JP2006195036A - Multiple optical signal processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a module which shapes and intensity modulates a plurality of optical signals at a time, and which transmits optical information to various networks by processing optical labels to be used in optical routing by one operation. <P>SOLUTION: The problem is solved by devising a planar light wave circuit module which is a PLC module having a substrate 2, an optical waveguide 3 formed on the substrate, and a mirror 4, wherein the optical waveguide is equipped with: two slab waveguides (5, 6); an array waveguide 7; an input waveguide 8 which is connected to one of the slab waveguides, and to which an optical signal is inputted from the outside of the planar light wave circuit module, is subjected to a prescribed processing, and subsequently the optical signal is outputted to the outside of the planar light wave circuit module; and an output waveguide 9 provided with L pieces of optical waveguides to connect the other remaining slab waveguide (the second slab waveguide 6) out of the two slab waveguides and the mirror 4 to each other, wherein the output waveguide 9 is equipped with an intensity modulator 10 and a phase modulator 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a planar lightwave circuit module and the like. More particularly, the present invention relates to a multiplexed optical signal processing device such as a planar lightwave circuit module used for photonic MPLS (multiprotocol label switching).

  In recent years, information communication using information communication networks such as the Internet has been widely used and the amount of information communication has been increasing. For this reason, research has been conducted on photonic networks that can transmit large amounts of information at high speed. In order to realize a photonic network, two elemental technologies are required: photonic transmission technology and photonic transfer technology.

  Optical code multiplexing (OCDM) has been developed as a photonic transmission technology. On the other hand, regarding information transfer, conventionally, optical information is once converted into electrical information and then converted back to optical information. However, in order to transfer optical information by electrical information, there is a problem that the effect of the photonic network is spoiled because it takes time. Instead of such an electrical router, a router that transfers optical information as is is expected. This is a photonic internet (IP) router, and the development of IP routing technology using such a router is desired.

  A manufacturing method of an arrayed waveguide grating type wavelength multiplexer / demultiplexer (AWG) and its application in the fields of optical communication, optical information processing, etc. are known (for example, Patent Document 1 below (Japanese Patent Laid-Open No. 11-38239)). (See the following Patent Document 2 (Japanese Patent Laid-Open No. 11-6928).)

Japanese Patent Laid-Open No. 11-38239 Japanese Patent Laid-Open No. 11-6928

  An object of the present invention is to provide a module capable of shaping a plurality of optical signals at a time and performing intensity modulation.

  It is an object of the present invention to provide a module that can be used for optical routing and collectively process optical labels and transfer optical information to different networks.

  The present invention is based on the knowledge that by applying intensity modulation and phase modulation to the output of AWG or the like, a plurality of optical signals can be shaped at once and intensity modulation can be performed. If used, it is possible to shape and amplify optical signals of a plurality of wavelengths at once. That is, the present inventors provide the following inventions.

  [1] A planar lightwave circuit module having a substrate, an optical waveguide formed on the substrate, an intensity modulator, a phase modulator, and a mirror, the optical waveguide comprising two slab waveguides and the 2 An planar waveguide having N optical waveguides for connecting two slab waveguides, and one of the two slab waveguides (first slab waveguide), and the planar lightwave circuit module M optical waveguides (M is an integer greater than or equal to 1) input waveguides from which optical signals are input from outside and subjected to predetermined processing and then output to the outside of the planar lightwave circuit module; A remaining slab waveguide (second slab waveguide) of the two slab waveguides, and an output waveguide having L optical waveguides connecting the mirrors, the output waveguide comprising intensity modulation And phase modulator Lena lightwave circuit module.

[2] The module as described above, wherein the phase modulator is a phase modulator using a thin film heater type thermo-optic phase shifter.

[3] A planar lightwave circuit module having a substrate and an optical waveguide formed on the substrate, wherein the optical waveguide includes two slab waveguides and N optical waveguides connecting the two slab waveguides. An arrayed waveguide having a waveguide and one of the two slab waveguides (first slab waveguide) are connected to each other, and an optical signal is input from outside the planar lightwave circuit module, and a predetermined process is performed. And M (where M is an integer of 1 or more) input waveguides from which the optical signal is output to the outside of the planar lightwave circuit module, and the remaining slab waveguides of the two slab waveguides An output waveguide comprising L optical waveguides coupled to (second slab waveguide), the output waveguide comprising: a first portion comprising an intensity modulator and a phase modulator; Is equivalent to part 1 A planar lightwave circuit module comprising a second portion (see FIG. 2).

[4] A module comprising M optical circulators provided in an optical path, M optical fibers connecting the planar lightwave circuit module and the optical circulator, and the planar lightwave circuit module according to any one of the above. .

  ADVANTAGE OF THE INVENTION According to this invention, the module which can shape a some optical signal at once and can perform intensity | strength modulation can be provided.

  ADVANTAGE OF THE INVENTION According to this invention, the module which processes the optical label used for optical routing collectively, and can transfer optical information to a different network can be provided.

  Hereinafter, the planar lightwave circuit (PLC) module according to the first embodiment of the present invention will be described. FIG. 1 shows a basic configuration of a planar lightwave circuit (PLC) module of the present invention. As shown in FIG. 1, a PLC module 1 according to the present invention is a PLC module having a substrate 2, an optical waveguide 3 formed on the substrate, and a mirror 4. The optical waveguide includes two slabs. A waveguide (5, 6), an arrayed waveguide 7 having N optical waveguides connecting the two slab waveguides, and one of the two slab waveguides (first slab waveguide) The optical signal is input from outside the planar lightwave circuit module and is subjected to predetermined processing, and then the M optical signals (M is output from the planar lightwave circuit module). (An integer greater than or equal to 1) input waveguide 8, the remaining slab waveguide (second slab waveguide 6) of the two slab waveguides, and L optical waveguides connecting the mirror 4. And an output waveguide 9 for transmitting the output waveguide. Road 9 relates planar lightwave circuit module having an intensity modulator 10 and phase modulator 11. In FIG. 1, 21 is an input port, 22 is an optical circulator, 23 is a PC (polarization controller and polarizer), 24 is an optical gate switch, and 25 is a correlation signal generator.

The substrate 2 and each waveguide 3 are not particularly limited as long as they can propagate light. For example, a Ti-diffusion lithium niobate waveguide may be formed on an LN substrate, or a silicon dioxide (SiO ₂ ) waveguide may be formed on a silicon (Si) substrate. Alternatively, an optical semiconductor waveguide in which an InGaAsP or GaAlAs waveguide is formed on an InP or GaAs substrate may be used. As the substrate, lithium niobate (LiNbO ₃ : LN) cut out so as to achieve X-cut Z-axis propagation is preferable. This is because a large electro-optic effect can be used, so that low power driving is possible and an excellent response speed can be obtained. The optical waveguide 3 is formed on the surface of the X-cut surface (YZ surface) of the substrate 2, and the guided light propagates along the Z axis (optical axis). A lithium niobate substrate other than the X-cut may be used. Further, a uniaxial crystal such as a trigonal crystal system or a hexagonal crystal system having an electro-optic effect, or a material whose crystal point group is C _3V , C ₃ , D ₃ , C _3h , D _3h can be used as the substrate. . These materials have a function of adjusting the refractive index so that the change in refractive index is different depending on the mode of propagating light by applying an electric field. Specific examples include lithium tantalate (LiTO ₃ : LT), β-BaB ₂ O ₄ (abbreviation BBO), LiTO _{3 and the} like in addition to lithium niobate.

  The size of the substrate is not particularly limited as long as a predetermined waveguide can be formed. The width, length, and depth of each waveguide are not particularly limited as long as the module of the present invention can exert its function. The width of each waveguide is, for example, about 1 to 20 micrometers, preferably about 5 to 10 micrometers. Further, the depth (thickness) of the waveguide is 10 nanometers to 1 micrometer, preferably 50 nanometers to 200 nanometers.

  The mirror 4 is not particularly limited as long as it can reflect light, and a known mirror can be used. The mirror may be provided in close contact with the substrate as shown in FIG. 1, or may be provided in the substrate.

The arrayed waveguides 7 are designed such that each one differs in length by a predetermined optical waveguide length (ΔL) and becomes longer sequentially. As a result, a phase difference (ΔΦ) occurs in each optical waveguide.
The wavelength interval (Δλ) of such an AWG type optical wavelength multiplexer / demultiplexer is defined by the array waveguide pitch (d), the optical waveguide length difference (ΔL), the effective refractive index (n _c ), and the group refractive index ( _ng). ), the optical waveguide spacing at the output channel optical waveguide and the input channel optical waveguide ([Delta] x), that the curvature of the slab optical waveguide radius (focal length) and (f) setting the value of such effective refractive index (n _s) it can. Further, referred to as a central light waveguide of the output channel optical waveguide frequency the center frequency of the light obtained from (diffraction angle of 0 degrees) (f _0), the center frequency (f _0), the diffraction light speed, the m C as orders, the details of f ₀ = mC / can be obtained by (n _c · ΔL) (AWG type optical wavelength demultiplexer, T.Takahashi, et al., J. Lightwave Technol. 12, p.989 , 1994). In the arrayed waveguide, each of a plurality of input optical signals can be output to the slab waveguide with a phase difference.

  The intensity modulator 10 is a device for controlling the intensity (amplitude) of an optical signal propagating through the output waveguide 9. A known variable optical attenuator (VOA) can be used as the intensity modulator. For example, a metal thin film heater formed on a waveguide is used as a heat source to change the refractive index in one arm waveguide of a Mach-Zehnder interferometer by a thermo-optic effect, thereby adjusting the output intensity of the interferometer ( For example, refer to JP 2000-352699 A). A VOA element using LN may be used as the intensity modulator 10 (see, for example, Japanese Patent Laid-Open No. 10-142569).

  The phase modulator 11 is a device for controlling the phase of the optical signal propagating through the output waveguide 9. As the phase modulator, a metal thin film heater formed on a waveguide is used as a heat source to cause a refractive index change in the waveguide by a thermo-optic effect, thereby controlling the phase of a propagating optical signal. The intensity modulator 10 and the phase modulator 11 are preferably connected to an external signal source so that the modulation timing is controlled.

  The operation of the PLC module of the present invention will be described below with reference to FIG. The optical path of the optical signal input from the input port 21 is adjusted by the optical circulator 22. And it inputs into the polarization controller (PC: Polarization Controller 23) which is arbitrary elements, and the deflection surface is adjusted. Thereafter, the signal is input to the input waveguide 8 of the PLC 1. Then, it passes through the AWG composed of the first slab type waveguide 5, the array type waveguide 7, and the second slab type waveguide 8, is spectrally decomposed, and is output to the output waveguide 9.

For example, in an AWG having five channels of input and output, when optical signals of λ ₁ , λ ₂ , λ ₃ , λ ₄ , and λ ₅ are input to all five input channels, the light output from the output channel The signals are, for example, (1) λ ₁ , λ ₂ , λ ₃ , λ ₄ , λ ₅ ; (2) λ ₂ , λ ₃ , λ ₄ , λ ₅ , λ ₁ ; (3) λ ₃ , λ ₄ , λ ₅ , λ ₁ , λ ₂ ; (4) λ ₄ , λ ₅ , λ ₁ , λ ₂ , λ ₃ ; (5) λ ₅ , λ ₁ , λ ₂ , λ ₃ , λ ₄ . That is, optical signals of the same wavelength input from a plurality of input channels to different input channels of the first slab waveguide 5 are always output from the output channel of the second slab waveguide 6 without excess or deficiency. .

  In the output waveguide, the intensity and phase of the optical signal are controlled by the intensity modulator 10 and the phase modulator 11 and reach the mirror 4. Since the modulation by the intensity modulator 10 and the phase modulator 11 is modulation in the output waveguide, even an optical signal from a different input channel differs depending on the output channel. This modulation also affects all optical signals propagating through the same output channel. Therefore, the waveform shaping and rate conversion of the five optical signals can be collectively adjusted by inputting an optical pulse train whose waveform is known in advance to the input channel port that matches the modulation amount of the five frequency plane channels. it can.

  On the other hand, the optical signal that has reached the mirror 4 is totally reflected by the mirror, passes through the phase modulator 11, the intensity modulator 10, and the AWG (6 to 8) again, and enters the optical circulator 22 from the input waveguide 8. And reach. The optical signal that reaches the optical circulator is output to the output port.

  With the module of the present invention, for example, after receiving an optical signal from the main network, an optical label having a plurality of wavelengths included in the optical signal is analyzed, and after performing spectral shaping and intensity correction, the local network The optical signal can be transferred to other networks. Therefore, even when an optical signal is transferred to a different network as in the prior art, it can be transferred as it is without being converted into an electrical signal once. Further, the waveform of the optical signal can be shaped and the intensity can be adjusted with the optical signal as it is.

  The PLC of the present invention is produced, for example, by the following method. That is, a waveguide is first formed on a substrate. The waveguide can be provided by performing a proton exchange method or a titanium thermal diffusion method on the surface of the lithium niobate substrate. For example, Ti metal stripes of about a few micrometers are formed on the LN substrate 2 in a row on the LN substrate by photolithography. Thereafter, the LN substrate 2 is exposed to a high temperature around 1000 ° C. to diffuse Ti metal into the substrate. In this way, a waveguide can be formed on the LN substrate.

  The electrode can be manufactured in the same manner as described above. For example, in order to form an electrode, the gap between the electrodes is set to about 1 to 50 micrometers with respect to both sides of a large number of waveguides formed with the same width by photolithography technology in the same manner as the formation of the optical waveguide. To form.

When a silicon substrate is used, for example, the module of the present invention can be manufactured as follows. A lower cladding layer mainly composed of silicon dioxide (SiO ₂ ) is deposited on a silicon (Si) substrate by flame deposition, and then silicon dioxide (SiO ₂ ) doped with germanium dioxide (GeO ₂ ) as a dopant is deposited. A core layer as a main component is deposited. Then, it is made into transparent glass by an electric furnace. Next, an optical waveguide portion is manufactured by etching, and an upper clad layer mainly composed of silicon dioxide (SiO ₂ ) is deposited again. Then, a thin film heater type thermo-optic intensity modulator and a thin film heater type thermo-optic phase modulator are formed on the upper cladding layer. Then, attach a mirror to the end of the PLC. In this way, the module of the present invention can be manufactured.

  In the following, another embodiment of the module of the present invention will be described with reference to FIG. The basic configuration and each element of the module of the present invention according to this aspect are the same as those described above. Therefore, in order to avoid repetition, these descriptions are applied mutatis mutandis and are omitted here. In the module of this embodiment, the mirror is removed from the module in FIG. 1, and an optical path to be a mirror image is provided on the substrate instead. Therefore, the operation is the same as that in FIG.

  However, although the module of the present invention described in FIG. 2 has more elements and requires a larger space than those of FIG. 1, for example, more intensity modulators and phase modulators than those of FIG. Each modulator can be manufactured relatively easily. Moreover, in FIG. 2, it is comprised symmetrically. In the module, an optical signal is output from the input waveguide 8 due to the sign. In this case, the input waveguide 8 to which light is output functions as an output waveguide. Needless to say.

  In FIG. 2, two intensity modulators 10 and two phase modulators 11 are provided in each waveguide, but one of them may be omitted.

The first embodiment relates to an OSS (optical spectrum synthesizer) using the PLC of the present invention.
FIG. 3 is a schematic configuration diagram of an OSS (optical spectrum synthesizer) using the PLC of the present invention. As shown in FIG. 3, the OSS includes an optical circulator that connects an input port, an output port, and a PLC, and a deflection controller (PC: Polarization Controller) provided between the optical circulator and the PLC. The PLC includes two slab waveguides, an arrayed waveguide provided between the two slab waveguides, an input waveguide, an output waveguide, and a mirror. A modulator (VOA) and a phase modulator (VOPS) were provided. The two slab waveguides and the arrayed waveguide constitute an AWG. The mirror used was a total reflection mirror. The AWG has 32 channels and a channel spacing of 19.90656 GHz.
FIG. 4 shows a schematic configuration diagram of an intensity modulator (VOA). As shown in FIG. 4, the VOA in the present embodiment has a Mach-Zehnder type structure and has a structure in which the upper and lower arms have heaters. The intensity of the optical signal transmitted through the waveguide can be controlled by controlling the value of the current flowing through the heaters. The current value applied to the heater was controlled every 3 ms.

  FIG. 5 shows a schematic configuration diagram of the phase modulator (VOPS). As shown in FIG. 5, the VOPS in this embodiment has a structure having a heater in the waveguide. The phase of the optical signal transmitted through the waveguide can be controlled by controlling the value of the current flowing through the heater. The current value applied to the heater was controlled every 3 ms. The optical path on the PLC was adjusted so that the length from the input end of the 32-channel AWG to the mirror was the same for all spectrum channels.

  The operation of the OSS of this embodiment will be described below. The optical signal input from the input port is input to the PC via the optical circulator, and its deflection surface is adjusted. Thereafter, the signal is input to the input waveguide of the PLC. Then, it passes through the first slab type waveguide, the array type waveguide, and the second slab type waveguide (32 channel AWG), is spectrally resolved, and is output to the output waveguide. In the output waveguide, the intensity and phase of the optical signal are controlled by the VOA and VOPS, and reach the mirror. The optical signal that reaches the mirror is totally reflected by the mirror, passes through the VOPS, VOA, and AWG again and reaches the optical circulator from the input waveguide. The optical signal that reaches the optical circulator is output to the output port.

  FIG. 6 is a conceptual diagram for explaining the principle of optical spectrum shaping. FIG. 6A is a diagram illustrating an example of an input optical signal having a comb-like spectrum shape. FIG. 6B is a diagram illustrating an example of intensity modulation and phase modulation for each frequency. FIG. 6C is a diagram showing the spectrum of the optical signal after the input optical signal of FIG. 6A has undergone the modulation shown in FIG. 6B.

  Each wavelength channel of the OSS of this embodiment can be shifted as a whole in accordance with the center wavelength of the optical signal to be controlled. For example, when an input optical signal having a comb-like spectral shape shown in FIG. 6A is input to the OSS of this embodiment, the OSS displays, for example, in FIG. 6B for each mode. Apply the indicated intensity modulation and phase modulation. Then, the input signal on the input comb is shaped according to the modulation function shown in FIG. 6 (B) and becomes an optical signal as shown in FIG. 6 (C). Thus, the spectrum of the output signal can be controlled by adjusting the functions controlled by the intensity modulator and the phase modulator.

  The second embodiment relates to a variable rate pulse generation system using the PLC of the present invention. In the present embodiment, 20 GHz, 40 GHz, 80 GHz, and 160 GHz RZ pulse trains and CS (carrier suppression) -RZ pulse trains were generated.

  FIG. 7 is a schematic configuration diagram of a rate variable pulse generation system using the PLC of the present invention. As shown in Fig. 7, the rate-variable pulse generation system of this embodiment is composed of a 10 GHz signal generator (SG), a mode-locked laser (MLLD), a time division multiplexing device (OTDM-MUX) from 10 GHz to 20 GHz, an optical spectrum OSS including analyzer (OSA) and / or streak camera, polarization adjuster (PC), optical circulator, PC, and PLC. In the present embodiment, the part related to the OSS is the same as that of the first embodiment. Each device is connected by a dispersion compensating fiber (DSF). Although not specifically shown, optical loss in the system is compensated by an optical fiber amplifier such as EDFA. The MLLD was used to generate an RZ (return to zero) pulse train with a repetition rate of 9.95328 GHz, a full width at half maximum (FWHM) of 2 ps, and a center frequency of 1552.69 nm. Optical pulses generated by MLLD are multiplexed into a pulse train of 19.90656 GHz (twice the equivalent of OC-192) by OTDM-MUX. The optical pulse is then input to the OSS via the optical circulator. In the OSS, as described in the first embodiment, predetermined modulation is performed according to functions given to the intensity modulator and the phase modulator. The spectrum of the output optical signal from OSS was observed with OSA and streak camera. The results are shown in FIGS.

  FIG. 8 is a diagram showing the spectrum of the RZ pulse train generated by this embodiment. FIGS. 8A, 8B, 8C, and 8D are spectrum diagrams of RZ pulse trains of 20 GHz, 40 GHz, 80 GHz, and 160 GHz, respectively. FIG. 8F is a spectrum diagram of a 160-GHz CS-RZ pulse train. FIG. 9 is a diagram showing a spectrum waveform observed by a streak camera. FIG. 9A, FIG. 9B, FIG. 9C, and FIG. 9D are diagrams showing spectrum waveforms of RZ pulse trains of 20 GHz, 40 GHz, 80 GHz, and 160 GHz, respectively. FIG. 9F shows a spectrum waveform of a 160-GHz CS-RZ pulse train.

  The 20 GHz RZ spectrum sequence shown in FIG. 8A shows a 32-channel original spectrum distribution in which the 10 GHz optical pulse signal output from the MLLD is doubled by OTDM-MUX. When every other 32 channel signal is suppressed by an OSS intensity modulator, those pulses are suppressed, and an RZ pulse train having the spectrum shown in FIG. 8B can be obtained. That is, as shown in FIG. 9B, a pulse train having a period of 40 GHz can be generated. Similarly, an RZ pulse train such as 160 GHz could be obtained by repeating predetermined operations. Once the OSS control conditions were set, the rate could be changed repeatedly in 3 ms.

In this embodiment, a CS (carrier suppression) -RZ pulse train is generated as follows.
The CS-RZ modulation method can compress the spectral band more than the RZ modulation method, and is less susceptible to dispersion caused by fiber propagation such as pulse waveform distortion.

  FIG. 10 is a diagram for explaining the difference between the RZ pulse and the CS-RZ pulse. When a CS-RZ pulse train is generated, the OSS modulation mode may be controlled as shown in FIG. As a result, it is possible to create a state in which the phases of adjacent pulses are inverted by π. That is, if the PLC (OSS) of the present invention is used, not only the RZ modulation signal but also the CS-RZ modulation signal can be obtained. The results are as shown in FIGS. 8E and 9E.

  In this example, it was confirmed as follows that the CS-RZ pulse train generated as described above is a pulse train that repeats phase inversion. FIG. 11 is a conceptual diagram of a 1-bit shift interferometer for confirming that the CS-RZ pulse train generated in the second embodiment is a pulse train that repeats phase inversion. As shown in FIG. 11, in this verification experiment, verification was performed by inputting a 160 GHz RZ pulse train generated using the above system and a 160 GHz CS-RZ pulse into a 1-bit interference system. The result is shown in FIG.

  FIG. 12 is a spectrum diagram showing the result of the verification experiment in the example. FIG. 12A is a spectrum diagram in which one memory on the horizontal axis is every 2 ns. On the other hand, FIG. 12B is a spectrum diagram in which one memory on the horizontal axis is every 20 ps.

  In the following, it is shown that the pulse waveform shaping can be performed using the variable rate pulse generation system of the second embodiment. The system basically uses the system of Example 2 shown in FIG. 7 as it is, but inserts a dispersion medium after OTDM-MUX, and distorts the 20 GHz pulse output from OTDM-MUX. A pulse with distortion was input to the OSS. The result is shown in FIG.

  FIG. 13 is a spectrum showing the result of the waveform shaping experiment in Example 3. FIG. 6A shows a pulse that has been distorted by a dispersion medium and spread. FIG. 6 (B) shows the spectrum after the distortion is received by the dispersion medium and the spread pulse is input to the OSS and the amplitude and phase of each mode of the spectrum are adjusted and shaped. FIG. 6C shows a SHG correlation waveform of a pulse that has been distorted by the dispersion medium and spread. FIG. 6D shows an SHG correlation waveform after the pulse that has been distorted by the dispersion medium is input to the OSS and the amplitude and phase of each mode of the spectrum are adjusted and shaped.

  Before shaping, the half width of the correlation waveform was 5.458 ps, whereas the half width of the correlation waveform after shaping was 3.286 ps. Therefore, it was found that the waveform can be shaped effectively by using OSS. Furthermore, it is considered that the spectrum waveform can be shaped with higher accuracy by increasing the number of OSS channels.

Signals of λ ₁ to λ ₅ are input to each input waveguide. The input signal is subjected to spectral decomposition via the AWG, and (1) λ ₁ , λ ₂ , λ ₃ , λ ₄ , λ ₅ ; (2) λ ₂ , λ ₃ , λ ₄ , λ ₅ , λ ₁ ; (3) λ ₃ , λ ₄ , λ ₅ , λ ₁ , λ ₂ ; (4) λ ₄ , λ ₅ , λ ₁ , λ ₂ , λ ₃ ; (4) λ ₅ , λ ₁ , λ ₂ , It is output as λ ₃ and λ ₄ . The output optical signal is subjected to intensity modulation and phase modulation in the output waveguide, and reaches the mirror. Furthermore, it is converted into an optical signal via the AWG.

An optical spectral domain matched filtering experiment using three OSSs of the present invention was conducted. Optical packet switching (OPS) technology using optical label processing is expected to drastically improve the transfer rate in a photonic network node. The optical domain matched filtering technology plays an important role in realizing optical packet switching. FIG. 14 shows a schematic configuration diagram of an optical spectrum domain matched filtering (all-optical label recognition) experiment system using OSS. The system consists of 10GHz-MLLD, LiNbO3 optical intensity modulator (LN-IM), pulse pattern generator (PPG), OTDM-MUX, PC, 3dB coupler, monitors, and OSS3 set connected via optical circulator. Composed. In this experimental system, OOS is. Functions as a spectral domain encoder and decoder. The 10 GHz pulse output from MLLD (mode-locked laser diode) is frequency-divided to 1/64 by LN-IM (lithium niobium intensity modulator) and then input to OTDM-MUX (multiplexer) Is done. As a result, a pair of pulses with intervals of 50 ps, corresponding to 20 GHz, was obtained one after another with repetitions equivalent to 10/64 GHz. Here, the time interval equivalent to 10/64 GHz was regarded as the minimum value of the interval at which packets fly. The generated pulse pairs with 50 ps intervals were input to two independent OSS and encoded into different combinations of spectral shapes. In the experimental system, the prime code was used for encoding. The two encoded signals were combined by a coupler and then decoded by a third OSS.

  The experimental results of Example 5 are shown in FIG. FIG. 15 (a) is a graph showing the waveforms of the generated pulse pairs at intervals of 50 ps having repetitions equivalent to 10/64 GHz. FIGS. 15B and 15C are graphs showing signal waveforms encoded by the OSS set to different codes. FIGS. 15D and 15E are graphs showing the spectra of the respective encoded signals. FIGS. 15 (f) and 15 (g) are graphs showing time waveforms and spectra of two types of codes that are combined. Comparing FIGS. 15 (f) and 15 (g) with FIGS. 15 (b) and 15 (c) and FIGS. 15 (d) and 15 (e), two types of signals are combined in the time domain and the spectral domain. Can be confirmed. FIGS. 15 (h) and (i) are graphs showing the output waveforms of the receiving OSS functioning as a decoder, and FIGS. 15 (j) and (k) are graphs showing the spectrum of the decoded signal in each case. It is. 15 (h) shows a case where the code of the decoder matches the code in FIG. 15 (d), and FIG. 15 (i) shows a case where the code of the decoder matches the code of FIG. 15 (e). It corresponds to. From this experimental result, it was confirmed that matched filtering in the optical spectrum region using OSS functions well.

  ADVANTAGE OF THE INVENTION According to this invention, the module which can shape a some optical signal at once and can perform intensity | strength modulation can be provided. Therefore, the present invention can be suitably used in optical information communication, particularly wavelength division multiplexing communication. Further, according to the present invention, it is possible to provide a module capable of collectively processing optical labels used for optical routing and transferring optical information to different networks. Therefore, the present invention can be used as a photonic internet router.

FIG. 1 is a schematic configuration diagram of a module according to the first embodiment of the present invention. FIG. 2 is a schematic configuration diagram of a module according to the second embodiment of the present invention. FIG. 3 is a schematic configuration diagram of an OSS (optical spectrum synthesizer) using the PLC of the present invention. FIG. 4 is a schematic configuration diagram of an intensity modulator (VOA). FIG. 5 is a schematic configuration diagram of a phase modulator (VOPS). FIG. 6 is a conceptual diagram for explaining the principle of optical spectrum shaping. FIG. 6A is a diagram illustrating an example of an input optical signal having a comb-like spectrum shape. FIG. 6B is a diagram illustrating an example of intensity modulation and phase modulation for each frequency. FIG. 6C is a diagram showing the spectrum of the optical signal after the input optical signal of FIG. 6A has undergone the modulation shown in FIG. 6B. FIG. 7 is a schematic configuration diagram of a rate variable pulse generation system using the PLC of the present invention. FIG. 8A is a spectrum diagram of a 20 GHz RZ pulse train generated by this embodiment. FIG. 8B is a spectrum diagram of the 40 GHz RZ pulse train generated by this embodiment. FIG. 8C is a spectrum diagram of an 80 GHz RZ pulse train generated by this embodiment. FIG. 8D is a spectrum diagram of the 160 GHz RZ pulse train generated by this example. FIG. 8E is a spectrum diagram of a 160 GHz RZ pulse train generated by this example. FIG. 8F is a spectrum diagram of a 160-GHz CS-RZ pulse train generated by this example. FIG. 9A is a diagram showing a spectrum waveform observed by a streak camera of a 20 GHz RZ pulse train generated according to this embodiment. FIG. 9B is a diagram showing a spectrum waveform observed by a streak camera of a 40 GHz RZ pulse train generated according to this embodiment. FIG. 9C is a diagram showing a spectrum waveform observed by the streak camera of the 80 GHz RZ pulse train generated by the present embodiment. FIG. 9D is a diagram showing a spectrum waveform observed by a streak camera of an RZ pulse train of 160 GHz generated according to the present embodiment. FIG. 9E is a diagram showing a spectrum waveform observed with a streak camera of a 160 GHz RZ pulse train generated according to the present embodiment. FIG. 9F is a diagram showing a spectrum waveform observed with a streak camera of a 160-GHz CS-RZ pulse train generated according to the present embodiment. FIG. 10 is a diagram for explaining the difference between the RZ pulse and the CS-RZ pulse. FIG. 11 is a conceptual diagram of a 1-bit shift interferometer for confirming that the CS-RZ pulse train generated in the second embodiment is a pulse train that repeats phase inversion. FIG. 12 is a spectrum diagram showing the result of the verification experiment in the example. FIG. 12A is a spectrum diagram in which one memory on the horizontal axis is every 2 ns. On the other hand, FIG. 12B is a spectrum diagram in which one memory on the horizontal axis is 20 ps. FIG. 13 is a spectrum showing the result of the waveform shaping experiment in Example 3. FIG. 14 is a schematic configuration diagram of a spectral domain matched filtering experiment system in the fourth embodiment. FIG. 15 is a graph showing the results of a matched filtering experiment in Example 5. FIG. 15 (a) is a graph showing the waveforms of the generated pulse pairs at intervals of 50 ps having repetitions equivalent to 10/64 GHz. FIGS. 15B and 15C are graphs showing signal waveforms encoded by the OSS set to different codes. FIGS. 15D and 15E are graphs showing the spectra of the respective encoded signals. FIGS. 15 (f) and 15 (g) are graphs showing time waveforms and spectra of two types of codes that are combined. FIGS. 15 (h) and (i) are graphs showing the output waveforms of the receiving OSS functioning as a decoder, and FIGS. 15 (j) and (k) are graphs showing the spectrum of the decoded signal in each case. It is.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Planar lightwave circuit (PLC) module 2 Substrate 3 Waveguide 4 Mirror 5 1st slab waveguide 6 2nd slab waveguide 7 Array waveguide 8 Input waveguide 9 Output waveguide
10 Intensity modulator
11 Phase modulator
21 Input port
22 Optical circulator
23 PC (polarization controller)
24 optical gate switch
25 Correlation signal generator

Claims (4)

A planar lightwave circuit module having a substrate and an optical waveguide, an intensity modulator, a phase modulator, and a mirror formed on the substrate,
The optical waveguide is
Two slab waveguides,
An arrayed waveguide comprising N optical waveguides connecting the two slab waveguides;
The optical signal is connected to one of the two slab waveguides (first slab waveguide), and an optical signal is input from outside the planar lightwave circuit module and subjected to predetermined processing, and then the optical signal Are output to the outside of the planar lightwave circuit module M (M is an integer of 1 or more) input waveguides;
A remaining slab waveguide (second slab waveguide) of the two slab waveguides, and an output waveguide having L optical waveguides connecting the mirrors;
The output waveguide is a planar lightwave circuit module including an intensity modulator and a phase modulator.   The module according to claim 1, wherein the phase modulator is a phase modulator using a thin film heater type thermo-optic phase shifter. A planar lightwave circuit module having a substrate and an optical waveguide formed on the substrate,
The optical waveguide is
Two slab waveguides and an arrayed waveguide comprising N optical waveguides connecting the two slab waveguides;
The optical signal is connected to one of the two slab waveguides (first slab waveguide), and an optical signal is input from outside the planar lightwave circuit module and subjected to a predetermined process. M is output to the outside of the planar lightwave circuit module (M is an integer of 1 or more),
An output waveguide comprising L optical waveguides coupled to the remaining slab waveguide (second slab waveguide) of the two slab waveguides;
The output waveguide includes a first portion comprising an intensity modulator and a phase modulator;
A planar lightwave circuit module comprising a second portion equivalent to the first portion. M optical circulators provided in the optical path;
M optical fibers connecting the planar lightwave circuit module and the optical circulator;
A module comprising the planar lightwave circuit module according to claim 1.

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