RU2380837C1 - Multichannel optical input/output multiplexer with dynamic functionality - Google Patents

Abstract

FIELD: information technologies.

SUBSTANCE: device for fiber-optic communication system with wavelength-division multiplexing 2^N channels where N is integer and N≥2 with spectral interval between adjacent channels Δv₀ for performing input/output of 2^M channels where M is integer and 1≤M<N, has one entering port, one exiting port, 2^M output ports, 2^M input ports and contains: controlled optical input/output multiplexer, optical demultiplexer of "1×2^M" configuration, optical multiplexer of "2^M×1" configuration and controller. This device can be used as multichannel controlled or multichannel reconfigurable optical input/output multiplexer.

EFFECT: performing input and output of multiple channels from optical signal with channel wavelength-division multiplexing using controlled dynamic filtering elements capacity restructuring.

13 cl, 16 dwg, 3 tbl

Description

The invention relates to fiber-optic communication systems with spectral channel multiplexing, in particular to multi-channel reconfigurable and controlled optical channel I / O multiplexers (hereinafter t-OADM and ROADM) and can be used both in dense spectral multiplexing (DWDM) systems and moderate spectral multiplexing (CWDM).

New technologies in fiber-optic communication systems using spectral multiplexing are becoming dominant in modern communication systems. Dense spectral multiplexing, DWDM, is used in long trunk lines, moderate spectral multiplexing, CWDM, is used in urban and local communication systems.

DWDM technologies are characterized by extremely high bandwidth, but are very expensive. The standard for the grid of wavelengths, introduced by the International Telecommunication Committee (hereinafter ITU-Standard), provides for the spectral interval between channels 200, 100, 50 or 25 GHz. The recommended ITU-Standard spectral spacing between channels for CWDM systems is 20 nm. CWDM is easier to use and cheaper than DWDM.

At the VOCS nodal points, optical input / output multiplexers (hereinafter OADM) are used for channel input / output. They allow you to remove one or more channels from the line and simultaneously enter a signal at the same wavelengths with new information, and the efficiency of using communication systems is increased. Moreover, the number of input / output channels is usually significantly less than the total number of channels in the line.

Multichannel OADMs have, as a rule, fixed I / O channel frequencies. Systematically increasing bandwidth requirements for communication systems require more flexibility, in particular, the use of reconfigurable and managed multi-channel OADMs. These devices, in addition to use in optical communication networks, can have other applications, for example, in multi-channel sensor systems, for optical filtering, in analog systems for various purposes.

Currently known reconfigurable OADM (hereinafter ROADM) have a number of significant drawbacks, the main one being that these devices are very complex and expensive, and managed OADM (hereinafter t-OADM) allow you to enter / output only one channel. Note that the authors of the present invention, speaking of multi-channel ROADM and t-OADM, mean devices in which for each output and newly introduced channel there is an individual port.

The approach to the task of creating ROADM, well known to specialists in the field of optical communication systems, consists in using a pair — a 1 × K configuration demultiplexer and a K × 1 configuration multiplexer, the outputs and inputs of which are connected and form K paths (K is the total number of channels in system). An optical electromechanical switch (hereinafter MEMS) is installed in each of the tracks. The specified optical demultiplexer divides the optical signal into K channels and directs each channel to one of the K paths. MEMS pass part of the channels to the optical multiplexer, and the other part of the channels are sent to the output ports. The specified optical multiplexer combines all the channels, including newly introduced using the same MEMS, and returns them to the optical line. Obviously, if implemented using this approach, the device would have a high cost, the greater the greater the number of channels K and the smaller the spectral interval between adjacent channels.

Another approach (US, 6602000, B2) is to use also a pair of demultiplexer and multiplexer, but simpler configurations “1 × L” and “L × 1”, where L = K / P, K is the total number of channels and P is an integer number. The outputs and inputs of the demultiplexer and multiplexer are again connected and form L traces, each path contains several, in the amount of P, OADM I / O multiplexers, each based on an asymmetric Mach-Zehnder interferometer (hereinafter referred to as MZI) with Bragg diffraction gratings integrated in the arms of the interferometer . When controlling the temperature effect, the period of the diffraction grating can vary within certain limits: be equal to or not equal to the wavelength of one of the K channels, and, therefore, with the help of such OADM, channel input / output with the corresponding wavelength can or may not be made.

When a signal including K channels with an interval between adjacent channels Δν arrives at the input of the device in question, the channels are separated by an optical demultiplexer into L subsets, in each subset - P channels with intervals between channels L · Δν. When a signal passes along one of the traces using the OADM chain, any given channels can be output. All other channels, together with newly introduced channels at the frequencies of the output channels, are combined using an optical multiplexer and enter the optical line.

It is clear that in the case of a large number of channels in the optical system, this device would also be very difficult to manufacture and expensive. Moreover, a structure containing a large number of IMCs, each of which has its own Bragg individual diffraction gratings in two arms and a thermal control system, would be cumbersome and unreliable in operation.

Thus, at present, there are no multichannel reconfigurable and controlled OADMs that would really be suitable for use in optical communication lines and at the same time be technologically advanced to manufacture, reliable in operation, and have an acceptable cost.

An object of the present invention is to provide a multi-channel OADM with dynamic functionality, which in various embodiments can be used as a multi-channel ROADM or as a multi-channel t-OADM. The device should be simpler in the design solution than the known approaches suggest, satisfy the existing requirements for channel isolation and introduced dispersion, and be suitable for integrated optical performance. Whenever possible, the device should be as dynamic and flexible as possible for use in a wide variety of WDM systems.

When creating the invention, the task was to develop a device for input / output of multiple channels from an optical signal with spectral channel multiplexing using controlled dynamic tuning of the filtering bandwidth.

The problem was solved by creating a multi-channel controlled optical input / output multiplexer with dynamic functionality for a fiber-optic communication system with spectral multiplexing of 2 ^N channels with N being an integer and N≥2 with a spectral interval between adjacent channels Δν ₀ for input / output 2 ^M channels at M is an integer and at the same time 1≤M <N, having one input port, one output port, 2 ^M output ports, 2 ^M input ports and including:

- a controlled optical input / output multiplexer that provides the output of 2 ^M channels to one output port and the input of new 2 ^M channels at the carrier frequencies of the output channels to one output port;

- optical demultiplexer configuration "1 × 2 ^M " connected by its input port to the output port of the specified managed optical input / output multiplexer,

- optical multiplexer configuration "2 ^M × 1" connected to its output port with the input port of the specified controlled optical input / output multiplexer,

- controller.

Moreover, according to the invention, it is advisable that the specified controlled optical input / output multiplexer had:

- (N-M) -step structure, containing in each stage one optical filter having one input and two outputs, made with the possibility of controlled adjustment of transmission coefficients, characterized in the n _1st stage with n ₁ = 1,2, ..., (NM) the frequency interval between adjacent extremes in the dependences of the transmission coefficients on the frequency Δν _n1 = 2 ^n1-1 Δν ₁ ;

- an optical adder having N-M + 1 inputs and one output connected to the output port.

In addition, according to the invention, it is advisable that in the specified (N-M) -step structure:

- the optical filter of each stage, except for the last stage, was connected by one of the outputs to the input of the optical filter of the next stage, and by the other output was connected to one of the inputs of the optical adder;

- the optical filter of the first stage with its input was connected to the input port;

- the optical filter of the last stage with one output was connected to another one input of the optical adder, and the other output was connected to the output port;

- The optical adder to the other of the inputs was connected to the input port.

- the output of the optical adder was connected to the output port.

Moreover, according to the invention, it is advisable that the multi-channel multiplexer be adapted to control the input / output of the channels in a reconfigurable mode, while these optical demultiplexer and multiplexer have fixed spectral characteristics and the controller is electrically connected to the specified controlled optical input / output multiplexer.

In addition, according to the invention, it is advisable that the multichannel multiplexer be adapted to control the input / output of channels in a tunable mode, while these optical demultiplexer and multiplexer have tunable spectral characteristics and the controller is electrically connected to these controlled optical input / output multiplexer, optical demultiplexer and multiplexer.

Moreover, according to the invention, in a multi-channel multiplexer adapted to control channel input / output in a tunable mode, said optical demultiplexer included an M-step structure of the “tree” type, containing in each n _2- th stage with n ₂ = 1,2, ..., M2 ^n2-1 optical filters having at least one input and two outputs, adapted to be controllable tuning the transmission coefficients, characterized in n _2-th stage frequency interval between adjacent extrema in dependence of n coefficients soap has the frequency equal to

Δν _n2 = 2 ^{n2 + NM-1} Δν ₁ .

Moreover, according to the invention, it is advisable that in the indicated optical demultiplexer in the indicated M-stage structure one of the inputs of the optical filter of the first stage is connected to the input port, each of the two outputs of the optical filter of the last stage is connected to one of their output ports and optical filters in each stage, except the last, each of their two outputs were connected to the input of one of the optical filters of the next stage.

In addition, according to the invention, it is advisable that the specified optical multiplexer includes an M-step structure of the type "tree" containing in each n _3rd stage with n ₃ = 1.2, ..., M at least 2 ^M-n3 optical filters, having two inputs and at least one output, made with the possibility of controlled adjustment of the transmission coefficients, characterized in the n _3rd stage by the frequency interval between adjacent extrema in the dependences of the transmission coefficients on the frequency Δν _n3 = 2 ^N-n3 · Δν ₁ .

Moreover, according to the invention, it is advisable that in the specified optical multiplexer in the indicated M-stage structure two inputs of the optical filters of the first stage are connected to the input ports, one output of the optical filter of the last stage is connected to the output port and the optical filters in each stage, except the first and last, were connected by each of the two inputs with the output of one of the optical filters of the previous stage, and with one output - with one of the inputs of one of the optical filters of the next stage.

Moreover, according to the invention, it is advisable that single-stage and / or two-stage and / or multi-stage asymmetric Mach-Zehnder interferometers be used as the indicated optical filters.

In addition, according to the invention, it is advisable that these optical filters contain electro-optical or thermo-optical phase shift devices to control the adjustment of transmission coefficients.

Moreover, according to the invention, it is advisable that the multichannel multiplexer was made by integrated-optical technology on a single chip.

Moreover, according to the invention, it is advisable that in the multi-channel multiplexer the input port, output port, M output ports and M input ports are made using optical fibers.

The invention is further illustrated by the description of embodiments of a multi-channel controlled optical input / output multiplexer with dynamic functionality according to the invention and the accompanying drawings, which show:

Figa - diagram of a single-stage MZI;

Figb - conditional image of a single-stage MZI shown in Fig.1A;

Figa - diagram of a two-stage MZI;

Fig.2B - conditional image of a two-stage MZI shown in Fig.2A;

Figa is a diagram of a multi-stage MZI used to separate the channels into odd and even;

Fig.3B is a conditional image of a multi-stage MZI shown in Fig.3A;

Figa is a diagram of a multi-stage MZI for combining odd and even channels;

Fig. 4B is a schematic illustration of a multi-stage MZI shown in Fig. 4A; 5A is a diagram of a t-OADM controlled optical input / output multiplexer;

Fig. 5B is a schematic view of the t-OADM controlled optical input / output multiplexer shown in Fig. 5A;

6A is a diagram of a t-Demux controlled optical demultiplexer;

Fig.6B is a conditional image of the controlled optical demultiplexer t-Demux shown in Fig.6A;

7A is a diagram of a t-Mux controlled optical multiplexer;

Fig. 7B is a schematic representation of the t-Mux controlled optical multiplexer shown in Fig. 7A;

Fig. 8 is a diagram of a multi-channel OADM with dynamic functionality according to the invention used in a reconfigurable input / output mode using t-OADM and an optical demultiplexer and a multiplexer with fixed spectral characteristics;

Fig. 9 is a diagram of a multi-channel OADM with dynamic functionality according to the invention used in a controlled input / output mode using t-OADM, t-Demux and t-Mux.

Moreover, the accompanying drawings and the described embodiments of the invention do not limit the application of the invention and do not go beyond the scope of the present invention.

According to the invention, a key element for functional devices that are part of a multi-channel OADM with dynamic functionality according to the present invention is an asymmetric Mach-Zehnder interferometer or, as they agreed to call it, a single-stage MZI.

A single-stage MZI can be performed using various components and technologies, including using fiber optic splitters, beam splitters, prism mirrors, polarizers, and other elements. The best option for multi-channel OADM with dynamic functionality according to the present invention is a single-stage MZI in planar design.

On Figa shows a schematic representation of a waveguide version of a single-stage MZI 10, its conditional image is shown in Fig.1B. The device 10 is placed on one substrate 11, where the cascaded MZI 12 itself is formed by two arms 12-1 and 12-2 located between the first 13 and second 14 splitters, formed by waveguides of unequal length l ₁ and l ₂ , respectively. The coupling coefficients k ₁ and k _{2 of the} splitters 13 and 14 are equal and divide the optical power in a ratio of 50/50. The one-stage MZI 10 has conclusions a and b on the one hand and conclusions c and d on the other hand.

In this case, the single-stage MZI 10 in the arm 12-2 contains a phase shift device 15 that introduces an additional phase shift φ into the phase of the traveling wave and is a controllable element used to adjust the spectral characteristics.

The magnitude of the phase shift φ is controlled by the thermo-optical or electro-optical effect using electric current or voltage. Accordingly, the phase shift device 15 can be manufactured using a thermo-optical material, such as silicone, or an electro-optical material, such as lithium niobate (LiNbO3) or gallium arsenide. Such phase shift devices are known in the spectral densification technique as a tool for tuning the spectral characteristics of optical filters based on the IMC, and are also used in other devices - modulators and switches.

When a unit power radiation is input through port a, the light intensity at the two output ports c and d can be expressed using the transmission coefficients K _ac (ν, φ) and K _ad (ν, φ):

where D = 2πnΔLν / c is the phase delay due to different optical lengths

shoulders 12-1 and 22-2; ΔL = l ₁ -l ₂ ; n is the refractive index of the material; ν is the optical frequency and c is the speed of light in the void.

When excited through port b, the light intensity at the same output ports c and d can be represented using the transmission coefficients К _bс (ν, φ) and К _bd (ν, φ):

Considered on any frequency interval v (wavelengths A,), transmission coefficients (1) ÷ (4) become the spectral characteristics of a single-stage MZI. As you can see, the spectral characteristics (1) ÷ (4) are periodic functions of the frequency of light ν (and wavelength λ), the difference in arm lengths ΔL, refractive index n, and phase shift φ.

The following properties are essential for the performance of a single-stage MZI:

- the distances between adjacent extremes in the spectral characteristics (1) ÷ (4) in units of optical frequency Δν and in units of wavelengths Δλ are equal to:

и

and

- transmission coefficients (1) ÷ (4), corresponding to the transition of optical radiation from one input port (port a or b) to two output ports (ports c or d), differ in phase by π;

- transmission coefficients when changing two indices do not change, that is

K _ad (ν, φ) = K _bc (ν, φ) and K _ac (ν, φ) = K _bd (ν, φ);

- changing the magnitude of the phase shift φ, you can change the spectral characteristics (1) ÷ (4), shifting them along the axis of frequencies (wavelengths); this leads, in particular, when changing the phase shift by δφ = ± π, to the inversion of the signals at the outputs;

- transmission coefficients do not change during permutation of indices, that is, a single-stage MZI is a reversible device.

In turn, from these properties it follows that when a single-stage MZI receives an optical signal containing several channels whose frequencies (wavelengths) coincide with the position of the extrema in the dependences of the transmission coefficients on frequency (wavelength), the signals are divided into two groups, which are output to different outputs. One group contains odd channels, the other group contains even channels, in both groups the spectral interval between channels becomes twice as large as at the input of a single-stage MZI. When the same optical signal arrives at another input, the even and odd channels at the outputs change places.

Since a single-stage MZI is a reversible device, in another situation, when odd channels are applied to one input and even channels are fed to the other input, both groups of channels are combined into one optical stream with a denser channel arrangement.

Devices that perform the function of dividing channels into odd and even and the inverse function, combining odd and even channels into one stream, are called interleaves in foreign literature; in the domestic literature there is no term for devices of a similar purpose and in the present text they are called optical filters.

The distance between adjacent extrema Δν (or Δλ,) in the spectral characteristics for a real single-stage MZI should be formed at the stage of its manufacture by selecting the corresponding difference in arm lengths ΔL and refractive index n. The controllable adjustment of the position of the extreme values of the transmission coefficients relative to the set frequencies {v _i } (or wavelengths {λ ₁ }) should be carried out using the appropriate adjustment of the phase shift φ when using an optical filter as part of any particular device.

The lack of spectral characteristics of a single-stage MZI is nonplanar peaks and slowly falling edges of the spectral bands, which, with a small spectral interval between channels, can cause crosstalk between adjacent channels.

Another known disadvantage is that with a large difference in shoulder lengths ΔL, the introduced dispersion can be very large. These disadvantages limit the possibility of using single-stage MZIs in devices used in communication systems with spectral channel multiplexing.

A significant improvement in the spectral characteristics of the optical filter for devices and spectral densification systems is provided, as is known (US, 6782158, B), with two-stage MZIs, which can be performed using fiber optic splitters, beam splitters, prism mirrors, polarizers, and planar form, and at the same time contain phase shift devices.

On figa shows a schematic representation of the waveguide version of the two-stage MZI 20, its conditional image is shown in figb. It uses three splitters 21, 22 and 23 with coupling coefficients k ₁ , k ₂ and k ₃ , respectively, forming two single-stage MZIs 24 and 25. The device 20 is placed on a single substrate 26.

Moreover, the first single-stage MZI 24 is formed by two waveguides 24-1 and 24-2 of unequal length l _24-1 and l _24-2 , respectively. The second single-stage MZI 25 is formed by two waveguides 25-1 and 25-2 of unequal length l _25-1 and l _25-2 , respectively. The phase delays D ₁ = 2πn (l _24-1 -l _24-2 ) / λ and D ₂ = 2πn (l _25-1 -l _25-2 ) / λ are related by the relation: D ₂ = 2 · D ₁ .

MZI 24 and 25 use phase shift devices 27 and 28, the phase shifts introduced by them are φ and ϕ, respectively. The two-stage MZI has conclusions a and b on the one hand and conclusions e and f on the other hand.

The spectral characteristics of the two-stage MZI 20 are not difficult to obtain analytically. For the three splitters 21-1, 21-2 and 21-3, one should introduce matrices T (k _i ) (i = 1,2,3), which connect the amplitudes of the light at the input and output with the parameters of the splitters:

and for two single-stage MZIs 23 and 24 - matrices T (D1) and T (D2):

и

and

Then the transmission matrix M (ν, φ, ϕ) of the two-stage MZI is determined by the product of five matrices:

Since the transmission coefficients of the two-stage MZI associate the optical intensities at the output with the optical intensity at the input, expressions of the type should be used to determine them:

From the expressions (6) ÷ (9), all the basic properties of two-stage MZIs can be obtained. It is easy to verify that the two-stage MZI, when radiation is input through ports a and b, remains a device that performs the function of separating and combining the odd and even channels. So, when applying an optical signal to port a of a two-stage MZI, the channels will be divided into two groups containing one group of odd channels, and the other group of even channels. We note an important property that is preserved in two-stage MZIs: when an optical signal is applied to another input, the port in (Fig. 2A), the groups with odd and even channels change places on the output ports e and f.

The distances between adjacent extrema Δν and Δλ in the spectral characteristics are also determined by the expressions (5), where ΔL is the difference in the length of the arms in the first cascade: ΔL = l _24-1 -l _24-2 . The possibility of a controlled shift of the spectral characteristics is preserved, now with the help of two phase shifts φ and ϕ. To shift the spectral characteristics K _ae (ν, φ, ϕ) and K _af (ν, φ, ϕ) along the frequency axis by δv, it is necessary to change the phases φ and ϕ using the appropriate phase shift devices:

и

and

You can also verify with the help of (6) ÷ (9) that when a signal is input through ports e and f, the possibility of dividing channels into odd and even and, accordingly, combining odd and even channels is lost. This is a consequence of the fact that matrices (6), (7) are non-commutative. Thus, two-stage MZIs are not reversible devices - two ports a and b on the one hand can only be used as input ports, and the other two ports e and f on the opposite side can only be used as outputs.

The spectral characteristics of a two-stage MZI have a much better shape, close to rectangular - with a flat top and a steep decline along the edges of the spectral bands. Therefore, a two-stage MZI used as an optical filter provides better crosstalk suppression and high channel isolation. Nevertheless, the introduced dispersion of the two-stage MZI remains large, and therefore its use as a filter in communication systems with a high data transfer rate is limited.

It is known (US, 6782158, B2) that the situation can be changed for the better when using filters obtained by cascading two-stage MZIs. In one embodiment of such devices, complementary two-stage MZIs with identical transmittance but opposite in dispersion sign can be used. Complementarity of two-stage MZIs is provided by a certain ratio of coupling coefficients k ₁ , k ₂ , k ₃ in the used two-stage MZIs.

On figa shows one of the options for multi-stage MZI 30, which can be used to separate the odd and even channels; conditional image of a multi-stage MZI is shown in Fig.3B.

The device 30 in planar execution is placed on one substrate (crystal) 31 and includes three complementary two-stage MZIs: in the first cascade, two-stage MZI 32 of type I are used, and in the second cascade two two-stage MZIs 33 and 34 are used, both types I ', respectively, with another sign of variance.

When a signal is entered into port a of the two-stage MZI 32 channels, as usual, are divided into two groups: in one group - odd channels, and in the other - even ones. In the second stage, MZI 33 passes odd channels to its output e, and MZI 34 passes even channels to its output f, so that the odd and even channels are in the external ports p and k, respectively. Since the variances of the two-stage MZI 32 and each of the two-stage MZIs 33 and 34 have opposite signs, as a result, the variance of the multi-stage MZI 50 is compensated — zero or almost zero.

On figa shows one of the variants of the multi-stage MZI 40, which can be used to combine the odd and even channels; conditional image of a multi-stage MZI is shown in Fig.4B. The entire device 40 in planar execution is placed on one substrate (crystal) 41 and includes three two-stage MZIs: in the first cascade two two-stage MZIs 42 and 43 are used, both types I, and in the second cascade - a two-stage MZI 44 type I ', respectively, with opposite sign of variance.

When you enter the odd and even channels, respectively, through the external ports z and w, the MZI 42 and 43 simply pass one odd and the other even channels to their output ports f. The channels are combined using MZI 44, and as a result, the odd and even channels are output to the external port v. Since the dispersion of the two-stage MZI 42 and 43 and each of the two-stage MZI 44 have opposite signs, this ensures zero or almost zero dispersion of the entire device 40.

We now consider three functional devices based on the described optical filters, which in turn will be the starting points for creating the multi-channel controlled input / output multiplexer according to the present invention. We consider each of the three functional devices using one of the possible implementations as an example.

A diagram of one embodiment of the used controlled optical input / output multiplexer 50 is shown in Fig. 5A, its conditional image is shown in Fig. 5B. The device 50 (hereinafter referred to as t-OADM 50) is a three-stage structure and has an input port “In”, an output port “Out”, an output “Drop” port, an input “Add” port and includes three optical filters 51-1.51- 2 and 51-3. The multiplexer further comprises an optical adder 52 having 4 inputs “1” ÷ “4” and one output 2. All three filters 51-1, 51-2 and 51-3 and the adder 52 are integrated on a single substrate 53. The connections of the filters are made by waveguides 54 .

Dynamic control of the operation of the controlled input / output multiplexer 50 is carried out by tuning the spectral characteristics of the three filters 51-1, 51-2, and 51-3 when all three filters of the corresponding voltages are applied to the phase-shift devices. Management is carried out using an external controller (not shown in the drawing), which is connected to the optical filters with an electric bus 55.

The optical filters 51-1, 51-2 and 51-3 are connected in series with each other so that the output of one is connected to the input of the other, the second output of each filter is connected to one of the inputs of the optical adder, the input of the first filter 51-1 is connected to the input “In” port, the output of the last filter 51-3 is connected to the “Drop” output port, the optical adder 52 is connected by an additional input to the “Add” input port, and the output is connected to the “Out” output port.

=50 ГГц. Так как спектральный интервал между каналами весьма малый, то в качестве оптических фильтров следует использовать многокаскадные ИМЦ, показанные на Фиг.3А. Расстояния между соседними экстремумами в спектральных характеристиках трех оптических фильтров должны быть следующие: Δν_51-1=50 ГГц, Δν_51-2=100 ГГц и Δν_51-3=200 ГГц. Соответственно, разности длин плеч интерферометров в первых ступенях многокаскадных ИМЦ должны быть равны: ΔL_51-1=1000 мкм, ΔL_51-2=500 мкм, и ΔL_51-3=250 мкм (предполагается, что n=1,5).To explain the design and operation of the device in question, we will assume that an 8-channel optical signal arrives at the “In” input port of the controlled I / O multiplexer, the center frequencies of the channels of which {v _i } = ν ₁ , ν ₂ , ..., ν ₈ , and the frequency interval between the channels at the input Δ

= 50 GHz. Since the spectral interval between the channels is very small, multicascade MZIs shown in Fig. 3A should be used as optical filters. The distances between adjacent extremes in the spectral characteristics of the three optical filters should be as follows: Δν _51-1 = 50 GHz, Δν _51-2 = 100 GHz and Δν _51-3 = 200 GHz. Accordingly, the difference in the arm lengths of the interferometers in the first steps of the multi-stage MZIs should be equal to: ΔL _51-1 = 1000 μm, ΔL _51-2 = 500 μm, and ΔL _51-3 = 250 μm (it is assumed that n = 1.5).

Without loss of generality, we assume that for one of the waves, let for the wave ν ₃ , for some fixed values of the phases {φ ∗ _n } = φ ∗ _51-1 , φ ∗ _51-2 , φ ∗ _55-3 and {ϕ ∗ _n } = ϕ ∗ _51-1 ,

ϕ ∗ _51-2 , ϕ ∗ _51-3 (phases, respectively, in the first and second cascades of two-stage MZIs), the conditions are satisfied that ensure that the V3 wave runs along the path from the “In” input port to the “Drop” output port.

The operation of t-OADM 50 with these phases {φ ∗ _n } and {ϕ ∗ _n } occurs as follows. The optical filter 51-1 of the first stage divides the channels entering the input port "In" into two groups - the group of odd waves ν ₁ ν ₃ , ν ₅ and ν ₇ , which are directed to the optical filter 51-2 of the second stage, and the group of even waves ν ₂ , ν ₄ , ν ₆ and ν ₈ , which are directed to the optical adder 52.

The process is repeated: first, the optical filter 51-2 again divides the waves and directs the waves ν ₃ and ν ₇ to the optical filter 51-3 of the third stage, and the waves ν ₁ and ν ₅ to the adder 52; the third optical filter 51-3 divides the two waves ν ₃ and ν ₇ coming to it. As a result, the wave ν _{3 is released} , which passes to the Drop output port, and all other 7 waves are fed to the three inputs of the adder 52 and with its help appear in the output port “Out”. The wave ν ' ₃ , introduced through the port "Add", enters the fourth input of the adder and also appears in the output port 52.

In order for any other channel to be subjected to input / output, it is necessary in accordance with expressions (10) to change the values of the phases {φ _n } and {ϕ _n }. For example, to switch to the input / output mode of a neighboring wave V4, it is necessary to change the phase shifts as follows: δφ _51-1 = π, δφ _51-2 = π / 2, δφ _51-3 = π / 4 and δφ _51-1 = 2π , δφ _51-2 = π, δφ _51-3 = π / 2.

If, on the input of the multiplexer, signals begin to arrive, the new channel frequencies of which {ν ' _i } are all shifted by δν <Δν ₁ = 50 GHz, that is, ν' _i = ν _i + δν, then in order to input / output channels with new optical carriers, it is necessary, again in accordance with expression (10), to introduce the corresponding correction in the phase shifts {φ ∗ _n } and {ϕ ∗ _n }. For example, in order to carry out the input / output of the wave ν ' ₃ when the channel frequencies are shifted by δν = 12.5 GHz, the necessary phase changes should be: δφ _51-1 = -π / 8, δφ _51-2 = -π / 16, δφ _51-3 = -l / 32 and δφ _51-1 = -π / 4, δφ _51-2 = -π / 8, δφ _51-3 = -π / 8.

, а также типом используемых оптических фильтров. При этом для оптических фильтров n₁-й ступени при n₁=1,2,…N₁ расстояния между соседними экстремумами в спектральных характеристиках должны устанавливаться следующим образом:In general, the functional device used as t-OADM in the present invention may differ from t-OADM 50 by the number of steps N ₁ in the multi-stage structure, the spectral interval between adjacent channels at the input Δν

as well as the type of optical filters used. Thus for n ₁ optical filters -th stage ₁ with n = 1,2, ... N ₁ distances between adjacent extremums in spectral characteristics should be as follows:

Among the characteristics of a functional device used as t-OADM is the free dispersion region, which plays an important role in the present invention. Recall that the spectral characteristics of optical devices can be cyclically repeated over a wide spectral range. In this case, the repetition period, or the spectral range F, within which there is no cyclic repetition of the characteristics, is called the region of free dispersion.

=F. Аналогично через порт «Add» могут быть введены несколько новых канал, частоты которых совпадают с частотами выводимых каналов, а спектральный интервал между каналами равен Δν

=F.The concept of the free dispersion region with respect to t-OADM means that if the input signal contains many channels whose spectral range does not exceed the free dispersion region F, then there will be only one channel in the output port of this device. If the spectral range of the channels at the input is wider than the free dispersion region, then there will be more than one channel in the Drop output port; the spectral interval between the channels in this case will be equal to the value of F, that is, Δν

= F. Similarly, several new channels can be introduced through the Add port, the frequencies of which coincide with the frequencies of the output channels, and the spectral interval between the channels is Δν

= F.

и имеющего многоступенчатую структуру с числом ступеней N₁ область свободной дисперсии F есть:For t-OADM 50, designed to distinguish one channel from multiple channels with a spectral interval between channels at the input Δν

and having a multi-stage structure with the number of steps N _{1 the} region of free dispersion F is:

The scheme of the used controlled optical demultiplexer 60 (hereinafter - t-Demux 60) according to the present invention is shown in Fig.6A, a conditional image of it is shown in Fig.6B.

At the same time, t-Demux 60 also has a three-stage tree structure. The first optical filter 61 (the first stage of the multi-stage structure) is connected with its output ports to the next two - optical filters 62-2 and 62-3 (second stage), which in turn are connected by their output ports to the following four optical filters 63-1, 63 -2, 63-3 and 63-4 (third stage). The whole device is made on one substrate (crystal) 64

The Σ _{Demux port is} used as an input port; eight С1 ÷ _{С8 ports} are used for individual output of channels. The optical filters of all three levels are connected by waveguides 65 formed on the substrate. Dynamic control of the operation of the controlled demultiplexer 60 is carried out by tuning the spectral characteristics of the optical filters when applying phase shift devices contained in all the filters, the corresponding voltages. Management is carried out using an external controller (not shown in the drawing), which is connected to the optical filters with an electric bus 66.

=400 ГГц.To illustrate the operation of t-Demux 60, suppose that an 8-channel signal with a spectral interval between adjacent channels Δν is input to Σ _Demux

= 400 GHz.

As the optical signal passes through the t-Demux 60 from one stage to the next stage, the spectral intervals between the channels become two times wider. For the filter 61 of the first stage, the spectral interval between the channels is minimal, for filters 63-1 ÷ 63-4 of the third stage, on the contrary, the maximum and for filters 62-1 and 62-2 of the second stage, the intermediate interval. Therefore, the requirements for the characteristics of the filters are different. As optical filters in this example, the following can be used: in the first stage - a multi-stage MZI (Fig. 3A), in the second stage - two-stage MZI (Fig. 2A) and in the third stage - single-stage MZI (Fig. 1A).

The distances between adjacent extremes in the spectral characteristics for the optical filters in the three steps of the device under consideration were selected as follows: for multi-stage MZI 61 ΔF ₆₁ = 400 GHz, for two-stage MZI 62-1 and 62-2 Δν _62-1 = Δν _62-2 = 800 GHz and for single-stage MZIs 63-1 ÷ 63-4 Δν _63-1 = Δν _63-2 =

Δν _63-3 = Δν _63-4 = 1600 GHz. Accordingly, the difference in the arm lengths of interferometers according to expression (5) in the first cascades of two-stage MZIs that make up the multistage MZI 61 is ΔL ₆₁ = 250 μm, in the first stages of two-stage MZIs 62-1 and 62-2 the difference in the lengths of the arms is ΔL _62-1 = ΔL _62-2 = 125 μm and for single-stage MZIs 63-1 ÷ 63-4 the difference in the lengths of the shoulders is ΔL _64-1 = ΔL _64-2 = ΔL _64-3 =

ΔL _64-4 = 62.5 μm.

Obviously, for some fixed phase shifts in the first and second cascades of the used IMC {φ ∗ _n } and {ϕ ∗ _n }, it is possible to provide a mode for dividing channels into groups containing odd and even channels. In this state, the t-Demux 60 functions as a traditional demultiplexer with fixed channel frequencies.

An optical signal containing eight channels, the center frequencies of the channels of which {ν ₁ } = ν ₁ , ν ₂ , ..., ν ₈ , is input. The multistage MZI 61 divides the channels (waves) into odd ν ₁ , ν ₃ , ν ₅ and ν ₇ and even ν ₂ , ν ₄ , ν ₆ and ν ₈ , which are directed to the two-stage MZI 62-1 and 61-2. The two-stage MZIs 62-1 and 61-2 again divide the waves coming to them, while the two-stage MZIs 62-1 directs the waves ν ₁ and

ν ₅ to a single-stage MZI 63-1 and waves ν ₃ and ν ₇ to a single-stage MZI 63-2, and a two-stage MZI 62-2 sends waves ν ₂ and ν ₆ to a single-stage MZI 63-3 and waves ν ₄ and ν ₈ - to the single-stage MZI 63-4. At the last third stage, all waves are completely separated and output individually to individual ports in accordance with Table 1.

Table 1
Channel allocation by output ports Output port C1 C2 C3 C4 C5 C6 C7 C8 Channel carrier frequency ν ₁ ν ₅ ν ₃ ν ₇ ν ₂ ν ₆ ν ₄ ν ₈

Now let the signals go to the input of the controlled t-Demux 60, the new center frequencies of the channels of which {ν ' _i } are all shifted by δν <Δν ₂ = 400 GHz.

To demultiplicate channels with new optical carriers on separate output ports, it is necessary to make phase changes {φ ∗ _n } and {ϕ ∗ _n } in accordance with expression (10). For example, to switch to the mode of demultiplication of channels whose frequencies are shifted by δν = 50 GHz, it is necessary to change the phase shifts as follows: δφ ₆₁ = -π / 8, δφ _62-1 = δφ _62-2 = -π / 16, δφ _63-1 ÷ δφ _63-4 = -π / 32. In this case, the distribution of channels at the output ports remains the same, and the channel with the carrier frequency ν ₁ will be output to port C1, channel ν _{5 is to} port C2.

, а также типом используемых оптических фильтров. При этом для оптических фильтров n₂-й ступени при n₂=1,2,…М расстояния между соседними экстремумами в спектральных характеристиках должны устанавливаться равнымиIn the general case of constructive implementation of the t-Demux configuration of “1 × 2 ^M ” in the form of a multi-stage tree-like structure of optical filters, it can differ from device 60 by the number of steps M, the spectral interval between adjacent channels at the input Δν

as well as the type of optical filters used. In this case, for optical filters of the n _2nd stage with n ₂ = 1.2, ... M, the distances between adjacent extrema in the spectral characteristics should be set equal

The third functional device 70 has an opposite purpose to the functional device 60 and is used to combine channels. The two functional units 60 and 70, intended for the multi-channel OADM with dynamic functionality discussed below, must be compatible. This implies that the inputs of the functional device 70 must be supplied with channels whose carrier frequencies coincide with the frequencies of the channels at the outputs of the functional device 60, and the spectral interval between the channels should be like that of t-Demux 60.

The scheme of the used controlled optical multiplexer (hereinafter - t-Mux 70) according to the present invention is shown in Fig.7A, a conditional image of it is shown in Fig.7B.

t-Mux 70 is a multi-stage tree-like structure with seven optical filters.

Four optical filters 71-1 ÷ 71-4, comprising the first stage of a multi-stage structure, are connected with their output ports to two subsequent optical filters 72-1 and 72-2, comprising a second stage, which in turn are connected by their output ports to another optical filter IMC 73, which is the third stage. The entire device is made on the same substrate 74.

Eight ports B1 ÷ B8 are used to input each of the eight channels, the Σ _Muх port serves as a common output port. The optical filters of all three levels are connected by waveguides 75 formed on a substrate 74.

The t-Mux 70 is dynamically controlled by adjusting the spectral characteristics of seven optical filters when applying phase shift devices contained in all optical filters with the corresponding voltages. Management is carried out using an external controller (not shown in the drawing), which is connected to the optical filters with an electric bus 76.

In t-Mux 70, as the optical signal passes from one stage to the next stage, the spectral intervals between channels become two times narrower. For the optical filters 71-4 ÷ 71-4 in the first stage, the spectral interval between the channels is maximum; for the optical filter 73, on the contrary, is the minimum. Therefore, the requirements for the characteristics of the optical filters used in the corresponding steps are different. As optical filters in this example can be used: in the first stage - single-stage MZI (Fig. 1 A), in the second stage - two-stage MZI (Fig. 2A) and the third - multi-stage MZI (Fig. 4A).

In accordance with the fact that t-Mux 70 must be compatible with the t-Demux 60 controlled demultiplexer, the distances between adjacent extremes in the spectral characteristics for optical filters in three stages of the device under consideration should be as follows: for single-stage MZIs 71-1 ÷ 71-4 Δν _71-1 = Δν _71-2 = Δν _71-3 = Δν _71-4 = 1600 GHz, for two-stage MZIs 72-1 and 72-2 - Δν _72-1 = Δν _72-2 = 800 GHz and for multi-stage MZI 63 Aν ₇₃ = 400 GHz.

It can be seen that the design of the t-Mux 70 differs from that described by the t-Demux 60 only in the used multistage MZIs: in one case it is multistage MZIs (Fig. 3A), and in the other case it is multistage MZIs (Fig. 4A). The channel combining process performed using t-Mux 70 is the opposite of the υ channel splitting process discussed above in t-Demux 60.

, а также типом используемых оптических фильтров. При этом для оптических фильтровIn the general case, the t-Mux design of the “2 ^M × 1” configuration in the form of a multi-stage tree-like structure of optical filters can differ from t-Mux 70 by the number of steps M, the spectral interval between adjacent channels at the output Δν

as well as the type of optical filters used. Moreover, for optical filters

n ₃ = of the first stage with n ₃ = 1.2, ... M the distances between adjacent extrema in the spectral characteristics should be set equal

A diagram of one embodiment of a multi-channel OADM with dynamic functionality according to the invention is shown in FIG. This device is intended for use in an optical system with spectral multiplexing as a ROADM with a total number of channels in the optical system of 64, the spectral interval between adjacent channels Δν ₀ = 50 GHz, with 8 channels being subject to reconfigurable input / output.

The multi-channel OADM 80 with dynamic functionality is based on the t-OADM described above (FIG. 5A). This device, designated 81-1, has a free dispersion region 8 times smaller than the spectral range of the optical signal at the input.

=400ГГц. Оба устройства демультиплексор 81-2 и мультиплексор 81-3 имеют фиксированные спектральные характеристики и могут быть выбраны из существующей номенклатуры подобных устройств или изготовлены специально.A couple of devices are also used: an optical demultiplexer 81-2 of the configuration “1 × 8” and an optical multiplexer 81-3 of the configuration “8 × 1”. The characteristics of the demultiplexer / multiplexer pair should provide demultiplication and multiplication of 8 channels with a spectral interval Δν

= 400 GHz. Both devices demultiplexer 81-2 and multiplexer 81-3 have fixed spectral characteristics and can be selected from the existing range of such devices or made specially.

Three multiplexer devices 81-1, 81-2 and 81-3 are connected by optical fibers 82, while the drop output port and the add t-OADM input port are connected to the input

Σ _{Demux of the} optical demultiplexer and Σ _{Mux output of the} optical multiplexer, respectively. The input port 83 and the output port 84 are made in the form of optical fibers and are connected, respectively, to the ports "In" and "Out" t-OADM. Eight output ports 85-1 ÷ 85-8 are connected to the outputs C1 ÷ C8 of the optical demultiplexer, and eight input ports 86-1 ÷ 86-8 are connected to the inputs B1 ÷ B8 of the optical multiplexer. The output ports 85-1 ÷ 85-8 and input 86-1 ÷ 86-8 are also made in the form of optical fibers. The device 80 also contains a controller 87, from which control voltages {U _t-OADM } are supplied to the t-OADM control elements via an electric bus 88.

The input optical signal containing 64 channels, the frequencies of which correspond to the ITU-Standard, is fed to the t-OADM input. Since the free dispersion region of t-OADM is smaller than the spectral range of the optical signal at input 83, 8 channels are output to the Drop port in one of the 8 combinations shown in Table 2. A specific combination of channels is defined by control voltages {U _t-OADM }. All other channels go to output port 84.

table 2
Combinations of channels output to the Drop port of device 81-1 Channel combinations Channel numbers 1st 1, 9, 17, 25, 33, 41, 49 and 57 2nd 2, 10, 18, 26, 34, 42, 50 and 58 ... ... 8th 8, 16, 24, 32, 40, 48, 56 and 64

Eight channels from the "Drop" port of the device 81-1 are fed to the input of the optical demultiplexer 81-2, through which the channels are output separately from each other to the output ports 85-1 ÷ 85-8. At the same time, instead of the output channels using the optical multiplexer 81-3 can be introduced a new 8 channels. Thus, from 64 channels any of 8 combinations of channels can be entered / withdrawn.

A diagram of another embodiment of a multi-channel OADM with dynamic functionality according to the invention is shown in Fig.9. This device is intended for use in an optical system with spectral multiplexing like t-OADM. The total number of channels in the optical system is also 64, the channel frequencies {ν ' _i } can be tuned, but the spectral interval between channels Δν ₀ = 50 GHz remains constant, and 8 channels are subject to controlled input / output.

The multi-channel OADM 90 with dynamic functionality is built on t-OADM (Fig. 5A) and an optical demultiplexer and a multiplexer with tunable spectral characteristics, which are used as discussed above t-Demux configuration "1 × 8" and t-Mux configuration "8 × 1 "(Figa and Figa).

Three multiplexer devices in integrated optical design are placed on the same substrate 91: t-OADM 92-1, t-Demux 92-2 configuration "1 × 8", and t-Mux 92-3 configuration "8 × 1". They are connected by waveguides 93 formed on a common substrate 91. In this case, the Drop output port and the Add t-OADM input port are connected to the input Σ _Demux t-Demux 92-2 and the output Σ _Muh t-Mux 92-3, respectively .

Multichannel OADM 90 with dynamic functionality has an input port 94, an output port 95, which are connected by waveguides to the ports "In" and "Out" t-OADM 92-1. Eight output ports 96-1 ÷ 96-8 are connected to the outputs C1-1C8t-Demux 92-2, and eight input ports 97-1 ÷ 97-8 with inputs B1 ÷ B8 t-Mux 92-3.

All external outputs, that is, input port 94, output port 95, output ports 96-1 ÷ 96-8 and input ports 97-1 ÷ 97-8 are made in the form of optical fibers. The device 90 also contains a controller 98, from which control voltages {U _t-OADM }, {U _Demux } and {U _Muх } are supplied to the control elements of the three functional subsystems via an electric bus 99.

An input optical signal containing 64 channels is input to t-OADM 92-1. Control voltages {U _t-OADM } are applied to the same device, corresponding to the output to the “Drop” port of 8 channels out of 64 with frequencies {ν ' _i } in one of the combinations according to Table 2. All other channels go to output port 95.

Eight channels are fed to the input of the optical demultiplexer 92-2, through which the channels are output separately from each other to the output ports 96-1 ÷ 96-8. At the same time, instead of the output channels using the optical multiplexer 92-3, new 8 channels can be introduced. At the same time, these two devices must be supplied with control voltages {U _Demux } and {U _Muх }, which provide demultiplication and multiplication, respectively, of 8 output / input channels whose frequencies are selected from the set {ν ' _i }.

Thus, any of 8 combinations of channels from the multi-channel OADM present at the input with the dynamic functionality of 64 channels with channel frequencies {ν ' _i } can be introduced / withdrawn.

The device 90 can also be used in the reconfigurable input / output mode of 8 channels, when it is necessary to output / input 8 preset channels from 64 channels with fixed channel frequencies. In this mode, the control voltages {U _Demux } and {U _Muх } must be set appropriately once, providing separation / combining of channels with frequencies corresponding to the ITU Standard. The control of the output / input of 8 preset channels in this case should be carried out by appropriate changes only of the control signals {U _t-OADM }.

A multi-channel OADM with dynamic functionality intended for use as a ROADM or as a t-OADM in any particular optical communication system may differ from the considered devices 80 and 90. In general, the parameters included in the composition of a multi-channel OADM with dynamic functionality of the functional devices of three types (t-OADM, Demux, and Mux) are determined by the total number of channels in the optical system 2 ^N at N≥2, the spectral interval between adjacent channels Δν _0, and the number of channels to be input / output 2 ^M (M is the integer the layer and at the same time 1≤M <N. The main parameters of the three functional devices, taking into account the compatibility of these devices, are given in Table 3.

The infinity symbol “∞” in two positions in table 3 corresponds to the fact that only one channel is output or input through the corresponding ports of these devices. The number of input / output channel combination options is 2 ^NM .

The use of integrated optical technologies for manufacturing seems to be a decisive factor in order for the multi-channel controlled optical input / output multiplexers according to the present invention to meet the requirements for devices of a similar purpose: they can input / output a large number of channels, are resistant to external influences, have high performance. The use of standardized standard elements in the design - single-stage, and / or two-stage, and / or multi-stage MZIs - allows the use of automated technological operations, which will provide high technical characteristics and relatively low manufacturing cost of multiplexers.

In addition to being used in optical communication networks, multichannel OADMs with dynamic functionality according to the invention can also have other applications, for example, in multichannel sensor systems, for optical filtering, in analog systems of various purposes.

The examples discussed explain the principle of operation, characteristics and possible design options of the present invention. Specialists in the field of fiber-optic communication systems should be obvious that in the framework of the present invention, other modifications and alternative structural options for multi-channel OADM with dynamic functionality according to the invention are possible, without going beyond the scope of the claims.

The multi-channel OADM with dynamic functionality according to the present invention can be used in fiber optic lines and communication systems with spectral multiplexing of channels, including trunk lines where DWDM technology is used, and in regional, city and local communication systems where CWDM is used -technology.

The multi-channel OADM with dynamic functionality according to the present can be implemented using existing integrated optical technologies.

Claims (13)

1. A multi-channel controlled optical input / output multiplexer with dynamic functionality for a fiber-optic communication system with spectral multiplexing of 2 ^N channels at N is an integer and N≥2 with a spectral interval between adjacent channels Δν ₀ for input / output of 2 ^M channels when M is an integer and at the same time 1≤M <N, having one input port, one output port, 2 ^M output ports, 2 ^M input ports and including:
a controlled optical input / output multiplexer that provides the output of 2 ^M channels to one Drop output port and the input of new 2 ^M channels at the carrier frequencies of the output channels to one input add port;
optical configuration demultiplexer “1 × 2 ^M ” connected by its input port Σ _Demux to the Drop port of the output of the specified managed optical input / output multiplexer,
an optical configuration multiplexer “2 ^M × 1” connected by its output port Σ _Mux to the input port Add specified specified optical optical input / output multiplexer,
a controller for supplying control voltages to the control elements electrically connected to the specified controlled optical input / output multiplexer. 2. The multi-channel multiplexer according to claim 1, characterized in that said controlled optical input / output multiplexer has:
(N-M) -step structure, containing in each stage one optical filter having one input and two outputs, made with the possibility of controlled adjustment of transmission coefficients, characterized in the n- _1st stage with n ₁ = 1,2, ..., ( NM) the frequency interval between adjacent extrema in the dependence of the transmission coefficients on the frequency Δν _n1 = 2 ^n1-1 Δν ₁ ;
an optical adder having N-M + 1 inputs and one output connected to the output port Out. 3. The multi-channel multiplexer according to claim 2, characterized in that in said (N-M) -step structure:
the optical filter of each stage, except for the last stage, has one of the outputs connected to the input of the optical filter, respectively, of the next stage, and the other output is connected to one of the inputs of the optical adder;
the optical filter of the first stage is connected by its input to the input port In;
the optical filter of the last stage with one output connected to another one input of the optical adder, and the other output connected to the Drop port of the output;
an optical adder is connected to the Add port by another input;
the output of the optical adder is connected to the output port Out. 4. The multichannel multiplexer according to claim 1, characterized in that it is used to control the input / output of the channels in a reconfigurable mode, wherein said optical demultiplexer and multiplexer have fixed spectral characteristics. 5. The multichannel multiplexer according to claim 1, characterized in that it is used to control the input / output of channels in a tunable mode, wherein said optical demultiplexer and multiplexer have tunable spectral characteristics and the controller is electrically connected to said optical demultiplexer and multiplexer. 6. The multichannel multiplexer according to claim 5, characterized in that said optical demultiplexer includes an M-step structure of the "tree" type, containing in each n _2- nd stage with n ₂ = 1,2, ..., M2 ^n2-1 optical filters having at least one input and two outputs, made with the possibility of controlled tuning of transmission coefficients, characterized in the n _2nd stage by the frequency interval between adjacent extrema in the dependence of the transmission coefficients on the frequency equal to Δν _n2 = 2 ^{n2 + NM-1} Δν ₁ . 7. The multichannel multiplexer according to claim 6, characterized in that in the indicated optical demultiplexer in the indicated M-stage structure, one of the inputs of the optical filter of the first stage is connected to the input port Σ _Demux , each of the two outputs of the optical filter of the last stage is connected to one of the output ports and optical filters in each stage, except the last, are connected by each of their two outputs to the input of one of the optical filters of the next stage. 8. The multichannel multiplexer according to claim 5, characterized in that said optical multiplexer includes an M-step structure of the "tree" type, containing in each n _3rd stage with n ₃ = 1.2, ..., M at least 2 ^{M- n3} optical filters having two inputs and at least one output, made with the possibility of controlled tuning of transmission coefficients, characterized in the n _3rd stage by the frequency interval between adjacent extrema in the dependence of the transmission coefficients on the frequency Δν _n3 = 2 ^N-n3 · Δν ₁ . 9. The multichannel multiplexer according to claim 8, characterized in that in the indicated optical multiplexer in the indicated M-stage structure, two inputs of the optical filters of the first stage are connected to the input ports, one output of the optical filter of the last stage is connected to the output port Σ _Mux and the optical filters in each stage, except the first and last, are connected by each of two inputs to the output of one of the optical filters of the previous stage, and by one output to one of the inputs of one of the optical filters of the next stage. 10. A multi-channel multiplexer according to any one of claims 2, 6, 8, characterized in that single-stage and / or two-stage and / or multi-stage asymmetric Mach-Zehnder interferometers are used as the indicated optical filters. 11. A multichannel multiplexer according to any one of claims 2, 6, 8, characterized in that said optical filters comprise electro-optical or thermo-optical phase shift devices for controlling the adjustment of transmission coefficients. 12. The multi-channel multiplexer according to claim 1, characterized in that it is made by integrated-optical technology on a single chip. 13. The multi-channel multiplexer according to claim 1, characterized in that the input port, output port, M output ports and M input ports are made using optical fibers.

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