An optical module for 5G fronthaul

Abstract

The present invention relates to the field of optical communication technology, and in particular to an optical module for 5G fronthaul. The optical module includes at least one pair of mutually coordinated single-fiber bidirectional optical components, the single-fiber bidirectional optical components include an optical transmitter, an optical receiver and a coordination unit, the coordination unit includes an etalon, a beam splitter and a collimating lens, the collimating lens is used to inject the light transmitted from the beam splitter into another single-fiber bidirectional optical component, and the collimating lens transmits the transmitted light emitted from another single-fiber bidirectional optical component, wherein the etalon includes two mutually parallel first and second film layers, the first and second film layers are used to transmit the light emitted by the optical transmitter to the beam splitter, and the second film layer is also used to reflect the transmitted light emitted from another single-fiber bidirectional optical component to the optical receiver, the etalon achieves precise wave locking through the two film layers, that is, transmits and reflects two different wavelengths of light respectively, and the interval between the two wavelengths is 1nm, so that the optical module achieves a small interval between the receiving and emitting wavelengths.

Description

Technical Field

[0001] The present invention relates to the field of optical communication technology, and in particular to an optical module for 5G fronthaul. Background Art

[0002] BIDI (Bidirectional) optical module is a single-fiber bidirectional optical module. It uses WDM technology to transmit and receive center wavelengths in two different directions to achieve bidirectional transmission of optical signals on one optical fiber. Traditional optical modules generally have two ports: a transmitting port (TX) and a receiving port (RX), while BIDI optical modules have only one port, which can be filtered by the filter in the optical module to simultaneously transmit one wavelength optical signal and receive another wavelength optical signal. Therefore, BIDI optical modules must be used in pairs. Compared with dual-fiber bidirectional modules, the most obvious advantage of BIDI optical modules is that they can reduce the number of ports on the fiber jumper panel, save the cost of fiber wiring infrastructure, reduce wiring space, facilitate fiber management, and reduce the number of optical fibers required.

[0003] In order to work efficiently, BIDI optical modules must be used in pairs, and bidirectional data transmission can be achieved by tuning the duplexer to match the desired wavelengths of the transmitter and receiver. For example, for two paired BIDI optical modules, the duplexer of optical module A must have a receiving wavelength of 1550nm and an emitting wavelength of 1310nm. The duplexer of optical module B must have a receiving wavelength of 1310nm and an emitting wavelength of 1550nm. Currently, the commonly used wavelengths of BIDI optical modules are 1310nm / 1550nm; 1310nm / 1490nm; 1510nm / 1590nm.

[0004] For 5G fronthaul applications, China Mobile proposed the MWDM solution. Based on the reuse of the first 6 wavelengths of 25G CWDM, the wavelength is shifted left and right by 3.5nm through temperature control to form 12 wavelengths. Since the wavelength intervals of these 12 waves are small, the commonly used BIDI optical modules on the market can no longer meet the requirements. Therefore, this application provides a new type of 25G adjustable BIDI optical module assembly for 5G fronthaul. Summary of the invention

[0005] The object of the present invention is to provide an optical module for 5G fronthaul, which has a small interval between receiving and emitting wavelengths.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] An optical module for 5G fronthaul, comprising at least one pair of single-fiber bidirectional optical components cooperating with each other, wherein the single-fiber bidirectional optical components comprise an optical transmitter, an optical receiver and a coordination unit, wherein the optical receiver is arranged on one side of the light output axis of the optical transmitter;

[0008] The coordination unit includes an etalon, a beam splitter and a collimating lens, the etalon includes a first film layer and a second film layer, the first film layer and the second film layer are arranged in parallel, the first film layer and the second film layer are used to transmit the light emitted by the optical transmitter to the beam splitter, and the second film layer is used to reflect the transmitted light emitted from another single-fiber bidirectional optical component to the optical receiver;

[0009] The collimating lens is used to convert the light transmitted from the beam splitter into parallel light and then inject it into another single-fiber bidirectional optical component, and is also used to transmit the transmitted light emitted from another single-fiber bidirectional optical component;

[0010] The beam splitter is used to direct the light transmitted from the collimating lens onto the etalon.

[0011] Preferably, the coordination unit further comprises a total reflection filter, and the total reflection filter is used for further vertically reflecting the light reflected by the second film layer into the light receiver.

[0012] Preferably, the beam splitter is V-shaped, and comprises a first coating surface and a second coating surface, wherein the first coating surface and the second coating surface intersect on a line.

[0013] Preferably, the coordination unit further includes a first side light-receiving detector, which is disposed below the first coating surface and is used for receiving reflected light from the first coating surface and monitoring the light output power of the light emitter according to the reflected light.

[0014] Preferably, the coordination unit also includes a second side light receiving detector, which is arranged below the second coated surface, and is used to receive reflected light from the second coated surface and monitor the output light power of another single-fiber bidirectional optical component based on the reflected light.

[0015] Preferably, the etalon is inclined at 5°-85° relative to the light output axis of the light emitter.

[0016] Preferably, the optical receiver comprises a tube cap, a base, a third etalon and a photodetector, and the tube cap is arranged on the base to form a receiving space for placing the third etalon and the photodetector;

[0017] The centers of the tube cap, the third etalon and the photodetector all coincide with the optical axis.

[0018] Preferably, the receiver further comprises a transimpedance amplifier, the transimpedance amplifier is electrically connected to the photodetector, and the transimpedance amplifier is used to convert the photocurrent signal into a voltage signal.

[0019] Preferably, the receiver further comprises a filter capacitor, and the filter capacitor is electrically connected to the transimpedance amplifier.

[0020] Preferably, it further comprises a shell, and the single-fiber bidirectional optical component is arranged in a accommodating cavity of the shell.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The optical module for 5G fronthaul of the present application includes at least one pair of single-fiber bidirectional optical components that cooperate with each other, and the single-fiber bidirectional optical component includes an optical transmitter, an optical receiver and a coordination unit. The coordination unit includes an etalon, a beam splitter and a collimating lens, wherein the etalon includes two mutually parallel first and second film layers, the first film layer and the second film layer are used to transmit the light emitted by the optical transmitter to the beam splitter, the horizontal light of a preset wavelength emitted by the optical transmitter passes through the first film layer, the second film layer, the beam splitter, and the collimating lens in sequence and is emitted to another single-fiber bidirectional optical component that cooperates with each other; the light of another preset wavelength emitted by the other single-fiber bidirectional optical component passes through the collimating lens and the beam splitter in sequence, and continues to be transmitted to the surface of the second film layer, the second film layer is used to reflect the transmitted light emitted from the other single-fiber bidirectional optical component to the optical receiver, the etalon achieves precise wave locking through the two film layers, that is, transmits and reflects two different wavelengths of light respectively, and the interval between the two wavelengths is small, thereby the optical module achieves a small interval between the receiving and emitting wavelengths. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0024] Figure 1 A schematic diagram of the structure of a single-fiber bidirectional optical component provided in an embodiment of the present invention;

[0025] Figure 2 A schematic diagram of the working principle of the optical module provided in an embodiment of the present invention;

[0026] Figure 3 A schematic diagram of the structure of an optical receiver provided in an embodiment of the present invention.

[0027] Illustration: optical transmitter 1, optical receiver 2, coordination unit 3, first optical transmitter 4, first optical receiver 5, first coordination unit 6;

[0028] Cap 21, base 22, filter capacitor 23, photodetector 24, transimpedance amplifier 25, third etalon 26;

[0029] Etalon 31, beam splitter 32, collimating lens 33, total reflection filter 34, first side light receiving detector 35, second side light receiving detector 36;

[0030] The first etalon 61, the first beam splitter 62, and the first collimating lens 63 DETAILED DESCRIPTION

[0031] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] In the description of the present invention, it is to be understood that when a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a centrally disposed component. When a component is considered to be "disposed on" another component, it may be directly disposed on the other component or there may be a centrally disposed component.

[0033] In addition, terms such as "long", "short", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only used to facilitate the description of the present invention. They do not indicate or imply that the device or component referred to must have this specific direction or operate with a specific direction structure, and should not be understood as a limitation of the present invention.

[0034] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0035] See also Figures 1 to 3 , an optical module for 5G fronthaul includes at least one pair of single-fiber bidirectional optical components that cooperate with each other, the single-fiber bidirectional optical component includes an optical transmitter 1, an optical receiver 2 and a coordination unit 3, and the optical receiver 2 is arranged on one side of the optical output axis of the optical transmitter 1;

[0036] The coordination unit 3 includes an etalon 31, a beam splitter 32 and a collimating lens 33. The etalon 31 is used to transmit the light emitted by the optical transmitter 1 to the beam splitter 32, and the etalon 31 is used to reflect the transmitted light emitted from another single-fiber bidirectional optical component to the optical receiver 2, wherein the etalon 31 is also called Etalon;

[0037] The collimating lens 33 is used to convert the light transmitted from the beam splitter 32 into parallel light and then inject it into another single-fiber bidirectional optical component. The collimating lens 33 is also used to transmit the transmitted light emitted from another single-fiber bidirectional optical component.

[0038] Specifically, the horizontal light of a preset wavelength emitted by the optical transmitter 1 first passes through the etalon 31, and then passes through the beam splitter 32 and the collimating lens 33 in sequence to be emitted into another single-fiber bidirectional optical component that cooperates with each other. The light of another preset wavelength emitted by the other single-fiber bidirectional optical component passes through the collimating lens 33 and the beam splitter 32 in sequence, and continues to be transmitted to the surface of the etalon 31, and the etalon 31 reflects the light of another preset wavelength to the optical receiver 2. Among them, the etalon 31 includes a first film layer and a second film layer, and the first film layer and the second film layer are arranged in parallel. The first film layer and the second film layer transmit the light emitted by the optical transmitter 1 to the beam splitter 32. In addition, the second film layer reflects the transmitted light emitted from the other single-fiber bidirectional optical component to the optical receiver 2. The etalon 31 realizes precise wave locking through the two film layers, that is, transmits and reflects two different wavelengths of light respectively, and the interval between the two wavelengths is small, so that the optical module realizes a small interval between the receiving and emitting wavelengths.

[0039] Further, combined with the Figure 2 The technical solution of the present invention is described in detail. The optical module for 5G fronthaul includes a first single-fiber bidirectional optical component and a second single-fiber bidirectional optical component, the first single-fiber bidirectional optical component includes a first optical transmitter 4, a first optical receiver 5 and a first coordination unit 6, the first coordination unit 6 includes a first standard tool 61, a first beam splitter 62 and a first collimating lens 63; the second single-fiber bidirectional optical component includes an optical transmitter 1, an optical receiver 2 and a coordination unit 3, the optical receiver 2 is arranged above the coordination unit 3, and the coordination unit 3 includes an standard tool 31, a beam splitter 32 and a collimating lens 33.

[0040] The optical transmitter 1 of the second single-fiber bidirectional optical component emits a horizontal light of 1268.63 nm, which is incident on the first single-fiber bidirectional optical component after passing through the etalon 31, the beam splitter 32 and the collimating lens 33 in sequence, and then passes through the first collimating lens 63 and the first beam splitter 62 in sequence, and then continues to be transmitted to the first etalon 61. The film layer of the first etalon 61 that first contacts the light feeds back the 1268.63 nm light to the first optical receiver 5. The first optical transmitter 4 of the first single-fiber bidirectional optical component emits a horizontal light of 1269.63 nm, which is incident on the second single-fiber bidirectional optical component after passing through the first etalon 61, the first beam splitter 62 and the first collimating lens 63 in sequence, and then passes through the collimating lens 33 and the beam splitter 32 in sequence, and then continues to be transmitted to the second film layer of the etalon 31. The second film layer reflects the 1269.63 nm light to the optical receiver 2. The MWDM solution for 5G fronthaul proposed by China Mobile has a total of 12 wavelengths, that is, 12 pairs of matching adjustable single-fiber bidirectional optical module components are required. This embodiment takes the wavelength combination 1268.63nm / 1269.63nm as an example, and the remaining 11 pairs of combinations can be analogized. In this application, the standard tool 31 can change the wavelength of projection and reflection by heating the electrode, so it is compatible with the 1260-1370nm band. In addition, the optical module for 5G fronthaul also includes a shell, and the single-fiber bidirectional optical component is arranged in the accommodating cavity of the shell.

[0041] In an optional embodiment, the coordination unit 3 further includes a total reflection filter 34 , which is disposed on one side of the light output axis and is used to further vertically reflect the light reflected by the second film layer into the light receiver 2 .

[0042] In an optional embodiment, the beam splitter 32 is V-shaped, and the beam splitter 32 includes a first coating surface and a second coating surface, and the first coating surface and the second coating surface intersect on a line.

[0043] In order to monitor whether the optical transmitter 1 is abnormal in a more timely manner, the coordination unit 3 optionally further includes a first side light-receiving detector 35, which is arranged below the first coating surface, and the first side light-receiving detector 35 monitors the optical power of the optical transmitter 1. Specifically, 95% of the emitted light with a wavelength of 1268.63nm passes through the first coating surface, and 5% is reflected to the first side light-receiving detector 35. Optionally, 5% of the emitted light can be vertically incident to the first side light-receiving detector 35. The first side light-receiving detector 35 monitors the wavelength of the emitted light. Once the wavelength drift through the standard tool 31 is large, the response optical power obtained by the first side light-receiving detector 35 is smaller. The first side light-receiving detector 35 will feed back this information to the optical transmitter 1. The optical transmitter 1 includes a semiconductor refrigerator, which controls the temperature of the chip surface, thereby changing the wavelength of the emitted light.

[0044] In an optional embodiment, the coordination unit 3 further includes a second side light receiving detector 36, which is disposed below the second coating surface, and is used to monitor the optical power of another single-fiber bidirectional optical component. Specifically, 95% of the light of the wavelength 1269.63nm of another single-fiber bidirectional optical component that cooperates with each other passes through the second coating surface, and 5% is reflected to the second side light receiving detector 36, and the second side light receiving detector 36 feeds back the measured data to the optical transmitter 1 of the other single-fiber bidirectional optical component.

[0045] In an optional embodiment, the etalon 31 is tilted 5°-85° relative to the light output axis of the light emitter 1, and the energy consumption required for the operation of the etalon 31 is relatively small. Preferably, the etalon 31 is tilted 8°-50° relative to the light output axis of the light emitter 1.

[0046] In an optional embodiment, the optical receiver 2 includes a tube cap 21, a base 22, a third standard tool 26 and a photodetector 24. The tube cap 21 is covered on the base 22 to form a receiving space for placing the third standard tool 26 and the photodetector 24. The centers of the tube cap 21, the third standard tool 26 and the photodetector 24 coincide with the optical axis.

[0047] Optionally, the receiver 2 further includes a transimpedance amplifier 25 , which is electrically connected to the photodetector 24 , and is used to convert the photocurrent signal into a voltage signal.

[0048] In an optional implementation, the receiver 2 further includes a filter capacitor 23 , which is electrically connected to the transimpedance amplifier 25 . The filter capacitor 23 filters out clutter, thereby improving the receiver 2 's ability to resist crosstalk and electromagnetic interference.

[0049] In summary, the optical module of this embodiment is described by taking a pair of mutually cooperating single-fiber bidirectional optical components as an example. The single-fiber bidirectional optical component includes an optical transmitter 1, an optical receiver 2 and a coordination unit 3. The coordination unit 3 includes an etalon 31, a beam splitter 32 and a collimating lens 33 arranged in sequence in the direction of the light output axis. The etalon 31 is used to transmit the light emitted by the optical transmitter 1 to the beam splitter 32 and the collimating lens 33, and the etalon 31 is used to reflect the transmitted light emitted from another single-fiber bidirectional optical component to the optical receiver 2. The etalon 31 realizes precise wave locking through two film layers, that is, transmits and reflects two different wavelengths of light respectively, and the interval between the two wavelengths is small, so that the optical module realizes a small interval between the receiving and emitting wavelengths. The receiving and emitting intervals of this embodiment are only 1nm, and the etalon 31 transmits a wavelength of 1268.63nm and reflects a wavelength of 1269.63nm.

[0050] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An optical module for 5G fronthaul, characterized in that: The invention comprises at least one pair of mutually cooperating single-fiber bidirectional optical components, wherein the single-fiber bidirectional optical components comprise an optical transmitter (1), an optical receiver (2) and a coordination unit (3), wherein the optical receiver (2) is arranged on one side of the optical output axis of the optical transmitter (1); The coordination unit (3) comprises an etalon (31), a beam splitter (32) and a collimating lens (33), wherein the etalon (31) comprises a first film layer and a second film layer, wherein the first film layer and the second film layer are arranged in parallel, and the first film layer and the second film layer are used to transmit light emitted by the optical transmitter (1) to the beam splitter (32), and the second film layer is also used to reflect the transmitted light emitted from another single-fiber bidirectional optical component to the optical receiver (2); The collimating lens (33) is used to convert the light transmitted from the beam splitter (32) into parallel light and then inject it into another single-fiber bidirectional optical component, and is also used to transmit the transmitted light emitted from another single-fiber bidirectional optical component; The beam splitter (32) is used to direct the light transmitted from the collimating lens (33) onto the etalon (31); The beam splitter (32) is V-shaped, and comprises a first coating surface and a second coating surface, wherein the first coating surface and the second coating surface intersect on a line; The optical module also includes a shell, and the single-fiber bidirectional optical component is arranged in a receiving cavity of the shell.

2. The optical module for 5G fronthaul according to claim 1, characterized in that: The coordination unit (3) further comprises a total reflection filter (34), and the total reflection filter (34) is used to further vertically reflect the light reflected by the second film layer into the light receiver (2).

3. The optical module for 5G fronthaul according to claim 1, characterized in that: The coordination unit (3) further comprises a first side light receiving detector (35), which is arranged below the first coating surface, and is used to receive reflected light from the first coating surface and monitor the light output power of the light transmitter (1) based on the reflected light.

4. The optical module for 5G fronthaul according to claim 3, characterized in that: The coordination unit (3) also includes a second side light receiving detector (36), which is arranged below the second coated surface, and the second side light receiving detector (36) is used to receive reflected light from the second coated surface and monitor the output light power of another single-fiber bidirectional optical component based on the reflected light.

5. The optical module for 5G fronthaul according to claim 1, characterized in that: The etalon (31) is inclined at 5°-85° relative to the light output axis of the light emitter (1).

6. The optical module for 5G fronthaul according to claim 1, characterized in that: The optical receiver (2) comprises a tube cap (21), a base (22), a third etalon (26) and a photodetector (24), wherein the tube cap (21) is covered on the base (22) to form a receiving space for accommodating the third etalon (62) and the photodetector (24); The centers of the tube cap (21), the third etalon (26) and the photoelectric detector (24) all coincide with the optical axis.

7. The optical module for 5G fronthaul according to claim 6, characterized in that: The receiver (2) further comprises a transimpedance amplifier (25), wherein the transimpedance amplifier (25) is electrically connected to the photodetector (24), and the transimpedance amplifier (25) is used to convert the photocurrent signal into a voltage signal.

8. The optical module for 5G fronthaul according to claim 7, characterized in that: The receiver (2) further comprises a filter capacitor (23), wherein the filter capacitor (23) is electrically connected to the transimpedance amplifier (25).

Images