Fiber optic cable power in repeatered systems
The optical pump unit with integrated monitoring and control components addresses the challenge of powering EDFAs in submarine repeaters, achieving significant power savings and voltage stability.
Patent Information
- Application Number
- JP2024212964
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-12-11
- Filing Date
- 2024-12-06
- Publication Date
- 2025-06-23
AI Technical Summary
Long-distance submarine optical communication systems face challenges in efficiently powering erbium-doped fiber amplifiers (EDFAs) in repeaters, leading to high power consumption and potential voltage drops.
The implementation of an optical pump unit (OPU) with a line voltage transistor, DC-DC converter, optical pump assembly, current control assembly, throttle valve back control assembly, and current/voltage sensor, which monitors and adjusts power to the OPU based on line current and voltage drops.
This solution reduces power consumption by 34% and minimizes voltage drops, ensuring stable operation of the submarine optical communication system.
Smart Images
Figure 2025093305000001_ABST
Abstract
Description
Technical Field
[0001] [Cross - Reference to Related Applications] This application claims the benefit of priority to a patent application entitled "FIBER OPTIC CABLE POWER IN REPEATERED SYSTEMS" filed on December 11, 2023, with U.S. Provisional Application No. 63 / 608519, and incorporates by reference all of its content into this application.
[0002] Embodiments of the present disclosure relate to the field of optical communication systems. More specifically, the present disclosure relates to the architecture in a submarine repeater for improving power usage in a repeatered submarine communication system.
Background Art
[0003] Long - distance optical communication systems (e.g., submarine optical communication systems) include many interconnected optical cables to facilitate the communication of data and information. For long - distance transmissions such as hundreds or thousands of kilometers, a device called a repeater is deployed in the optical communication system. Repeaters can be placed at intervals such as 50 km, 100 km, etc., and include components that amplify optical signals. Power can be supplied to optical communication components including repeaters via wires or cables, and these wires or cables can carry high - voltage DC current along the submarine communication path.
[0004] In particular, in a given repeater, an optical pump unit (OPU) is powered and amplifies the optical signals transmitted via the optical cable. The optical pump unit can control the operation of an erbium - doped fiber amplifier (EDFA), and the EDFA is used to amplify the optical signals transmitted by a given repeater. The optical pump unit includes circuits for controlling the operation of the pump lasers used in the EDFA to provide optical amplification.
[0005] Regarding the sustainability issue of optical repeaters, particularly in long-distance systems that may include dozens of repeaters spanning a cable span, it is necessary to effectively power the EDFA.
[0006] In view of the above and other considerations, the present disclosure is provided.
SUMMARY OF THE INVENTION
MEANS FOR SOLVING THE PROBLEM
[0007] In one embodiment, an optical pump unit for an optical repeater is provided. The optical pump unit may include a line voltage transistor coupled between an input side and an output side of the optical pump unit. The optical pump unit may further include a DC-DC converter having an input side coupled to the line voltage transistor, an optical pump assembly coupled to an output side of the DC-DC converter, and a current control assembly coupled to the optical pump assembly. The optical pump unit may further include a throttle valve back control assembly having an output coupled to the current control assembly, and a current / voltage sensor used to monitor a line current and a voltage drop in the optical repeater and coupled to an input of the throttle valve back control assembly. Thus, when a decrease in the line current or the voltage drop occurs, the throttle valve back control assembly may be configured to send a signal to the current control assembly to reduce the power in the optical pump assembly.
[0008] In another embodiment, a system for undersea optical communication is provided. The system includes a station that transmits an optical signal via a signal path, a plurality of optical repeaters that amplify the optical signal along the signal path, and a cable that conducts the optical signal along the signal path and conducts power to the plurality of optical repeaters. Accordingly, a predetermined optical repeater among the plurality of optical repeaters may include an erbium-doped fiber and an optical pump unit. The optical pump unit may include a line voltage transistor coupled between an input side and an output side of the optical pump unit, a DC-DC converter having an input side coupled to the line voltage transistor, and an optical pump assembly coupled to an output side of the DC-DC converter. The optical pump unit may further include a current control assembly coupled to the optical pump assembly, a throttle valve back control assembly having an output coupled to the current control assembly, and a current / voltage sensor that monitors a line current and a voltage drop of the repeater in the optical repeater and is coupled to an input of the throttle valve back control assembly. Accordingly, the throttle valve back control assembly may be configured to transmit a signal to the current control assembly to reduce the power in the optical pump assembly when a decrease in the line current or the voltage drop of the repeater occurs.
Brief Description of the Drawings
[0009]
Figure 1
Figure 2
Figure 3
Modes for Carrying Out the Invention
[0010] Now, the present embodiment will be more comprehensively described with reference to the drawings below, and exemplary embodiments are shown in the drawings. The scope of the embodiments should not be construed as being limited to the embodiments described in this specification. On the contrary, these embodiments are provided to thoroughly and completely disclose the present disclosure and to fully convey the scope of the embodiments to those skilled in the art. In the drawings, the same reference numerals always refer to the same components.
[0011] The present embodiment provides an architecture and components of a subsea communication system, and more specifically, provides an architecture of an optical pump unit of a repeater that controls the operation of an EDFA, where the EDFA is used to amplify optical signals transmitted through an optical cable of the subsea communication system.
[0012] Figure 1 shows a block diagram of a subsea optical communication system (shown as system 100) arranged according to an embodiment of the present disclosure. System 100 can be arranged for bidirectional communication and includes an onshore facility for generating and guiding optical communication signals, receiving optical communication signals, providing power to operate components of system 100 and other functions known in the art. In the illustration of FIG. 1, stations 102A and 102B are shown, and these stations can represent onshore facilities located at opposite ends of the subsea system. In some examples, system 100 can span a system length 101 of 1000 km, 5000 km, or 10000 km, or longer between station 102A and station 102B, and can be divided into a plurality of spans 120 such as span 120A, span 120B, … span 120N-1 and span 120N shown. Note that in a system having a length of 10000 km, the span length may be about 100 km, and system 100 may include dozens of spans. The link between stations 102A and 102B is spanned by an optical communication cable 140, which can conduct an optical signal transmitted from station 102A from west to east along signal path 104, where "west" and "east" are merely for representing opposite ends of system 100. Similarly, cable 140 can conduct an optical signal transmitted from station 102B from east to west along signal path 106. Although not shown individually, a plurality of optical fibers are included in cable 140 to provide a conductive path for transmitting optical signals between stations 102A and 102B. Cable 140 may include a conductor 148 (e.g., a copper wire) for powering a plurality of optical repeaters and is used to power components along system 100. The optical repeaters are represented in FIG. 1 as repeater 130A, repeater 130B, repeater 130N-1, and repeater 130N, respectively, where the total number N of repeaters may be dozens. At a given repeater, power is required to drive an optical pump unit that amplifies the optical signal conducted along system 100.The system voltage required for all components of the operating system 100 is determined mainly by the sum of the voltage drop of the cable 140 itself along the length of the cable 140 and the total voltage drop across both ends of all repeaters 130. In some examples, the system voltage may be in the range of 20 kV or more.
[0013] As further shown in FIG. 1, the optical pump unit may be included in a given repeater, where the optical pump unit (OPU) is denoted as OPU 150A, OPU 150B, OPU 150N-1, and OPU 150N, respectively. Each of these OPUs may include an optical pump (not shown individually) based on a semiconductor laser, where a given OPU provides a circuit to more effectively manage the power required to drive the optical pump and associated circuitry. In each embodiment of the present disclosure, one or more of the OPUs shown in FIG. 1 (e.g., each of the OPUs) can have an architecture according to the following embodiments, where the circuitry and components are provided to more effectively manage the power used by a given repeater.
[0014] FIG. 2 shows a block diagram of an optical pump unit arranged based on an embodiment of the present disclosure. The optical pump unit 200 or OPU 200 can be regarded as a variant of the OPU 150. The OPU 200 may include a line voltage transistor 202 coupled between the input side IN and the output side OU of the OPU 200. The line voltage transistor 202 can set the voltage drop of the OPU 200. The optical pump unit 200 may further include a DC-DC converter 204 whose input side is coupled to the line voltage transistor 202, and an optical pump assembly 208 coupled to the output side of the DC-DC converter 204. In the illustrated embodiment, the optical pump assembly 208 may include a pair of optical pumps (or two or more optical pumps in some variants) shown as optical pump 208A and optical pump 208B. The optical pump assembly 208 can provide a pair of optical pumps to provide redundancy in a given repeater. Also, the OPU 200 may include a current control assembly 210 coupled to the optical pump assembly 208. In the illustrated example, the current control assembly 210 may include current controllers 210A and 210B coupled corresponding to the optical pump 208A and the optical pump 208B. The OPU 200 may further include a throttle valve back control assembly 214 whose output is coupled to the current control assembly 210.
[0015] As further shown in FIG. 2, the OPU 200 may include a DAC 212 and a line current / voltage sensor 206. According to an embodiment of the present disclosure, the voltages of the line voltage transistor 202 and the DC-DC converter 204 are optimized to reduce the power consumption in the OPU 200, as will be described in detail below with reference to FIG. 3. Also, the circuit of the OPU 200 is arranged such that the pump power is maintained above the nominal line current. The line current / voltage sensor 206 may be arranged to monitor the line current and the voltage drop of the repeater in the optical repeater (see repeater 130), and is coupled to the input of the throttle valve back control assembly 214, where the throttle valve back control assembly 214 is configured to send a signal to the current control assembly 210 to reduce the power of the optical pump assembly 208 when a decrease in the line current occurs. Therefore, when the line current or the voltage of the repeater decreases, the power is throttled backward to prevent voltage collapse of the OPU 200.
[0016] FIG. 3 shows a schematic circuit arrangement of an optical pump unit 200A arranged according to an embodiment of the present disclosure. The OPU 200A can be regarded as a variant of the above OPU 200. The line voltage transistor 202 is implemented as a field effect transistor, and each of the optical pumps 208A and 208B is implemented as a pair of laser diodes providing a bidirectional optical pump and is used to amplify the signal transmitted through the signal path 104 or the signal path 106.
[0017] The current control assembly 210 in this embodiment is formed by a pair of current control transistors denoted as Q3 and Q4, where the first current control transistor (Q3) is connected to the first optical pump (optical pump 208A) of the optical pump assembly 208, and the second current control transistor (Q4) is individually connected to the second optical pump (optical pump 208B) of the optical pump assembly 208. The throttle valve back control assembly 214 of the optical pump unit 150A may include a pair of comparison circuits, where the first comparison circuit (U6 and U7) is connected to the first current control transistor (Q3), and the second comparison circuit (U8 and U9) is individually connected to the second current control transistor (Q4).
[0018] As further shown in FIG. 3, the optical pump unit 200A may include a surge voltage diode 220 coupled between the input side and the output side of the optical repeater including the OPU 200A. The optical pump unit 200A may further include a shunt voltage circuit 222 coupled between the input side and the output side of the optical repeater.
[0019] Some of the overall advantages of the above embodiments are to provide the possibility of adjusting the voltage drop. It should be noted that submarine optical communication can usually be designed to adapt to the optical fiber pair in the worst case where the total system voltage in the system becomes excessive. By installing the line voltage transistor 202, the voltage drop of the repeater is much smaller than that of the prior art system, and a large amount of power can be potentially saved. Experimental data
[0020] A simulation of a submarine optical communication system was performed on a cable with a length of 10,000 km. The cable had 144 bidirectional repeaters to determine the values of each operating parameter. In a known system with repeaters having known OPUs, the simulated nominal line current value was 0.783 A, the voltage drop of the repeater was 60.8 V, the total system voltage was 20.5 kV, and the total system power was 16.0 kW. In the system with one set of OPUs arranged in this embodiment, the nominal line current was 0.625, the average voltage drop of the repeater was 51.1 V, the total system voltage was 17.0 kV, and the total system power was 10.6 kW. Therefore, in one non-limiting example, the system having OPUs 150 and 200 may require a lower system voltage and was able to save 34% of the power.
[0021] The scope of the present disclosure is not limited by the specific examples described herein. In fact, in addition to what is described herein, various other examples and improvements of the present disclosure will be apparent to those skilled in the art from the above description and drawings. Therefore, these other examples and improvements are intended to be included within the scope of the present disclosure. Also, although this specification has described the present disclosure in the context of specific embodiments, since it is used for specific purposes in a specific environment, those skilled in the art will recognize that its usefulness is not limited thereto and that the present disclosure can be advantageously implemented for any number of purposes in any number of environments. Therefore, the claims described below should be construed based on the entire scope, breadth, and spirit of the present disclosure described herein.
Claims
1. 1. An optical pump unit for an optical repeater, comprising: a line voltage transistor coupled between an input and an output of the optical pump unit; a DC-DC converter having an input coupled to the line voltage transistor; an optical pump assembly coupled to an output of the DC-DC converter; a current control assembly coupled to the optical pump assembly; a throttle back control assembly having an output coupled to the current control assembly; a current / voltage sensor coupled to an input of the throttle valve back control assembly for monitoring line current and voltage drop in the optical repeater; the throttle back control assembly is configured to send a signal to the current control assembly to reduce power at the optical pump assembly when a drop in line current or voltage occurs; Optical pump unit for optical repeater.
2. the optical pump assembly includes at least two optical pumps, each of the at least two optical pumps being configured as a bidirectional optical pump; 2. An optical pump unit for an optical repeater according to claim 1.
3. the current control assembly includes a pair of current control transistors, a first current control transistor coupled to a first optical pump of the optical pump assembly and a second current control transistor coupled to a second optical pump of the optical pump assembly, 3. An optical pump unit for an optical repeater according to claim 2.
4. the throttle valve back control assembly includes a pair of comparator circuits, a first comparator circuit coupled to the first current control transistor and a second comparator circuit coupled to the second current control transistor, 4. An optical pump unit for an optical repeater according to claim 3.
5. a surge voltage diode coupled between the input and output of the optical repeater; 5. An optical pump unit for an optical repeater according to claim 1.
6. a shunt voltage circuit coupled between the input and output of the optical repeater; 5. An optical pump unit for an optical repeater according to claim 1.
7. a station for transmitting an optical signal in a signal path; a plurality of optical repeaters for amplifying the optical signal along the signal path; a cable used to conduct the optical signal along the signal path, the cable including a conductor that conducts power to the plurality of optical repeaters, A predetermined optical repeater among the plurality of optical repeaters is an erbium-doped fiber; an optical pump unit; The optical pump unit comprises: a line voltage transistor coupled between an input and an output of the optical pump unit; a DC-DC converter having an input coupled to the line voltage transistor; an optical pump assembly coupled to an output of the DC-DC converter; a current control assembly coupled to the optical pump assembly; a throttle back control assembly having an output coupled to the current control assembly; a current / voltage sensor coupled to an input of the throttle valve back control assembly for monitoring line current and repeater voltage drop in the optical repeater; the throttle valve back control assembly is configured to send a signal to the current control assembly to reduce power at the optical pump assembly when a drop in line current or repeater voltage drop occurs; A system for undersea optical communications.
8. the optical pump assembly includes a pair of optical pumps, each of the pair of optical pumps being configured as a bidirectional optical pump; A system for undersea optical communications according to claim 7.
9. the current control assembly includes a pair of current control transistors, a first current control transistor coupled to a first optical pump of the optical pump assembly and a second current control transistor coupled to a second optical pump of the optical pump assembly, A system for undersea optical communications according to claim 8.
10. the throttle valve back control assembly includes a pair of comparator circuits, a first comparator circuit coupled to the first current control transistor and a second comparator circuit coupled to the second current control transistor, A system for undersea optical communications according to claim 9.
11. a surge voltage diode coupled between the input and output of the optical repeater; A system for undersea optical communication according to any one of claims 7 to 10.
12. and further comprising a shunt voltage circuit coupled between the input and output of the given optical repeater. A system for undersea optical communication according to any one of claims 7 to 10.