JP4118756B2 - Multiplexer / demultiplexer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multiplexer / demultiplexer used for optical communication, and more specifically, in an apparatus having a plurality of optical transmission lines, which is used in wavelength division multiplexing optical transmission, etc., an optical signal having a specific wavelength, The present invention relates to a multiplexer / demultiplexer that can be extracted or inserted into each optical transmission line.
[0002]
[Prior art]
With the development of wavelength multiplexing transmission technology in recent years, attention has been focused on functional devices having a plurality of optical transmission paths (ports).
[0003]
In particular, a multiplexing / demultiplexing element that has one common port (common port) and a plurality of input / output ports (channel ports), and can extract or insert an optical signal of a specific wavelength from each channel port, Various systems and structures have been proposed in order to achieve characteristics such as small size, low cost, and low loss.
[0004]
An example of a technique related to the multiplexer / demultiplexer is shown in FIG. 9 (see Patent Document 1).
[0005]
As specifically shown in FIG. 9, this multiplexer / demultiplexer includes a plurality of wavelength specifying filters 01 to 04 that transmit only light of a specific wavelength and reflect light of other wavelengths on the surface of the optical block. A plurality of converging reflectors 05 to 07 are formed on another surface of the optical block.
[0006]
Therefore, the specific wavelength of the incident light 012 is reflected by the wavelength specific filters 01 to 04, the light rays are reflected by the convergence reflectors 05 to 07, and refocused toward the other wavelength specific filters 01 to 04, This is a method of propagating light rays in a relay manner.
[0007]
On the other hand, the light beam that has passed through each of the wavelength filters 01 to 04 is detected as a single-wavelength optical signal by the detectors 08 to 011 or the optical fiber prepared for each of the wavelength specifying filters 01 to 04.
[0008]
When the beam propagating inside this multiplexer / demultiplexer is coupled to a multimode fiber, photodiode, etc., the propagating beam can be designed as a geometrical ray, so that the behavior of the beam's focal point also deviates from the design value. On the other hand, it did not change rapidly.
[0009]
Further, since the light receiving diameters of these detectors (light receiving parts) 08 to 011 are relatively large, the tolerance in manufacturing the optical block is not so severe.
[0010]
However, when a single-mode fiber is mounted on this multiplexer / demultiplexer to emit or receive a beam, or when an edge-emitting LD is arranged in each channel to perform multiplexing operation, the propagation beam is regarded as a Gaussian beam. This is more appropriate, and it is necessary to consider the behavior of the beam near the beam waist in terms of wave optics.
[0011]
In addition, only a few manufacturing and experimental errors occur, and the beam coupling efficiency drops sharply. This increases the cost of obtaining and manufacturing parts according to the optical design and the mounting cost of aligning the parts as designed. A specific example is shown below.
[0012]
[Patent Document 1]
JP2000-162466
[0013]
[Problems to be solved by the invention]
1) For example, when an edge-emitting LD or a single mode fiber is mounted on each channel and used as a multiplexer, the beam propagating inside the multiplexer is directed toward the filter of each channel by the convergence reflector. The beam waist is formed near all the filters.
[0014]
If the beam waist and spot size of each beam emitted from each channel port do not match the beam waist formation position and spot size of the propagating beam, each beam emitted from each channel port is coupled to the common port. In this case, there is a problem in that the coupling efficiency is lowered and variation between channels occurs.
[0015]
Therefore, it is desirable to design and mount so that these beam waist formation positions and spot sizes match, but in order to manufacture and mount parts such as LD, single mode fiber, and lens system of each channel as designed. Since very high accuracy is required, there is a problem that tolerance becomes stricter than when a PD or multimode fiber is arranged in each channel and used as a duplexer.
[0016]
Moreover, although a channel port can also be comprised using commercially available components, in that case, there existed a problem that size reduction could not be performed due to restrictions on the size of optical components.
2) Since the beam propagating inside the multiplexer / demultiplexer is converged toward the filter by the converging reflector, the position of the beam waist formed in the vicinity of the filter due to a slight error in manufacturing the optical block. The spot size changes abruptly from the design value.
[0017]
Therefore, the propagation beam spreads rapidly as the number of channels increases, and the spot size of the propagation beam becomes larger than the effective diameter of the converging reflector, resulting in power loss and a decrease in coupling efficiency.
[0018]
The present invention has the above-described problem, that is, occurs when a beam having a specific wavelength is extracted or inserted into a plurality of optical transmission lines by a method of multiply-reflecting the propagation beam inside the multiplexer / demultiplexer. To
1) Reduced part manufacturing tolerance
2) Reduced component mounting tolerance
3) Increased power loss
The purpose is to solve such problems.
[0019]
[Means for Solving the Problems]
(1) In the first invention, a light beam such as a Gaussian beam (hereinafter simply referred to as a Gaussian beam) is incident on and reflected by a light reflecting / condensing element that reflects a beam waist at a specific position. The reflected beam from the reflective condensing element enters and reflects the wavelength selection element that transmits the beam in the specific wavelength range and reflects the beam in the other wavelength range, and the reflected beam from the wavelength selection element reflects the light. A multiplexer / demultiplexer that is optically designed to be incident and reflected on a light reflecting / condensing element different from the condensing element, wherein the light reflecting / condensing element and the wavelength selecting element are arranged in parallel The reflected beam from the wavelength selection element is arranged on the virtual plane, and becomes a multiple reflection beam that propagates while repeating the reflection on the two virtual planes. wavelength The optical path length of the multiple reflection beam incident on until 択素Ko equals none, and the reflected beam incident from one of the wavelength selection element to another wavelength selecting element undergoes reflection by the plurality of light-reflecting light-collecting device And the angle formed between the incident optical axis incident on the wavelength selecting element and the virtual plane does not match the angle formed between the reflected optical axis reflected from the wavelength selecting element and the virtual plane. The optical parameters of the light reflecting and condensing element are optically designed so that the complex beam parameters of the beam reaching the wavelength selecting element are the same on all wavelength selecting elements. This is an optical multiplexer / demultiplexer.
Here, the “Gaussian beam” is generally characterized in that the intensity distribution is a Gaussian distribution, and the beam optical axis, beam waist position, spot size, beam wavefront curvature radius, etc. can be accurately defined. It refers to a single mode Gaussian beam.
[0020]
Therefore, a beam emitted from an edge-emitting laser diode or a single mode fiber can be handled as a single-mode Gaussian beam, but a beam emitted from a surface-emitting laser diode or a multimode fiber is strictly a single mode. It cannot be treated as a Gaussian beam.
[0021]
However, in some cases, these beams can also be handled as a superposition of point light sources that emit a single-mode Gaussian beam.
[0022]
Therefore, the Gaussian beam in the present invention is assumed to be a broad beam that can be regarded as a beam having the characteristics of a single-mode Gaussian beam according to each case of the target optical system.
[0023]
The complex beam parameter (q) of the Gaussian beam is the wavelength (λ), the circularity (π), the distance from the beam waist (z), the spot size (w (z)), the beam wavefront curvature radius (R (z) )) Is used to express w (z) and R (z) representing the characteristics of the Gaussian beam as a single complex number (q). Yes.
1 / q = 1 / R (z) -iλ / (π · w (z) ² (1)
For convenience of the following detailed explanation,
The part that emits a signal from outside the multiplexer / demultiplexer as a Gaussian beam is the “emission point”, the part that receives the propagation beam inside the multiplexer / demultiplexer and transmits it as a signal to the outside is the “light receiving point”, and the emission point , And a component consisting of a lens system for efficiently propagating the beam from the exit point to the inside of the multiplexer / demultiplexer, the transmission port, the light receiving point, and the propagation beam inside the multiplexer / demultiplexer are efficiently A component consisting of a lens system for coupling to a light receiving point is a “receive port”, a transmission or reception port for inputting / outputting a single wavelength optical signal is a “channel port”, and a wavelength multiplexed optical signal is A transmission or reception port for input / output is defined as a “common port”.
[0024]
As specific examples of the emission point or the light receiving point, an end face of a single mode fiber, an end face of a multimode fiber, a tip of a tip spherical fiber, or the like can be considered.
[0025]
Further, a laser diode can be used for the emission point and a photodiode can be used for the light receiving point, and a signal input / output to / from the multiplexer / demultiplexer can be an electrical signal.
[0026]
Specific examples of the lens system constituting the transmission port or the reception port include an optical lens such as a pole lens, a plano-convex lens, a biconvex lens, an aspheric lens, a GRIN lens, and a combination of these optical lenses. It is done.
[0027]
Specific examples of the wavelength selection element include a band pass filter, a low pass filter, and a high pass filter that use a dielectric multilayer film when a specific wavelength is fixed.
[0028]
Further, the wavelengths to be transmitted may be changed independently by external control.
[0029]
In that case, a wavelength tunable filter using an electro-optic effect or a thermo-optic effect, an etalon filter using MEMS technology, or the like can be considered.
[0030]
Moreover, the case where the wavelength band which a wavelength selection element permeate | transmits contains all the wavelength bands of an incident light ray is also considered, In that case, it corresponds to an optical transmission window.
[0031]
Conversely, when not transmitting all the wavelength bands of incident light, it has the same function as a plane mirror.
[0032]
Specific examples of the light reflecting and condensing element include a concave mirror, a plano-convex lens formed with a reflective film on the flat surface, and a Fresnel mirror applying the Fresnel lens principle.
[0033]
In order to determine the arrangement of the above component group, two planes opposed in parallel are considered and defined as a “virtual plane”.
[0034]
The transmission port and the reception port are arranged so that the beam emitted from the transmission port passes through the virtual plane and propagates to the reception port. At least one pair of the transmission port and the reception port is transmitted from the transmission port. The emitted beam becomes a “multiple reflected beam” that reflects in a zigzag manner between the two virtual planes, and is arranged so that the beam propagates to the receiving port. The “control element” is one of a wavelength selection element, a light reflection / condensing element, and a planar reflection surface.
[0035]
Further, the entire control element arranged between adjacent wavelength selection elements on the optical path of the multiple reflected beam is defined as a “relay optical system”.
[0036]
The area between the two virtual planes facing each other is an area where the propagating beam is multiple-reflected. When the beam is multiple-reflected in the space, an array element mounting block in which a plurality of control elements are formed on the surface A configuration in which two are prepared and facing them in parallel is conceivable.
[0037]
In the case where the beam is multiple-reflected in a medium such as glass or transparent resin, a configuration in which a plurality of control elements are formed on both surfaces of a flat optical waveguide block formed of glass or transparent resin can be considered.
[0038]
The principle of the demultiplexing operation of the present invention is as follows.
[0039]
The common port is a transmission port, the plurality of channel ports are reception ports, and the wavelength multiplexed optical signal output from the common port is divided into a plurality of channel ports according to the wavelength range transmitted by each wavelength selection element. Waved.
[0040]
That is, the beam emitted from the transmission port passes through the virtual plane and reaches the first wavelength selection element.
[0041]
The beam may undergo reflection from a plurality of control elements before reaching the first wavelength selection element.
[0042]
In the first wavelength selection element, a beam in a specific wavelength band is transmitted and emitted toward the reception port.
[0043]
The beam in the other wavelength range is reflected, delivered to another control element on the opposing virtual plane, and reaches the second wavelength selection element through reflection from a plurality of light reflecting and condensing elements.
[0044]
In order to repeat the above-described operations, the installation positions and angles of the transmission / reception ports and the control elements arranged on the virtual plane are optically designed.
[0045]
The principle of the multiplexing operation of the present invention is as follows.
[0046]
A plurality of channel ports are transmission ports, a common port is a reception port, and a plurality of single-wavelength optical signals output from the channel ports are common ports according to the wavelength range that each wavelength selection element transmits. To be combined.
[0047]
That is, the beam emitted from the first transmission port reaches the first wavelength selection element formed on the first virtual plane.
[0048]
In the first wavelength selection element, a beam in a specific wavelength range is transmitted and emitted toward the control element formed on the second virtual plane.
[0049]
Beams in other wavelength ranges are reflected and are not combined.
[0050]
The transmitted beam that has reached the second imaginary plane becomes a multi-reflected beam and reaches the second wavelength selection element, but by the time it reaches, it is reflected from at least one light reflecting and condensing element.
[0051]
The multiple reflected beam is combined with a beam that is emitted from the second transmission port and passes through the second wavelength selection element, becomes a multiple reflection beam again, and reaches the third wavelength selection element.
[0052]
In order to repeat the above-described operations, the installation positions and angles of the transmission / reception ports and the control elements arranged on the virtual plane are optically designed.
[0053]
The operations and effects exhibited by the first invention are as follows.
[0054]
On the optical path of the multi-reflection beam, a wavelength selection element is arranged between the plurality of light reflection condensing elements, and a beam output from the channel port or a beam input to the channel port (hereinafter referred to as “channel port”). The input / output beam) passes through the wavelength selection element.
[0055]
Since the channel port input / output beam and the multiple reflected beam propagate through the same relay optical system, if the propagation state of these beams does not match, the coupling efficiency between the transmission / reception ports decreases, or the coupling occurs. Variations in efficiency between channel ports occur.
[0056]
Therefore, in order to prevent these phenomena, the channel port optical system and the relay optical system are set so that the beam waist position and spot size of the channel port input / output beam coincide with the beam waist position and spot size of the multiple reflected beam. Need to design.
[0057]
At this time, if all the channel port optical systems and optical systems such as light reflecting and condensing elements corresponding to each channel port among the relay optical systems (hereinafter referred to as “channel optical system”) are optically designed separately, The cost of obtaining and manufacturing parts as designed, and the cost of mounting parts as designed will increase.
[0058]
Therefore, an optical design in which all channel optical systems are made identical, or an optical design in which several types of channel optical systems are prepared and can be periodically reused with respect to the number of channels is desirable.
[0059]
Focusing on the propagation state of the multiple reflected beam, this corresponds to equalizing the complex beam parameters of the multiple reflected beam on all wavelength selection elements or periodically changing the number of channels. Hereinafter, this propagation state is referred to as “identification / periodization” of multiple reflected beams.
[0060]
However, when the reflected beam from the wavelength selection element is incident on another wavelength selection element after being reflected from one light reflection condensing element, the complex beam parameter of the multiple reflection beam is set to all wavelengths as described above. In order to “identify / periodize” on the selection element, the optical parameters of all the light reflecting and condensing elements are made the same, the distances between the plurality of wavelength selecting elements on the optical path of the multiple reflected beam are made equal, It is necessary to form a beam waist at an intermediate point between a plurality of light reflecting and condensing elements.
[0061]
In this case, the channel port optical system must be designed so that the beam waist of the channel port input / output beam is also formed at the midpoint between the light reflecting and condensing elements. -There was a problem that the manufacturing cost increased.
[0062]
Moreover, although a channel port can also be comprised using commercially available components, in that case, there existed a problem that size reduction could not be performed due to restrictions on the size of optical components.
[0063]
FIG. 7 is a schematic configuration diagram of the multiplexer / demultiplexer when the multiple reflected beam is incident on another wavelength selection element after being reflected from one light reflecting / condensing element.
[0064]
In the figure, a Gaussian beam propagating inside the multiplexer / demultiplexer is conceptually shown.
[0065]
In the figure, 701 is a common port, 702-705 is a channel port, 706-709 is a wavelength selection element, 710-712 is a light reflecting / condensing element, and 713-714 is a virtual plane facing each other in parallel.
[0066]
On the first virtual plane 713, a plurality of wavelength selection elements 706-709 are arranged in an array at equal intervals, and on the second virtual plane 714, a plurality of light reflecting / condensing elements 710-712 are arranged in an array. It is arranged at equal intervals.
[0067]
Regarding the wavelength selecting elements 706-709 and the light reflecting / condensing elements 710-712, the reflecting surfaces into which the propagating beam enters and reflects are all parallel to each other, and can also be arranged in parallel with the virtual plane 713-714.
[0068]
In addition, the arrangement interval of the wavelength selection elements 706-709 and the arrangement interval of the light reflection condensing elements 710-712 on the virtual plane are the same.
[0069]
Further, the light reflection condensing elements 710 to 712 disposed between the wavelength selection elements 706 to 709 on the optical path of the multiple reflection beam correspond to a “relay optical system”.
[0070]
When this multiplexer / demultiplexer is used as a demultiplexer, a Gaussian beam that is a wavelength multiplexed signal emitted from the transmission port 701 passes through the virtual plane 714 and is incident on the first wavelength selection element 706.
[0071]
In the first wavelength selection element 706, a beam including a specific wavelength band is transmitted through the first wavelength selection element and propagated to the first reception port 702.
[0072]
A beam including a wavelength region that is not transmitted by the first wavelength selection element 706 is reflected, is reflected by the first light reflection condensing element 710, and is propagated to the adjacent second wavelength selection element 707.
[0073]
FIG. 8 is a conceptual diagram for explaining the propagation principle of multiple reflected beams in the multiplexer / demultiplexer shown in FIG.
[0074]
In this drawing, the light reflecting and condensing means is replaced with an optical lens, and the propagation optical axis of the multiple reflected beam is developed in a straight line.
[0075]
The dotted line represents the propagation optical axis of the multiple reflected beam, and the broken line represents the beam diameter of the multiple reflected beam.
[0076]
In the figure, reference numerals 801 to 810 denote wavelength selection elements, 811 to 818 denote optical lenses corresponding to light reflecting and condensing means, and 819 to 828 denote arrows indicating the beam waist positions of the actually propagating beams.
[0077]
FIG. 8A corresponds to the case where the angle formed by the incident optical axis incident on the control element and the virtual plane matches the angle formed by the reflected optical axis reflected from the control element and the virtual plane.
[0078]
Therefore, the wavelength selection elements 802-804 are located at the midpoint between the plurality of light reflecting / condensing elements 811-814.
[0079]
FIG. 8B corresponds to the case where the angle formed between the incident optical axis incident on the control element and the virtual plane does not match the angle formed between the reflected optical axis reflected from the control element and the virtual plane. This corresponds to the case where the optical axis of the channel port input / output beam and the virtual plane on which the control element is arranged are orthogonal to each other.
[0080]
Therefore, the wavelength selection elements 807 to 809 do not coincide with the midpoint of the plurality of light reflecting and condensing elements 815 to 818.
[0081]
As shown in FIGS. 8 (a) and 8 (b), in order to make the complex beam parameter of the multiple reflected beam identical on all wavelength selection elements, It is necessary to equalize the optical parameters, make the distances between the plurality of wavelength selection elements on the optical path of the multiple reflected beam equal, and form a beam waist at an intermediate point between the plurality of light reflecting and condensing elements.
[0082]
Therefore, when the optical axis of the channel port input / output beam and the virtual plane on which the control element is arranged are orthogonal to each other, a beam waist cannot be formed on the wavelength selection element, and the beam waist is converted into the wavelength selection element. When formed above, the angle formed between the incident optical axis incident on the control element and the virtual plane must match the angle formed between the reflected optical axis reflected from the control element and the virtual plane. The optical axis of the output beam and the virtual plane on which the control element is arranged cannot be orthogonal.
[0083]
However, when a reflected beam from a wavelength selection element is incident on another wavelength selection element after being reflected from a plurality of light reflection and condensing elements, relay optics between the wavelength selection elements on the optical path of the multiple reflection beam By making the system the same as the basic unit, the optical design can be made so that the complex beam parameters of the multiple reflected beam are made identical and periodic on all wavelength selection elements.
[0084]
In this case, the beam waist of the multiple reflected beam is not necessarily formed at the intermediate point between the plurality of light reflecting and condensing elements, and depending on how the optical parameters of several kinds of light reflecting and condensing elements are set, The spot size can be controlled.
[0085]
Therefore, even when the optical axis of the channel port input / output beam and the virtual plane on which the control element is arranged are orthogonal, an optical design that forms a beam waist on the wavelength selection element is possible. Even when forming on the selection element, there is no need to match the angle formed between the incident optical axis incident on the control element and the virtual plane, and the angle formed between the reflected optical axis reflected from the control element and the virtual plane. Optical design is possible in which the optical axis of the input / output beam is orthogonal to the virtual plane on which the control element is arranged.
[0086]
Considering the above effects in general, due to the cost, size, and manufacturing constraints of the channel port optical system, even if the position and spot size of the beam waist of the channel port input / output beam are limited, By designing the optical parameters of several kinds of light reflecting and condensing elements, it means that it is possible to make an optical design that matches the beam waist position and spot size of the multiple reflected beam and the channel port input / output beam. .
[0087]
As a result, it is possible to prevent a decrease in coupling efficiency between the transmission and reception ports and a variation in coupling efficiency between the channel ports.For example, when a commercially available part is applied to the lens system, the emission point, or the light receiving point that constitutes the channel port, Control the beam waist of the multi-reflected beam by the design of the relay optical system even if the beam waist position of the channel port input / output beam cannot be freely designed, such as when there is a size restriction in the lens system that constitutes the channel port. In addition, by matching the beam waist position and the spot size, it is possible to prevent a reduction or variation in coupling efficiency between the transmission and reception ports.
[0088]
Therefore, since a commercially available part can be used, the part cost can be reduced, and a channel port having a small lens system can be used, so that the channel port can be reduced in size.
[0089]
When the reflected beam from the wavelength selective element is reflected from a plurality of light reflecting and condensing elements and enters another wavelength selective element, a relay optical system between the multiple wavelength selective elements on the optical path of the multiple reflected beam is provided. By making it the same as the basic unit, it is possible to perform an optical design in which the complex beam parameters of the multiple reflected beam are made identical on all wavelength selection elements.
[0090]
Therefore, even if the lens system of a plurality of channel ports and the emission and light receiving points are made the same, there is no variation in coupling efficiency between channels, and an array of lenses, fibers, LD, PD, etc. are applied, and a plurality of channel ports are applied. Can be formed at once.
[0091]
Therefore, the mounting cost for assembling and aligning the components of each channel port can be reduced.
[0092]
When a reflected beam from a wavelength selection element enters a different wavelength selection element after being reflected from one light reflection / condensing element, two adjacent light reflection / condensing elements are on the optical path of the multiple reflection beam. If there is an optical path between the optical paths where no beam waist is arranged, the complex beam parameters of the multiple reflected beams on the two light reflecting and condensing elements are different from each other, so that they are separated from the light reflecting and condensing element by the same distance. The complex beam parameters on the two wavelength selective elements arranged at the points are also different from each other.
[0093]
In other words, in order to make the complex beam parameters of the multiple reflected beam identical on all wavelength selection elements, it is assumed that a beam waist is always arranged between the optical paths of two adjacent light reflecting and condensing elements. .
[0094]
However, in this case, only slight errors in manufacturing the relay optical system, such as errors in the optical parameters of the light reflecting and condensing elements and errors in the optical path length between the light reflecting and condensing elements, occur. The position and spot size of the beam waist arranged between the optical paths of the light beam change abruptly from the design value.
[0095]
Therefore, as the number of channels increases, the multiple reflected beam diffuses rapidly, the spot size of the propagating beam becomes larger than the effective diameter of the light reflecting and condensing element, power loss occurs, and the coupling efficiency decreases.
[0096]
However, when the reflected beam from the wavelength selection element is reflected from a plurality of light reflecting and condensing elements and is incident on another wavelength selection element, a relay optical system is formed, and two adjacent beams on the optical path of the multiple reflected beam are formed. Optical design can be made to make the complex beam parameters of multiple reflected beams identical on all wavelength selection elements, even if no beam waist is placed between some of the optical paths of the two light reflecting and condensing means. is there.
[0097]
For example, a case where a multiple reflected beam propagating between the optical paths of two light reflecting / condensing means is designed to have a sufficiently large spot size and a beam waist is not disposed between the optical paths may be considered.
[0098]
In this case, the spot size of the multiple reflected beam propagating between the optical paths can be regarded as almost constant.
[0099]
Therefore, compared with the case where the beam waist is always arranged between the optical paths of two adjacent light reflecting and condensing elements, the optical parameter error of the light reflecting and condensing elements arranged near the optical path, and the distance between the optical paths. Even if this optical path length error occurs, it is possible to regard the change in the spot size of the multiple reflected beam propagating between the optical paths as sufficiently small.
[0100]
Therefore, an optical design that suppresses rapid diffusion of multiple reflected beams and does not generate power loss is possible.
[0101]
Further, the spot size on the wavelength selection element can be periodically changed according to the optical path length from the common port so as not to diverge.
[0102]
Furthermore, depending on the optical design of the channel port, the coupling efficiency between each channel port and the common port can be periodically varied according to the optical path length from the common port so as not to monotonously decrease.
[0103]
When the optical design is as described above, even if an error in the optical parameters of the light reflecting and condensing means constituting the relay optical system or an error in the optical path length between the control elements occurs, the coupling between the transmission and reception ports Reduction in efficiency and variation can be prevented.
[0104]
Therefore, since the tolerance for manufacturing the components constituting the relay optical system can be increased, the component cost can be reduced.
[0105]
The reflected beam from the wavelength selection element is reflected from one light reflection condensing element and then incident on another wavelength selection element. In the case of entering the selection element, the distance between the plurality of wavelength selection elements on the optical path of the multiple reflected beam can be increased.
[0106]
Therefore, if the incident angle and the reflection angle of the multiple reflected beams that enter and reflect the wavelength selection elements are the same, the arrangement interval of the wavelength selection elements on the virtual plane can be increased.
[0107]
Accordingly, it is possible to increase the size of the wavelength selection element and the channel port optical system, and it is possible to increase the tolerance in manufacturing the component, thereby reducing the component cost.
[0108]
Furthermore, workability when mounting the channel port can be improved.
[0109]
Conversely, if the arrangement intervals of the wavelength selection elements on the imaginary plane are the same, the incident angle and reflection angle of the multiple reflected beam that enters and reflects each wavelength selection element can be reduced.
[0110]
Therefore, it is advantageous for improving the filter characteristics of the beam that passes through the wavelength selection element and for reducing the coma aberration of the beam that enters and reflects the light reflecting and condensing element.
[0111]
further, First 1 Invention In the wave The optical parameters of the light reflecting and condensing element are optically designed so that the complex beam parameters of the beam reaching the long selection element are the same on all wavelength selection elements. The following actions and effects are obtained. .
[0113]
Since the control elements are arranged and optically designed so that all the channel beam parameters are the same, the combination of the distances between the elements for the light receiving or emitting point, the receiving or transmitting lens system, and the wavelength selecting element is set. Even if all channel ports are made identical and the transmission or reception lens system of the channel port is made identical for all channel ports, there is no variation in optical loss between ports in each channel port.
[0114]
Therefore, for each channel port, optical design cost to reduce optical loss and eliminate port-to-port variations, component cost to obtain designed parts, and mounting to position those parts as designed Costs can be significantly reduced.
[0115]
Due to the above effects, a plurality of channel ports can be integrated at one time by using a lens array, a fiber array, an LD array, a PD array, etc., which have the same emission or light receiving point and the same lens system integrally formed in an array. It is possible to form.
[0116]
Therefore, it is possible to reduce manufacturing tolerances when obtaining parts as designed, and to reduce the mounting cost for positioning the parts for each channel port.
[0117]
Due to the above effects, it is possible to use a plurality of the same components in which the transmission or reception lens system and the emission or reception point are integrally formed, such as a lens fiber module and an LD lens built-in type CAN package module.
[0118]
Therefore, it is possible to reduce the mounting cost for positioning the parts constituting each channel port.
[0119]
( 2 No. 2 The invention of The Gaussian beam enters and reflects the light reflecting condensing element that reflects so as to form a beam waist at a specific position, and the reflected beam from the light reflecting condensing element transmits a beam in a specific wavelength region, and otherwise. It is optically designed to enter and reflect the wavelength selection element that reflects the beam in the wavelength range, and the reflected beam from the wavelength selection element enters and reflects to a light reflection and collection element different from the light reflection and collection element. The light reflection condensing element and the wavelength selection element are arranged on two virtual planes facing in parallel, and the reflected beam from the wavelength selection element is divided into two virtual The multi-reflected beam propagates while repeating reflection on the plane, and the optical path length from one wavelength selection element to another adjacent wavelength selection element on the optical path of the multi-reflection beam is the same. One When propagated from the wavelength selection element to another wavelength selecting element is configured to undergo reflections from the plurality of light-reflecting light-collecting device, The spot size of the multiple reflection beam and the absolute value of the beam wavefront curvature radius are the same on all wavelength selection elements, and the beam wavefront curvature radius of the multiple reflection beam is the same on the wavelength selection element adjacent to the optical path of the multiple reflection beam. The multiplexer / demultiplexer is characterized in that the optical parameters of the light reflecting and condensing elements are optically designed so that the sign changes alternately.
[0120]
This corresponds to the case where the complex beam parameter of the multiple reflected beam is periodically changed with respect to the number of channels in the first invention.
[0121]
First 2 The operations and effects of the invention are as follows.
[0122]
Even if no beam waist is formed on the wavelength selection elements, the spot sizes of the multiple reflected beams reaching all the wavelength selection elements can be made the same.
[0123]
Therefore, variation between channel ports regarding filter characteristics can be suppressed.
[0124]
The complex beam parameters of the multi-reflected beam that reaches all the wavelength selection elements can be limited to two types.
[0125]
Since the two types of beam parameters represent beams in the same propagation state only in the traveling direction, the channel port of the transmission port is made to correspond to the wavelength selection element having one beam parameter, and the other beam parameter is set to The channel port of the reception port can be made to correspond to the wavelength selection element having.
[0126]
At that time, even if the channel path and the optical path length to each wavelength selection element are made the same, and the channel port composed of the optical system having the same configuration is applied to the transmission port and the reception port, the coupling efficiency does not vary. .
[0127]
Therefore, when transmission / reception channel ports coexist in one multiplexer / demultiplexer and they are alternately arranged, the cost for obtaining and manufacturing the channel ports can be reduced.
[0128]
Further, when the light receiving point or the emitting point is an optical fiber, the lens systems of all the channel ports can be made identical, so that the lens system can be obtained, manufactured and mounted.
[0129]
(4) According to a fourth aspect of the present invention, in the multiplexer / demultiplexer according to any one of claims 1 to 3, all the wavelength selecting elements are arranged in one of two virtual planes. It is.
[0130]
The actions and effects exhibited by the fourth invention are as follows.
[0131]
Since the wavelength selection elements are all arranged in one virtual plane, all channel ports can be arranged on one side of one virtual plane.
[0132]
Therefore, a plurality of channel ports can be collectively formed, the alignment workability can be improved, and the mounting space can be saved, so that the component cost and the mounting cost can be reduced.
[0133]
( 3 No. 3 The invention of The Gaussian beam enters and reflects the light reflecting condensing element that reflects so as to form a beam waist at a specific position, and the reflected beam from the light reflecting condensing element transmits a beam in a specific wavelength region, and otherwise. It is optically designed to enter and reflect the wavelength selection element that reflects the beam in the wavelength range, and the reflected beam from the wavelength selection element enters and reflects to a light reflection and collection element different from the light reflection and collection element. The light reflection condensing element and the wavelength selection element are arranged on two virtual planes facing in parallel, and the reflected beam from the wavelength selection element is divided into two virtual The multi-reflected beam propagates while repeating reflection on the plane, and the optical path length from one wavelength selection element to another adjacent wavelength selection element on the optical path of the multi-reflection beam is the same. One When propagated from the wavelength selection element to another wavelength selecting element is configured to undergo reflections from the plurality of light-reflecting light-collecting device, The beam propagating inside the multiplexer / demultiplexer Two types of spot sizes Form a beam waist However, spot sizes on adjacent wavelength selection elements on the optical path of the multiple reflected beam are different from each other. In this way, the multiplexer / demultiplexer is characterized in that the optical parameters of the light reflecting and condensing element are optically designed.
[0134]
First 3 The operations and effects of the invention are as follows.
[0135]
By forming the beam waist of the multiple reflected beam at the arrangement point of the wavelength selection element, the beam incident on the wavelength selection element can be regarded as a plane wave.
[0136]
Accordingly, it can be considered that the beam wavefront incident on the wavelength selecting means is incident at substantially a single angle, so that uniform filter characteristics can be obtained.
[0137]
By forming the beam waist of the multiple reflection beam on the wavelength selection element, the in-plane optical axis position shift on the surface of the wavelength selection element can be reduced with respect to the optical axis shift of the multiple reflection beam.
[0138]
Therefore, it is possible to reduce the size of the wavelength selection element, and it is possible to reduce the influence of the in-plane dependency of the filter characteristics of the wavelength selection element.
[0139]
When the common port is a transmission port and is used as a duplexer with multiple channel ports, if the optical axis shifts when mounting the common port, each wavelength selection element from the common port increases as the number of channels increases. In general, the amount of optical axis deviation of the multiple reflected beam on the wavelength selection element increases.
[0140]
However, a beam waist of a multiple reflection beam is formed on each wavelength selection element, and optical design is performed so that both the optical axis angle deviation and the optical axis position deviation of the multiple reflection beam incident on the wavelength selection element are not amplified simultaneously. Is possible.
[0141]
In addition, the amount of deviation between the optical axis angle deviation and the optical axis position deviation varies periodically according to the optical path length from the common port, so even if the number of channel ports increases, the deterioration of the filter characteristics increases monotonously. There is nothing.
[0142]
( 5 No. 5 The invention of claim 1 to claim 1 4 In the multiplexer / demultiplexer described in (1), at least one of the light reflecting and condensing elements is a spherical mirror.
[0143]
First 5 The operations and effects of the invention are as follows.
[0144]
By using the spherical mirror, the wavelength dependence of the light beam reflected by the light reflecting / condensing element can be ignored.
[0145]
Therefore, the usable wavelength band of the propagation beam inside the multiplexer / demultiplexer can be widened.
[0146]
By using the spherical mirror, the optical design parameter of the light reflecting and condensing element is limited only to the radius of curvature.
[0147]
Therefore, it is possible to facilitate the part manufacturing tolerance design, and to shorten the design time, thereby reducing the manufacturing cost.
[0148]
By using a spherical mirror, the beam incident on the mirror surface is translated, and the incident position is changed slightly to maintain the optical parameters such as the radius of curvature while changing the optical axis direction of the reflected beam in a three-dimensional manner. be able to.
[0149]
Accordingly, the degree of freedom in designing the optical axis of the propagating beam inside the multiplexer / demultiplexer can be greatly improved.
[0150]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. However, the following embodiments do not limit the present invention.
[ Reference example ]
FIG. 1 illustrates the present invention. Reference example It is a schematic block diagram of the multiplexer / demultiplexer which concerns on.
[0151]
In the figure, a Gaussian beam propagating inside the multiplexer / demultiplexer is conceptually shown.
[0152]
In the figure, 101 is a common port, 102-104 is a channel port, 105-107 is a wavelength selection element, 108-111 is a light reflecting and condensing element, 112-113 is a planar reflecting surface, and 114-115 are parallel. It is the virtual plane made to oppose.
[0153]
The common port 101 and the channel ports 102-104 are composed of an emission point or light receiving point 116-119 and a lens system 120-123.
[0154]
In the first virtual plane 114, a plurality of wavelength selection elements 105-107 and planar reflecting surfaces 112-113 are alternately arranged in the form of an array at equal intervals. The reflective condensing elements 108-111 are arranged at regular intervals in an array.
[0155]
Regarding the wavelength selection element 105-107, the planar reflection surface 112-113, and the light reflection condensing element 108-111, the reflection surfaces on which the propagation beam enters and reflects are all arranged in parallel with the virtual plane 114-115. Therefore, the incident angle and the reflection angle formed by the optical axis of the propagating beam and the virtual plane are all the same, and the arrangement interval of the wavelength selection elements 105-107 and the arrangement interval of the light reflection condensing elements 108-111 are the same.
[0156]
Further, the control elements 108-113 arranged between the wavelength selection elements 105-107 on the optical path of the multiple reflected beam correspond to “relay optical system”.
[0157]
As a specific example, Reference example The operation principle when the multiplexer / demultiplexer according to the above is used as a demultiplexer will be described.
[0158]
A Gaussian beam that is a wavelength multiplexed signal emitted from the transmission port 101 passes through the virtual plane 115 and enters the first wavelength selection element 105.
[0159]
In the first wavelength selection element 105, a beam including a specific wavelength band is transmitted through the first wavelength selection element and propagated to the first reception port 102.
[0160]
A beam including a wavelength region that is not transmitted by the first wavelength selection element 105 is reflected, is reflected by the first light reflecting / condensing element 108, is reflected by the planar reflecting surface 112, and is reflected by the second light reflecting / converging element. The light enters / reflects the optical element 109 and propagates to the adjacent second wavelength selection element 106.
[0161]
As described above, each time the multi-reflected beam is incident on each wavelength selection element, a beam including a specific wavelength is emitted toward the receiving port, and a beam including the other wavelengths is reflected, and a plurality of light reflections are performed. The light is transmitted to the adjacent wavelength selection element via the condensing element.
[0162]
By repeating these processes, the propagation beam is demultiplexed.
[0163]
As described above, the beam can be used as a multiplexer by reversing the traveling direction of the beam when used as a duplexer.
[0164]
That is, the beams emitted from the plurality of transmission ports 102-104 are incident in parallel to each other so as to pass through the plurality of wavelength selection elements 105-107.
[0165]
At that time, a beam including a specific wavelength that is transmitted through the wavelength selection element 105-107 and incident inside is reflected by the light reflection condensing element 108-111 a plurality of times, and the reflected beam is transmitted to the adjacent wavelength selection element. Install at an incident angle so that it is incident.
[0166]
In this manner, the outgoing beams from the plurality of transmission ports 102-104 are overlapped by multiple reflection inside, and are combined by being propagated as one propagation beam toward the reception port 101. The
[0167]
However, in the case of the use form as a multiplexer, among the beams incident on the wavelength selection elements 105-107 from the transmission ports 102-104, the beam including the reflected wavelength region and the propagation beam are internally reflected multiple times. In this case, a beam in a wavelength region that is transmitted by another wavelength selection element and does not become a multiple reflection beam is not multiplexed.
[0168]
In the above application example as a multiplexer / demultiplexer, the number of wavelength selection elements is three, the number of light reflecting and condensing elements is three, and the number of channel ports is three, but these numbers are limited. is not.
[0169]
When the channel ports 102-104 are all transmission ports, the common port 101 is a reception port and therefore operates as a multiplexer. However, when the channel ports 102-104 are all reception ports, the common port 101 is a transmission port. Therefore, it operates as a duplexer.
[0170]
Further, when both the transmission port and the reception port are included as channel ports, it is possible to simultaneously realize both the multiplexing operation and the demultiplexing operation by one multiplexer / demultiplexer having one common port.
[0171]
In this case, a wavelength selection element is disposed between the wavelength selection element for the demultiplexing operation and the wavelength selection element for the multiplexing operation to prevent interference of the wavelength of the multiplexing / demultiplexing operation. It is also possible to emit a beam in the region outside the multiplexer / demultiplexer.
[0172]
FIG. 2 shows the present invention shown in FIG. Reference example It is a conceptual diagram of the optical system which shows the propagation state of the multiple reflected beam about the multiplexer / demultiplexer which concerns on.
[0173]
In this drawing, the light reflecting and condensing means is replaced with an optical lens, and the propagation optical axis of the multiple reflected beam is developed in a straight line.
[0174]
The dotted line represents the propagation optical axis of the multiple reflected beam, and the broken line represents the spot size of the multiple reflected beam.
[0175]
Of the beams transmitted through the wavelength selection element, a beam in a specific wavelength region corresponds to a beam input to the channel port or a beam output from the channel port, but is not represented in this drawing.
[0176]
In the figure, 201-209 are wavelength selection elements, 210-223 are optical lenses corresponding to light reflecting and condensing means, and 224-233 are arrows indicating the beam waist position of the actually propagating beam.
[0177]
FIG. 2A is a conceptual diagram when a beam waist is always formed between a plurality of light reflecting and condensing elements, and FIG. 2B is a diagram illustrating light in which a wavelength selection element is included in an optical path. FIG. 2C is a conceptual diagram when a beam waist is not formed between the reflective condensing elements. FIG. 2C is a diagram illustrating a case where the beam waist is provided only between the light reflecting condensing elements in which the wavelength selection element is included in the optical path. It is a conceptual diagram in the case of being formed.
1) As shown in FIG. 2A, when the complex beam parameters of the multiple reflected beam are made identical on all the wavelength selection elements 201-203, a plurality of light reflection condensing elements 211-214 The wavelength selection element 202-203 is disposed at the intermediate point of the optical path so that the optical parameters of the two light reflection condensing elements 210-213 included between the optical paths of the plurality of wavelength selection elements 201-203 change alternately. Therefore, the optical design can be made so that the beam waists 225 to 228 are formed at equidistant points before and after the light reflecting / condensing elements 211 and 213 as viewed from one side.
[0178]
Controlling the distance from the light reflecting / condensing element to the beam waist corresponds to controlling the distance from the wavelength selection element to the beam waist.
[0179]
In this case, only a slight error occurs when the relay optical system is manufactured, and the position and spot size of the beam waist arranged between the light reflecting and condensing elements change abruptly from the design value. Although there is a problem that when the transmission port is mounted, even if a positional deviation or angular deviation of the propagation beam optical axis occurs, the beam waist is arranged between the optical paths of all the light reflecting and condensing elements. Amplification of the positional deviation and angular deviation between all these optical paths can be prevented, and an increase in power loss of the beam propagated to all channel ports can be prevented.
2) Also, as shown in FIG. 2B, when the complex beam parameters of the multiple reflected beam are made identical on all the wavelength selection elements, the optical paths of the plurality of light reflecting and condensing elements 216 to 219 The wavelength selection elements 205-206 are arranged at the midpoint between the optical parameters of the two light reflection condensing elements 215-218 included between the optical paths of the plurality of wavelength selection elements 204-206. The beam waist is not formed between the optical paths including the wavelength selection elements 205 to 206 among the plurality of light reflecting and condensing element optical paths, and between the optical paths not including the wavelength selection elements. The optical design can be such that 229-230 is formed.
[0180]
Controlling the distance from the light reflecting and condensing element to the beam waist corresponds to controlling the beam spot size and the beam wavefront curvature radius on the wavelength selection element.
[0181]
In this case, if a positional deviation or an angular deviation of the propagation beam optical axis occurs when the transmission port is mounted, a specific portion of the light path between the plurality of light reflecting / condensing element optical paths is not formed. In this case, there is a problem that the positional deviation and the angular deviation are amplified, but even if an error in the optical parameters of the light reflecting / condensing element or an error in the optical path length between the light reflecting / condensing elements occurs, Changes in the spot size and beam wavefront curvature radius of the multiple reflected beam propagating between the non-formed optical paths can be regarded as sufficiently small with respect to the error, thus preventing amplification of the error between these optical paths. It is possible to prevent an increase in power loss of the beam propagated to all channel ports.
[0182]
In addition, if the beam waist of the channel port input / output beam cannot be formed near the channel port due to the limitations of the channel port optical system, the method of changing the distance between the channel port and the wavelength selection element can be used to It is not necessary to match the beam waist formation point of the port input / output beam, and it is possible to cope with the method of controlling the position of the beam waist by the optical design of the light reflecting / condensing element.
[0183]
Therefore, it is possible to prevent an increase in the size of the multiplexer / demultiplexer and a decrease in the optical axis deviation tolerance.
3) Further, as shown in FIG. 2C, when the complex beam parameters of the multiple reflected beam are made identical on all the wavelength selection elements, the optical paths of the plurality of light reflecting and condensing elements 221 to 222 The wavelength selection element 208 is disposed at an intermediate point between the optical parameters of the two light reflection condensing elements 220-223 included between the optical paths of the plurality of wavelength selection elements 207-209, so that The beam waist 231-232 is formed between the optical paths including the wavelength selection elements 207-208, and between the optical paths not including the wavelength selection elements. The optical design can be made so that the beam waist is not formed.
[0184]
Controlling the distance from the light reflecting / condensing element to the beam waist corresponds to controlling the distance from the wavelength selection element to the beam waist.
[0185]
Also in this case, as described above, even if an error in the optical parameters of the light reflecting / condensing element or an error in the optical path length between the light reflecting / condensing elements occurs, the multiplexing that propagates between the optical paths in which the beam waist is not formed. Changes in the spot size of the reflected beam and the beam wavefront curvature radius can be considered sufficiently small with respect to the error, so that the amplification of the error between these optical paths can be prevented and propagated to all channel ports. An increase in power loss of the beam can be prevented.
[0186]
In addition, even if there is a restriction on the beam waist formation position of the channel port input / output beam due to restrictions on the optical system of the channel port, the position of the beam waist is controlled by the optical design of the light reflecting / condensing element. The beam waist of the reflected beam, the beam waist forming point of the channel port input / output beam, and the spot size can be matched.
[0187]
Therefore, it is possible to prevent a decrease in the coupling efficiency of the multiplexer / demultiplexer.
[0188]
[Example 1 ]
FIG. 3 shows the first aspect of the present invention. 1 It is a schematic block diagram of the multiplexer / demultiplexer which concerns on embodiment of this, and showed in FIG. Reference example This is an application example.
[0189]
Less than, Reference example Differences from the case will be described.
[0190]
In the figure, regarding the wavelength selection element 305-307, the planar reflection surface 312-313, and the light reflection condensing element 308-311, the minute reflection planes on which the propagation beams enter and reflect are all parallel to each other, but are virtual planes It is not arranged in parallel with 314-315.
[0191]
These control elements are formed so that the optical axis of the beam that passes through the wavelength selection elements 305-307 and is input to and output from the channel ports 302-304 is orthogonal to the virtual plane 314-315.
[0192]
FIG. 4 shows a first embodiment of the present invention shown in FIG. 1 It is a conceptual diagram of the optical system which shows the propagation state of a multiple reflected beam about the multiplexer / demultiplexer which concerns on this embodiment.
[0193]
The symbols on the drawing are the same as those in FIG.
[0194]
Reference numerals 401 to 406 denote wavelength selection elements, reference numerals 407 to 415 denote optical lenses corresponding to light reflecting and condensing means, and reference numerals 416 to 423 denote arrows indicating beam waist positions of the actually propagating beams.
[0195]
FIG. 4A is a conceptual diagram when a beam waist is always formed between a plurality of light reflecting and condensing elements, and FIG. 4B is a diagram showing light in which a wavelength selection element is included between optical paths. It is a conceptual diagram in case the beam waist is formed only between reflective condensing elements.
1) As shown in FIG. 4 (a), since the optical path lengths from one wavelength selection element to two light reflection condensing elements arranged in the immediate vicinity thereof are different, a plurality of light reflecting condensing elements The wavelength selection elements 402-403 cannot be arranged at the midpoint of the optical path 408-411.
[0196]
However, the optical parameters of the two light reflecting and condensing elements 407 to 410 included between the optical paths of the plurality of wavelength selecting elements 401 to 403 are alternately changed so that one of the light reflecting and condensing elements is changed. light Optical design can be made to form beam waists 417-420 at equidistant points before and after viewing from the elements 408, 410.
[0197]
Controlling the distance from the light reflecting and condensing element to the beam waist corresponds to controlling the distance from the wavelength selecting element to the beam waist, so that the beam waist forming position matches the arrangement point of the wavelength selecting element, In addition, the complex beam parameters of the multiple reflected beam can be made identical on all the wavelength selection elements 401-403.
[0198]
In this case, only a slight error occurs when the relay optical system is manufactured, and the position and spot size of the beam waist arranged between the light reflecting and condensing elements change abruptly from the design value. Although there is a problem that when the transmission port is mounted, even if a positional deviation or angular deviation of the propagation beam optical axis occurs, the beam waist is arranged between the optical paths of all the light reflecting and condensing elements. Amplification of the positional deviation and angular deviation between all these optical paths can be prevented, and an increase in power loss of the beam propagated to all channel ports can be prevented.
2) As shown in FIG. 4B, since the optical path length from one wavelength selection element to two light reflection condensing elements arranged in the immediate vicinity thereof is different, a plurality of light reflection condensing elements The wavelength selection element 422 cannot be arranged at the midpoint of the optical path 413-414.
[0199]
However, the optical parameters of the two light reflecting and condensing elements 412 to 415 included between the optical paths of the plurality of wavelength selecting elements 421 to 423 are alternately changed, and among the plurality of light reflecting and condensing element optical paths, Optical design is made so that a beam waist 421-423 is formed between the optical paths including the wavelength selection elements 404-406, and no beam waist is formed between the optical paths not including the wavelength selection elements. Can do.
[0200]
Controlling the distance from the light reflecting and condensing element to the beam waist corresponds to controlling the distance from the wavelength selecting element to the beam waist, so that the beam waist forming position matches the arrangement point of the wavelength selecting element, In addition, the complex beam parameters of the multiple reflected beam can be made identical on all wavelength selection elements 404-406.
[0201]
In this case, if a positional deviation or an angular deviation of the propagation beam optical axis occurs when the transmission port is mounted, a specific portion of the light path between the plurality of light reflecting / condensing element optical paths is not formed. In this case, there is a problem that the positional deviation and the angular deviation are amplified, but even if an error in the optical parameters of the light reflecting / condensing element or an error in the optical path length between the light reflecting / condensing elements occurs, Changes in the spot size and beam wavefront curvature radius of the multiple reflected beam propagating between the non-formed optical paths can be regarded as sufficiently small with respect to the error, thus preventing amplification of the error between these optical paths. It is possible to prevent an increase in power loss of the beam propagated to all channel ports.
3) In both the case shown in FIG. 4A and the case shown in FIG. 4B, the installation angle of the beam optical axis input / output from the channel port is made orthogonal to the virtual plane. Therefore, the installation angle of the channel port and the common port can be simplified and made identical, and the mounting cost for alignment can be reduced.
[0202]
In addition, since various types of array-like components can be used, the position and angle of a plurality of channel ports can be collectively adjusted, and the mounting cost for alignment can be reduced.
[0203]
[Example 2 ]
FIG. 5 shows the first aspect of the present invention. 2 It is a schematic block diagram of the multiplexer / demultiplexer which concerns on embodiment of this, and showed in FIG. Reference example This is an application example.
[0204]
Less than, Reference example Differences from the case will be described.
[0205]
In the figure, reference numerals 501 to 503 denote channel ports, which are arranged on one virtual plane side so that transmission channel ports 502 and reception channel ports 501 and 503 are alternately adjacent to each other.
[0206]
Since a transmission port and a reception port coexist as channel ports, it is possible to simultaneously realize both multiplexing and demultiplexing operations with one multiplexer / demultiplexer having two common ports for transmission and reception. It is possible, and an add-drop multiplexer for wavelength division multiplexing communication can be realized in a small size and at low cost.
[0207]
Further, since the transmission channel port and the reception channel port are adjacent to each other, these two channel ports can be combined to form an integrated transmission / reception module, which can be attached to and detached from the multiplexer / demultiplexer.
[0208]
FIG. 6 shows a first embodiment of the present invention shown in FIG. 2 It is a conceptual diagram of the optical system which shows the propagation state of a multiple reflected beam about the multiplexer / demultiplexer which concerns on this embodiment.
[0209]
The symbols on the drawing are the same as those in FIG.
[0210]
In the figure, 601-606 are wavelength selection elements, 607-615 are optical lenses corresponding to light reflecting and condensing means, and 616-620 are arrows indicating the beam waist position of the actually propagating beam.
[0211]
FIG. 6A is a conceptual diagram in the case where a beam waist is formed only between the light reflecting and condensing elements in which the wavelength selection element is included in the optical path, and FIG. 6B is the wavelength selection element. FIG. 6 is a conceptual diagram when a beam waist is not formed between the light reflecting and condensing elements included between the optical paths.
[0212]
1) As shown in FIG. 6A, when the beam waists 616-618 of multiple reflected beams are arranged on all the wavelength selection elements 601-603, a plurality of light reflection condensing elements 608-609 are arranged. The wavelength selection element 602 is disposed at the intermediate point of the optical path, and the optical parameters of the four light reflection condensing and condensing elements 607-610 included between the optical paths of the three wavelength selection elements 601-603 are limited to two types. The two light reflecting and concentrating elements 608 to 609 arranged in the immediate vicinity of the second wavelength selecting element 602 have the same optical parameters, and the two light reflecting elements arranged in the immediate vicinity of the first and third wavelength selecting elements 601 and 603 are used. The optical design can be made so that the optical parameters of the condensing elements 607 and 610 are the same.
[0213]
In this case, the spot sizes formed on the adjacent wavelength selection elements change alternately, but the ratio of the sizes can be controlled within a specific range, and the transmission channel port and the reception channel port respectively. It is possible to correspond to this optical system.
[0214]
Therefore, even if the channel waist spot size of the channel input / output beam cannot be designed freely due to the restrictions of the optical system of the channel port, both spot sizes can be controlled by controlling the beam waist spot size of the multiple reflected beam. Can be matched within a certain range.
[0215]
Therefore, it is possible to prevent a decrease in the coupling efficiency of the multiplexer / demultiplexer.
2) As shown in FIG. 6B, when the multiple reflected beams have the same spot size on all the wavelength selection elements 604 to 606 and only the sign of the beam wavefront curvature radius changes alternately, The wavelength selection elements 605-606 are arranged at the midpoint of the optical paths of the plurality of light reflection condensing elements 612-615, and four light reflection condensing elements 611- included between the optical paths of the three wavelength selection elements 604-606. The optical parameters of 614 are limited to two types, and the optical parameters of one of the two light reflecting and condensing elements 611 to 612 arranged in the optical path between the first wavelength selecting element 604 and the second wavelength selecting element 605 are set as follows. The first wavelength selection is performed by making the optical parameters of the two light reflecting and condensing elements 613-614 arranged in the optical path between the third wavelength selection element 606 and the second wavelength selection element 605 the same. Element 6 The optical design can be made so that the beam waist 619-620 is formed at an intermediate point between the fourth and second wavelength selection elements 605 and at an intermediate point between the third wavelength selection element 606 and the second wavelength selection element 605. .
[0216]
In this case, when a channel port consisting of an optical system with the same configuration is applied to the transmission port and the reception port, even if the spot size and beam wavefront curvature radius of the channel input / output beam cannot be freely controlled due to optical system restrictions, all Since the spot size of the multiple reflected beam formed by the wavelength selection element and the absolute value of the beam wavefront curvature radius can be controlled within a specific range, an optical design that suppresses variation and decrease in coupling efficiency is possible.
3) In both the case shown in FIG. 6A and the case shown in FIG. 6B, when a positional deviation or an angular deviation of the propagation beam optical axis occurs when the transmission port is mounted, a plurality of Among the light reflection condensing element optical paths, there is a problem that the positional deviation and the angle deviation are amplified in a specific case between the optical paths where the beam waist is not formed. Even if errors in optical parameters or errors in the optical path length between light reflecting and condensing elements occur, changes in spot size and beam wavefront curvature radius of multiple reflected beams propagating between optical paths where no beam waist is formed Therefore, it is possible to prevent amplification of the error between these optical paths, and it is possible to prevent an increase in power loss of the beam propagated to all channel ports.
[0217]
As described above, according to the present invention, the wavelength is changed while propagating the light beam while performing multiple reflection between the virtual planes by the light reflection condensing element and the wavelength selection element arranged on the two virtual planes facing in parallel. A wavelength selection element that multiplexes or demultiplexes an optical signal by extracting a light beam (optical signal) of a specific wavelength from the selection element or inserting a light beam (optical signal) of a specific wavelength from the wavelength selection element. Since the main configuration is that the light reflection condensing element and the wavelength selection element are arranged so as to undergo reflection from a plurality of light reflection condensing elements while the reflected beam from the light enters the other adjacent wavelength selection element, It is easy to prevent a decrease in coupling efficiency between transmission / reception ports and a variation in coupling efficiency between channel ports, and a high-accuracy and low-cost multiplexer / demultiplexer is realized.
[0218]
【The invention's effect】
As described above in detail, according to the multiplexer / demultiplexer according to the present invention, a beam having a specific wavelength is applied to a plurality of optical transmission lines by a method of multiply-reflecting the propagation beam inside the multiplexer / demultiplexer. Can solve the problems that occur when extracting or inserting
1) Optical design cost reduction
2) Reduced part costs for obtaining parts as designed by using commercially available products, reducing manufacturing tolerances, and forming parts at once.
3) Reduction in mounting cost for positioning parts as designed by improving alignment workability and forming multiple channel ports at once.
4) Miniaturization and high accuracy of channel port
5) Suppression of characteristic deterioration due to increase in the number of channel ports
6) Downsizing of wavelength selection element, reduction of in-plane dependence, uniform filter characteristics
7) Broadening the usable wavelength band of propagating beams
8) Improve freedom of optical axis design for propagating beam
9) Optimizing tolerance of optical axis position deviation and optical axis angle deviation of propagating beam
Etc. can be provided.
[Brief description of the drawings]
FIG. 1 of the present invention Reference example It is a schematic block diagram of the multiplexer / demultiplexer which concerns on.
2 is a view of the present invention shown in FIG. Reference example It is a conceptual diagram of the optical system which shows the propagation state of the multiple reflected beam about the multiplexer / demultiplexer which concerns on.
FIG. 3 shows the first aspect of the present invention. 1 It is a schematic block diagram of the multiplexer / demultiplexer which concerns on this embodiment.
FIG. 4 shows a first embodiment of the present invention shown in FIG. 1 It is a conceptual diagram of the optical system which shows the propagation state of a multiple reflected beam about the multiplexer / demultiplexer which concerns on this embodiment.
FIG. 5 shows the first aspect of the present invention. 2 It is a schematic block diagram of the multiplexer / demultiplexer which concerns on this embodiment.
FIG. 6 shows a first embodiment of the present invention shown in FIG. 2 It is a conceptual diagram of the optical system which shows the propagation state of a multiple reflected beam about the multiplexer / demultiplexer which concerns on this embodiment.
FIG. 7 is a schematic configuration diagram of a multiplexer / demultiplexer when a multi-reflected beam is incident on another wavelength selection element after being reflected from one light reflecting / condensing element.
FIG. 8 is a conceptual diagram for explaining the propagation principle of a multiple reflected beam when a reflected beam from a wavelength selection element is incident on another wavelength selection element after being reflected from one light reflection / condensing element; is there.
FIG. 9 is a schematic diagram showing a specific example of the multiplexer / demultiplexer described in Patent Document 1.
[Explanation of symbols]
101 common port
102-104 channel port
105-107 Wavelength selection element
108-111 Light Reflecting and Condensing Element
112-113 Planar reflective surface
114-115 virtual plane
116-119 Emission point or light receiving point
120-123 lens system
201-209 Wavelength selection element
210-223 Optical lens equivalent to a light reflecting and condensing element
224-233 Beam waist position
301 common port
302-304 channel port
305-307 Wavelength selection element
308-311 Light reflection condensing element
312-313 Planar reflecting surface
314-315 Virtual plane
401-406 Wavelength selection element
407-415 Optical lens equivalent to a light reflecting and condensing element
416-423 Beam waist position
501-503 channel port
504 to 506 Wavelength selection element
507-512 Light reflecting condensing element
513-515 Flat reflecting surface
601-606 wavelength selection element
607-615 Optical lens equivalent to a light reflecting and condensing element
616-620 Beam waist position
701 common port
702-705 channel port
706-709 Wavelength selection element
710-712 Light reflection condensing element
713-714 virtual plane
801-810 Wavelength selection element
811-818 Optical lens equivalent to a light reflecting and condensing element
819-828 beam waist position

Claims (5)

Gaussian beam is then inputted and reflected on the light reflecting condensing element which reflects to form a beam waist in a particular position, the reflected beam from the light-reflecting light collecting element, it is transmitted through the beam of a specific wavelength range Optical design so that the reflected light from the wavelength selecting element is incident on and reflected by a light reflecting condensing element different from the light reflecting condensing element. A multiplexer / demultiplexer,
The light reflection condensing element and the wavelength selection element are arranged on two virtual planes facing each other in parallel, and the reflected beam from the wavelength selection element is propagated while being repeatedly reflected on the two virtual planes. The optical path length from one wavelength selection element to another adjacent wavelength selection element on the optical path of the multiple reflection beam is equal, and the multiple reflection beam is changed from one wavelength selection element to another wavelength selection element. And the angle formed between the incident optical axis incident on the wavelength selection element and the imaginary plane, and from the wavelength selection element. The angle formed by the reflected optical axis to be reflected and the virtual plane does not match,
The multiplexer / demultiplexer, wherein the optical parameters of the light reflecting and condensing elements are optically designed so that the complex beam parameters of the beams reaching the wavelength selecting elements are the same on all the wavelength selecting elements . The Gaussian beam enters and reflects the light reflecting condensing element that reflects so as to form a beam waist at a specific position, and the reflected beam from the light reflecting condensing element transmits a beam in a specific wavelength region, and otherwise. It is optically designed to enter and reflect the wavelength selection element that reflects the beam in the wavelength range, and the reflected beam from the wavelength selection element enters and reflects to a light reflection and collection element different from the light reflection and collection element. A multiplexer / demultiplexer,
The light reflection condensing element and the wavelength selection element are arranged on two virtual planes facing each other in parallel, and the reflected beam from the wavelength selection element is propagated while being repeatedly reflected on the two virtual planes. The optical path length from one wavelength selection element to another adjacent wavelength selection element on the optical path of the multiple reflection beam is equal, and the multiple reflection beam is changed from one wavelength selection element to another wavelength selection element. Configured to undergo reflection from a plurality of light reflecting and condensing elements when propagating to
The spot size of the multiple reflection beam and the absolute value of the beam wavefront curvature radius are the same on all wavelength selection elements, and the beam wavefront curvature radius of the multiple reflection beam is the same on the wavelength selection element adjacent to the optical path of the multiple reflection beam. A multiplexer / demultiplexer characterized in that the optical parameters of the light reflecting and condensing elements are optically designed so that the sign changes alternately. The Gaussian beam enters and reflects the light reflecting condensing element that reflects so as to form a beam waist at a specific position, and the reflected beam from the light reflecting condensing element transmits a beam in a specific wavelength region, and otherwise. It is optically designed to enter and reflect the wavelength selection element that reflects the beam in the wavelength range, and the reflected beam from the wavelength selection element enters and reflects to a light reflection and collection element different from the light reflection and collection element. A multiplexer / demultiplexer,
The light reflection condensing element and the wavelength selection element are arranged on two virtual planes facing each other in parallel, and the reflected beam from the wavelength selection element is propagated while being repeatedly reflected on the two virtual planes. The optical path length from one wavelength selection element to another adjacent wavelength selection element on the optical path of the multiple reflection beam is equal, and the multiple reflection beam is changed from one wavelength selection element to another wavelength selection element. Configured to undergo reflection from a plurality of light reflecting and condensing elements when propagating to
Beam propagating inside demultiplexer forms a beam waist of the two kinds of spot size on the wavelength selection element, a so that different spot sizes on adjacent wavelength selecting element is mutually in the optical path of the multiple reflected beam An optical multiplexer / demultiplexer characterized in that the optical parameters of the light reflecting / condensing element are optically designed. The multiplexer / demultiplexer according to any one of claims 1 to 3,
All the wavelength selection elements are arranged on one of two virtual planes. The multiplexer / demultiplexer according to any one of claims 1 to 4 ,
At least one of the light reflecting and condensing elements is a spherical mirror.

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