JP4572141B2 - COMMUNICATION SYSTEM, COMMUNICATION METHOD, AND COMMUNICATION DEVICE - Google Patents

Description

  The present invention relates to a communication system, a communication method, and a communication apparatus, and more particularly to a communication system, a communication method, and a communication apparatus using time-division multiplexed optical signals.

  With the development of information technology in recent years, there is an increasing demand for a high-capacity and high-quality Internet environment at home. In order to meet such a demand, FTTH (Fiber To The Home) service for connecting a subscriber to the Internet network via an optical fiber is rapidly spreading.

  The FTTH configuration uses a single star network that connects a base station and each subscriber's home with a dedicated optical fiber, and an optical fiber with one end branched into a plurality of base stations and a plurality of subscriber homes. It is classified as a double star network that is connected in a 1: n relationship. In providing the FTTH service, a double star network that requires less optical fiber installation is more cost effective.

  In a double star network, multiple subscriber homes are connected to the base station via the same optical fiber. Therefore, when transmitting data from the base station to the designated subscriber home, The data is transmitted all at once to the subscriber's home, and each subscriber's home extracts the data addressed to itself.

In order to realize such a configuration, a time division multiplexing method has been generally used. For example, in Patent Document 1, downlink data is transmitted in a time-division multiplexed manner for each bit or byte on the base station side, and an optical signal transmitted at each subscriber's home is time-division separated for each bit or byte. A configuration for reproducing the original data is disclosed.
JP 11-298430 A

  By the way, the base station generates an optical signal at a necessary modulation speed according to the number of subscriber houses to be connected and the communication speed between the base station and each subscriber house. And a base station will transmit the optical signal of a higher modulation speed with the increase in a subscriber's house, and the improvement of communication speed.

  On the other hand, each subscriber's house converts all optical signals transmitted from the base station into electrical signals, and extracts data addressed to itself by electrical processing. Therefore, the photoelectric converter according to the modulation speed of the optical signals Or a processing circuit is required.

  Therefore, if an attempt is made to increase the modulation rate of the optical signal in order to increase the number of subscriber houses and communication speed, a high-speed photoelectric converter is required at each subscriber house, which increases the cost of the entire system. There was a problem.

  Accordingly, the present invention has been made to solve such a problem, and an object of the present invention is to provide a time division multiplexing communication system, a communication method, and a communication system capable of realizing a high communication speed while suppressing costs at a subscriber's home. It is to provide a communication device.

  According to the present invention, a transmission line, a first communication device that transmits a plurality of data with different destinations via the transmission line, and a plurality of data transmitted from the first communication device are addressed to itself. It is a communication system provided with the 2nd communication apparatus which extracts and receives data. The first communication device includes a first sending means for sending a first optical signal time-division-multiplexed by sequentially assigning a plurality of data to time slots divided at a predetermined time interval, and a first sending means, Second transmission means for transmitting the second optical signal having the maximum intensity to the transmission line in the same period as the period in which the data having the same destination in the optical signal is assigned, and the second communication device includes: Synchronization means for receiving the first and second optical signals and synchronizing the time slot to which data destined for the first optical signal is assigned and the timing having the maximum intensity in the second optical signal; Based on the optical interaction generating means for generating an optical interaction between the first optical signal and the second optical signal synchronized in the synchronizing means, and the third optical signal generated in the optical interaction generating means Decrypt data And means.

  Preferably, the second optical signal is an optical pulse having a time width equal to or less than a time slot in the first optical signal.

Preferably, the synchronization unit includes a delay unit that delays the second optical signal by a predetermined time.
Preferably, the first and / or second communication device further includes dispersion compensation means for compensating for chromatic dispersion occurring in the transmission path.

  Preferably, the second communication device further includes transmission means for transmitting data to the first communication device using the second optical signal as a carrier wave, and the first communication device is connected to the second communication device. It further includes receiving means for receiving the transmitted data.

  Preferably, the transmission means modulates the second optical signal with the transmission data and then converts it into an optical diffusion code, and the reception means decodes the optical diffusion code received from the second communication device into transmission data.

  Preferably, the optical communication device further includes an optical signal generation unit that supplies the second optical signal to the first communication device, and the second transmission means transmits the second optical signal received from the optical signal generation unit, and the optical signal The generation unit supplies the second optical signal to the first communication device in another communication system in addition to the first communication device.

  In addition, according to the present invention, between the first communication device that transmits a plurality of data with different destinations via the transmission path, and the second communication device that extracts and receives the data addressed to itself It is a communication method. A first transmission step of transmitting a first optical signal time-division-multiplexed by sequentially allocating a plurality of data to time slots divided by a predetermined time interval by the first communication device; A second sending step in which the communication device sends a second optical signal having the maximum intensity to the transmission line in the same period as the period in which data having the same destination is assigned in the first optical signal; Synchronization in which the device receives the first and second optical signals and synchronizes the time slot in which data destined for itself is assigned in the first optical signal and the timing having the maximum intensity in the second optical signal An optical interaction generating step for generating an optical interaction between the first optical signal and the second optical signal that are synchronized in the synchronization step in the second communication device; and Interaction Based on the third optical signal generated in step and a decoding step of decoding the data.

  Preferably, the method further includes a dispersion compensation step in which the first and / or second communication device compensates for chromatic dispersion generated in the transmission path.

  Preferably, a transmission step in which the second communication apparatus transmits data to the first communication apparatus using the second optical signal as a carrier wave, and data transmitted from the second communication apparatus by the first communication apparatus. And a receiving step for receiving.

  Moreover, according to this invention, it is a communication apparatus which transmits several data from which a destination differs via a transmission line. A first sending means for sending a first optical signal time-division-multiplexed by sequentially assigning a plurality of data to time slots divided by a predetermined time interval, and a first optical signal and an optical interaction; So that the data addressed to any one of the plurality of destinations can be decoded, have a wavelength different from that of the first optical signal, and have the same destination in the first optical signal. And a second sending means for sending a second optical signal having the maximum intensity to the transmission line in the same cycle as the data is assigned.

  Moreover, according to this invention, it is a communication apparatus which extracts and receives the data destined for itself among a plurality of data having different destinations transmitted via the transmission path. The first optical signal time-division-multiplexed by sequentially assigning a plurality of data to time slots divided by a predetermined time interval and the same period as the data having the same destination in the first optical signal are assigned. Synchronization means for receiving a second optical signal having a maximum intensity in a period and synchronizing a time slot in which data addressed to itself is included in the first optical signal and a timing having the maximum intensity in the second optical signal; Based on the optical interaction generating means for generating an optical interaction between the first optical signal and the second optical signal synchronized in the synchronizing means, and the third optical signal generated in the optical interaction generating means Decoding means for decoding the data.

  According to the present invention, the first optical signal obtained by time-division-multiplexing a plurality of data sequentially assigned to the time slots divided by a predetermined time interval, and the same cycle as the cycle in which the data having the same destination is assigned at the maximum By transmitting a second optical signal having an intensity and synchronizing a time slot in the first optical signal and a timing at which the second optical signal has the maximum intensity, data directed to a desired destination is transmitted. Extract. Therefore, on the receiving side, it is only necessary to synchronize the desired time slot with the timing of maximum intensity regardless of the data modulation rate. Accordingly, it is possible to realize a time division multiplexing communication system, communication method, and communication apparatus having a high communication speed while suppressing costs.

  Embodiments of the present invention will be described in detail with reference to the drawings. Note that the same or corresponding parts in the drawings are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
FIG. 1 is a schematic configuration diagram of a communication system 100 according to the first embodiment of the present invention.

  Referring to FIG. 1, a communication system 100 includes a base station side device 1 and subscriber premises side devices 2.1, 2.2,. n, transmission lines 20 and 24, an optical distribution unit 22, and an optical coupling unit 26. The base station apparatus 1 includes a transmission unit 1.1 and a reception unit 1.2.

  The transmission unit 1.1 in the base station side device 1 is a subscriber home side device 2.1, 2.2,... From the Internet network or WAN (Wide Area Network) (not shown), respectively. 2. An optical data signal obtained by time-division multiplexing downlink data 1, 2,..., n to be transmitted to n is generated and transmitted via the transmission path 20. The transmission unit 1.1 includes an encoding unit 30, a light source 10, an optical modulation unit 32, a pulse generation unit 12, and an optical coupling unit 34.

  The encoding unit 30 receives the downlink data 1, 2,..., N from the outside, and assigns the downlink data 1, 2,. Sequential assignment is encoded into a binary data string composed of one-dimensional “0” and “1”. Then, the encoding unit 30 outputs the encoded data string to the optical modulation unit 32.

  The light source 10 is composed of a laser oscillator and generates laser light having a wavelength λ1 having a predetermined light intensity. Then, the light source 10 outputs the generated laser light to the light modulation unit 32.

  Based on the data string received from the encoding unit 30, the optical modulation unit 32 modulates the intensity of the laser light output from the light source 10 to generate an optical data signal. In the first embodiment, the light modulation unit 32 performs modulation so that the light intensity is zero or maximum, that is, “off” or “on”, corresponding to “0” or “1” of the data string. . In this way, the optical modulation unit 32 generates an optical data signal obtained by time-division multiplexing the downlink data 1, 2,. Then, the optical modulation unit 32 outputs the generated optical data signal to the optical coupling unit 34.

  In the optical data signal generated by the optical modulation unit 32, the pulse generation unit 12 has a cycle in which data having the same destination is allocated, that is, until the allocation of the downlink data 1, 2,. An optical pulse signal having a period of time required is generated. Further, the pulse width generated by the pulse generator 12 is equal to or less than the time slot. Then, the pulse generator 12 outputs the generated optical pulse signal to the optical coupler 34.

  The optical coupling unit 34 couples the optical data signal received from the optical modulation unit 32 and the optical pulse signal received from the pulse generation unit 12, and outputs them to the transmission path 20.

  The transmission path 20 is composed of an optical fiber, connects the transmission unit 1.1 and the optical distribution unit 22, and transmits the optical data signal and the optical pulse signal transmitted from the transmission unit 1.1 to the optical distribution unit 22. .

  The optical distribution unit 22 divides the optical data signal and the optical pulse signal received via the transmission path 20 into n, and the divided optical data signal and optical pulse signal are respectively connected to the subscriber premises devices 2.1, 2.2, ..., 2. output to n.

  1. Subscriber premises equipment 2.1, 2.2,... n extracts data addressed to itself from the optical data signal received from the base station side apparatus 1, and decodes and outputs the data to downlink data 1, 2,..., n, respectively. Further, the subscriber premises equipment 2.1, 2.2,. n transmits an optical data signal including uplink data 1, 2,..., n to be transmitted to the base station side apparatus 1.

  The subscriber premises apparatus 2.1 includes a waveform shaping unit 14, a delay unit 84.1, an optical distribution unit 60, an optical interaction generation unit 18, a decoding unit 86, an encoding unit 74, an optical modulation Part 75.

The waveform shaping unit 14 includes a dispersion compensation unit 16 and a wavelength selective light distribution unit 62.
The dispersion compensation unit 16 compensates for chromatic dispersion generated in the optical data signal and the optical pulse signal by propagating through the transmission line 20. The dispersion compensation unit 16 includes, for example, a dispersion compensation fiber (DCF: Dispersion Compensation Fiber) having the same magnitude as the chromatic dispersion of the transmission line 20 and having chromatic dispersion of the opposite sign.

  The wavelength selective light distributor 62 divides the optical data signal and the optical pulse signal received via the dispersion compensator 16 into two according to the wavelength. Then, the wavelength selective light distribution unit 62 outputs the optical data signal (wavelength λ1) to the optical interaction generation unit 18, and outputs the optical pulse signal (wavelength λ2) to the delay unit 84.1.

  The delay unit 84.1 delays the optical pulse signal by a predetermined time so that the timing when the maximum intensity in the optical pulse signal is synchronized with the time slot to which the downlink data 1 is assigned in the optical data signal. Then, the delay unit 84.1 outputs the delayed optical pulse signal to the optical distribution unit 60.

  The optical distribution unit 60 divides the optical pulse signal received from the delay unit 84.1 into two, and outputs the divided optical pulse signals to the optical interaction generation unit 18 and the optical modulation unit 75, respectively.

  The optical interaction generator 18 generates an interaction due to an optical nonlinear effect between the optical data signal and the optical pulse signal. In particular, the optical interaction generation unit 18 generates four-wave mixing (FWM: Four Wave Mixing), which is a kind of optical Kerr effect, and a difference Δλ between the wavelength λ1 of the optical data signal and the wavelength λ2 of the optical pulse signal (= Two new interaction lights having different wavelengths (λ1-Δλ) and (λ2 + Δλ) by | λ2-λ1 |) are output. As described above, since the timing at which the optical pulse signal has the maximum intensity is synchronized with the time slot to which the downlink data 1 is assigned, four-wave mixing occurs only during the period of the time slot to which the downlink data 1 is assigned. . Therefore, the optical interaction generation unit 18 outputs only the interaction light corresponding to the light intensity of the downlink data 1 out of the optical data signal to the decoding unit 86. That is, the optical interaction generator 18 extracts an optical signal modulated with data 1 from the optical data signal using the optical pulse signal. Hereinafter, the optical signal extracted from the optical data signal is also referred to as a DEMUX signal (separated signal).

  The decoding unit 86 generates a data string according to the light intensity of the DEMUX signal received from the optical interaction generation unit 18 and outputs the data string as downlink data 1.

  The encoding unit 74 receives the uplink data 1 from the outside and encodes it into a binary data string composed of one-dimensional “0” and “1”. Then, the encoding unit 74 outputs the encoded data string to the optical modulation unit 75.

  Based on the data string received from the encoding unit 74, the optical modulation unit 75 modulates the optical intensity of the optical pulse signal received from the optical distribution unit 60 to generate an optical data signal. Then, the light modulation unit 75 outputs the generated optical data signal to the optical coupling unit 26.

  Subscriber premises equipment 2.2, ..., 2. n, instead of the delay unit 84.1, delay units 84.2,. Except for the point that n is used, it is the same as subscriber premises apparatus 2.1, and therefore detailed description will not be repeated.

  Note that the delay units 84.1, 84.2,. n delays the optical pulse signal so that the timing at which the maximum intensity is synchronized with the time slot to which downlink data 1, 2,. , 84.2,. The amount of delay at n varies from time slot to time interval. Therefore, the delay units 84.1, 84.2,. The optical pulse signals output from n do not overlap each other on the time axis. Therefore, the subscriber premises equipment 2.1, 2.2,. The optical data signals transmitted from n do not interfere with each other.

  The optical coupling unit 26 includes subscriber premises devices 2.1, 2.2,. The optical data signals received from each of n are combined and output to the transmission line 24. As described above, the subscriber premises equipment 2.1, 2.2,. Since the optical data signals transmitted from n do not overlap with each other on the time axis, the combined optical data signal output from the optical coupling unit 26 is equivalent to the time-division multiplexed optical data signal.

  The transmission path 24 is composed of an optical fiber, connects the optical coupling unit 26 and the base station side device 1, and transmits the optical signal received from the optical coupling unit 26 to the base station side device 1.

  The receiving unit 1.2 in the base station side device 1 includes subscriber home side devices 2.1, 2.2,. The optical data signals received from n are decoded into upstream data 1, 2,..., n, respectively, and output to the Internet network or WAN (not shown). The receiving unit 1.2 includes a decoding unit 80.

  The decoding unit 80 converts the optical data signal received via the transmission path 24 into an electrical signal, and generates a binary data string “0” or “1”. And the decoding part 80 isolate | separates the produced | generated data sequence for every predetermined | prescribed time slot, decodes it to downlink data 1, 2, ..., n, and outputs it. The time interval of the time slot included in the optical data signal received through the transmission path 24 is the same as the time interval of the time slot of the data string generated by the encoding unit 30.

FIG. 2 is a schematic configuration diagram of the optical interaction generator 18.
Referring to FIG. 2, the optical interaction generator 18 includes an optical coupler 34, an optical amplifier 36, a highly nonlinear fiber 38, and an optical filter 40.

  The optical coupling unit 34 couples the optical data signal having the wavelength λ1 and the optical pulse signal having the wavelength λ2 and outputs the combined signal to the optical amplifier 36.

  The optical amplifier 36 amplifies the optical data signal and the optical pulse signal received from the optical coupling unit 34 so as to generate an optical nonlinear effect, and outputs the amplified signal to the highly nonlinear fiber 38.

  The highly nonlinear fiber 38 is made of a medium having a high nonlinear coefficient, and has a wavelength (λ1−Δλ) and a wavelength (λ2 + Δλ) by four-wave mixing of an optical data signal of wavelength λ1 having a predetermined light intensity and an optical pulse signal of wavelength λ2. ) Two new interaction lights.

  The optical filter 40 receives the optical data signal, the optical pulse signal, and the two interaction lights output from the highly nonlinear fiber 38, suppresses the optical data signal and the optical pulse signal, and selects one of the two interaction lights. Pass one or the other. Then, the optical filter 40 outputs the passed interaction light as a DEMUX signal.

FIG. 3 is a diagram for explaining four-wave mixing in the optical interaction generator 18.
FIG. 3A shows the frequency spectrum of the optical signal input to the optical interaction generator 18.

  FIG. 3B is a frequency spectrum of the optical signal output from the highly nonlinear fiber 38.

FIG. 3C shows the frequency spectrum of the optical signal output from the optical filter 40.
Referring to FIG. 3A, the optical data signal (wavelength λ1) and the optical pulse signal (wavelength λ2) amplified to a predetermined light intensity by the optical amplifier 36 are input to the optical interaction generator 18.

  Referring to FIG. 3B, when the optical data signal and the optical pulse signal propagate through the highly nonlinear fiber 38, four-wave mixing occurs and has a wavelength separated by a wavelength difference Δλ between the optical data signal and the optical pulse signal. Two interaction lights are generated.

  Referring to FIG. 3C, the optical filter 40 passes only one interaction light among the optical data signal, the optical pulse signal, and the two interaction lights, and outputs it as a DEMUX signal.

  In the first embodiment, for example, the wavelength λ1 of the optical data signal is set to 1550 [nm], and the wavelength λ2 of the optical pulse signal is set to 1555 [nm].

  FIG. 4 is a diagram for explaining data extraction in the subscriber premises devices 2.1 and 2.2. FIG. 4 is an example of a communication system including four customer premises devices 2.1, 2.2, 2.3, and 2.4.

FIG. 4A is a time waveform of the optical data signal output from the waveform shaping unit 14.
FIG. 4B is a time waveform of the optical pulse signal output from the waveform shaping unit 14.

  FIG. 4C is a time waveform of an optical pulse signal given to the optical interaction generator 18 in the subscriber premises apparatus 2.1.

  FIG. 4D shows a DEMUX signal output from the optical interaction generator 18 in the subscriber premises apparatus 2.1.

  FIG. 4E shows a time waveform of an optical pulse signal given to the optical interaction generator 18 in the subscriber premises apparatus 2.2.

  FIG. 4F shows a DEMUX signal output from the optical interaction generator 18 in the subscriber premises apparatus 2.2.

  Referring to FIG. 4A, the optical data signal has a light intensity corresponding to a binary data string consisting of “0” and “1”. Then, if the time interval of one time slot is t, the time T required for all the downlink data to make a round is T = t × 4.

  Referring to FIG. 4B, the optical pulse signal transmitted from the base station side device 1 has a light intensity peak at every time T during which all the downlink data allocation is completed.

  Referring to FIG. 4 (c), the delay unit 84.1 in the subscriber premises apparatus 2.1 uses the optical pulse signal so that the peak of the light intensity is synchronized with the time slot to which the downlink data 1 is allocated. Is delayed by the delay time Td1. Since the period of the time slot to which downlink data 1 is assigned coincides with the period of the optical pulse signal, there is no need to adjust the delay time Td1 for each time slot.

  Referring to FIG. 4D, the optical interaction generator 18 in the subscriber premises apparatus 2.1 outputs a DEMUX signal corresponding to the downlink data 1 in a period in which the optical intensity peak of the optical pulse signal exists. To do.

  Referring to FIG. 4 (e), the delay unit 84.1 in the subscriber premises apparatus 2.2 uses the optical pulse signal so that the peak of the light intensity is synchronized with the time slot to which the downlink data 2 is allocated. Is delayed by the delay time Td2. At this time, the delay time Td2 is longer by the time interval t of the time slot than the delay time Td1 of the delay unit 84.1 in the subscriber premises apparatus 2.1.

  Referring to FIG. 4 (f), similarly to FIG. 4 (d), the optical interaction generator 18 in the subscriber premises apparatus 2.2 is in the down period during the period in which the light intensity peak of the optical pulse signal exists. A DEMUX signal corresponding to data 2 is output.

  In the first embodiment, the encoding unit 30, the light source 10, and the light modulation unit 32 implement the first sending unit, the pulse generating unit 12 implements the second sending unit, and the delay units 84.1 and 84. 2, ..., 84. n realizes the synchronization means, the optical interaction generation unit 18 realizes the optical interaction generation means, the decoding unit 86 realizes the decoding means, the waveform shaping unit 14 realizes the dispersion compensation means, and the encoding unit 74 The optical modulation unit 75 implements a transmission unit, and the decoding unit 80 implements a reception unit.

(Modification 1)
Instead of the above-described optical interaction generator 18 made of a highly nonlinear fiber, an optical interaction generator made of a semiconductor optical amplifier can be used.

FIG. 5 is a schematic configuration diagram of the optical interaction generator 19 according to the first modification of the first embodiment.
Referring to FIG. 5, optical interaction generator 19 is obtained by replacing optical amplifier 36 and highly nonlinear fiber 38 with semiconductor optical amplifier 42 in optical interaction generator 18 shown in FIG. 2.

  The semiconductor optical amplifier 42 is an optical amplifier composed of semiconductor optical amplifiers (SOA: Semiconductor Optical Amplifiers), and increases the light intensity and at the same time causes an interaction due to an optical nonlinear effect. The semiconductor amplifying element is a semiconductor such as InP, InGaAs, or InGaAsP, for example.

  Optical coupling unit 34 and optical filter 40 are similar to optical interaction generation unit 18, and therefore detailed description will not be repeated.

  According to the modified example 1, since the optical interaction generator 19 does not use a highly nonlinear fiber, it is possible to realize a smaller size than the optical interaction generator 18 shown in FIG.

(Modification 2)
Instead of the above-described optical interaction generator 18 made of a highly nonlinear fiber, an optical interaction generator having a highly nonlinear fiber arranged in a loop shape can be used.

FIG. 6 is a schematic configuration diagram of the optical interaction generator 70 according to the second modification of the first embodiment.
Referring to FIG. 6, the optical interaction generating unit 70 is also called a nonlinear loop mirror, and includes optical branching units 66 and 68 and a highly nonlinear fiber 38.

  The optical branching unit 68 has four ports, two of which are connected to both ends of the highly nonlinear fiber 72. The remaining two ports function as an input port that receives an optical data signal and an output port that outputs a DEMUX signal.

  The optical branching unit 66 is inserted between the optical branching unit 68 and the highly nonlinear fiber 38, receives an optical pulse signal, and sends it to the highly nonlinear fiber 72.

  The highly nonlinear fiber 72 is made of a medium having a high nonlinear coefficient, and changes the phase of the optical data signal by an optical nonlinear effect between the optical data signal having the wavelength λ1 and the optical pulse signal having the wavelength λ2.

Hereinafter, the operation of the optical interaction generator 70 will be described.
The optical branching unit 68 receives the optical data signal, divides it into two, and outputs optical data signals that propagate clockwise and counterclockwise, respectively. If the optical pulse signal is not input, each of the divided optical data signals propagates through the highly nonlinear fiber 72 and then returns to the optical branching unit 68. Then, the optical data signals interfere with each other at the optical branching unit 68 and cancel each other. Therefore, no optical signal is output from the optical branching unit 68.

  On the other hand, when an optical pulse signal is input to the highly nonlinear fiber 72 via the optical branching unit 66, the rotational phase of the optical data signal changes due to the optical nonlinear effect in the process of propagating through the highly nonlinear fiber 72. Therefore, the optical data signals do not cancel each other due to insufficient interference at the optical branching unit 68. Therefore, a DEMUX signal corresponding to the optical interaction between the optical data signal and the optical pulse signal is output from the optical branching unit 68.

  In other words, specific data can be extracted from the optical data signal by synchronizing the time slot in the optical data signal with the optical intensity peak of the optical pulse signal and inputting it to the optical interaction generator 70.

  According to the second modified example, since an optical interaction can be generated even with an optical signal having a low light intensity, it is not necessary to excessively amplify the optical signal. For this reason, even if a low-power optical amplifier is used, sufficient optical interaction can be generated. Therefore, it is possible to realize a light interaction generator having a more economical configuration.

  According to the first embodiment of the present invention, the base station side apparatus makes a round of allocation of the optical data signal in which the downlink data is sequentially allocated to the time slots divided at predetermined time intervals and time-division multiplexed and the downlink data is allocated. An optical pulse signal having a period of time required for the transmission is transmitted to all the subscriber premises devices. Each subscriber premises apparatus delays the optical pulse signal by a predetermined time, and synchronizes the optical intensity peak with the time slot to which the downlink data addressed to itself is allocated in the optical data signal, so that the data addressed to itself is transmitted. To extract. Therefore, since the subscriber premises equipment does not need to monitor all the optical data signals transmitted from the base station side equipment, a high-speed photoelectric converter or processing circuit is not required, and the subscriber premises equipment is reduced. It can be realized at a cost. Further, even when the time interval of the time slot of the optical data signal is shortened along with the increase in the number of subscriber premises devices, each subscriber premises device has an optoelectric converter and processing circuit corresponding to its own communication speed. Therefore, it is sufficient to improve the communication speed of the entire system.

  Also, according to Embodiment 1 of the present invention, each subscriber premises apparatus transmits uplink data using the optical pulse signal received from the base station side apparatus as a carrier wave, so a high-speed optical pulse generator No need for a light modulation unit. Therefore, the subscriber premises apparatus can be realized at a low cost. Further, since the optical pulse signal generated according to the communication speed of the downlink data is used for the carrier wave, the uplink data can be transmitted at the same communication speed as that of the downlink data.

[Embodiment 2]
In the first embodiment, the case where the chromatic dispersion accumulated in the transmission path is compensated for both the optical data signal and the optical pulse signal has been described.

  On the other hand, in the second embodiment, a case where chromatic dispersion is compensated only for an optical pulse signal will be described.

FIG. 7 is a diagram for explaining the influence of chromatic dispersion in the transmission path.
FIG. 7A shows a time waveform of an optical data signal transmitted from the base station side device 1.

FIG. 7B is a time waveform of the optical data signal received by the subscriber premises apparatus 2.1.
FIG. 7C is an example of a time waveform of the optical pulse signal.

FIG. 7D is an example of a time waveform of the DEMUX signal.
Referring to FIG. 7A, the optical data signal transmitted from the base station side apparatus 1 has a pulse-like time waveform corresponding to the time slots divided at predetermined time intervals.

  Referring to FIG. 7B, chromatic dispersion is caused by propagation of the optical data signal through the transmission line 20, so that the pulse-like time waveform is distorted and causes interference with adjacent time slots.

  With reference to FIG. 7C and FIG. 7D, even if the time waveform of the optical data signal is distorted and interferes with an adjacent time slot, if there is a portion that does not interfere on the time axis, Data can be extracted by shortening the time during which the optical interaction with the optical pulse signal occurs.

  Accordingly, the subscriber premises apparatus 2.1 can extract the downlink data 1 addressed to itself from the optical data signal received from the base station apparatus 1 by performing dispersion compensation only on the optical pulse signal.

  FIG. 8 is a schematic configuration diagram of the waveform shaping unit 46 according to the second embodiment. The communication system according to the second embodiment is obtained by replacing the waveform shaping unit 14 with a waveform shaping unit 46 in the communication system 100 according to the first embodiment shown in FIG. Then, the waveform shaping unit 46 receives the optical data signal and the optical pulse signal, and performs dispersion compensation only on the optical pulse signal.

  Referring to FIG. 8, the waveform shaping unit 46 includes a wavelength selective light distribution unit 62 and a dispersion compensation unit 44.

  The wavelength selective light distribution unit 62 divides the optical data signal and the optical pulse signal into two according to the wavelength. Then, the wavelength selective light distribution unit 62 outputs the optical data signal having the wavelength λ1 to the outside as it is, and outputs the optical pulse signal having the wavelength λ2 to the dispersion compensation unit 44.

  The dispersion compensator 44 includes a fiber Bragg grating (FBG), a tunable dispersion compensator (VIPA: Virtually Imaged Phased Array), and the like, and compensates chromatic dispersion for an optical signal having a wavelength λ2.

In the second embodiment, the waveform shaping unit 46 realizes dispersion compensation means.
According to the second embodiment of the present invention, in addition to the effect of the first embodiment, dispersion compensation only needs to be performed on the optical pulse signal, so that dispersion compensation is performed on both the optical data signal and the optical pulse signal. Compared to the case of performing the above, a dispersion compensation unit having a narrow wavelength band can be configured. Therefore, since an inexpensive dispersion compensator can be employed, the subscriber premises apparatus can be realized at a lower cost.

[Embodiment 3]
In the first and second embodiments, the case where the received optical pulse signal is shaped by giving chromatic dispersion has been described.

  On the other hand, in the third embodiment, a case where an optical pulse signal is generated according to a change in light intensity included in the received optical pulse signal will be described.

  FIG. 9 is a schematic configuration diagram of the waveform shaping unit 64 according to the third embodiment. The communication system according to the third embodiment is obtained by replacing the waveform shaping unit 14 with the waveform shaping unit 64 in the communication system 100 according to the first embodiment shown in FIG. Then, the waveform shaping unit 64 newly generates and outputs an optical pulse signal in accordance with the light intensity change included in the optical pulse signal.

  Referring to FIG. 9, the waveform shaping unit 64 includes a wavelength selective light distribution unit 62 and an injection locked laser 48.

  The wavelength selective light distribution unit 62 divides the optical data signal and the optical pulse signal into two according to the wavelength. Then, the wavelength selective light distributor 62 outputs the optical data signal having the wavelength λ1 to the outside as it is, and outputs the optical pulse signal having the wavelength λ2 to the injection locking laser 48.

  When an optical pulse signal is input, the injection-locked laser 48 generates and outputs an optical pulse signal in synchronization with the input. The injection locking laser 48 includes an optical branching unit 56 and an optical amplifier 58.

  The optical branching unit 56 has four ports, two of which are connected to both ends of the optical amplifier 58. The remaining two ports function as an input port that receives an optical pulse signal and an output port that outputs the generated optical pulse signal.

In the second embodiment, the waveform shaping unit 64 implements dispersion compensation means.
According to the third embodiment of the present invention, in addition to the effects of the first embodiment, a new optical pulse signal is generated. Therefore, compared with the case where the optical pulse signal is shaped by applying dispersion compensation, the optical pulse signal is sharper. A simple light pulse can be applied to the light interaction generator. Therefore, even when the time waveform is distorted due to the influence of chromatic dispersion and the amount of interference with adjacent time slots becomes large, decoding with suppressed detection errors can be realized.

[Embodiment 4]
In the first and second embodiments, the case where the chromatic dispersion accumulated in the transmission line in the subscriber premises apparatus is compensated has been described.

  On the other hand, in Embodiment 4, a case will be described in which reverse dispersion is applied in advance in the base station side apparatus for transmission.

FIG. 10 is a schematic configuration diagram of a communication system 102 according to the fourth embodiment of the present invention.
Referring to FIG. 10, the communication system 102 includes a base station side device 3 and subscriber home side devices 4.1, 4.2,. n, transmission lines 20 and 24, an optical distribution unit 22, and an optical coupling unit 26. The base station side device 3 includes a transmission unit 3.1 and a reception unit 1.2.

  The transmission unit 3.1 is obtained by adding an inverse dispersion applying unit 96 to the transmission unit 1.1 of the base station apparatus 1 in the first embodiment.

  The inverse dispersion applying unit 96 is interposed between the pulse generating unit 12 and the optical coupling unit 34, and the subscriber home side devices 4.1, 4.2,. The optical pulse signal transmitted to n is given the same magnitude as the chromatic dispersion of the transmission line 20 and the chromatic dispersion of the opposite sign.

  Receiving unit 1.2, transmission path 20, and light distribution unit 22 are the same as those in the first embodiment, and thus detailed description will not be repeated.

  Subscriber premises equipment 4.1, 4.2,. n is the subscriber premises apparatus 2.1, 2.2,. In n, the dispersion compensation unit 16 is removed.

  As described above, since the optical pulse signal transmitted from the base station side apparatus 3 is previously given the same chromatic dispersion as the chromatic dispersion of the transmission line 20 and the opposite wavelength chromatic dispersion, the chromatic dispersion in the transmission line 20 It is canceled out and the subscriber premises equipment 4.1, 4.2,. n can receive an optical pulse signal having the same time waveform as the optical pulse signal generated by the pulse generator 12.

Since other functions are the same as those in the first embodiment, detailed description will not be repeated.
Since optical coupling unit 26 and transmission path 24 are the same as in the first embodiment, detailed description will not be repeated.

  In the fourth embodiment, the encoding unit 30, the light source 10, and the light modulation unit 32 implement the first transmission unit, the pulse generation unit 12 implements the second transmission unit, and the delay units 84.1 and 84. 2, ..., 84. n realizes the synchronization means, the optical interaction generation unit 18 realizes the optical interaction generation means, the decoding unit 86 realizes the decoding means, the inverse dispersion applying unit 96 realizes the dispersion compensation means, and the encoding unit 74 and the light modulation unit 75 implement a transmission unit, and the decoding unit 80 implements a reception unit.

  According to the fourth embodiment of the present invention, in addition to the effects in the first embodiment, the base station side device transmits the optical pulse signal by compensating in advance the chromatic dispersion generated in the transmission path. There is no need to reshape the optical pulse signal. Therefore, since the waveform shaping unit or the like is not required in the subscriber premises apparatus, the subscriber premises apparatus can be realized at a lower cost.

[Embodiment 5]
In the first to fourth embodiments, the case has been described in which uplink data is transmitted by the time division multiplexing method using the optical pulse signal transmitted from the base station side apparatus.

  On the other hand, in Embodiment 5, a case will be described in which uplink data is converted into an optical spreading code and transmitted using an optical pulse signal transmitted from the base station side device.

FIG. 11 is a schematic configuration diagram of a communication system 104 according to the fifth embodiment of the present invention.
11, communication system 104 includes base station side device 5 and subscriber premises side devices 6.1, 6.2,. n, transmission lines 20 and 24, an optical distribution unit 22, and an optical coupling unit 26. The base station side device 5 includes a transmission unit 1.1 and a reception unit 5.2.

Transmitting section 1.1 is the same as that in the first embodiment, and therefore detailed description will not be repeated.
Moreover, since transmission line 20 and light distribution unit 22 are the same as those in the first embodiment, detailed description will not be repeated.

  Subscriber premises equipment 6.1, 6.2,... n is the subscriber premises apparatus 2.1, 2.2,. n, optical encoders 76.1, 76.2,. n is added. Then, the subscriber premises devices 6.1, 6.2,. n further converts the optical data signal modulated by the uplink data 1, 2,..., n to be transmitted to the base station side device 5 into an optical spreading code and transmits it. Since other functions are the same as those in the first embodiment, detailed description will not be repeated.

  Optical encoders 76.1, 76.2,. n converts an optical data signal received from the optical modulation unit 75 into an optical diffusion code based on a predetermined orthogonal code sequence, and outputs the optical diffusion signal to the optical coupling unit 26. In the following description, conversion to an optical diffusion code is also referred to as “optical code conversion”.

  Since optical coupling unit 26 and transmission path 24 are the same as in the first embodiment, detailed description will not be repeated.

  The receiving unit 5.2 includes an optical distribution unit 50 and optical decoders 52.1, 52.2,. n and a decoding unit 54.

  The optical distribution unit 50 divides the optical signal received via the transmission path 24 into n, and the divided optical signals are optical decoders 52.1, 52.2,. output to n.

  Optical decoders 52. 1, 52. n converts the optical diffusion code received from the optical distribution unit 50 into an optical data signal based on a predetermined orthogonal code sequence, and outputs the optical data signal to the decoding unit 54. In the following description, conversion from an optical diffusion code to an optical data signal is also referred to as “optical code reverse conversion”.

  The decoding unit 54 includes optical decoders 52.1, 52.2,. The light intensity of the optical data signal received from each of n is integrated for each time slot, and a binary data string of “0” or “1” is based on whether the value is equal to or greater than a predetermined threshold value. Is generated. Then, the decoding unit 54 decodes the generated data string into uplink data 1, 2,.

  Since optical coupling unit 26 and transmission path 24 are the same as in the first embodiment, detailed description will not be repeated.

FIG. 12 is a schematic configuration diagram of the optical encoder 76.1.
Referring to FIG. 12, the optical encoder 76.1 includes an optical distribution unit 90, an optical coupling unit 92, and optical delay paths 94.1, 94.2, 94.3, 94.4.

  The optical distribution unit 90 equally distributes the pulsed optical data signal received from the optical modulation unit 75 into four, and outputs them to the optical delay paths 94.1, 94.2, 94.3, 94.4, respectively.

  The optical delay path 94.1 outputs the optical data signal received from the optical distribution unit 90 to the optical coupling unit 92 without delay.

  The optical delay path 94.2 delays the optical data signal received from the optical distribution unit 90 by the time of the pulse width and outputs the optical data signal to the optical coupling unit 92.

  The optical delay path 94.3 delays the optical data signal received from the optical distribution unit 90 by a time that is twice the pulse width and outputs the delayed signal to the optical coupling unit 92.

  The optical delay path 94.4 delays the optical data signal received from the optical distribution unit 90 by a time that is three times the pulse width and outputs the optical data signal to the optical coupling unit 92.

  In addition, since the optical signal is a “transverse wave” that vibrates perpendicular to the traveling direction, an optical phase difference occurs when observed at two different points in the traveling direction. Therefore, an optical phase difference corresponding to the transmission path length occurs between the optical signal input to the transmission path and the optical signal output from the transmission path.

  Therefore, in the optical delay paths 94.1, 94.2, 94.3, and 94.4, the optical phase of the input optical signal and the output optical signal is in phase or in accordance with the orthogonal code sequence, respectively. The transmission path length is set so as to be in reverse phase, that is, “0” or “π”.

  The length required to delay the optical signal by the pulse width of the optical data signal is on the order of several centimeters, whereas the length required to invert the phase of the optical signal is on the order of several μm. It is. Therefore, since there is a difference of 10 6 between the two, a desired delay time and optical phase difference can be given by adjusting the length of the transmission line.

  The optical coupling unit 92 couples the optical data signals output from the optical delay paths 94.1, 94.2, 94.3, 94.4.

The optical decoder 52.1 is the same as the optical encoder 76.1.
Furthermore, optical encoders 76.2,. n and optical decoders 52. Since n is the same as that of optical encoder 76.1, detailed description will not be repeated.

  FIG. 13 is a diagram for explaining data transmission by the optical code division multiplexing method from the subscriber premises apparatus 6.1 to the base station apparatus 5 in the communication system 102.

FIG. 13A shows an optical data signal output from the optical modulator 75.
FIG. 13B shows an optical diffusion code after optical code conversion by the optical encoder 76.1.

FIG. 13C shows an optical data signal after optical code reverse conversion by the optical decoder 52.1.
FIG. 13D shows an optical data signal given to the decoding unit 54.

FIG. 13E shows an optical data signal after optical code reverse conversion by the optical decoder 52.2.
FIG. 13F shows an optical data signal given to the decoding unit 54.

  Referring to FIG. 13A, the optical modulator 75 modulates an optical pulse signal having a pulse width t received from the base station side device 5 and outputs an optical data signal.

  Referring to FIG. 13B, optical encoder 76.1 has, for example, a 4-bit orthogonal code sequence “0101”, spreads the input optical data signal into four optical pulses, Thus, optical phase differences of “0”, “π”, “0”, “π” are given.

  Referring to FIG. 13C, the optical decoder 52.1 has the same orthogonal code sequence “0101” as that of the optical encoder 76.1, and receives the optical data signal received from the subscriber premises apparatus 6.1. Further, the light is diffused into four optical pulses to give optical phase differences of “0”, “π”, “0”, and “π”, respectively. On the time axis, optical pulses having the same optical phase are intensified, and optical pulses having different optical phases are intensified. As a result, the optical decoder 52.1 outputs an optical signal having a light intensity characteristic as shown in FIG. And the decoding part 54 integrates light intensity for every period T of an optical pulse signal, and judges the presence or absence of an optical pulse.

  By the way, the optical signal transmitted from the subscriber premises apparatus 6.1 is added to the other optical decoders 52.2,. Also distributed to n.

  Referring to FIG. 13 (e), the optical decoder 52.2 has, for example, an orthogonal code sequence “0000” different from that of the optical encoder 76.1, and receives the optical data signal received from the subscriber premises apparatus 6.1. Further, the light is further diffused into four optical pulses to give optical phase differences of “0”, “0”, “0”, and “0”, respectively. As a result, the optical decoder 52.2 outputs an optical signal having a low level noise characteristic light intensity as shown in FIG.

  As described above, the base station side device 5 and the subscriber home side devices 6.1, 6.2,. If n has different orthogonal code sequences, the optical data signal cannot be normally decoded. Therefore, data transmission is established only when they have the same orthogonal code sequence, and data transmission is not established when they have different orthogonal code sequences. Therefore, the uplink data 1 transmitted from the subscriber premises apparatus 6.1 does not affect the other uplink data 2,..., N in the base station apparatus 5.

  As described above, in the optical code division multiplexing method, the optical encoder and the optical decoder need to perform the same processing. Therefore, the optical encoder 76.1 and the optical decoder 52.1 have the same configuration. Furthermore, optical encoders 76.2,. n and optical decoders 52. Each of n has the same configuration.

  In the fifth embodiment, the encoding unit 30, the light source 10, and the light modulation unit 32 implement the first transmission unit, the pulse generation unit 12 implements the second transmission unit, and the delay units 84.1 and 84. 2, ..., 84. n realizes the synchronization means, the optical interaction generation unit 18 realizes the optical interaction generation means, the decoding unit 86 realizes the decoding means, the waveform shaping unit 14 realizes the dispersion compensation means, and the encoding unit 74 , Optical modulator 75 and optical encoders 76.1, 76.2,. n realizes a transmission means, and an optical distribution unit 50, optical decoders 52.1, 52.2,. n and the decoding part 54 implement | achieve a receiving means.

  According to the fifth embodiment of the present invention, in addition to the effects in the first embodiment, each decoding unit in the base station side device receives only data from one corresponding subscriber premises side device. There is no need to temporally separate optical data signals transmitted from a plurality of base station side devices. Further, even if the number of connected base station side devices increases, the base station side device only needs to add a decoding unit accordingly. Therefore, it is possible to realize a communication system that can flexibly cope with an increase in communication speed and an increase in subscriber premises equipment.

[Embodiment 6]
In Embodiments 1-5, the base station side apparatus provided with the pulse generation part was demonstrated.

  On the other hand, in the sixth embodiment, a case where the pulse generation unit is shared with other base station side devices will be described.

FIG. 14 is a schematic configuration diagram of a communication system 106 according to the sixth embodiment of the present invention.
Referring to FIG. 14, the communication system 106 includes a pulse generator 12, a base station side device 7, and subscriber premises side devices 2.1, 2.2,. n, transmission lines 20 and 24, an optical distribution unit 22, and an optical coupling unit 26. The base station side device 7 includes a transmission unit 7.1 and a reception unit 1.2.

  The pulse generator 12 is a period in which data having the same destination is assigned in the optical data signal generated by the optical modulator 32 of the base station side device 7, that is, the downlink data 1, 2,. An optical pulse signal having a period of time required for one round of allocation is generated. Then, the pulse generator 12 outputs the generated optical pulse signal to the base station side device 7 and other base station side devices 7.

  Transmitter 7.1 is obtained by removing pulse generator 12 from transmitter 1.1 in the first embodiment. Then, the transmitter 7.1 transmits the optical pulse signal received from the pulse generator 12 to the subscriber premises devices 2.1, 2.2,. to n. Since other functions are the same as those in the first embodiment, detailed description will not be repeated.

  1. Transmission path 20, optical distribution unit 22, and subscriber premises equipment 2.1, 2.2,. n, since optical coupling unit 26 and transmission path 24 are the same as those in the first embodiment, detailed description thereof will not be repeated.

  In the sixth embodiment, the encoding unit 30, the light source 10, and the light modulation unit 32 implement the first sending unit, the optical coupling unit 34 implements the second sending unit, and the delay units 84.1 and 84. 2, ..., 84. n realizes the synchronization means, the optical interaction generation unit 18 realizes the optical interaction generation means, the decoding unit 86 realizes the decoding means, the waveform shaping unit 14 realizes the dispersion compensation means, and the encoding unit 74 The optical modulation unit 75 implements a transmission unit, and the decoding unit 80 implements a reception unit.

  According to the sixth embodiment of the present invention, in addition to the effect in the first embodiment, the optical pulse signal output from one pulse generator is shared by a plurality of base station side devices. The configuration can be simplified. Furthermore, when the pulse width of the optical pulse signal is shortened due to the improvement of the modulation speed of the optical data signal due to the improvement of the communication speed or the increase of the subscriber premises equipment, it is only necessary to replace the common pulse generator. That's it. Therefore, it is possible to realize a communication system that can flexibly cope with an increase in communication speed and an increase in subscriber premises equipment at a lower cost.

[Other forms]
In the above-described first to sixth embodiments, the case where the base station side device and the subscriber premises side device are respectively connected by two different transmission paths for uplink data and downlink data has been described. It is good also as a structure connected by one common transmission line. Since the optical signal is a transverse wave, no interference occurs between two optical signals having different propagation directions. Therefore, bidirectional data transmission for upstream data and downstream data is possible using a common transmission path.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic block diagram of the communication system according to Embodiment 1 of this invention. It is a schematic block diagram of a light interaction generation | occurrence | production part. It is a figure explaining 4 light wave mixing in a light interaction generation part. It is a figure explaining extraction of the data in a subscriber premises apparatus. FIG. 6 is a schematic configuration diagram of an optical interaction generator according to a first modification of the first embodiment. It is a schematic block diagram of the optical interaction generation part according to the modification 2 of Embodiment 1. FIG. It is a figure explaining the influence of the wavelength dispersion in a transmission line. FIG. 10 is a schematic configuration diagram of a waveform shaping unit according to a second embodiment. FIG. 10 is a schematic configuration diagram of a waveform shaping unit according to a third embodiment. It is a schematic block diagram of the communication system according to Embodiment 4 of this invention. It is a schematic block diagram of the communication system according to Embodiment 5 of this invention. It is a schematic block diagram of an optical encoder. It is a figure explaining the data transmission by the optical code division multiplexing system from the subscriber premises apparatus in a communication system to a base station side apparatus. It is a schematic block diagram of the communication system according to Embodiment 6 of this invention.

Explanation of symbols

  1, 3, 5, 7 Base station side device, 1.1, 3.1, 7.1 Transmitter, 1.2, 5.2 Receiver, 2, 4, 6 Subscriber home side device, 10 Light source, 12 Pulse generator, 14, 46, 64 Waveform shaping unit, 16, 44 Dispersion compensation unit, 18, 19, 70 Optical interaction generator, 20, 24 Transmission path, 22, 50, 60, 90 Optical distribution unit, 26 , 34, 92 Optical coupling unit, 30, 74 Coding unit, 32, 75 Optical modulation unit, 36, 58 Optical amplifier, 38, 72 Highly nonlinear fiber, 40 Optical filter, 42 Semiconductor optical amplifier, 48 Injection-locked laser, 52 Optical decoder, 54, 80, 86 Decoding unit, 56, 66, 68 Optical branching unit, 62 Wavelength selective optical distribution unit, 76 Optical encoder, 84 delay unit, 94 optical delay path, 96 Inverse dispersion applying unit, 100, 102 , 104, 106 communication system

Claims (10)

A transmission line;
A first communication device that transmits a plurality of data with different destinations via the transmission path;
And a plurality of second communication device which receives and extracts data addressed to itself from among the plurality of data transmitted from the first communication device,
The first communication device is:
First sending means for sending a first optical signal time-division-multiplexed by sequentially assigning the plurality of data to time slots divided at a predetermined time interval to the transmission line;
Second sending means for sending a second optical signal having the maximum intensity to the transmission line in the same period as the period in which data having the same destination is assigned in the first optical signal;
Each of the second communication devices is
Synchronization that receives the first and second optical signals and synchronizes a time slot in which data destined for itself is assigned in the first optical signal and a timing having the maximum intensity in the second optical signal Means,
Optical interaction generation means for generating an optical interaction between the first optical signal and the second optical signal synchronized in the synchronization means;
Decoding means for decoding data based on a third optical signal generated in the optical interaction generating means ;
Using said second optical signal on a carrier wave, saw including a transmitting means for transmitting data to the first communication device,
The first communication device further includes a receiving unit that receives data transmitted from the plurality of second communication devices .   The communication system according to claim 1, wherein the second optical signal is an optical pulse having a time width equal to or less than a time slot in the first optical signal. The communication system according to claim 1, wherein the synchronization unit includes a delay unit that delays the second optical signal by a predetermined time different from that of the other second communication apparatus .   4. The communication system according to claim 1, wherein the first and / or second communication device further includes a dispersion compensation unit that compensates for chromatic dispersion generated in the transmission path. 5. The transmission means modulates the second optical signal with transmission data, and then converts it into an optical spreading code using an orthogonal code sequence different from that of the other second communication device ,
The receiving unit decodes the transmission data to another second communication apparatus of the transmission source of the light spreading code received from said plurality of second communication device, according to any one of claims 1-4 Communication system. An optical signal generator for supplying the second optical signal to the first communication device;
The second sending means sends the second optical signal received from the optical signal generator,
The said optical signal generation part supplies the said 2nd optical signal to the said 1st communication apparatus in another communication system in addition to the said 1st communication apparatus, The any one of Claims 1-5. Communication system. Via the transfer sending passage, the first communication device transmitting a plurality of data having different destination, a communication method between a plurality of second communication device which receives and extracts data addressed to itself ,
A first sending step for sending a first optical signal time-division-multiplexed by sequentially assigning the plurality of data to time slots divided by the first communication device at predetermined time intervals;
A second sending step in which the first communication device sends a second optical signal having the maximum intensity to the transmission line in the same period as the period in which the data having the same destination in the first optical signal is assigned; When,
A time slot in which the second communication device receives the first and second optical signals and is assigned data destined for itself in the first optical signal; and a maximum intensity in the second optical signal. A synchronization step for synchronizing the timing with
An optical interaction generation step in which the second communication device generates an optical interaction between the first optical signal and the second optical signal synchronized in the synchronization step;
A decoding step in which the second communication device decodes data based on the third optical signal generated in the optical interaction generation step ;
A transmission step in which the second communication device transmits data to the first communication device using the second optical signal as a carrier wave;
A receiving step in which the first communication device receives data transmitted from the plurality of second communication devices . The communication method according to claim 7 , further comprising a dispersion compensation step in which the first and / or second communication device compensates for chromatic dispersion occurring in the transmission path. A communication device for transmitting a plurality of data with different destinations via a transmission path,
First sending means for sending a first optical signal time-division-multiplexed by sequentially assigning the plurality of data to time slots divided at a predetermined time interval to the transmission line;
The first optical signal has a wavelength different from that of the first optical signal so that the data directed to any one of the plurality of destinations can be decoded by optically interacting with the first optical signal; and Second sending means for sending a second optical signal having the maximum intensity to the transmission line in the same period as the period in which data having the same destination in the first optical signal is assigned ;
And a receiving unit configured to receive a plurality of signals generated by using the second optical signal as a carrier wave and to receive each data included therein . A communication device that extracts and receives data addressed to itself among a plurality of data having different destinations transmitted via a transmission path,
The same period as the first optical signal time-division-multiplexed by sequentially assigning the plurality of data to the time slots divided by a predetermined time interval and the data having the same destination in the first optical signal is assigned. Synchronization that receives a second optical signal having a maximum intensity in a period and synchronizes a time slot in which data addressed to itself is included in the first optical signal and a timing having the maximum intensity in the second optical signal. Means,
Optical interaction generation means for generating an optical interaction between the first optical signal and the second optical signal synchronized in the synchronization means;
Decoding means for decoding data based on a third optical signal generated in the optical interaction generating means ;
A communication device comprising: transmission means for transmitting data using the second optical signal as a carrier wave .

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