
申请号：JP6119287
申请日：1987-03-18
申请人： NEC CORP
发明人： TAJIMA KAZUTO
IPC分类号： H04B10/2507 , H04B10/2513 , H04B10/556
摘要： PURPOSE:To reduce influence caused by the wavelength dispersion of an optical fiber and to prevent an optical receiver from being deteriorated in reception sensitivity by giving a prescribed time difference to the time during which each intermediate frequency signal is transmitted to a difference synthesizer. CONSTITUTION:Signal light 1 transmitted through the optical fiber is multiplexed with local oscillation light received from a light source having CW oscillation with an optical frequency slightly different from the light 1. This synthetic light is received by a photodetector such as a photodiode. For the light 1, the mark component is set ahead of the space component when the light 1 reaches a receiver. This relative time difference is eliminated by means of a delay line 12. In other words, the line 12 is put into one of two circuit systems separated by the BPF 6 and 7 so that said relative time difference is corrected. Then the difference synthesization is carried out for reproduction of a correct base band signal.

你已经成功收藏专利！

检索式保存成功!

IPRDB

热门服务

关于我们

友情链接

联系方式