KR20080030356A - Passive amplifying optical-circuit and bi-directional amplifying optical communicating system comprising the same optical-circuit - Google Patents

Abstract

A passive optical amplifying circuit and a bidirectional optical amplifying optical communication system including the same are provided to amplify a downlink signal or the downlink signal and an uplink signal optically without additional power supply, thereby realizing a miniaturized PON(Passive Optical Network) system by being integrated together with an optical distributor in a miniaturizing way. A first WDM(Wavelength Division Multiplexing) coupler(110) separates an uplink signal of second wavelength from an OLT(Optical Line Terminal) transceiving end signal consisting of a downlink signal of first wavelength and a pumping signal of third wavelength for amplifying the downlink signal. A partial WDM coupler(120) inputs the OLT transceiving end signal to divide the pumping signal into the same wavelength of the first and second pumping signals. An amplifying medium(130) inputs the first pumping signal and the downlink signal, and inputs the second pumping signal to amplify the downlink signal. A second WDM coupler(140) multiplexes the amplified downlink signal and the uplink signal.

Description

Passive amplifying optical-circuit and bi-directional amplifying optical communicating system comprising the same optical-circuit

1 is a structural diagram schematically showing a structure of a conventional general passive optical subscriber network (PON).

2 is a structural diagram schematically showing a structure of a bidirectional optically amplified PON according to an embodiment of the present invention.

3 is a block diagram illustrating in detail a passive optical amplification optical circuit used in the PON of FIG.

4 is a block diagram illustrating an OLT of a PON in detail using the passive optical amplification optical circuit of FIG. 3.

FIG. 5 is a detailed block diagram illustrating a passive optical amplification optical circuit used in the PON of FIG. 2 according to another embodiment of the present invention.

Description of the main parts of the drawing

100: unidirectional passive optical amplification optical circuit 101,501: OLT single waveguide

102,502: ONU / ONT single waveguide

110,140,150,510,526,546,550: WDM 120,522,542: Partial WDM

130,524,544: optical amplification medium 150: optical splitter

200: OLT 201,250,450: optical fiber

210: flat panel optical circuit board 220: transmitter

222: disconnect device 230: pump LD

240: optical amplification receiver 242: receiver

244: VCSOA 300: ONU / ONT

400: optical splitter 500: bidirectional passive optical amplification optical circuit

520: upward optical amplification optical circuit 540: downward optical amplification optical circuit

The present invention relates to an optical communication network technology having a single fiber bidirectional optical transmission / reception structure including a subscriber network having a PON structure.

In order to expand and spread the Passive Optical Network (PON), it is required to provide a high level of service and maintain a certain level of service price. In particular, the next-generation subscriber network requires a high optical output specification with a larger number of branches in order to economically implement a high-speed, high-capacity subscriber network for implementing a converged convergence service including a high quality image. Conventional optical amplification technologies, such as erbium-doped fiber amplifiers (SEFAs) and semiconductor optical amplifiers (SOA), can provide sufficient technical specifications to meet these requirements. However, no optical transmission / reception means have been developed that can provide high output and high reception sensitivity.

For example, the PON subscriber network does not have optical amplification means in the optical splitter, and if necessary, an independent active optical amplifier that requires power supply to the optical splitter has to be added. In addition, in the past, there was no means for performing optical amplification bidirectionally in a bidirectional transmission / reception module that can be configured as a small single-circuit. Simultaneous assembly and use on the substrate requires precise flip-chip bonding and soldering techniques and effectively controls crosstalk between heating and signals when simultaneously integrating transceivers and optical amplifiers. There was a limit.

FIG. 1 is a schematic view illustrating a structure of a conventional general PON, and illustrates a structure of a conventional time division multiplexing (TDM) -PON for bidirectional transmission and reception without including a separate wavelength for a video overlay. .

Referring to FIG. 1, the optical splitter 20 branches a continuous mode downlink signal from an OLT (10, optical line terminal) and transmits the signal to an ONU / ONT (30, Optical Network Unit or Terminal). A burst mode uplink signal from the ONU / ONT 30 is multiplexed by the TDM scheme and transmitted to the OLT 10. On the other hand, the transmission of these downward and upward signals is made in both directions through the optical fibers (15, 25).

At this time, the sum of the light intensities of the input terminal and the output terminal of the optical splitter 20 maintains a similar level except for the intermediate loss. In order to compensate for the distribution loss when increasing the optical split number (1 xn) in the PON configuration, an optical amplifier is used at the input / output terminal of the OLT system or an optical amplifier is required to supply power to a specific position of the optical fiber. It is necessary. In the former case, in order to implement an integrated optical transmission / reception module capable of bidirectional optical amplification, a relatively large form is required, or a very high level of optical device assembly technology is required for a small size. In the latter case, since a separate power supply system is required, there is a difficulty in configuring and operating a subscriber network.

Accordingly, the technical problem to be achieved by the present invention is a bidirectional including a passive optical amplification optical circuit capable of effectively bidirectional optical amplification without the need for a power supply, and an optical splitter device manufactured in a compact single-thin form using the optical amplification optical circuit. An optical amplification PON system is provided.

In order to achieve the above technical problem, the present invention provides an OLT transceiver end signal and a second signal consisting of a downlink signal having a first wavelength λ ₁ and a pumping signal having a third wavelength λ ₃ for amplifying the downlink signal. A first wavelength division multiplexer (WDM) for separating an uplink signal of wavelength lambda ₂ ; A partial WDM receiving the OLT transceiver signal and dividing the pumping signal into first and second pumping signals having the same wavelength; An amplifying medium for receiving a downlink signal and a first pumping signal from the partial WDM through an input terminal, and receiving the second pumping signal through an output terminal to amplify the downlink signal; And a second WDM for multiplexing the amplified downlink signal and the uplink signal.

In the present invention, the passive optical amplification optical circuit receives the second pumping signal between the optical amplification medium and the second WDM input to the output terminal of the optical amplification medium and receives the amplified downlink signal It may include a third WDM input to the 2 WDM.

In order to achieve the above technical problem, the present invention also provides an OLT transceiver signal comprising a downlink signal of a first wavelength λ ₁ and a pumping signal of a third wavelength λ ₃ for amplifying the downlink signal. A first WDM for separating an uplink signal having two wavelengths λ ₂ and dividing the pumping signal into first and second pumping signals; A downlink optical amplification optical circuit for amplifying the downlink signal using the first pumping signal; An uplink optical amplification optical circuit for amplifying the uplink signal using the second pumping signal; And a second WDM for multiplexing the amplified downlink signal and the uplink signal.

In an embodiment, the downlink optical amplification optical circuit may include: a first partial WDM configured to receive the downlink signal and the first pumping signal and divide the first pumping signal into third and fourth pumping signals; And a downlink optical amplifying medium receiving the downlink signal and the third pumping signal from the first partial WDM through an input terminal, and receiving the fourth pumping signal through an output terminal to amplify the downlink signal. The uplink optical amplification optical circuit may include: a second partial WDM configured to receive the second pumping signal and divide the second pumping signal into fifth and sixth pumping signals; And an uplink optical amplification medium configured to receive a fifth pumping signal from the second partial WDM through an output terminal and to receive the uplink signal and the sixth pumping signal to an input terminal and amplify the uplink signal.

The downlink optical amplification optical circuit may receive the fourth pumping signal between the downlink optical amplification medium and the second WDM, input the output signal of the downlink optical amplification medium, and receive the amplified downlink signal to receive the second WDM. And a third WDM for inputting the signal, wherein the uplink optical amplification optical circuit inputs the uplink signal and the sixth pumping signal between the uplink optical amplifier and the second WDM to an input terminal of the uplink optical amplifier. And a fourth WDM configured to multiplex the uplink signal amplified by the uplink optical amplification medium with the second pumping signal to output the first WDM to the first WDM. Can function.

The optical amplification medium is Erbium-Er doped optical waveguide (Erbium-doped Waveguide (EDW), Praseodymium (Pr) doped optical waveguide (PDW) and Thulium (Tm) doped optical waveguide (TDW) ), And the third wavelength may be selectively determined according to a material constituting the optical amplification medium.

Meanwhile, the first and second pumping signals may have the same light intensity, and the third to sixth pumping signals may have the same light intensity.

The passive optical amplification optical circuit may be used in an optical splitter device of a passive optical network (PON), and the passive optical amplification optical circuit is an OLT transceiver of the PON in front of the optical splitter. The first WDM may be connected to the OLT, and the second WDM may be connected to the optical splitter. Meanwhile, when the passive optical amplification optical circuit is an optical amplification optical circuit including only one partial WDM, that is, a unidirectional optical amplification optical circuit, the OLT of the PON may include an amplifier for up-signal amplification.

Furthermore, in order to achieve the above technical problem, the present invention transmits an OLT transceiver end signal including a downlink signal of a first wavelength λ ₁ and a pumping signal of a third wavelength λ ₃ and transmits a second wavelength λ ₂ . OLT transceiver for receiving an uplink signal of the; An optical splitter including a passive optical amplification optical circuit according to claim 1 or 3 for amplifying a downlink signal, or a downlink signal and an uplink signal, and an optical splitter for optically distributing a downlink signal from the passive optical amplification optical circuit; And an ONU / OLT transceiver for transmitting the uplink signal and receiving the downlink signal.

In the present invention, the optical communication system is a PON system, and the optical amplification optical circuit can be integrated with the optical splitter in front of the optical splitter.

The OLT transceiver may further include a flat panel optical circuit board including a WDM for branching or combining an uplink signal and a downlink signal, and determining an optical coupling direction with a light source; A transmitter unit having a transmitter for generating the downlink signal; A pump laser diode (LD) unit configured to generate the pumping signal; And a receiver having a receiver for receiving the uplink signal. It may include.

Meanwhile, the transmitter unit may include an isolator for preventing the downlink signal from being reflected to the transmitter and the receiver includes a photo-diode (PD) and a trans-impedance amplifier (TIA). Or it may consist of avalanche photo-diode (APD) and TIA. In addition, when the optical amplification optical circuit is a unidirectional optical amplification optical circuit, the receiver unit may include a surface-emitting vertical-cavity SOA (VCSOA).

The passive optical amplification optical circuit of the present invention can optically amplify a downlink signal, a downlink signal and a downlink signal without additional power supply, and can also be manufactured with an optical splitter in a small size to implement a small size PON system. The compact PON system of the present invention implemented as described above enables to implement a reliable optical communication system while solving the electrical and optical crosstalk noise and heat generation problems that occur incidentally in the conventional optical reception module fabrication.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention; In the following description, when a component is described as being on top of another component, it may be directly on top of another component, and a third component may be interposed therebetween. In addition, in the drawings, the thickness or size of each component is omitted or exaggerated for convenience and clarity of description, and the same reference numerals in the drawings refer to the same element. On the other hand, the terms used are used only for the purpose of illustrating the present invention, but are not used to limit the scope of the invention described in the meaning limitation or claims.

2 is a structural diagram schematically showing a structure of a bidirectional optically amplified PON system according to an embodiment of the present invention.

Referring to FIG. 2, the bidirectional optical amplification PON system of the present invention includes an OLT transceiver (200, OLT), an optical splitter (400), and an ONU / OLT transceiver (300, Optical Network Unit or Terminal: ONU / ONT). Include. The OLT transceiver 200 transmits an OLT transceiver signal consisting of a downlink signal of a first wavelength λ ₁ and a pumping signal of a third wavelength λ ₃ and receives an uplink signal of a second wavelength λ ₂ . . The optical splitter 400 divides the downlink signal or the downlink signals of the passive optical amplification optical circuit 100 and the passive optical amplification optical circuit 100 into a 1: N optical amplifier. 150). On the other hand, the ONU / OLT transceiver 300 transmits an uplink signal and receives a downlink signal.

The downlink signal, the pump signal, and the uplink signal are transmitted between the OLT 200 and the optical splitter 400 through the first optical fiber 250 and between the optical splitter 400 and the ONU / ONT 300. The downlink signal and the uplink signal are transmitted through the optical fiber 450.

Referring to the configuration and operation method of the PON including the passive optical amplification optical circuit 100 provided in this embodiment briefly, in the PON system for bidirectional optical transmission and reception optical amplification, the optical amplification of the downlink signal is divided into the optical splitter 400 In the OLT (200) is made manually by remote control, the optical amplification of the uplink signal may be made manually in the optical splitter 400 or directly in the OLT (200). To this end, the optical splitter 400 is a method capable of amplifying a downlink signal or a direction-selective optical amplification for the downlink signal and the downlink signal, as illustrated in FIG. 3 or 5, that is, the passive optical amplification optical circuit 100. It includes. For example, in the case of downlink signal amplification, a pumping downlink signal having a first wavelength λ ₁ transmitted downward with a second wavelength λ ₂ from the OLT 200 through a single optical fiber 250 is pumped. After optical amplification through the signal, only the downlink signal 302 of the optically amplified first wavelength λ ₁ is sent down to the ONU / ONT 300. In the case of the uplink signal, similarly to the downlink signal, the optical amplification through the pumping signal or the burst signal (burst mode) uplink signal is transmitted to the OLT 200 without undergoing a separate optical amplification in the optical splitter 400 and OLT ( 200) After the WDM (Wave Division Multiplexing) process is internally branched to the received optical signal is finally amplified by the receiver unit including the optical amplifier.

Hereinafter, the passive optical amplification optical circuit 100 of the optical splitter 400 will be described in detail with reference to FIGS. 3 and 5, and the OLT 200 will be described in detail with reference to FIG. 4.

FIG. 3 is a detailed block diagram illustrating a passive optical amplification optical circuit used in the PON of FIG. 2 and illustrates a configuration and an operation method of the passive optical amplification optical circuit including a direction selective optical amplification function.

Referring to FIG. 3, the passive optical amplification optical circuit 100 is a unidirectional optical amplification optical circuit, and includes a first wavelength division multiplexer 110, a second WDM 150, and a third WDM 140. , A partial WDM 120 and an amplifying medium 130.

The first WDM 110 includes an OLT transceiver signal and a second wavelength λ _{2 including} a downlink signal having a first wavelength λ ₁ and a pumping signal having a third wavelength λ ₃ for amplifying the downlink signal. The second WDM 150 serves to multiplex the uplink signal and the uplink signal amplified through the optical amplification medium 130. Here, when the signal flow is upward, the first WDM multiplexes the OLT transceiver signal and the uplink signal, and the second WDM separates the downlink signal and the uplink signal. Hereinafter, the description will be mainly based on the downward direction. The partial WDM 120 receives the OLT transmit / receive end signal and divides a pumping signal into first and second pumping signals having the same wavelength, and the optical amplification medium 130 is inputted from the partial WDM 120 through an input end. It receives a downlink signal and a first pumping signal and receives a second pumping signal through an output terminal to amplify the downlink signal. On the other hand, the input of the second pumping signal to the output terminal of the optical amplification medium 130 is made through the third WDM 140, the third WDM 140 is the optical amplification medium 130 and the second WDM (150) ) And the amplified downlink signal output from the optical amplification medium 130 is multiplexed with the second pumping signal and input to the second WDM 150.

The function of the passive optical amplification optical circuit configured as described above will be described briefly. Input / output wavelengths from the single input / output terminal, that is, the OLT-stage waveguide 101 are the downlink signals of the first wavelength λ ₁ downward from the first WDM 110. And an OLT transceiver signal consisting of a pumping signal having a third wavelength λ ₃ and an upstream signal having a second wavelength λ ₂ upward. The OLT transmit / receive end signal is transmitted to the partial WDM 120 through the waveguide 113 and the partial WDM 120 partially diverts the pumping signal, so that the partial pumping signal is transmitted through the waveguide 121 together with the downlink signal. The pumping signal is transmitted to the input terminal of the 130, and the remaining pumping signal is input to the output terminal of the optical amplification medium 130 through the third WDM 140 through the waveguide 123.

Here, the optical amplification medium 130 is formed as a doped waveguide doped with doping elements, Er (Erbium) doped EDW (Erbium), Tm (Thulium) doped TDW, or Pr (Praseodymium) It may be formed of a doped waveguide such as a doped PDW. Herein, the optical amplification operation will be briefly described. The high level energy excited by the pumping signal light input of the third wavelength λ ₃ is induced at a low level corresponding to the first wavelength λ ₁ of the downlink signal. As a result, the downlink signal is optically amplified. In this case, the third wavelength λ ₃ of the pumping signal input into the optical amplification medium 130 is determined by the characteristics of the material constituting the optical amplification medium 130. That is, a signal having a wavelength sufficient to raise the energy level of the constituent material should be input as a pumping signal. On the other hand, in order to generate the induced emission more efficiently, the pumping signal of the same light intensity must be input together to the input terminal and the output terminal of the optical amplifier 130. Therefore, it is preferable that the branching of the pumping signal in the partial WDM 120 has the same light intensity.

The optically amplified high power downlink signal is transmitted to the second WDM 150 through the waveguide 141, multiplexed with the uplink signal from the second WDM 150, and input to the optical splitter 150 of FIG. 2. The downlink signal input to the optical splitter 150 is distributed in the distribution ratio of the optical splitter, for example, 1: N and transmitted to the ONU / ONT 300 through the output terminal of the optical splitter 150, that is, the ONU / ONT stage waveguide 102. do.

The passive optical amplification optical circuit of this embodiment can be used as it is in the existing PON. That is, the passive optical amplification optical circuit has a conventional optical splitter 150 having a plurality of optical splitting output stages, that is, ONU / ONT stage waveguide 102, with respect to one input terminal, that is, the OLT stage waveguide 101 in the case of a downlink signal. Can be used in combination. Similarly, the uplink signal has a structure of a plurality of optical input terminals, that is, the ONU / ONT stage waveguide 102 as one output stage, that is, the OLT stage waveguide 101, and thus maintains the structure of bidirectional optical transmission and reception at all input and output stages. do. Accordingly, the passive optical amplification optical circuit of the present embodiment can be combined with an existing passive optical splitter to provide an effective optical amplification method for a specific direction, for example, a downward signal.

FIG. 4 is a block diagram illustrating an OLT of the PON using the passive optical amplification optical circuit of FIG. 3 in more detail. The downlink signal of the first wavelength λ ₁ and the third wavelength λ ₃ are provided through the OLT optical fiber 201. ) Shows a structure of an OLT 200, that is, a bidirectional optical transmission / reception module, that outputs a pumping signal of) and receives an upstream signal of a second wavelength λ ₂ .

Referring to FIG. 4, the bidirectional OLT 200 includes a flat plate optical circuit board 210, a transmitter unit 220, a pump LD unit 230, a pump laser diode sub-assembly, and an optical amplification receiver unit 240. do.

The planar optical circuit board 210 includes waveguides 211, 213, and 215 for transmitting optical signals from the transmitter unit 220, the pump LD unit 230, or the optical amplification receiver unit 240 to the optical amplifier. Combined WDM 212 for multiplexing downlink signals and pumped signals transmitted through an OLT transmit / receive end signal, and multiplexed OLT transmit / receive end signals from the combined WDM 212 with an uplink signal to transmit and receive OLT The signal includes a branching WDM 214 for branching the uplink signal to the optical fiber 201 through the receiving waveguide 215 to the optical amplifier receiver 240.

Here, the downlink signal waveguide 211 combines the optical output of the second wavelength (λ ₂ ) carrying the downlink signal of the transmission data from the transmitter 220 to the coupling WDM 212, the pumping signal waveguide 213 ) Optically couples the optical output of the third wavelength λ ₃ carrying the pumping signal from the pump LD unit 230 to the coupling WDM 212. The reception waveguide 215 optically couples an uplink signal having a second wavelength λ ₂ branched from the branching WDM 215 to the optical amplification receiver 240.

Transmitting the base 220 is cut off to prevent the signal of the first wavelength (λ ₁₎ In the same wavelength (λ _1), the downstream signal is reflected to a transmitter element for generating the downlink signal of the re-incident on the transmitter element The device 222 may include an isolator. The transmitter 220 has a structure for optically coupling with the downlink signal waveguide 211 of the flat plate optical circuit board 210 formed in the same optical axis direction as the optical fiber 201.

The pump LD unit 230 is optically coupled to the pumping signal waveguide 213 formed in the right (or left) direction with respect to the downlink signal waveguide 211 and is disposed close to the transmitter unit 220. The optical amplifier receiver 240 is optically coupled to the receiving waveguide 215 formed in the right (or left) direction, like the pump LD unit 230, and is preferably disposed to be close to the optical fiber 201.

On the other hand, the optical amplifier receiver 240 includes a receiver 242 and an amplifier for amplifying the uplink signal. The receiver 242 may be composed of a photo-diode (PD) and a trans-impedance amplifier (TIA), or may be composed of an avalanche photo-diode (APD) and a TIA, and the amplifier may have an active optical amplification function. SOA 244 (VCSOA), which may be disposed in front of receiver 242 and assembled together as a sub-assembly with receiver 242. Since the passive optical amplification optical circuit in FIG. 3 amplifies only the downlink signal, the OLT 200 of the present embodiment includes a VCSOA 244 to the receiver unit 240, so that the low output input from the receiving waveguide 215 can be obtained. The upstream signal is first optically amplified and then photoelectrically converted and received.

In general, the wavelength band used in the TDM-PON is assigned a wavelength of 1490 nm for the downlink signal operating in the continuous mode as defined by the EPON (Ethernet PON) and GPON (Gigabit PON) standards. A 1310 nm wavelength is allocated to an uplink signal operating in a burst mode. In addition, the current standard assigns 1550 nm as the wavelength band for video overlay. However, in the construction of large-capacity high-speed TDM-PON without video overlay, it is advantageous to use the 1550 nm wavelength band rather than the 1490 nm wavelength band for the transmission of the downlink data signal. It is necessary to further define 1550 nm as well as 1490 nm in the wavelength band. In the case of applying this to the PON system according to the present invention, the most efficient use of the wavelength is 1550 nm as the first wavelength λ ₁ of the downlink signal, 1310 nm as the second wavelength λ ₂ of the uplink signal, and the third wavelength ( λ ₃ ) means allocating a wavelength band of 980 nm or 1480 nm. On the other hand, when following the current standard wavelength band, a band of 1490 nm for the first wavelength λ ₁ , 1310 nm for the second wavelength λ ₂ , and 1050 nm or 1400 nm for the third wavelength λ ₃ are allocated. As described above, the third wavelength λ ₃ of the pumping signal is determined according to the wavelength of the optical amplifier and the signal to be amplified, for example, the downlink signal.

FIG. 5 is a detailed block diagram illustrating a passive optical amplification optical circuit used in the PON of FIG. 2 according to another embodiment of the present invention. The passive optical amplification optical circuit 500 for bidirectional optical amplification using a single wavelength pump light source is shown in FIG. ).

Referring to FIG. 5, the passive optical amplification optical circuit 500 according to the present embodiment includes an OLT including a downlink signal of a first wavelength λ ₁ and a pumping signal of a third wavelength λ ₃ for amplifying the downlink signal. A first WDM 510 which separates a transmitting / receiving end signal and an uplink signal having a second wavelength λ ₂ , and divides the pumping signal into first and second pumping signals, and a downlink which amplifies the downlink signal using the first pumping signal. An optical amplification optical circuit 540, an uplink optical amplification optical circuit for amplifying an uplink signal using a second pumping signal, and a second WDM 550 for multiplexing the amplified downlink signal and the uplink signal.

The downlink optical amplification optical circuit 540 receives a downlink signal and the first pumping signal and divides a first pumping signal into third and fourth pumping signals, and a first partial WDM through an input terminal. And a downlink optical amplification medium 544 for receiving the downlink signal and the third pumping signal from the signal 542 and receiving the fourth pumping signal through the output terminal, and amplifying the downlink signal. Receives a fifth pumping signal from the second partial WDM 522 through the second partial WDM 522 and the output stage which receives the second pumping signal and divides the second pumping signal into the fifth and sixth pumping signals, and receives an upward signal to the input stage. And an upward optical amplifying medium 524 that receives the sixth pumping signal and amplifies the upward signal.

Meanwhile, similar to FIG. 3, inputs of the up and down optical amplification mediators 524 and 544 to the input terminal and the output terminal are the fourth WDM 526 between the uplink optical amplification mediator 524 and the second WDM 550, and Via a third WDM 546 between the downstream optical amplification medium 544 and the second WDM 550. In this case, the second partial WDM 522 functions to multiplex the uplink signal amplified by the uplink optical amplification medium 524 with the second pumping signal and output an uplink signal to the first WDM 510. 526 multiplexes the sixth pumping signal and the uplink signal and inputs them together to the uplink optical amplification medium 524.

The function of the bidirectional passive optical amplification optical circuit 500 according to the present embodiment will be briefly described. The downlink signal and the third wavelength λ _{3 of} the first wavelength λ ₁ are simultaneously transmitted through the input / output terminal, that is, the OLT stage waveguide 501. The pumping signal of is inputted and the uplink signal of the amplified second wavelength λ ₂ is output, and the downlink signal of the amplified first wavelength λ ₁ is transmitted to the input / output terminal in the opposite direction, that is, the ONU / ONT stage waveguide 502. Is output and the uplink signal of the second wavelength λ ₂ is input.

The downlink signal is branched to the waveguide 513 via the first WDM 510 and is input to the downlink optical amplification optical circuit 540. The uplink signal is branched to the waveguide 551 via the second WDM 550 and is upwardly beamed. The amplification optical circuit 520 is input. The pumping signal is input together with the downlink signal through the OLT-stage waveguide 501 and is the same as the waveguide 511 and the waveguide 513 through the first WDM 510 which serves as an optical splitter for the third wavelength λ ₃ . The ratio is divided and input to the upstream and downstream optical amplification optical circuits 520 and 540, respectively.

The function of the downlink optical amplification optical circuit 540 is almost similar to the passive optical amplification optical circuit 100 described with reference to FIG. 3. However, since the pumping signal is already divided into two signals in the first WDM 510, the pumping signal input to the first portion WDM 542 has the light intensity of 1/2 of the first pumping signal, and also the downlink light. The pumping signal input and output to the input and output stages of the amplifying medium 544 has a light intensity of 1/4 of the first pumping signal.

In the case of the uplink optical amplification optical circuit 520, the pumping signal divided in the first WDM is divided into two pumping signals of the same light intensity again in the second part WDM 522, one for the fourth WDM 526. The signal is input to the input terminal of the uplink optical amplifier 524 together with the uplink signal, and the other is input to the output terminal of the uplink optical amplifier 524 to optically amplify the uplink signal. The optically amplified uplink signal through the pumping signal is transmitted to the OLT 200 via the second WDM 522 and the first WDM 510.

The bidirectional optical amplification optical circuit of the present embodiment uses the pump LD 230 light source in the OLT 200 in FIG. 4 for amplifying the downward and upward signals. Meanwhile, since the uplink signal is also optically amplified by the two-way optical amplification optical circuit, the VCSOA 244 of the receiver 240 may be selectively used only when more amplification of the uplink signal is required.

In the bidirectional optical amplification optical circuit of this embodiment, the material of the optical amplification medium described in FIG. 3 and the principle of optical amplification are applied as it is, and the contents for efficient wavelength use described in the description of FIG. The same may apply to the example.

In the case of the bidirectional optical amplification optical circuit 500 of the present embodiment, by simultaneously optically amplifying both the upper and lower signals through a single optical fiber, the optical amplifier element in the OLT can be selectively employed. In addition, in the PON-type optical subscriber network as shown in FIG. 2, the optical splitter 150 may be integrated with the optical splitter 150 to implement a PON capable of bidirectional passive optical amplification in the optical splitter 150.

The unidirectional or bidirectional optical amplification optical circuit of the present invention can be applied to not only PON type optical communication network, but also all kinds of optical communication networks for two-way optical transmission and reception.

So far, the present invention has been described with reference to the embodiments shown in the drawings, which are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. will be. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described in detail above, the passive optical amplification optical circuit according to the present invention can optically amplify a downlink signal, a downlink signal, and an uplink signal without additional power supply, and is also integrated with an optical splitter in a small size to provide a small size. PON system can be implemented.

In addition, the passive optical amplification optical circuit can be applied to all bidirectional optical amplification network for transmitting and receiving up and down through a single optical fiber including a bidirectional optical communication system, such as a PON-type optical subscriber network can provide an efficient method for bidirectional optical amplification .

Accordingly, the optical communication system of the present invention including a passive optical amplification optical circuit enables a power budget required for large-capacity high-speed bi-directional transmission and reception, or a long-distance bi-directional transmission, and at the same time enables economical and compact system implementation. . In addition, it is possible to provide an optical communication system that can ensure reliability while mitigating problems such as electrical and optical crosstalk noise and heat generation problems that occur in the production of optical modules for the configuration of such a compact short system.

Claims (17)

An optical line terminal (OLT) transmitting and receiving terminal signal having a downlink signal of a first wavelength λ ₁ and a pumping signal of a third wavelength λ ₃ for amplifying the downlink signal and a second wavelength λ ₂ . A first wavelength division multiplexer (WDM) for separating an uplink signal; A partial WDM receiving the OLT transceiver signal and dividing the pumping signal into first and second pumping signals having the same wavelength; An amplifying medium for receiving a downlink signal and a first pumping signal from the partial WDM through an input terminal, and receiving the second pumping signal through an output terminal and amplifying the downlink signal; And And a second WDM for multiplexing the amplified downlink signal and the uplink signal. According to claim 1, And a third WDM receiving the second pumping signal between the optical amplification medium and the second WDM to an output terminal of the optical amplification medium and receiving the amplified downlink signal to the second WDM. Passive optical amplification optical circuit characterized. An optical line terminal (OLT) transmitting and receiving terminal signal having a downlink signal of a first wavelength λ ₁ and a pumping signal of a third wavelength λ ₃ for amplifying the downlink signal and a second wavelength λ ₂ . A first WDM for separating an upstream signal and dividing the pumping signal into first and second pumping signals; A downlink optical amplification optical circuit for amplifying the downlink signal using the first pumping signal; An uplink optical amplification optical circuit for amplifying the uplink signal using the second pumping signal; And And a second WDM for multiplexing the amplified downlink signal and the uplink signal. The method of claim 3, wherein The downlink optical amplification optical circuit A first partial WDM which receives the downlink signal and the first pumping signal and divides the first pumping signal into third and fourth pumping signals; And A downlink optical amplifying medium receiving the downlink signal and the third pumping signal from the first partial WDM through an input terminal, and receiving the fourth pumping signal through an output terminal to amplify the downlink signal; The upward optical amplification optical circuit A second partial WDM which receives the second pumping signal and divides the second pumping signal into fifth and sixth pumping signals; And A passive optical amplification medium configured to receive a fifth pumping signal from the second partial WDM through an output terminal, and to receive the uplink signal and the sixth pumping signal at an input terminal and amplify the uplink signal; Amplification optical circuit. The method of claim 4, wherein The downlink optical amplification optical circuit, And a third WDM configured to receive the fourth pumping signal between the downlink optical amplification medium and the second WDM, to the output terminal of the downlink optical amplification medium, and to receive the amplified downlink signal to the second WDM. and, The upward optical amplification optical circuit, A fourth WDM for inputting the uplink signal and the sixth pumping signal to an input terminal of the uplink optical amplification medium between the uplink optical amplification medium and the second WDM; The second partial WDM of the uplink optical amplification optical circuit is configured to multiplex the uplink signal amplified by the uplink optical amplification medium with the second pumping signal and output the same to the first WDM; Optical circuits. The method according to claim 1 or 4, The optical amplification medium is Erbium-Er doped optical waveguide (Erbium-doped Waveguide (EDW), Praseodymium (Pr) doped optical waveguide (PDW) and Thulium (Tm) doped optical waveguide (TDW) Passive optical amplification optical circuit, characterized in that consisting of any one of). The method according to claim 1 or 4, And the third wavelength of the pumping signal is determined according to a material constituting the optical amplification medium. The method according to claim 1 or 4, The passive optical amplification optical circuit is a passive optical amplification optical circuit, characterized in that used in an optical splitter device of a passive optical network (PON). The method of claim 10, The passive optical amplifier optical circuit is formed in the direction of the OLT transceiver end of the PON in front of the optical splitter, And said first WDM is connected to said OLT and said second WDM is connected to said optical splitter. The method of claim 8, The passive optical amplification optical circuit is the optical amplification optical circuit of claim 1, Passive optical amplification optical circuit, characterized in that the OLT of the PON includes an amplifier for amplifying an uplink signal. An OLT transceiver for transmitting an OLT transceiver signal comprising a downlink signal of a first wavelength λ ₁ and a pumping signal of a third wavelength λ ₃ and receiving an uplink signal of a second wavelength λ ₂ ; An optical splitter including a passive optical amplification optical circuit according to claim 1 or 3 for amplifying a downlink signal, or a downlink signal and an uplink signal, and an optical splitter for optically distributing a downlink signal from the passive optical amplification optical circuit; And And an optical network unit or terminal (ONU / OLT) transceiver for transmitting the uplink signal and receiving the downlink signal. The method of claim 11, wherein The optical communication system is a PON system, The optical amplification optical circuit can be integrated with the optical splitter in front of the optical splitter. The method of claim 12, The OLT transceiver, A flat panel optical circuit board including a WDM for branching or combining an uplink signal and a downlink signal, and determining an optical coupling direction with a light source; A transmitter unit having a transmitter for generating the downlink signal; A pump laser diode (LD) unit configured to generate the pumping signal; And And a receiver unit having a receiver for receiving the uplink signal. The method of claim 13, The optical amplification optical circuit is an optical amplification optical circuit of claim 1, The receiver unit has a surface-emitting vertical-cavity SOA (VCSOA), characterized in that the bidirectional optical amplification optical communication system. The method of claim 13, The optical amplification optical circuit is an optical amplification optical circuit of claim 1, And a third WDM receiving the second pumping signal between the optical amplification medium and the second WDM to an output terminal of the optical amplification medium and receiving the amplified downlink signal to the second WDM. A bidirectional optical amplification optical communication system. The method of claim 13, The optical amplification optical circuit is an optical amplification optical circuit of claim 3, The downlink optical amplification optical circuit A first partial WDM which receives the downlink signal and the first pumping signal and divides the first pumping signal into third and fourth pumping signals; And And a downlink optical amplification medium receiving the downlink signal and the third pumping signal from the first partial WDM through an input terminal, and receiving the fourth pumping signal through an output terminal to amplify the downlink signal. The upward optical amplification optical circuit A second partial WDM which receives the second pumping signal and divides the second pumping signal into fifth and sixth pumping signals; And And an uplink optical amplification medium configured to receive a fifth pumping signal from the second partial WDM through an output terminal, and to receive the uplink signal and the sixth pumping signal to an input terminal and amplify the uplink signal. Amplified Optical Communication System. The method of claim 16, The downlink optical amplification optical circuit, A third WDM receiving the fourth pumping signal between the downlink optical amplification medium and the second WDM, inputting the fourth pumping signal to an output terminal of the downlink optical amplification medium, and inputting the amplified downlink signal to the second WDM; The upward optical amplification optical circuit, A fourth WDM for inputting the uplink signal and the sixth pumping signal to an input terminal of the uplink optical amplification medium between the uplink optical amplification medium and the second WDM; The second partial WDM of the uplink optical amplification optical circuit has a function of multiplexing the uplink signal amplified by the uplink optical amplification medium with the second pumping signal to output to the first WDM. Optical communication system.

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