JP2003500894A - Optical communication system - Google Patents

Abstract

(57) [Problem] To provide a system having low cost and practical utility. An encoder receives a light source, a data source providing a data stream, and a light output from the light source, the encoder including a first spectral filtering assembly representing a first code, the first spectral filtering assembly including: The code is an array of N numbers each having one of at least two values, and the assembly spectrally encodes the light output of the light source with a first code to each of the light source outputs. Separating the first code into spectral elements corresponding to each number, attenuating each spectral element according to the value of the corresponding code number, and recombining the spectral elements to generate an encoded optical signal. And an encoder, wherein the encoder is coupled to the light source and the light source To generate a data modulated and encoded optical signal.

Description

Detailed Description of the Invention

PHOTONIC Integrated Circuit Priority for Optical CDMA filed September 14, 1998, including provisional patent application, 223 fully referenced provisional patent application 60/100 Applications claim priority.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to optical communication systems. And, in particular, one or more photonic integrated circuits are used in the implemented optical coded division multiple access communication system.

[Prior art]

In recent years there has been an increase in science and technology such as satellite communications, video programming distribution networks such as cable television and spread spectrum telephones including, for example, coded split multiple call telephones, which have seen a fast expanding demand for communication bandwidth. Such science and technology became common after the end use. And the well was integrated into everyday communication. The growing demand for communication bandwidth has brought significant investment in new communication science and technology and in new communication infrastructures. For example, the cable television industry, telephone companies, internet providers and various government entities have invested in distance fiber optic networks and in equipment for fiber networks. This undercarriage addition, in turn, resulted in a demand for new technology and additional investment in the undercarriage that stimulated the demand for bandwidth use. Placing optical fibers over the distance is expensive. Moreover, conventional fiber optics or other optical communication networks utilize only a small fraction of the effective bandwidth of the communication system. There is considerable interest as a result in obtaining higher utilization of fiber networks or otherwise increasing the bandwidth of fiber optic systems. Techniques have been developed to increase the bandwidth of fiber optic communication systems and carry information over fiber systems from multiple sources. In general, these technique seeks that use more of the readily available optical bandwidth of fiber optics by compensating for a relatively simple coding scheme, which is conventionally exhausted such a system. In some improved bandwidth fiber systems, the optical fiber is
The channel carries an optical carrier signal composed of one, narrow wavelength band. Then, multiple users access the fiber using time division multiple access (TDW or (TDMA)) time division multiple access. The time division method sends a structure of data by allocating consecutive time slots in the structure to a special channel. Optical TDM requires short pulsed diode lasers and provides only modest bandwidth utilization improvements. In addition, improving the transmission rate on TDM networks requires that all of the transceivers connected to the network be upgraded to higher transmission rates. Partial networks do not upgrade the possibility that some less desirable flexible TDM systems are less desirable. On the other hand, the TDM system
It provides highly desirable predictable and even data flows in multi-user systems that experience "bursty" usage. In this way, the TDM method wins allows the full system to obtain the required communication bandwidth of continued importance in the system, but in other optical communications that other methods must be familiar with.
Therefore, it is desirable to provide increased bandwidth in optics compatible with TDM communication techniques. One strategy to improve the utilization of optical communication networks is
Wavelength division multiplexing (WDM) or wavelength division multiple access (WDMA) is used for increasing system bandwidth. And supporting some more independent multi-user access formats allowed by TDM. WDM systems provide a plurality of optical channels, one of each set of non-overlapping wavelengths strapping to provide extended bandwidth. Information is typically generated by a narrow wavelength band optical source, such as a laser or a light emitting diode, sent in each of the optical channels using a light beam within an independently assigned wavelength band. Each of the light sources is differently multiplexed onto the fiber and coupled to the fiber optics, tuned by data for all of the wavelength bands that are transmitted and the resulting regulated light output. The narrow wavelength band optical modulation corresponding to each channel can encode a channel defined simple digital data stream or further multiplicity. Small interference occurs between channel definitions within different wavelength bands. At the receiving end, each of the WDM channels terminates in a receiver that is assigned a wavelength band used to carry a known number on that WDM channel. It classifies all commonly accepted optical signals into conjugate difference product wavelengths using demultiplexers, such as tunable filters, and separates narrow wavelength band optical signals into wavelengths for that particular channel. You may be proficient in the system by pointing to the receiver assigned to. Source is VV'D with least theoretically well-tuned optical effectiveness
Limits the number of users that can be supported on the M system. For purposes of illustration as a function of operating temperature, wavelength stability can also affect the operational characteristics of WDM systems. As a more practical material, the cost of WDM systems limits the application of this technology. One example of a WDM optical fiber communication system is US Patent No. 5,57.
9,143 described as a video distribution network with 128 conjugate difference product channels. The 128 conjugate difference product channels are confirmed using 128 closely spaced, but 128 conjugate difference product lasers operating at distinct wavelengths. These lasers are precisely wavelength selected and require good deterministic mode structure and gain characteristics for communication systems. Lasers suitable for WDM video distribution systems are individually expensive. Therefore, it has the required operational characteristics 12
The requirement for a laser of 8 makes the whole system very expensive. The cost of the system makes it undesired for use in applications such as local area computer networks, or otherwise limits the application of the technology. As described below, the present invention can provide a video distribution network 5,579,143 No. of the present invention and the examples can provide the US Patent, media and wide area network applications (such systems Other types, which makes the product more flexible and more economical). Unlike the US Patent No. 5,579,143 WDM multiple laser system, the embodiments of the present invention can be sufficiently flexible and economical to be used in at least some types of local area networks. . Embodiments of the present invention, as described below, use spread spectrum communication techniques to obtain improved loading of the bandwidth of fiber optic communication systems in a more economical manner than known VVDM systems. Spread spectrum communication techniques are known to have significant advantages and considerable practical utility. Especially in secure military applications and mobile phones. Therefore, there was a proposal for optical communication science and technology that a spread spectrum technique (most notably Coded Division (CDMA) Multiple Access) could have been applied. Sufficient that the bandwidth of optical communication systems, such as those based on fiber optics, can be used to affect the data rate of electrically generated signals that can now be inputs to optical communication systems. The spread spectrum approach is desirable in optical communication systems because it is so many dimensions of coding.
The conjugate difference product channel of the data can be deterministic in this frequency domain. Then, an independent data stream can be provided on the conjugate difference product channel without limiting the data rate within one of the channels. From a simplistic point of view, the V; DM system described above may be regarded as the limiting fact of a spread spectrum system in its multiple data channel R-determination for the conjugate difference product wavelength. The different wavelength channels are definite in the optical frequency domain. The time domain signal can then be sent on each of the wavelength channels. From CDMA perspective, the VVDM described above
The well-defined wavelength channel of the communication system provides a trivial position encoding. There is no overlap between the code vectors, so where the individuals code the vectors are right angles. In general, there have been proposals for similar optical CDMA systems for traditional forms of radio frequency CDMA, such as Kavehrad, et al., "Noncoherentb.
Sources (J), "Optical Code Division Multiplexe on Spectral Encoding"
d Systems Based ". Lightwave Tech. To Vol. No.3 (pp) () 13.534545 (1995)
. In contrast to the WDM system described above, the proposed optical CDMA system uses a broad spectrum source to combine the frequencies (equal, wavelength) specifying the genetic code in addition to the time domain coding. . A schematic diagram of the theoretical optical CDMA proposed in the Kavehrad clause is
Presented in 1. The proposed optical CDMA system uses a broad spectrum, unobtrusive source 12, such as a pulsating LED, an excellent light emitting diode or an erbium-doped fiber amplifier. In a pictured CDMA system, the wideband source is a time domain data stream 10.
The broad spectrum light 14 tuned by and time domain tuned is directed to a spatial light modulator 16 by a mirror 18 or other beam steering optics. Inside the spatial light modulator 16, the light beam 20 is on a grating 22 that spatially spreads the spectrum of the light 24 to produce a beam of light 24 that has its various component wavelengths stretched in spaced areas. It is an event of. The spatially broadened spectral beam 24 is then incident on a spherical lens 26 which directs this beam onto a spatially patterned mask 28 which filters light incidents. The light recombines this light through the second spherical lens 30 by the pass of the mask 28
Spatially rubbed onto the th diffractive grid 34. The mask 28 is a centered path between a pair of confocal lenses 26, 30 and the diffraction grating 22. 34 are placed on each focal plane of a confocal lens pair 26 (30).
The broad optical spectrum of the incoherent source is spatially broadened into a spatially imitated mask 28 minutes. The mask then spatially spreads out and adjusts the spectral light. Since the spectrum of the main light is spatially broadened, the spatial modulation results in a modulation at the wavelength of the main light, or equally at the frequency of the main light. In this way, the adjusted light has a frequency pattern characteristic of the special mask used to adjust the main light. This frequency pattern can then be used to identify special users within the optical network or special channels within the multi-channel transmission system. After passing through the mask 28, the spatially tuned light path through lens 30 and this wavelength, the light beam 32 is then spatially compressed by a second grating 34. This wavelength is modulated and the spatially compressed light beam 36 passes from the spatial light modulator 16 and is directed by a mirror 38 or other beam steering optics to a fiber network or transmission system 42. CD mentioned in this point
Part of the MA system is the photonic CDMA system down present system and its part of the transmitter where the optical path from the fiber network 42 commands the receiver for the photographic system. The receiver is configured to identify special transmitters within the network that include many users. This is accomplished by providing a mask 28 of the characteristic space inside the transmitter. In this receiver, the spatial coding characteristic of the transmission mask is detected from many transmitted signals inside the optical network. As explained in the Kavehrad clause, changing is important to the mask 28, so the transmitter can choose from a variety of conjugate difference products for possible receivers on the network. In other words, a user with a photo transmitter chooses a special receiver or user to change the spatial pattern of the mask 28 and receive the transmitted data stream. And, therefore, the frequency coding of the transmitted beam 40 so that the transmitter mask 28 corresponds to the spatial coding characteristics of the intended receiver. The receiver illustrated in FIG. 1 detects the spatial (frequency or wavelength) modulation characteristics of the transmitter mask 28, which detects the data sent from a particular transmitter, and has modulation patterns of different characteristic spaces. By turning off the signal you are doing. Light received from the fiber optic network 42 is coupled by a coupler 44 to two different receive channels. The first receiver channel includes a spatial light demodulator 46 which makes the mask identical to that used in the spatial light modulator 16. And at the moment the receiver channel contains a mask up to the spatial light modulator 16 of the transmitter, including the optical demodulator 48 of a similar structure in space, the "transmitter" conflicts with the exception of having a mask. Ct is an optical demodulator 46, 48 in the "cover 28 with a mask" space, which has the function of filtering the received optical signal, and the coupled light detectors 50, 52 respectively.
A photodetector 50 that distributes to (detection 52, which determines that the struck light signals and the output signals to a differential amplifier 54). The output of the differential amplifier is a low-pass filter 56.
Is offered up to. Then, the data 58 originally sent is read. FIG2 provides an illustration of the receiver circuitry in a larger subdivision.
In this illustration, spatial light demodulators 46 and 48 are generally similar to spatial light modulator 16 shown in FIG. One and so individual components of the system are not described separately. The received light 60 is the input to its receiver, a splitting coupler 62, a little light guided by the spatial light demodulator 46 and another spatial light demodulator 48. With mirror 64 in another part of the light. A spatial light demodulator 46 is used in the spatial light modulator 16 of the transmitter to filter the received light 60 handling the same spatial light (frequency, wavelength), and a light detection function. It provides the filtered light to the container 50. The spatial light demodulator 48 filters the generally accepted light using a complementary spatial filtering function and provides its output to a detection circuit 52. Amplifier 54 subtracts its output signal from the two photodetectors. The spatial light demodulator 46 includes exactly the same mask 66 up to the transmitter mask 28 to produce the same filtering function as the spatial light modulator 16 of the transmitter. The spatial light demodulator 48 uses the spatial light demodulator 48 as a filtering function for the spatial light modulator 16 (46).
Includes a mask 68 that performs complementary filtering functions on masks 28 and 66 to perform complementary filtering functions. In Kavehrad clause, each of these masks 16 (66) is a liquid crystal element 68 because the mask is fully programmable. The special coding expressed in the mask must be suitable for the proposed optical application. Although CDMA has been widely used in radio frequency (RF) domain communication systems, its application in frequency (wavelength) domain coding in optical systems has been limited. This is because the success of the RFCDMA system is critically well-designed bipolar code order (it depends on the use of i. E. Ordering within +1 and 1 values) with good correlation properties. Such encodings are M-order, Gold-order, Kas
Includes sami ordering and right-angled Walsh encoding. These bipolar codes can be used in the RF domain because the electromagnetic signal contains phase information that can be discovered. RFCDMA method
Not applicable to optics that are easily used for incoherent light sources and direct detection (ie, intensity squared detection using photodetectors), because such optics cannot Discover the information. Code sequences defining negative symbol values cannot be used in such optics. As a result, only unipolar coding (ie 0 and 1 value code sequences) can be used in the direct detection optics for CDMA. The Kavehrad clause proposes various bipolar code adaptations within the system illustrated in FIGS for that mask. Including 1 and 2, the mask provided the unipolar (only O's and 1's) in Hadamard-encoded M-sequence or unipolar formats. For these types of bipolar coded, Kavehrad hire in apprenticeship contracts, it indicates a length of 2N and a unipolar code sequence in which a system including such encoding of it can support a total length. N1 users whose N bipolar code must be converted. With a small examination of the practical implementation of such systems, the Kavehrad clause mainly describes the theoretical examination of CDMA systems. A more practical example of an optical CDMA system with varying bipolar code sequences was recommended for transmission and detection of bipolar code sequences in unipolar systems. This system is described by L. in a series of papers. Nguyen (B.) Aazh
ang and JF. Optical C with "Spectral Encoding and Bipolar Codes" (Proc)
Young including "DMA". The 29th Annual Conf. Information Sciences and Systems (
March 2224 () Johns Hopkins University 1995), and "Bipolar Codes" (Ele
"All Optical CDMA" in c). Lett March 16, 1995. Vol. No.6 (pp) ()
3.469470. This work is also summarized in Young, et al. In US Patent No. 5,760,941, and this work is collectively referenced herein as the Young patent. Roughly illustrated in FIG. In Young, the patent is a system 3, the transmitter 80 uses a broad spectrum light source 82. The split by the beam splitter 84 into two beams 86 and 88 which are processed in any of its outputs is by the two spatial light modulators 90 and 92. The first spatial light modulator 90 collimates selectively onto the first spatial coding mask 98, which either passes or blocks the spectral components of the light beam,
Includes a ghostly dispersion grating 94 to scatter a light beam 86 and a lens 96 to guide the scattered light. The lens 100 collects the components of the spectrum of the spatially modulated light beam, and the recombination grating 102
Spread to 04 and rejoin the beam. The "pass" and "block" states of the coding mask represent the order of O's and Ps (ie unipolar coded binary). The encoding 106 for the first mask 98 is the encoding U where U is a unipolar encoding of length N (U with DU is its complement. And "0" is the two encodings). The second encoder 92 (details not shown) is similar up to the first encoder 90 in the structure, except that its encoding mask has the encoding U (DU). Symbol source 108
Outputs the sequence of pulses representing the O's. Then, one is at the first ON / OFF modulator 110 and at the second ON / OFF modulator 114 through the inverter 112. The two modulators 110 and 114 condition the two spatially adjusted beams of light, and the two beam ares combine the beam splitter 116 to combine the two encoded light beams 118 and 120. Combined to use. The conditioned light beam is instead coupled to the output port depending on whether the bit from its source is a 0 or a 1. Then, the system can use the receiver with differential detection of two complementary channels, which was illustrated in FIG's receiver. 2. Coded UOU and U
A channel that is a receiving channel with an order of 1 each with a mask carrying & U and an O's and a channel signal reception associated with the mask for that channel. The system proposed in the Young patent is RFC
The use of bipolar codes developed for DMA technology allows them to be used in optical CDNU systems. However, for a mask of length 2N, only the N-coding is defined, since it has to be concatenated from the coding U and its complement U and a representative of that mask has to be chosen. be able to. Therefore, raising excessive interference is the object of the invention to provide an optical communication system incorporating a frequency domain CDNU coding / decoding scheme and such a scheme in which the number of users is maximized. It is another object of the invention to provide a system that provides a relatively simple system for encoding and decoding light other than efficiently using the effective spectrum. Optical CDAIA systems have been described above, and those optical CDMA systems described in the applications listed below and incorporated by reference in the relevant applications right inverse mapping are gratings, lenses and detectors. It's all increased from discrete optical elements such as circuits. The use of discrete optics is in many desirable instances since discrete optics readily provide precision and flexibility. On the other hand, discrete optics tend to be large and expensive. For some aspects of the present invention, most widely used, it is desirable to provide more compact optics made from focusing optics. Optical CDMA communication systems implemented as optical or photonic integrated lines must have the advantage of smaller size and must be more bumpy than discrete optics. Desirably, as some have run out of local networks and home applications,
An optical CDMA system implemented on a photonic integrated line may be cheap enough or bumpy. There have been attempts to implement in component coded partitioning techniques in at least partially implemented communication systems in optical integrated circuits. Illustration (US Patent to Rzeszewski
No.4,989,199), "Photonic Switch Architecture U
tilizing Code and Wavelength Multiplexing "is the wavelength division multiplexing (
WDM) and a communication system that incorporates phase types. The Rzeszewski system uses multiple sets of coherent sources (each set of coherent sources that have the same wavelength) and, on top of that source, uses a phase-coding scheme to identify that source within a set. Phase modulation is performed to distribute. Each set of coherent sources is an input to one of the corresponding phase encoders. Different phase encoders adjust the set of sources having conjugate differential product wavelengths so that the outputs from the different phase encoders can be combined in a wavelength division multiplexing scheme. Since this system uses a phase code scheme to identify some of its channels, the optics to which these signals are sent must remain phase and coherent. Therefore, when a signal encoded by the Rzeszewski patented technique is sent over an optical fiber, a special fiber must be used, and then the system appears to be the preferred earl for the fiber over the fiber. Due to long distances it is not possible to signal communication systems.
Therefore, it is desirable to provide a centralized optical communication system that does not rely on the use of consistent signals.

[0002]

DETAILED DESCRIPTION OF THE INVENTION

Summary of the Preferred Embodiments These and other objects relate to an optical CDMA system in which a spatial encoder is implemented.
At least partially within the scope of photonic integrated circuits. Wide range
The light source is adjusted to be sent with the data. Broad spectrum light beam
Within a spatially scattered, photonic integrated circuit, for example using a diffraction grating
Through the spatial spectral coding mask embodied in. The spatial coding mask is preferably a set of balanced bipolar orthogonal codes.
Unipolar code belonging to a set of unipolar coding derived from
Embodiment is implemented. Then the encoded tuned light beam arm
The scattered frequencies in the optical fiber or another optical communication system
Provides a spread-tuned, encoded spectrally spread optical signal
Rejoined to do. Instead, the phase of the invention is that the receiver is at least partially photonic.
It may provide an optical CDDAA system implemented within an integrated circuit.
A wide spectral source tuned by the spatial coding function U is
Be received. The generally accepted light is split into two components,
It is provided to a pair of complementary decoders. Within each of the complementary encoders, the generally accepted part of the light beam is
For example, using a diffraction grating, spatially dispersed and implemented within a photonic integrated circuit.
Go through the decoding mask of the embodied space. That decoder
One of the embodiments implements the coding function U of the original sending mask and the other space
Complementary function U.Th containing the decoding mask of the space that the complementary decoder contains
e-space coding function U, a set of balanced bipolar orthogonal codes
Unipolar code belonging to a set of unipolar coding obtained from
Embodiment is implemented. Lighting spread spatially within each of the complementary decoders
The traffic light Earl rejoined after passing through the decoding mask. Then the signal passing through the complementary decoding mask is
It is provided to the conjugate difference product input of the path and is originally adjusted within the range of its light.
Data is retrieved. For example, the relevant differential detection circuit includes a back diode.
It may be. Optical including a data source providing another phase data stream within the invention
Relevant for communication systems and encoders. Encoder outputs
Adjusted in the data stream, and the first encoding is for each code in the set.
The coding is orthogonal to the difference between the other codings in the set and the complements of the other codings
Where the first coding and coding is selected, where a set of unipolar codings is chosen.
Each number that has at least one of the two to represent is
An encoder that provides an optical defined as the order of N numbers evaluated by
Corresponding to one of N potential spectral ranges, which may be the output from
Each of the encoding N digits. The optical output from the encoder is N potential spectral ranges (M components).
Each Mth component corresponds to the corresponding coded digit value
Within the range (in that point characterized by optical level)
Includes M components corresponding to the spectrum range. Therefore,
The optical output of the encoder was defined in the data stream, and like a ghost
It is a broad spectrum light tuned by a coding function. The encoder is ph
Includes otonic integrated circuits. Yet another aspect of the invention is a decoder for receiving a light signal from an optical communication system.
The optical communication system that is connected to retrieve the transmitted data.
provide. The decoder has roughly equal power and a second lighter component
The first optical power separator to split the generally accepted lighting signal
Including data. The first and second spectral filters are the first and second optical components
Filter of the first coding and the second spectrum coupled to receive
The first spectral filter embodying the
As an embodiment. First the first and second spectral filter outputs and seconds are generally
The perceived light components were filtered. Optical detectors are generally accepted
The first and second rubbed components of the ignite receiving and electrical
To provide the signal output of. The first encoding is each code in the set
Is orthogonal to the difference between the other encodings in the set and the complements of the other encodings.
Have one of at least two selected from a set of unipolar encodings
A coded code in a set defined as the order of N digits that each digit evaluates to
The set of N-digitized N-digit corresponding to one of the N potential spectral ranges
Each of the codes. The generally accepted light signal is that the broad spectrum light is the data stream,
The M components within a range of N potential spectra, M different spaces.
A ghostly defined coded function that adapts to the range of Khutor
And the decoder uses a photonic integrated circuit.
Including. (Cross-referenced patents and applications) The following patents and applications are in their entirety by reference in relation to current applications.
Each is incorporated into this application. 1. "High Level Capacity Spread Spectrum Optical Communications System" (
US Patent No.5,867,290) came out on February 2, 1999. 2. “Optical CDMA System” (Application Serial No.09 / 126,310)
Submitted 30th a month. 3. "Optical CDMA System Using Sub Band Coding" (Application Serial No.0
9 / 126,217) was submitted on July 30, 1998. 4. In “Optical CDMA” (Application Serial No.09 / 127,343), “Reduced interference
Means for and Apparatus "submitted July 30, 1998. Detailed Description of the Preferred EMBODIMENTS A particularly preferred embodiment of the present invention is either on optical fiber or otherwise.
To achieve better bandwidth utilization over communication links
Providing optical CDMA communication system applying spread spectrum method to communication
To do. Optical fiber communication system components integrated photonic
Preferentially executed on the line. For example, the implementation of the encoder
The decoder of an optical or optical CDMA system makes the system so expensive,
Optical CDMA system using more bumpy and completely discrete components
Can be easier to line up than system implementations. Integrated with optical components implemented as a photonic integrated line
A particularly preferred embodiment of the invention with an electrical element implemented as an isolated line
I am confident that will provide a centralized encoder and decoder. These ins
Implementation is used to implement at least an integrated electrical line.
On the same semiconductor substrate, it is advantageous to have some photonic collections.
Incorporate product circuit components. An optical CDMA system according to the present invention prefers a single channel binar.
Lee, or a receiver using analog coding and a two-channel space decoder.
Send the signal using the spatial encoder with the take signal. As its encoder
And one of the decoder channels implementing the same transmit coding.
The other side of the decoder channel embodying signal-encoding complement
The decoder contains two channels. The channel to which that known number is sent
Is a coding that identifies a spatially broad spectral source.
adjust. Most typically, the broad spectrum light source is the least partially incoherent.
There is The spatial modulation of the light source is achieved by spatially scattering the input light
For example, using an arrayed waveguide grating or diffraction grating. Then spread out spatially
The spectrum obtained is provided to a spectrum coding mask. How much
, Which can be chosen to represent the spatial modulation function
Achieved by providing a broad spectrum for a line of optical switches.
Be done. If the switch does not need to be selectable, then an optical link or
A non-optical link with discrete wavelengths or frequency bins between points
A coding mask such as any one provided within that mask on each side is
More simply can be implemented. Most preferably, in the bins of equal bandwidth, the spectrum of the light traffic light,
Alternatively, the lamp is to be divided into multiple bins of equal brightness instead.
The spectrum of the optical signal is broadened. Used to adjust the light traffic light
The coding mask of the space in which the signal is presented reduces the signal presented to that bin independently.
Provide the corresponding number of For example, each bin may be switched to pass or that bin
May block the light signal input to the, so binary encoding
May perform formatting. Each successive bin in the mask is a wavelength
Spatial modulation of the mask as it is presented light within the optical range
May be used in CDMA communication systems as an over-the-light encoding.
Divide the frequency distribution that does not exist. The described spatial coding mask is a preferred pair of balanced bipolars.
Unipo belongs to a set of unipolar codings derived from La orthogonal coding
Embodiment encoding. After spatial modulation, the encoded luminous flux are
The scattered frequencies of the optical fiber or another optical communication system for injecting
To provide a tuned, encoded spread-spectrum optical signal
Combined again for. In addition to the spatial coded modulation, the input light also preferably has a data in its time domain.
Adjusted in the stream. Photonic integrated circuit (“PIC”) encoder
In the preferred embodiment of the present invention, the modulation of the input light signal is in the range of PIC.
May be achieved within. For example, if the encoder is a IIIN semiconductor (eg
, InGaAsP, AlGaAs or other similar systems)
If created, its modulation is achieved by the components of the photonic integrated circuit.
May be formed. Similarly, the encoder is an electronic eye material such as LiNb03.
The PIC encoder may achieve that modulation if implemented in
Absent. To define the spatial mask function for any of these embodiments
The switch used to create the time domain modulation of the light
You can also The recovery of the signal sent is implemented within the coding mask or coding.
Through the use of a decoder that corresponds to the spectral modulation function. Receiver (
Beam separator), which is a particularly preferred embodiment of
A zation-insensitive demultiplexer (splitting the beam into two equal intensities). That
Each of the parts of the light signal spatially describes the spectrum of that part of the light signal.
Spread using spatially an arrayed waveguide grating or diffraction grating to decouple
. The spatially spread received signal allows the channel to be recovered and the other
In order to present the mask to one of two conjugate difference product masks, one of which is
, Which is complementary to the coded mask to be retrieved for that channel.
Through the two decoding masks, again using an arrayed waveguide grating or diffraction grating
All light transits are recombined, and the two light traffic lights are electrical signals.
Converted by differential detection. For example, two decoded light traffic lights
The back-to-back diode conjugate difference product may be provided. As a result
The resulting electrical signal is that the low path is preferably strained, and that
Therefore, in a particularly advantageous embodiment, the
An electrical signal is provided to the mitting element. In a particularly preferred embodiment, the masks in the encoder and decoder are
Contains unipolar binary code including O's, and 1 Walsh
There is like coding. Delivering benefits, utilities and their encoding
Section is referenced and cross-referenced by reference above.
Applications are discussed in the applications incorporated in the right inverse mapping. That of those applications
Their right inverse mapping is not repeated here for brevity. But their right inverse mapping forms the part of this announcement. Also, other encodings
Systems (including the use of discrete analog basis functions) are among their related applications.
Described. Within the scope of the illustrative embodiments described herein, special emphasis is given to
Binary mask (that is, the bin is moving or disengaged, sends a signal over the air)
Mask, which does not send a signal by radio wave). like that
In the embodiment, defining the L1 communication path for the total of L1 users is
Possible to provide a position mask. Those of ordinary skill, the photonic integrated described below admitting it
For the line to generate an analog transmission function for each of its mask bins
May be used and is quite adapted to implement a set of orthogonal radicals
The given Earl works. Currently, systems embodying aspects of the present invention
Is a special emphasis on the implementation of the optical CDN / 1A system,
Described within one or more photonic integrated lines. FIG3 is a CDNU communication system that roughly includes a PIC encoder and PIC decoder
The embodiment will be shown. Great light emitting diode (SLD) or erbium doped phosphor
Broadband light source 90, such as Fiber Source (EDFS), is a CDMA PIC encoder
-92. Encoder 92 is the spatial light modulator shown in FIG. 1
May provide some functionality similar to 6. I encode such a spatially tuned broad spectrum flux.
But more preferably, the encoder 92 has a time domain where the encoder 92
Incoming or data-based input from a data source 94 using PCM or PCM.
It includes a spatial modulation function that adjusts the power light and a time domain known number modulation function. 4, photonic integrated circuit encoder, as roughly illustrated in FIG.
92 is the array of beams that are spatially adjusted along the axis of the array waveguides that are in contact with each other.
Includes a substrate 120 having a diffraction grating 122 that extends the spectrum. Array waveguide
Tubular lattices are known in the art, and patented to Dragone, for example.
Within US Patent No. 5,002,350, Earl fully described the reference
. Semi-conductively above the semiconductor substrate compositionally through waveguide determination
Semiconductor channel formed by making an etching on a body substrate
A suitable embodiment of the waveguide with light propagating with light propagating through is II
May be formed within an IV or silicon semiconductor system. Again
Arrayed waveguides may be implemented in electronic eye materials such as LiNb03
Not etched by doping or by channel, for example with titanium
Define the waveguide by drawing in. Alternative PIC implementations of spatial expansion elements
Aspects are within the range of semiconductors, electronic photonic circuits or another suitable waveguide material.
Is a curved grid implemented in. An example of such a system (provided within the AlGaAs PIC range) is
Lang in patent No. 5,355,237, and other patents, hereby fully referenced
I will be taught or accepted. Embodiment in FIG. 4 can be achieved
Within the smaller spacing possible, a significant level of spatial separation of that light component
Use a curved grid using a conventional planar grid to achieve
. Yet another possible implementation is silicon, which is discussed below.
Use silica after assembling. Advantageously, the rather preferred PIC implementation of spatial expansion devices
, Incorporating both beam shaping elements, ie (collimating and
Focus) and dispersive elements (lattice, within PIC)
(Or array waveguide). Conjugate difference product with spatial expansion element diverging its beam
The number of bins will change for conjugate difference product applications. 128 for current examination
A total of bins of is assumed, but a system with only 16 bins
Is immediately effective and immediately useful for many current applications. The spatially spread light flux then passes through the coding mask and modulator array 124.
To be done. The coding mask and modulator 124 is equivalent to the number of bins (eg 128)
The spatial expansion element of 122 years, defined by its mask at the total base number of the bin /
Lots of independently swit defining the attenuation provided by the conjugate difference product bin of the modulator
Includes chable optics. The mask definition function and the time domain modulation function are the same as the mask / modulator 1.22.
Is the input to the array of switches that make. 94 inputs / modulations of signal to its mask
The device selectively or adds various switching elements / modulators of its mask.
Those that are turned or are sending at least a time domain modulation function
Applies to switch elements. Typically, the same time domain modulation function is
It applies to all of the switch elements regardless of. The mask / modulator
A second array waveguide grating, curved into a broad spectrum beam
Recombined the back by a diffractive grating or another similar element 126
Providing a spatially encoded, conditioned beam of light. Rejoining like a ghost, spatially then the conditioned signal is due to injective
The output time domain is, and the fiber is a single mode fiber
May be 96. Optical coupler like star coupler, Y coupler or favorite
The Puller 98 allows for long distance transmission of the fiber over a larger network.
It may be used to join the encoded beam for. Change
Runi, the FIG network. 3 out of the two non-denied users shown
May simply have a star configuration. Still to mention to FIG. 3, adjusted lights, optical fiber or other
A decoder with two channels 104, which is sent over the optical communication link 100.
For Dar, 106 combined PICs 108 and 110 with two decodings. An illuminated traffic light containing a potential plurality of spread spectrum signals, a separator.
102 with optical coupler (not shown) and part of split Into 2
Distracted from the fiber 100. Its separator is the most insensitive element
G is the Polarization so illustrated in FIG. Twelve and the theory
Discussed below with reference to that calculation. One part of the generally accepted light is
Provided up to a CDMA PIC decoder 108 on a bar or other link 104; generally
Another part of the observed light is a second one on another fiber or other link 106.
Up to the eye CDMA PIC decoder 110 is provided. Each fixed mass 110 may have in the CDMA PIC decoder 108
Or a selectable mask may be expressed by a line of switches
unknown. Such a preferred embodiment of the invention is better for one user
Other users who are attached to the network want to send and receive data
Suitable for potentially networked system environments. Such switchable
For (mask decoder) it so much each decoder in its mask
-Rather preferred among 108, 110 is the respective mask signal 112 (select mask distribution
114). In general, the preferred masks are the marks that complement each other
An encoding mask is embodied. Therefore, that mask signals 112, 114 is a bit wise complement of each other.
It may be. FIG5, PIC decoder 108, 110 provided on semiconductor (silica / silicon)
FIG. 1 illustrates an embodiment of an electronic eye substrate 130 that may be exhausted.
Show the stem. 3. Incoming light is spatially arrayed with reference to FIG.
Spread along the axis by a grating or a curved diffraction grating 132, which
From the detection or decoding mask 134. One of the decoders 108
In order for the decoding mask 134 to transmit the required channel of light
Embodying the same coding function U used to encode
The other of the decoders 110 then implements the complement U of the transmission coding function.
What is rather preferred is rather preferred. Then, the light passed through the decoding mask 134 is passing through the second
Array waveguides or recombine light spatially spread into a broad spectrum beam
Is provided to another diffraction grating 136, which
It is the output of Dah. Most preferably the encoder, and
The decoder in Fig3 implements fixed or transformed binary Hadamard encoding.
Includes a mask that is switchably configured for implementation. Decoder 108 (and 110 are provided up to the differential detection circuit 116)
So naturally, it could be a pair of two back-to-back detector circuits diodes
Outputs that are not known perform the reduced operation. Other detection configurations
May be used, those of which have discussed the following:
I'm sure that. The two gain control lines are themselves within range of the decoder.
Then, by using multi-channel detection, the electrical signal of the derivative is found
From a decoder like known number recovery and also two separate signal outputs
May handle For example, known number recovery for digital data streams
It may include an integral square rule finding the difference signal in -118. The Embodiments of the present invention are links, backbone networks, including backbone communication.
Network, video distribution network, and many other different communication system environments.
Can be performed in. Certain of these applications have been described and identified.
The application illustrated in the larger sub-section of the application and related by reference above
Incorporated in the right reverse mapping. Also, the phase of the present invention encodes the system
Hybrids used in a transmission centered around discrete optical
You may find an application in a dead system. Alternatively, resend equipment and phot
An onic integrated circuit (PIC) CDMA receiver is provided at a remote receiving location. For example, such systems find particular application in video distribution systems.
You may get kicked. Among such applications, the discrete optical CDMA system is
Provided at a central distribution point, such as the head end of a cable TV distribution system
PIC CDMA receiver that may choose the conjugate difference product encoding
The server receives the conjugate cross product channel of the data at the local receiving station.
It may be offered selectively to adjust the sheer. Ideally, the loca
Local receiving station for use within the decoder box.
At home Instead, the only aspect of the invention is the PICCDMA component.
Running in a local area using
It may be. For decoding spectrum coding / system in a CDMA system
The basic requirement is to reduce all other users or remove interference from the signal.
While receiving, the decoding device at the receiving user sends the corresponding known number signal
It means that it can be recovered from the existing User. Some system
To ensure that a special receiver always receives the same channel of data,
The disc is fixed. Thus, a centrallized and switchable broadcaster
, Can direct data flow to selected receivers. Different for other systems
From many sources where a signal source is sent over a common transmission network or system
The receive mask is programmable so that it can be chosen. Non-interfering
In a spread spectrum CDMA system using an optical source,
Rent optics can only send positive signals (light intensity)
, And only the unipolar encoding is valid because the phase information is not valid.
May be used for incarnation. Unipolar binary code is attached
The letter i indicates 11h user pair (or channel), such as ui = 110011110101011
May be expressed in binary order. The number of digits in that order (N) is
Called its encoding length. As a practical matter, the binary unipolar encoding, which was particularly favored
A spatially imitated mask or light covering a surface, which in turn corresponds to a fixed frequency.
Its wavelength over a wide range of spatially tuned spectral beams.
Each of the mode values corresponds to a fixed, more transparent or opaque pitch slot. One mask is encoding and decoding (preferably they are
(Because of the chosen encoding). (1) ui * uj ＝ ・ ・ ・ M ifi ＝ j 0 ifi ≠ j Or Ui 0 Ujmifi = j 0 ifi # j Where “−” Two codings and M bit
It means that the smart inner product is a constant. Each transmission when orthogonal coding is used
Users may send a signal using one encoding mask, and
The corresponding reception while rejecting the signal that is blocking all other users
The user retrieves that signal from the corresponding sending user to the encoding mask
You may use one and the same decoding mask for: However, this desirable result when the encoding is chosen for binary basis vectors
Happens. u1 = 000 ...... 001 u2 = 000 ...... 010: un = 100 ...... 000 000U1001000U2010100UN000 This set of encodings is one number of all encodings
Is only 1, then the large majority of that bin is blocked while it is blocked.
Only one frequency bin on the disk has power passed through it, which is undesirable. like that
The system should be an unconventional Wave Division Multiple Access (WDMA) system
Can be seen. Undesirable code like source power IIN only
The are are sent. And that balance is wasted. In its encoding and decoding system shown in FIG. One Ma
Used for the encoding and the two masks are used for decoding
() 3 Even if the encoding ui in that set has departed orthogonality
A set of units, even if they are negatively orthogonal to the other encodings uj in the set according to
Nipolar encoding may be used. Rather, the coding ui is the difference
Is chosen to be a right angle between another encoding uj and its complement uj. That is, Ui (U-Ui
) = M is “constant” O = j 0 ifi # j () M. (2) ui = (u−uj *) ・ ・ ・ M * ifi ＝ j 0 ifi ≠ j Derivation such as Hadamard coding of the corresponding code set is performed by
Polar codeset (listed above, applied right inverse mapping related by reference
Are described in the application incorporated above). In addition to the different combinations of possible multiplexing schemes, also different networks
The Arabic number system may be implemented. For example, the present invention is a network
A variety of fiber communication systems
May apply to the texture and it may be multiple users S2.
.SN is connected to fiber optic media 130, and each user sj
May communicate with other users on top of EverEach users. Or
, Node sj assigned code uj to receive data from other users
Be done. And different user are preferred to assign conjugate differential product coding. Yu
When the user sends data to the user sj, the sending user receives
Encode the optical signal using the coding assigned to user sj.
And the receiving user is using the assigned encoding
Decode the signal. This is because the sending user is dynamically receiving the intended
Change the encoding used to send data based on the encoding of the sending user
You may need to be able to. The encoding for one node is
Allocated from one or more basic nodes distributed through the network
It may be. Therefore, when a node in the network comes on the line, it
Of the possible spread spectrum channels that communicate to the coding or coding for coding
Ask to choose one of them. When that node leaves the network,
The encoding used by another node is the conjugate difference product node
May be reset in. Various systems are assigned permanently
Carrier detection multiple access / collision detection (function) method or token pass
May be used to make such a request, such as a ringing scheme. Instead, the token-passing method is a secure coded split channel.
First, it may be used to get the encoding. While only the CDAIA method is described above, those of ordinary skill in the field
, The system is wavelength division multiplexed based on system parameters
And I think it may be used in cooperation with time division multiplexing. For example, for wavelength
The conjugate differential product coding scheme is
May be used for the conjugate difference product part of the spectrum. In addition to that
Coding shared on a time-sharing basis that provides for time-division multiplexing
May be done. In addition, CDMA in the optical space (frequency domain) is coded in the network.
Time domain optical CDMA to increase the number of users and their users
Can be combined. In the time domain broadened spectrum embodiment, the
With the conjugate difference product time domain before the data is provided to its optical encoder
Some user ar, which is
Expanded tor coding. However, these users are not able to use the scheme discussed above.
They can share the same wavelength encoding. Of course, that decoder
The conversion of generally accepted optical information into the electrical digital domain
, The digital signal is subject to time domain spread spectrum coding.
Therefore, it must be processed to recover the requested sent information. Variations of the FIG. 3 embodiment are illustrated in FIG. This illustration is
Does not provide an external wide band light source. Rather, the PIC CDMA encoder
The N-conjugate difference product wavelength, which includes a series of emitting N lasers, fluctuates. N-ray
The N wavelength outputs of the laser are coupled using interfering array waveguides?
Curved diffraction grating to provide its output from encoder 140
Let Its mask and modulation function are the spectrum assigned to that channel.
Can be achieved by turning on that laser in the pattern
Corresponding to possible unipolar coding. All of Laser Earl is this C
Modulate with the same time domain modulation function that distinguishes DMA embodiments from wavelength division modulation systems
did. By selecting the expansion element of the corresponding space, in the decoder,
The remaining components illustrated in FIG. 6 are the same as in the FIG. 3 embodiment.
Of. FIG.7 is also an encoder for FIG.4 that may be used as an encoder for FIG.5.
Show variations on the encoder. Light input to FIG.7 CDMA PIC is
Through coupler or circulator 150, and array waveguide grating or diffraction grating
Provided to the child 152. Grating 152 is the spectrum of the input light in the method described above.
Spread the spectrum light to the mask / function in the method
The parameters described for adjusting the input signal in the optical frequency domain
The controller 154 is provided. Preferentially, the coding is, that is, each view of the mask between two attenuation levels.
A binary one by choosing high and low attenuation levels within a range of
Is. Signal output from that mask / to the bin of that mask provided
Waveguides that are either modulator R or individually connected as usual. Rejoin the spread
Alternatively, but as in the previous embodiment, the signal are spectrum signal is
The high reflectivity coating through the disk / modulator 154 allows its fiber optic
Reflected behind, at the end of the ix or waveguide. Then, the light conditioned by the mask / modulator 154 is shining on its own.
-Recombined by waveguides, or initially disperse wide bands
The diffraction grating 152 used for This embodiment is the second array within the PIC.
It has the advantage of not requiring a Rayguide grating or diffraction grating. Then adjust spatially
The output of the captured signal is provided through the coupler or circulator 150.
Be served. It may also be substituted for that encoder and decoder of FIGS. 4 and 5.
Further variations of the FIG. 7 embodiment are shown in FIG. FIG.8 En
The coder / decoder is a deco that may be used in the FIG. 3 system.
A fixed mask embodiment of the radar and encoder is provided. Switch
Is not provided. Rather, array waveguide grating output or diffraction grating 152
Written by the coding assigned to that channel with a high mirror or anti-reflective coating
Of the patterns taken, it is selectively applied. For that channel by selectively applying high reflection and anti-reflection coating
Into a single binary state, as dictated by the encoding chosen by
The corresponding bin reflects the hght output from grid 152. Other binaries
-The bin corresponding to the state does not reflect light. Array waveguides
The lightly reflected back through the fig. 3 in a way a light signal is suitable for use.
Again to provide a wide range of spatially coordinated bands within the range of
Be combined. The other phases of the FIG.8 embodiment are similar to those of the FIG.7 embodiment. FI
G.8 embodiment has lower cost, fixed encoder and communication system have lower cost and sim
Providing a decoder that allows phcity to be implemented within a range of applications in the relationship
As such, the FIG. 8 embodiment is advantageous for certain embodiments of its invention.
It Yet another embodiment of the encoder / decoder is shown in FIG. 9.
It FIG. 9 embodiment is a silica / current emitter on silicon embodiment of the encoder.
A decoder according to Ming (generally similar to that illustrated in FIGS)
. Four and five. FIG.9 CDMA PIC is an arrayed waveguide grating 160 (by silica
164) provided on the silicon structure means. Two array waveguide cases
Between the two, the mask 162 provided in this embodiment also sits on the silicon structure.
Have Rika. In particular, the mask modifies its attenuation through a little silica waveguide
It consists of a series of temperature switches made in a known way to. For this embodiment, a photo temperature switch array is typically too
It takes time to adjust the optical signal at the required speed and then
Spectral light sources are tuned external to the CDA IAPIC line with pictures
Shiro is preferred. Because of this, the mask controller, which was generally provided in 166 years,
The control signal only controls the on / off state of the mask element to change the time domain.
Does not include key functions. The partial integration of an arrayed waveguide grating that may be used in accordance with the present invention is
, Illustrated in FIG. Half of the photo-guided array waveguide
May be implemented in either conductor, electro-optic or passive (Le.
Silica on silicon) material discussed here. The illustrated waveguide is efficient
It has the special advantage of dispersion when using the waveguide diffraction path. This compact
A permutation has two grids and an array of switches to make a mask
May be integrated into other PICs. Alternately, the waveguide output
Fixed in a compact, which may be selectively blocked in the result.
Mask encoder / decoder. Many very similar optics, as described below in a larger subdivision
Providing source code for many implementations of the current invention phase.
Desirable in. For example, at least 128 that are essentially identical in their extent and intensity distribution.
It is desirable in some embodiments to provide a light source of Currently imagined
Stems generally require many sources. Have the desired spectral similarity
There are particularly desirable people and especially economical implementations of multiple sources
, Its source output is a star demultiplexer into four components for illustration
Provides a single source light source that is tied to the fiber split by the vessel
It is supposed to be. Then each of the splits away from the component expands to the appropriate level.
Separated from each split and expanded components
Provided to each startsplitter. Divided, Divided, Expanded
In each successive source channel, the hierarchical structure of the expanded original source is
To develop multiple sources that have essentially the same spectral characteristics
Can be used for Difficulties have been found by the current inventor when it is conjugate difference
Watched carefully for an undesired level of worldly correlation between the product sources.
This level of correlation is the level of correlation between the conjugate difference product source and the associated conjugate difference product channel.
Can cause unwanted levels. Therefore, the preferred embodiment
Decorrelate the conjugate difference product source. This is a different source channel
You can insert different optical delays along each of the output paths.
May be achieved by. Such an optical delay may consist of an optical delay line
. Pass each of its sources through the conjugate differential product length of the fiber delay line
That may provide the appropriate delay. Delay is different opticc
May be generated in turn, using free space propagation through all paths
Yes. They implemented it for systems where the full optics are small enough.
While embodying this phase of the present invention to allow a wider range of
Can be provided by the immunity to vibrations with minimal spacing in the method.
Fiber delays are rather preferred since they can be handled and implemented
. FIG11 uses a single erbium-doped fiber source
Economical Method and Hierarchy of Erbium-Doped Painted Fiber Amplifiers
Source (with sufficient brightness to drive the channel of the optical communication system
Each of which produces multiple wide spectrum sources to provide sufficient channels
1 illustrates a device that is rather preferred for making. One erbium-doped fiber source, as shown
The 300 generally emits light in a broad spectrum that is acceptable, and is generally
The brightness of the source is roughly within the wavelength range of less than 5 decibels.
Offering a bandwidth of 28 nanometers. 28nanometer bandwidth is about 3
Corresponds to a system bandwidth of 0.5 THz. Erbium-doped paint
Fiber source (also known as a fiber source that emits
Output), splitting the input source signal onto the fiber,
Up to four fiber amplifiers 304 lined up on four fibers
It is provided to a duplexer, such as Star Coupler 302, which provides the output. Fiber Source 300 Output Split into 4 Conjugate Differential Product Sources
, Its brightness falls in the expected way. Source like this
Each of the four splits away from the
The four filters that provide roughly the same brightness as the original source 300 brightness.
Enlarged with Iber amplifier. For the illustrated 128 channel system, this
The process of is repeated through several more hierarchical stages. Thus, the output from the four fiber amplifiers 304 is
Also above is the corresponding set of four duplexers 306, which may be star couplers.
To be provided. Output from fiber amplifier to multiple outputs
The split duplexer 306 has reduced brightness. Then the output from the duplexer 306
What is split away from the source is the next set of source fluxes 310 that have the appropriate brightness.
To broaden the brightness of multiple channels of broad spectrum light to provide
To a further array of fiber amplifiers 308. This process is
Luminance are provided for the illustrative 128 channel fiber communication system.
A wide spectrum saw that is being generated for the independent source of Illustration 128.
Repeated until enough number of su. This hierarchical permutation uses one source and many fiber amplifiers.
The required set while compared to a fiber source
It is preferred to get a lower price of the shunt from the broad spectrum light source that utilizes it. Be generated after enough channels of sauce are lit, light are
That of the source that provided each to an array of spatial light modulators or encoders
A channel that shows the configuration in Figs. Three and four
. The 128 conjugate difference product encoders are the unipolar generated in the method discussed above.
Of 128 masks presenting one conjugate difference product of the
A spatially 128-bin mask is used to encode the incoming light traffic lights at each. Most
Also preferred, each of the masks has a toe of 128 equally sized bins.
Bin measuring the usefulness of a linear mask, with the mask holding a tal
It is a fixed mask with. Thus defining the next frequency interval, which provides a bandwidth of roughly 25 GHz
There are 128 bins in each adjacent bin, which is approximately 3.5 THz (28
Of nanometers). Each of its peers is a member of FIG
To a fixed mask bin that may be a decoder / decoder
Had made. 8 is divided according to the code vector to be merged or the other of the two binary values
Applied. Then each of the 128 channels of the communication system
Is defined by the spatial coding function, and again, each of its channels is
Conditioned with an inter-domain signal (using a modulator, for example). Various channels both
128 channels are also spatially (equal and rare) tuned and temporally tied
Combined and injected into fiber. Long-distance transmission for this fiber communication system is based on other conventional fiber communication systems.
It is managed in a manner similar to that managed by System R. As is traditional
It is typical to use some single mode fiber. In addition to that
The signal on the fiber experiences dispersion and loss. The signal on that fiber is an example
For example, expanding and using conventional fiber has a regular pitch of 40-80 km.
It is preferable that the amplifier is coated with a doped paint every time. At the other end of the transmission fiber, the combined light signal is split and expanded.
Provided to a line of 128 receivers, each connected to its fiber.
With a staggered 128 transmitters, corresponding to one of the fixed mask channel fixes.
The primary purpose of the illustrated embodiment is to spread its use or loading on the fiber.
Each receiver is dedicated to one of the 128 channels.
Therefore, the receiver also includes a fixed mask. The receiver, whose structure may be shown in FIGS. 3 and 8, is the transmitter
Range of receiver 1 to transmitter mask and second mask which is bit-like complement of mask
Special channel determination by a special transmitter by including the exact same mask within
Each is dedicated. In the illustrated embodiment, both transmissions of the communication system are
The use of a fixed mask at the end to keep the high volume fiber
A reduced cost system that offers significantly improved bandwidth for
To serve. Optical signal recovery from fiber communication links, as shown above
Is essentially two components that must have similar power levels.
, Using a receiver that separates the light flux received from the optics. A
Particularly preferred the aspects of the present invention to be illustrated in FIG. That input
Shows the beam separators favored by coders 12. Sepa according to the present invention
The rotator effectively requires the preferred differential detection scheme of an optical CDMA receiver.
The light generally accepted to allow to discover the desired user channel
It can be divided into two parts with power levels equal to minutes. Polarization insensitive beam separator mient embodi is
For each channel that has one conjugate difference product of the cross polarizations, typically
The first polarization that splits the perceived luminous flux into first and second channels of light
It may consist of sensitive elements. For example, one channel of light was polarized perpendicular to the generally accepted light
May include components and other channels generally accepted
It may include horizontally polarized components of the light bundle. then,
The polarization of one of the channels is the polarization of the other flux.
Converted to Due to the linear polarization, this will rotate the polarization of that light.
It may consist of rolling. Then the two channels of light reconnect.
It is combined and provided to the beam splitter. This beam splitter is typical
Well-defined and predictable spatially coupled beam polarization
A polar that splits an accurately combined beam into two beams of qualitatively equal power.
Rization sensitive element. Referring to FIG. 12, the light received from the single-mode fiber 350 is
Embodiments are described in. Negative Polari Fiber 350 generally holds
Was the zation and the light within the fiber 350 is likely to be linear
Since it can be polarized in any direction, the beam splitter 352 or
Use a conventional linear polariser as a polarization analyzer.
Is convenient. Polarization sensitive element 352 prefers the input light
Split the bundle into two right-angled polarization components, and
Providing those two components up to optical path 354 (356). Generally different
The power level that is present is along each path. The optical passage with the photograph passes through the free space.
May be propagated through or through the polarization maintaining fiber.
And then proceed. Either way, the polarization can be changed.
So, the polarization of light within the range of each arm is
It is a zation. One component of that light is provided along optical path 354 to provide optical communication.
Maintain vertical linear polarization 358 through path 354. Along the other optical path 356, initially
, Its polarization is horizontal 360, then the'second optical path
Shown in FIG. 12 at 364 for light polarization to be a linear vertical line.
As it is, its polarization has been 90 years since
To 362 "is rotated in a year. The second optical passage 356 is proliferated through free space.
When breeding, the rotation element should be 1/2 waveplate or the appropriate fara.
May be a day rotator. The second optical passage 356 is through polarization conserving fiber
When breeding, the rotation element 362 will rotate the mechanical
Most preferred in 900 years. Most commonly
The rotation of the fiber proceeds continuously over the fiber. of course
The end of the fiber in the second optical passage by inserting a rotation
Performing that rotation through other means such as
Is possible. Two beams on two optical paths correctly orient their polarization
If defined, the two beams are recombined, then a pair of essential
A split to power equal to is propagated along two additional beam paths
Radiate to. After the beams from paths 354 and 356 are combined, the beams are
Splitting into essentially equal power beams is a typical polarization
Possible to use a sensitive beamsplitter 366. The two required output beams are optical paths 368 and 370
Provided in the illustrated embodiment with linear polarization along a single mode optical fiber
To be done. Then, the split, generally accepted beam, is the decoder 108 (FIG.
Up to 110) will be provided. Those of ordinary skill admit it,
Polarization insensitive beamsplitter for example in collaboration with Rement
May be proficient in other waveguides with respect to fiber, as mentioned above. In the photo optical CDMA system, the higher number of channels
To be provided on a single fiber for the user, or
, Conjugate difference product It is very important to reduce that interference between the conjugate difference product channels
Desirable for. Various mechanisms have been identified to perform this task.
Described in the current application, and incorporated by reference herein into other applications
. The only way the current system reduces interference is to show one binary state
Beside injecting light into the optical communication system for the purpose. For example, if the source is
To produce output luminance to indicate one logical binary state,
A logical one whose source is a coordinated time domain. The light gave instructions
Logical 0 not provided for. This reduces total interference in the system.
Have results. Of course, in particular, the conjugate difference product channel with complementary filtering functions
Rather preferred coding schemes, including receiver systems including
Provides a mechanism to reduce interference. Also, the range of the signal detection circuitry of the decoder or receiver in the interference
It is possible to achieve a reduction within. Two channels of receiver are
Signals within the range of
Back-to-back configuration from the conjugate difference product of a pair of photodiodes
I found that light in my favor. Then the power from the photodiode
The Qi output is a difference measurement of the signals received in the two channels.
In a particularly preferred embodiment of the present invention, the electrical output signal is filtered and
With the low path that is then provided to the electric square ordered circuit element like a diode
is there. This square rule element or limiter is the one
Taking a negative part of the Qi signal, and also the generally accepted electrical signal
May be used to expand some of the positive going. Electrical
The negating part of the signal is immediately definable as noise and is a complete system.
So can be taken to improve the signal-to-noise ratio. The rather preferred electrical system (roughly illustrated in FIG. 3) is
To reduce interference. The subsystem illustrated in FIG. 13 is 11
Provides additional details on the back-to-back diode permutations shown in FIG. 3 in 6.
To do. The two complementary complementary optical signals will be
Back-to-back diode, which produces a light amplification function, but also a differential amplification function
Provided to. Optical detectors, differential detection and other combinations of electrical amplification are known and these functions
Will be used as a substitute. Among the particularly preferred embodiments of the present invention, the electrical one is the die
The signal from the pair of outputs is output, and the low and high paths are filtered by the filter 380.
did. For those decoders implemented in semiconductor devices, also the detection
Deliver circuitry provided within the same chip or on a single PIC line
May be done. Low pass filtering takes high frequency noise signals
To be executed. Multiple channels are available at a data rate of approximately 622 MHz from an optical communication system.
Photo system that may receive one of the channel video data
In the filter, its filtering passes frequencies below approximately 630650MHz.
It may be. Then, the struck electrical signal is a diode-like electrical positive
A rectangular regular circuit element 382 is provided. This square rule element or limit
Take the taking part of the negative of the generally accepted electrical signal,
It also expands the positive going part of the generally accepted electrical signal.
May be used for The negated part of the electrical signal can be immediately defined as noise,
So can be taken to improve the signal-to-noise ratio of the system. Then Rimi
The electrical signal output from the ter 382 is considered to have been signaled.
Above a threshold that is analyzed to find the signal. Another means of reducing interference is to estimate the correlation between the conjugate difference products of the noise signal.
Is to be reduced. When executing the source ploy shown in FIG
, The difficulties observed by the present inventor. 11 of this world between conjugate differential product sources
It is an undesired level of correlation. This level of correlation with the conjugate difference product source
During the associated conjugate difference product channel, the correlation of the noise source, or
Can cause a certain level. Therefore, the preferred embodiment is a conjugate
Decorrelate the difference product source. This is the output of different source channels.
By inserting different optical delays along each of the
May be achieved. One simple mechanism to achieve this is
Illustrated in FIG. 14. -For example, using the technique illustrated in FIG. Many
Explicit source 400403 is defined 11 and its source discussed is
To provide similar spectral bandwidth and spectral distribution for similar light output
Above. While four sources are shown, the system typically
Includes at least 128 full sources serving all users. Each output of Source 400403 goes through a delay that reduces world correlation.
Then, the conjugate difference product source is passed. Such optical delays are
Optical delay line or extended optical channel. Each of its sources
Passing through the conjugate differential product length of the fiber delay line is
It is the most favored mechanism for providing lei. Delay is conjugate
Alternately, using free-space propagation through the cross product optical path, it may be generated alternately
I can't. They implemented for the system with full optics at sufficiently small intervals
Embodying this phase of the present invention to allow a wider range of
Be implemented with only minimal spacing so that it can be provided while
Fiber delay has been the preferred choice since it was created. Say again to FIG.14
In addition, the appropriate delay is through the conjugate differential product length of single mode fiber 404407.
And is passed through each output of source 400403. Difference
The length of the fiber is about 1 and at least about 2 on a continuous source
Selected to impose that data rate delay of times. Approximately 622 Mbt /
Considering the data rate on the secondary side, the corresponding delay will be
Can be formed by and optical fiber for each (1.5G
Half foot (equivalent to Hz) required a delay. Thus, the first source 400
For this, the additional length of the fiber is
, Can't be added. For the second source 401, 1.5 fibers of additional fiber 405
Is included in the output path and for the third source 402
3 foot lengths of fiber 406 beyond the baseline length of the Iber 404
Provided. Similarly, at 4.5 feet (4.5 GHz) longer than fiber 404
The output from the source 403 is connected through a fiber 407. 12
Eight users may be summed, or more or equally multiplexed.
Users within the range of systems that may sum a known number of 128 channels
Each has a source-initiator from the central source and is
Was delayed from all other sources. To achieve optical delay
The conjugate cross product mechanism is known and practiced to achieve similar results.
Of course, good things are accepted. Another source of interference reduction and one that has been found to be particularly effective is its source.
Is the use of a known number modulation scheme that limits the amount of time that is supported in the on-state. time
Area is a known number provided by adjusting its source to an optical communication system.
Adjusted Earl. The source may be tuned directly or its source light
May be adjusted by passing the source through an adjustable element
I can't. Among the preferred embodiments of the present invention, light of a predetermined brightness
A single binary value will be sent in order to provide the optical pulse to the optical system.
And other light is sent when no light is provided to the optics.
Modulation is achieved when and. Modulate source with data stream
An example of the outline of is shown in FIG. In the adjusted data stream, the adjusted binary data and these bins
Defining a data rate for a data stream
Characterized clocks are typically near utilization. This is roughly black
Various data streams shown above the background of the clock cycle initiation
The frames (a) (c) are illustrated in FIG. 15 with the same vertical dashed lines. Conventionally each clock cycle defines a known period and its known number
Can consume some or even that clock cycle. That
If all of the clock cycles are consumed by that known number, its utilization
Is said to be 100%. That data erases only half of that clock cycle.
If paid, the usage rate is said to be 50%. This is shown in FIG
It 15 (a), and may be very "ON" like one half of that time
Not composed of signals. The light of the system between different users or channels
Further injected into the system to reduce the total amount of interference present within range
Is more desirable to reduce that time. Thus, the known number modulation is
Treats the data stream like that shown in FIG, with 25% utilization
Familiar with a particularly preferred embodiment of the present invention. 15 (b) or less
And even like that shown in FIG. 15 (c) with a usage rate of 12.5%. In a particularly preferred embodiment of the present invention, its utilization is low, but
It is generally preferred to be lowered to a still detectable level, 50%
With a usage rate of less than. This is a point in time within the fiber optic system.
Has the result of reducing some total optical signal. In other words,
The use of shorter usage rate was required to reduce its light output within the range of the system
Reduce experienced interference noise signal and its total by signal. Circuitry
Exists to significantly reduce usage. The optical signal is not detectable
As a practical substance to remain, however, the decrease in usage is
Must be restricted in the tent. Amplification of the input source or amplification of the detection system
, The known number must be increased in proportion to the decrease. then
, The noise floor associated with that amplifier establishes its limit on a small way
Its usage may be reduced. Its utilization is the level at which amplifier noise becomes dominant in the signal.
Can't be reduced down. The data source is responsible for providing the required utilization characteristics for the data stream.
May be chosen for. On the other hand, because the data that is input is flowing,
Shown in 50% FIG. 15 (a), which is typically preferred to provide greater flexibility.
The utilization stream can be converted into relatively short utilization pulses.
It FIG16 so in FIG.15 (a), so in FIG.15 (b) or 15 (c)
For converting the input data stream into the data stream indicated by
FIG. 7 is a schematic illustration of the device. The circuit of FIG.16 consists of its data source and its modulator.
Placed in between. The data stream is shown in FIG. 16 from its data source.
Input to the pulse qualifier 420. Because a little signal goes through the delay element 422
In, an electrical signal travels along two paths. The delay element 422 is
Create a delay for delayed signals. Both undelayed and delayed signals
Among the ways to produce a positive pulse while being a "1" of two are are
, Recombiner4 rejoined in 42 years. Delay circuit 422 is a programmable delay
Or it may consist of a series of inverters
Yes. For example, the recombiner may be an exclusive-OR gate. Soba
Use it in FIG. 16 orbiting pulses of selected utilization circulate
To provide. The present invention is described with particular emphasis on certain preferred embodiments of the present invention.
However, the present invention is not limited to the specific embodiments described herein. Ordinary
Those of ordinary skill recognize certain modifications and are within the scope of the teachings of the present invention.
While remaining in the enclosure, variations are made to the special embodiments of the present invention
It may be. For example, the above embodiments were resolved by mediating over fiber.
While being presented from the point of view of a communication system, the current aspects of the invention are immediately exhausted.
On top of the air optics. Thus, the scope of the present invention is the scope of the above claims.
It is to be determined by the range.

[Brief description of drawings]

FIG. 1 illustrates a conventional CDAIA communication system solved by optical fiber arbitration.

FIG. 2 provides a more detailed view of one receiver configuration that may be used within FIG's system. 1.

Figure 3 Optical CDM using a roughly photonic integrated line
Figure 3 illustrates a full view of the A system.

FIG. 4 illustrates one configuration of encoder PIC configurations.

FIG. 5 illustrates one of the PIC configurations of the decoder.

FIG. 6 illustrates an alternative configuration of the FIG's system. 3.

FIG. 7 illustrates another configuration of encoder or decoder PIC configurations.

FIG. 8 illustrates another configuration of an encoder or decoder PIC configuration.

FIG. 9 illustrates another configuration of encoder or decoder PIC configurations.

FIG. 10: A particularly compact configuration of the interdigitated array waveguide shown.

FIG. 11 To generate a squeeze N broad spectrum optical source with sufficient brightness on a fiber using means according to the present invention for N channels of communication to the generated light flux. 2 schematically illustrates the device.

FIG. 12 schematically illustrates a polarization insensitive beam separator rather generally preferred in accordance with a preferred embodiment of the present invention.

FIG. 13 shows an example in a larger subdivision whose photodetection circuitry is roughly illustrated in FIG.

FIG. 14 illustrates changes to the FIG. Source Generation mechanism.

FIG. 15 illustrates a set of data streams (a) (c) that may be used to condition a source according to aspects of the present invention.

FIG. 16 illustrates a line that may be used to generate a pulse stream such as that illustrated in FIG.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04B 10/142 10/152 10/22 (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SL, SZ, TZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD) , RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CR, CU, CZ, DE, DK DM, DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR , LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, TZ, UA, UG, UZ, VN, YU, ZA, ZW (72) Inventor Narragee, Manower United States 90230-6609 Culver City Uplander Way 5800 (72) Inventor Chan, James K United States 90230-6609 Culver City, CA Culver City Uplander Way 5800 F Term (Reference) 5K002 AA02 AA04 BA04 BA05 BA07 BA14 BA15 BA21 CA02 CA15 DA02 DA06 FA01 FA03 5K0 22 EE01 EE21 EE31

Claims (46)

[Claims] 1. A light source, a data source for providing a data stream, and an encoder for receiving a light output from the light source, the encoder comprising a first spectral filtering assembly representing a first code, the first spectral filtering assembly comprising: Code is an array of N numbers each having one of at least two values, and the assembly spectrally encodes the light output of the light source with a first code to output the light source output. Each of them is separated into spectral elements corresponding to each number of the first code, each spectral element is attenuated according to the value of the corresponding code number, and the spectral elements are recombined to generate an encoded optical signal. An optical communication system comprising: an encoder, wherein the encoder is connected to the light source. Modulating the output of the light source, and generates an optical signal that is encoded is data modulated. 2. The optical communication system according to claim 1, wherein the first code is selected from a set of unipolar codes, and each code in the set is different from the other codes in the set. It is orthogonal to the difference in the complements of the codes. 3. The optical communication system of claim 1, further comprising a decoder coupled to receive an optical signal from an optical fiber and receive transmission data from the optical fiber, the decoder comprising: It has a phase incentive optical power separator that splits the first and second optical elements of approximately equal output. 4. The optical communication system according to claim 3, wherein the decoder is: second and third spectral filtering assemblies coupled to receive the first and second optical elements, the second and third spectral filtering assemblies comprising: The spectral filtering assembly represents the first code, the third spectral filtering assembly represents the complement of the first code, and the second and third assemblies are of the first of the received light.
And a second spectral filtering assembly that outputs a second filtered element, and an optical detector that receives the first and second filtered elements and outputs an electrical signal. 5. The optical communication system according to claim 1, wherein the encoder is a photonic integrated circuit. 6. The optical communication system of claim 1, wherein the first spectral filtering assembly comprises an array waveguide. 7. The optical communication system of claim 4, wherein the spectral filtering assembly comprises an array waveguide. 8. The optical communication system of claim 4, wherein the spectral filtering assembly includes a plurality of arrayed waveguide gratings. 9. The optical communication system of claim 4, wherein the decoder is at least partially shaped as a photonic integrated circuit. 10. The optical communication system of claim 9, wherein the encoder is at least partially shaped as a photonic integrated circuit. 11. The optical communication system of claim 4, wherein the electrical signal output represents a difference between the first and second components of the received light. 12. The optical communication system according to claim 4, wherein the electric signal output is supplied to a limiting circuit for removing an electric noise signal having a sign opposite to that of the received data. 13. The optical communication system according to claim 4, wherein the electric signal output is provided to a limiting circuit including an electric square detector. 14. The optical communication system of claim 3, wherein the phase incentive optical power separator is: a first polarization sensitive element that receives an optical signal and splits the optical signal into first and second optical elements. A first optical signal having a first polarization and a second optical component having a second polarization output from the first polarization sensitive element; A first beam path in which the element travels and a second beam path in which the second light element travels and a polarization modifier placed along the second beam path, the second light element Receiving a polarization modifier and first and second light elements, wherein the first and second light elements are third and fourth light, respectively. Beam splitter to split into elements With the door. 15. An optical communication system, comprising: a data source for providing a data stream; and an encoder for providing an optical output modulated with the data stream and representing a first code, the first code being a set. Unipolar code, each code in this set is orthogonal to the difference between the other code in the set and the complement of the other code, and each code is of at least two values. An encoder that is present in a set defined by an array of N numbers having one of N, each N number of codes corresponding to one of N potential spectral ranges that may be output from this encoder, respectively. And the optical output from the encoder has M elements corresponding to M different spectral ranges within the N-child potential spectral range, each M The element is characterized by an Mth element optical level corresponding to the corresponding code number value, and an optical output from the encoder is a broad spectrum light modulated by a data stream and a spectrally defined code function. The encoder has a photonic integrated circuit. 16. The optical communication system according to claim 15, wherein M is equal to N in that the first code is a discrete analog function. 17. The optical communication system of claim 15, wherein the first code is binary and M is less at that point. 18. The optical communication system according to claim 15, wherein the first code is defined within a set of N waveguides. 19. The optical communication system of claim 18, wherein the M of the waveguide is terminated in the reflective coating. 20. The optical communication system according to claim 15, wherein the encoder includes a series of N sources. 21. The optical communication system according to claim 15, wherein the encoder includes a non-separable element such as a spectrum which is a photonic integrated circuit. 22. The optical communication system according to claim 21, comprising a waveguide in which non-separable elements such as spectra are arranged in a line. 23. The optical communication system according to claim 22, wherein the non-separable element such as spectrum is a curved grating. 24. The optical communication system of claim 15, wherein the first code is defined within the set of N waveguides by a switch that alters the optical properties of the waveguides. 25. The optical communication system of claim 24, wherein the switch produces heat to alter the optical properties of the waveguide. 26. The optical communication system of claim 24, wherein the data source comprises a wide band light source conditioned on the data stream. 27. An optical communication system according to claim 15, further comprising a decoder,
Includes a decoder to receive the optical signal from the optical fiber and connect the transmitted data back from the optical fiber: a phase incentive for splitting the generally accepted optical signal into roughly equal power and a second lighter element. Optical power separator. 28. The optical communication system according to claim 27, wherein the decoder further comprises: second and third spectral filtering assemblies representing first and second optical elements, first code. A second spectral filtering assembly and a first code for receiving the third, the second and the first of the received light
And a spectral filtering assembly representing a complement of a third spectral filtering assembly outputting a second filtered element; a generally accepted optical (providing electrical signal output An optical detector provided to receive the first and second strained elements of the optical detector). 29. The system of claim 28, wherein the electrical signal output represents a differential measurement between the generally recognized first and second struck elements of the light. 30. The optical communication system provided at that point wherein the electrical noise limiting circuit of claim 31 has an electrical signal output such that the sign of the recovered data is opposite. Signal to do. 31. The system of claim 28, wherein the electrical signal output is provided to a limiting circuit including an electrical squared detector. 32. The system of claim 27 wherein the incentive optical power separator comprises a phase) optical communication system: the first polarization sensitive element receives the optical signal, and The optical signal to the second optical element, the first optical element having the first polarization and the first as output
Placed a sensitive element to separate the second optical element having the second polarization from the second polarization; the first beam path traveled by the first light element and the second light element traveled by the second light element. A second beam path; a polarization modifier placed along a second beam path (a polarization modifier that causes the polarization of the second optical element to be predominantly the first polarization); And the beam splitter receiving the second light element and splitting the first and second light elements into the third and quarter ignite elements. 33. An optical communication system (including a decoder coupled to receive an optical signal from the optical communication system and recover the transmitted data including a decoder): First generally accepted for approximately equal power and second light element. An optical power separator for splitting the coupled optical signal; first and second spectral filters coupled to receive the first and second optical elements, a first code representing a first code Spectral filter and 1st code, 1st and 2nd outputting 1st
A spectral filter of the second and a second spectral filter representing the second complement filtered the received light element; each of the N digits of the code is a N potential Corresponding to one of the spectral ranges, the generally accepted optical signal is a broad spectrum light, at that point in the data stream, and with M elements within N potential spectral ranges, M different spectra. A spectrally defined code function that is intended to correspond to the range of and its decoder modulated at that point including a photonic integrated circuit. 34. In the optical communication system according to claim 33, M is equal to N in that the first code is a discrete analog function. 35. The optical communication system of claim 33, wherein the first code is binary and M is less at that point. 36. The system of claim 33, wherein the first code is defined within a set of N waveguides. 37. The system of claim 36, wherein the waveguide M is terminated in a reflective coating. 38. The system of claim 33, wherein the first filter comprises a spectrally inseparable element that is a photonic integrated circuit. 39. The system of claim 38, comprising a waveguide with an array of spectrally inseparable elements. 40. The system of claim 38, wherein the spectrally inseparable element is a curved grating. 41. The system of claim 33, wherein the first code is defined within the set of N waveguides by a switch that alters the optical properties of the waveguide. 42. The system of claim 41, wherein the switch produces heat to alter the optical properties of the waveguide. 43. The system of claim 33, wherein the electrical signal output represents a derivative measurement between the generally recognized first and second struck elements of the light. 44. The optical noise communication system according to claim 43, wherein the limiting circuit for picking up electrical noise has an electrical signal output, the optical communication system provided with positive and negative signs is such that conflicting data is recovered. Signal to do. 45. The system of claim 33, wherein the electrical signal output is provided to a limiting circuit that includes an electrical squared detector. 46. The optical communication system of claim 33 (wherein the power separator comprises an optical): the first polarization sensitive element receives the optical signal and outputs to the first and second optical elements. Optical signal, a first optical element having a first polarization and a first as output
Placed a sensitive element to separate the second optical element having the second polarization from the second polarization; the first beam path traveled by the first light element and the second light element traveled by the second light element. A second beam path; a polarization modifier placed along a second beam path (a polarization modifier that causes the polarization of the second optical element to be predominantly the first polarization); And the beam splitter receiving the second light element and splitting the first and second light elements into the third and quarter ignite elements.