WO2011143838A1

WO2011143838A1 - Dispersion compensator

Info

Publication number: WO2011143838A1
Application number: PCT/CN2010/074183
Authority: WO
Inventors: 王则钦; 陈彬; 谢红
Original assignee: 昂纳信息技术（深圳）有限公司
Priority date: 2010-05-18
Filing date: 2010-06-21
Publication date: 2011-11-24
Also published as: CN102255666A

Abstract

A dispersion compensator (30) comprises a light guide element, two groups of polarization changing element arrays, two groups of etalon element arrays, a reflector (35), and an optical circulator (31). A polarized light beam L is emitted into the optical circulator (31) via a first port (1) of the optical circulator (31), transmitted to the light guide element via a third port (3) of the optical circulator (31), and emitted into a first etalon element (341) via a first polarization changing element. The light reflected back from the first etalon element (341) is changed into a light beam L1, whose polarization state is perpendicular to the polarization state of the incident polarized light beam L, after passing through the first polarization changing element again. The light beam L1 is emitted into the light guide element again, and guided to a second polarization changing element and a second etalon element (342) after being offset a certain distance. The light is transmitted back and forth according to this rule, until being reflected back to the light guide element by the reflector (35), transmitted reversely according to the above optical path, and outputted from a second port (2) of the optical circulator (31). The dispersion compensator (30) satisfies the demand of bandwidth with a larger range, and the structure thereof is more compact.

Description

Dispersion compensator

Technical field

The invention belongs to the field of optical communication, and in particular relates to a dispersion compensator.

Background technique

Light propagating in an optical network usually suffers from chromatic dispersion (chromatic Dispersion) or polarization mode dispersion (PMD). These dispersions cause distortion of the optical signal waveform. If PMD occurs, the received signal waveform will generally spread (the waveform becomes thicker) and the correct data exchange cannot be performed. Since the PMD is randomly changed due to the influence of the optical fiber laying condition and the external environment, the communication quality is degraded. In particular, the higher the speed, the more susceptible it is to PMD, which is the most important cause of the degradation of communication quality in 100 Gbps systems.

The basic optical component used in the dispersion compensation module is a GT (Gires-Tournois) etalon, which is essentially an all-pass filter, that is, all wavelength signals are totally reflected, and the reflectivity is the same; Multiple reflections in the etalon cavity can eventually accumulate a large phase delay, which is strongly related to the wavelength, exhibiting a typical sharp resonant peak waveform, due to the required passband width in optical communication systems. However, the group delay curve of a single GT type etalon is too narrow to meet the passband requirement, and optical cascading of multiple etalon devices is generally used to achieve the passband width requirement. In the conventional dispersion compensation module scheme, a single fiber-coupled two-port etalon device is generally constructed first, and then multiple such etalon devices are combined into one module by fiber cascading. Since the conventional scheme involves multiple fiber couplings, the insertion loss is large; and at the same time, due to the limitation of the minimum coiling radius of the fiber, such modules generally have larger sizes.

The existing method of free-space beam propagation to achieve the defect of fiber-optic coiling, Chinese patent CN20091011107.X reveals this scheme, the incident light with P-polarization passes through the PBS prism group unobstructed, after the first quarter The wave plate is vertically incident on the first etalon element, and the light reflected from the first etalon element and passed through the first 1/4 wave plate again passes through the first 1/4 wave plate to become S-polarized light. And then incident on the spectroscopic surface of the PBS prism again, the optical path of the light propagating back and forth in such a way that the light passes through a plurality of quarter-wave plates and etalon components and is reflected from the spectroscopic surface of the PBS prism. After the transmission through the output port. The drawback of this solution is that in order to achieve more broadband requirements, it is necessary to increase the number or length of multiple quarter-wave plates, PBS prisms and etalons, which increases the volume of the device to a certain extent.

technical problem

The present invention provides a dispersion compensator that is more compact and miniaturized while satisfying a wider range of bandwidths.

Technical solution

In order to achieve the object, a dispersion compensator of the present invention comprises a light guiding element, two sets of polarization changing element arrays and two sets of etalon element arrays, wherein: further comprising a mirror and an optical circulator, the light beam L passing through the light ring The first port of the device is incident, transmitted to the light guiding element via the third port, and injected into the first standard element through the first polarization changing element, and the light reflected from the first etalon element passes through the first polarization changing element again a light beam L1 that becomes a polarization state perpendicular to the incident light beam L, the light beam L1 being incident again to the light guiding element, offset by a distance to the second polarization changing element and the second etalon element, from the second standard The light reflected by the element passes through the second polarization changing element and is converted into a light beam L2 that is in conformity with the polarization state of the light beam L. After the light guiding element is guided to the combination of the third polarization changing element and the third etalon element, the polarization state thereof is switched. a light beam L3 perpendicular to the polarization state of the light beam L, the light path of the light is reciprocally reflected and propagated according to this law until after passing through the light guiding element, The mirror is reflected back to the light guiding element, and is reversely transmitted according to the optical path, and the reflection is directed to the third polarization changing element and the third etalon element, and the light beam reflected from the third etalon element passes through the third polarization changing element again, and the light beam L4 is converted. The polarization directions of the sum beam L are perpendicular to each other, returning to the second polarization changing element and the second etalon via the light guiding element, and the beam reflected from the second etalon is again converted by the polarization changing element and the beam L3 of the polarization state of the beam L is uniform. By directing the light guiding element to the first polarization changing element and the first etalon element, the light beam L3 returned from the first etalon element is again converted by the first polarization changing element into a light beam L2 perpendicular to the polarization state of the light beam L. The third port of the component-guided optical circulator receives and outputs from the second port.

Preferably, the light guiding element is composed of a first PBS prism, a second PBS prism, a third PBS prism, an nth PBS prism, and a P-polarized light beam is incident through the first port of the optical circulator. The three ports are transmitted to the first PBS prism, and the first polarization changing element is incident on the first standard element, and the light reflected from the first etalon element passes through the first polarization changing element to become S-polarized light. And then incident on the spectroscopic surface of the first PBS prism again, the S-polarized light is reflected by the first PBS prism and directed to the second PBS prism, and is reflected by the spectroscopic surface of the second PBS prism to the second polarization changing element and a etalon element, the light reflected from the second etalon element passes through the second polarization changing element and then switched to P-polarized light and then through the combination of the third polarization changing element and the third etalon element, the polarization The state is switched to S-polarized light, and then the spectroscopic surface incident on the second PBS prism is reflected and guided to the third PBS prism, and the optical path of the light propagates back and forth according to the regularity until after being reflected by the Nth PBS prism. through After the mirror reflects back the Nth prism, the P-polarized light reflected to the third PBS prism is reversely transmitted according to the optical path, and the third polarization changing element and the third etalon are guided by the spectroscopic surface reflection of the third PBS prism. An element, the light beam reflected from the third etalon element passes through the third polarization changing element again, and the beam is converted into P-polarized light and returned to the second PBS prism and then to the second polarization changing element and the second etalon, from the second The reflected light beam of the etalon is again converted into S-polarized light by the polarization changing element, and returned to the second PBS prism, and then reflected by the spectroscopic surface thereof to the first PBS prism to guide the first polarization changing element and the first etalon element. The S-polarized light returned by an etalon element is again converted into P-polarized light through the first polarization changing element, passes through the first PBS prism, is received through the third port of the optical circulator, and is outputted from the second port.

Preferably, the light guiding element is a birefringent prism block.

Preferably, the polarization changing element is a quarter wave plate or a Faraday piece.

Preferably, the first etalon component, the second etalon component, and the Nth etalon component are integrated into two etalon A and an etalon B.

Preferably, the first polarization changing element, the second polarization changing element, the third polarization changing element, the Nth polarization changing element are integrated into two left and right polarization changing elements A and polarization changing elements B.

Beneficial effect

Thus, the present invention has an advantage in that the dispersion compensator is more compact and compact, because the bandwidth is satisfied in a wider range.

DRAWINGS

The optical path structure of a dispersion compensator of the present invention will be further described below with reference to the accompanying drawings and embodiments.

1 is a view showing the optical path structure of a first embodiment of a dispersion compensator according to the present invention.

2 is a view showing the optical path structure of a second embodiment of a dispersion compensator according to the present invention.

3 is a view showing the optical path structure of a third embodiment of a dispersion compensator according to the present invention.

4 is a view showing the optical path structure of a fourth embodiment of a dispersion compensator according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The working principle of a dispersion compensator of the present invention will be further described below with reference to the accompanying drawings.

1 is a schematic structural view of a first embodiment of a dispersion compensator according to the present invention. As shown in FIG. 1, the dispersion compensator 10 includes a plurality of sets of PBS prisms, quarter-wave plates, and etalon components (Etalon). And a mirror, the light splitting surface of the PBS prism is disposed at 45°, and is configured to transmit P-polarized light and reflect the S-polarized light. As shown in FIG. 1, the P-polarized light beam is incident through the first port 1 of the optical circulator 11, is transmitted to the first PBS prism 121 via the third port 3, and is incident on the first standard component 141 through the first quarter-wave plate 131. The light reflected from the first etalon element 141 passes through the first quarter-wave plate 131 again and becomes S-polarized light (indicated by a dot in the figure), and is then incident on the first PBS prism 121 again. The S-polarized light is reflected by the first PBS prism and directed to the second PBS prism 122, and is reflected by the spectroscopic surface of the second PBS prism 122 to the second quarter-wave plate 132 and the second etalon element. 142. The light reflected from the second etalon element 142 passes through the second quarter-wave plate 132 and is then switched into P-polarized light and then passed through the third quarter-wave plate 133 and the third etalon element 143. After being combined, the polarization state is switched to S-polarized light, and then the spectroscopic surface incident on the second PBS prism 122 is reflected and guided to the third PBS prism 123, and the optical path of the light is reciprocally reflected and propagated until the passage After the N PBS prisms 12n are reflected, after being reflected by a mirror 15 and returned to the Nth prism, the optical path is reversely transmitted according to the above-mentioned optical path. The P-polarized light that has hit the third PBS prism 123 is reflected by the spectroscopic surface of the third PBS prism 123 and directed to the third quarter-wave plate 133 and the third etalon element 143, and is reflected back from the third etalon element 143. The beam passes through the third quarter wave plate 133 again, and the beam is converted into S-polarized light and returned to the second PBS prism 122 to be guided to the second quarter wave plate and the second etalon 142, and reflected from the second etalon 142. The returned light beam is again converted into S-polarized light by the 1/4 wave plate, returned to the second PBS prism 122, and reflected by the splitting surface thereof to the first PBS prism 121 to guide the first quarter-wave plate 131 and the first etalon. The element 141, the S-polarized light returned from the first etalon element 141 is again converted into P-polarized light through the first PBS prism 121 and then received through the third port 3 of the optical circulator 11 through the first 1/4 wave plate. , output from the second port 2 output. In this embodiment, the light beam input from the first port 1 of the optical circulator 11 passes through a plurality of sets of PBS prisms, quarter-wave plates, and etalon components, and is reflected by a mirror 15 to pass through a plurality of sets of PBS prisms, 1 again. The /4 wave plate and the etalon element are output by the second port 2 of the optical circulator 11.

In this embodiment, the quarter-wave plate can be replaced by an equivalent Faraday piece.

2 is a schematic structural view of a second embodiment of the dispersion compensator of the present invention, as shown in FIG. 2: the first etalon element 141, the second etalon element 142, and the third etalon are compared with the first embodiment. The element 143...the Nth etalon element 14N is divided into left and right etalon 14A and etalon 14B; the first quarter wave plate 131, the second 1/4 wave plate 132, and the third 1/4 wave plate 133... The N1/4 wave plate 13N is integrated into the left and right 1/4 wave plate 13A and the 1/4 wave plate 13B; the first PBS prism 121, the second PBS prism 122, the third PBS prism 133, the Nth PBS prism 13N The integration of a PBS prism 13 has N spectroscopic surfaces. The dispersion compensator of the present embodiment includes an optical circulator 21, left and right etalon 14A, 14B, left and

right wave plates

13A, 13B, PBS prism 12 and a mirror 22. The light working principle of the present example is the same as that of the first embodiment, and will not be repeated again.

3 is a schematic structural diagram of a third embodiment of a dispersion compensator according to the present invention. As shown in FIG. 3, the dispersion compensator 10 includes a birefringent crystal block, a plurality of groups of quarter-wave plates, and a plurality of sets of etalon components. (Etalon), a mirror and an optical circulator, as shown in FIG. 3: the linearly polarized light beam L is incident via the first port 1 of the optical circulator 31, and transmitted to the birefringent crystal block 31 via the third port 3, perpendicularly The surface of the birefringent crystal block 31 is incident and transmitted in parallel to the first quarter-wave plate 331 in the birefringent crystal block 31, converted into circularly polarized light by the first quarter-wave plate 331, and then injected into the first standard component. 341. The light reflected from the first etalon element 341 passes through the first quarter-wave plate 331 and becomes a linearly polarized beam. Since the polarization state of the light is rotated by 90°, the beam is deflected in the original direction. The second quarter wave plate 332 and the second etalon element 342, the light reflected from the second etalon element 342 is again converted into a linearly polarized light beam through the second quarter wave plate 332 through the birefringent crystal block 31 and One light path is consistent, and then converted into circularly polarized light by the third quarter wave plate 333, acting on the third standard The combined post-reflection of the aligning element 343 is again returned to the third quarter-wave plate 333 to be converted from linearly polarized light into linearly polarized light, and the optical path of the light propagates back and forth in this manner until the Nth birefringent crystal block 31 passes. Thereafter, the birefringent crystal block 31 is reflected back through a mirror 15, and is reflected in the opposite direction of the optical path, and the reflection is directed to the third quarter wave plate 333 and the third etalon element 343, which are reflected from the third etalon element 343. The beam again passes through the third quarter-wave plate 333, and the beam is converted into linearly polarized light and returned to the birefringent crystal block 31, and then guided to the second quarter-wave plate 332 and the second etalon 342, reflected from the second etalon 342. The light beam passes through the second quarter-wave plate 332 again, and the circularly polarized light is converted into linearly polarized light, and the returned birefringent crystal block 31 is offset by a distance and then guided to the first quarter-wave plate 331 and the first etalon element 341. The circularly polarized light returned from the first etalon element 341 is again converted into linearly polarized light through the birefringent crystal block 31 through the first quarter wave plate, and then received through the third port 3 of the optical circulator 32, from the second port. 2 output is outgoing. In this embodiment, the light beam input from the first port 1 of the optical circulator 32 passes through the birefringent crystal block, the 1/4 wave plate, and the etalon element multiple times, and is reflected by a mirror 35 to pass through the birefringence again. The crystal block, the quarter-wave plate, and the etalon element are output by the second port 2 of the optical circulator 31.

4 is a schematic structural view of a fourth embodiment of the dispersion compensator of the present invention. As shown in FIG. 4, the dispersion compensator 40 includes an optical circulator 44, two

etalon components

411, 412, and the etalon component. A birefringent crystal block 42 is disposed between 411 and 412, and a quarter-wave plate 431 is disposed between the etalon 411 and the birefringent crystal block 42. The etalon element 412 and the birefringent crystal block 42 are disposed between There is a quarter wave plate 432 and a mirror 45. The linearly polarized input beam L is transmitted through the first port 1 of the optical circulator 34 through the third port 3 into the birefringent crystal block 42 for vertical and birefringent crystal block 42 surface, and then passed through the 1/4 wave plate 431. The circularly polarized light is reflected back to the 1/4 wave plate 431 by the etalon element 411, and becomes linearly polarized light again, but is offset by a distance in different directions, and is transmitted back through the 1/4 wave plate 432. It becomes circularly polarized light, returns to the 1/4 wave plate 432 by the action of the etalon element 412, and is converted into linearly polarized light, which is transmitted through the birefringence crystal block 42 to be shifted by a distance, and the optical path is repeated in the birefringent crystal block 42. Laterally offset in position, as shown in the vertical offset of FIG. 2, the last light is reflected by the mirror 45 back between the two etalons. After repeated times, the beam is passed by the optical circulator 44. Three-port 3 reception, output by the second port.

The present invention has an advantage in that the structure is more compact and miniaturized while satisfying the bandwidth in a wider range.

The above is only the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and equivalent changes or modifications made by the scope of the present invention are covered by the present invention.

Embodiments of the invention

Industrial applicability

Sequence table free content

Claims

A dispersion compensator includes a light guiding element, two sets of polarization changing element arrays, and two sets of etalon element arrays, further comprising a mirror and an optical circulator, the polarized light beam L passing through the first port of the optical circulator The incident light is transmitted to the light guiding element via the third port, and the first polarizing changing element is incident on the first standard element, and the light reflected from the first etalon element passes through the first polarization changing element again to become the incident beam. a light beam L1 of mutually perpendicular polarization states, the light beam L1 being incident again to the light guiding element, offset by a distance leading to the second polarization changing element and the second etalon element, the light reflected from the second etalon element After the second polarization changing element is converted into a light beam L2 that is in conformity with the polarization state of the light beam L, after being guided by the light guiding element to the combination of the third polarization changing element and the third etalon element, the polarization state thereof is switched to be perpendicular to the light beam L. Light beam L3 of the polarization state, the light path of the light propagates back and forth according to this law until it passes through the light guiding element and is reflected back through the mirror The guiding element is reversely transmitted according to the optical path, and the reflection is directed to the third polarization changing element and the third etalon element. The light beam reflected from the third etalon element passes through the third polarization changing element again, and the light beam L4 is converted into the light beam L polarization. The states are perpendicular to each other, returning to the second polarization changing element and the second etalon via the light guiding element, and the light beam reflected from the second etalon is again converted by the polarization changing element and the light beam L3 of the polarization state of the light beam L is guided by the light. The element is directed to the first polarization changing element and the first etalon element, and the light beam L3 returned from the first etalon element is again converted by the first polarization changing element into a light beam L2 perpendicular to the polarization state of the beam L, and guided to the optical circulator through the light guiding element The third port receives and outputs from the second port.
The dispersion compensator according to claim 1, wherein said light guiding element is composed of a first PBS prism, a second PBS prism, a third PBS prism... an nth PBS prism, and the P-polarized beam passes through the optical circulator The first port is incident, transmitted to the first PBS prism via the third port, and is incident on the first standard element through the first polarization changing element, and the light reflected from the first etalon element changes again through the first polarization The component then becomes S-polarized light, and then is incident again on the spectroscopic surface of the first PBS prism, and the S-polarized light is reflected by the first PBS prism to the second PBS prism, and is reflected by the spectroscopic surface of the second PBS prism. Directing the second polarization changing element and the second etalon element, the light reflected from the second etalon element is switched to P-polarized light and then through the third polarization changing element and the third standard by the second polarization changing element After the combination of the components, the polarization state is switched to S-polarized light, and then the spectroscopic surface incident on the second PBS prism is reflected and guided to the third PBS prism, and the optical path of the light propagates back and forth according to this law until After being reflected by the Nth PBS prism, after being reflected by a mirror back to the Nth PBS prism, the P-polarized light reflected to the third PBS prism is reflected by the optical path in the reverse direction, and is reflected by the spectroscopic surface of the third PBS prism. Directing the third polarization changing element and the third etalon element, the light beam reflected from the third etalon element passes through the third polarization changing element again, and the light beam is converted into P-polarized light and returned to the second polarization through the second PBS prism. Changing the component and the second etalon, the light beam reflected from the second etalon is again converted into S-polarized light by the polarization changing element, returned to the second PBS prism and reflected by the spectroscopic surface to the first PBS prism to guide the first polarization Changing the element and the first etalon element, the S-polarized light returned from the first etalon element is again converted by the first polarization-changing element into P-polarized light that passes through the first PBS prism and is received through the third port of the optical circulator, Output from the second port.
The dispersion compensator of claim 1 wherein said light directing element is a birefringent prism block.
A dispersion compensator according to claim 1, wherein said polarization changing element is a quarter wave plate or a Faraday piece.
A dispersion compensator according to any one of claims 1 to 4, wherein said first etalon element, second etalon element, ... Nth etalon element are integrated into two etalon A and standard With B.
The dispersion compensator according to any one of claims 1 to 4, wherein said first polarization changing element, said second polarization changing element, said third polarization changing element, said Nth polarization changing element are integrated into polarization changes of the left and right blocks Element A and polarization changing element B.