KR20050073381A - Wdm-pon for accommodating various modulation velocity - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to an optical subscriber network with different modulation rates per channel, in particular to a wavelength division multiplex optical subscriber network.

2. The technical problem to be solved by the invention

SUMMARY OF THE INVENTION An object of the present invention is to provide a wavelength division multiplexing optical subscriber network device capable of simultaneously utilizing light sources having different optimal modulation rates in an optical subscriber network requiring different transmission rates for each channel.

3. Summary of the Solution of the Invention

The present invention provides a wavelength division multiplexing passive optical subscriber network comprising a central base station, a local base station connected to the central base station by a single ray, and a plurality of subscriber devices connected to the local base station, wherein the central base station has a wide wavelength range. A broadband light source (BLS) for outputting an optical signal; A 1 × N waveguide type wavelength division multiplexing device which demultiplexes and transmits an optical signal having a wide wavelength range from the broadband light source to a light source for each subscriber device, and multiplexes and outputs a modulated optical signal from the light source for each subscriber device. 1 × N AWG); An optical path for inputting an optical signal having a wide wavelength range from the broadband light source to the 1 × N waveguide type wavelength division multiplexing device and transferring the multiplexed optical signal from the 1 × N waveguide type wavelength division multiplexing device to a subscriber end; An optical circulator for setting the; And a plurality of light sources for each subscriber device connected to the 1 × N waveguide type wavelength division multiplexing device to optically modulate and transmit data to be transmitted to an optical signal having a wavelength allocated to each subscriber device. The light source for each subscriber device of the is configured to accommodate a different modulation rate, characterized in that the difference in the modulation rate during the optical modulation.

4. Important uses of the invention

The present invention is used for wavelength division multiplex optical subscriber network.

Description

WDM-PON for Accommodating Various Modulation Velocity

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical subscriber network with different modulation rates per channel, in particular to a wavelength division multiplex optical subscriber network.

A wavelength-division-multiplexed (WDM) passive optical network (PON) provides a very high speed broadband communication service using a unique wavelength assigned to each subscriber. Thus, the confidentiality of the communication is assured, and the individual communication service or expansion of communication capacity required by each subscriber can be easily accommodated, and the number of subscribers can be easily expanded by adding a unique wavelength to be given to a new subscriber.

The wavelength division multiplexing light source used in the wavelength division multiplexing optical subscriber network includes a distributed feedback laser diode (DFB-LD), a distributed feedback laser array (DFB laser array), and multiple wavelengths. Multi-frequency lasers (MFLs), picosecond pulse light sources and the like have been used.

In addition, spectral-sliced light sources that do not require wavelength selectivity and stabilization in recent years and are easy to manage wavelengths and Fabry-Perot laser diodes that are immersed in incoherent light Research using a reflective semiconductor optical amplifier (RSOA) using an LD) and a wavelength of an injected optical signal as an economical wavelength division multiplexed light source has been made.

A wavelength division multiplex optical subscriber network for transmitting up / down data using such light sources is shown in FIG. 1.

1A to 1B are diagrams illustrating an embodiment of a light source device in a wavelength division multiple access optical subscriber network.

FIG. 1A is an exemplary diagram of using a Fabry-Perot laser diode (FP-LD), which is immersed in incoherent light, in a wavelength division multiplex optical subscriber network as a wavelength division multiplex light source. FIG. 1B is an exemplary diagram of using a reflective semiconductor optical amplifier (RSOA) as a wavelength division multiplex light source in a wavelength division multiplex optical subscriber network.

Looking at the transmission of the optical signal of the wavelength division multiplexing through Figure 1a, first, the light output from the broadband light source (BLS) 104 is passed through the circulator 103, the 1 × N waveguide type wavelength multiplexer ( Arrayed WaveGuide (1 × N AWG) 102 is demultiplexed and spectrally divided into respective FP-LDs 101-1 to 101-N, and the divided light is divided into FP-LDs 101-1 to 101-N. After the wavelength is locked to the same wavelength as the light source injected by the modulated output. The modulated signals are then multiplexed into a single signal in the 1 × N waveguide type wavelength division multiplexer 102 and transmitted to the subscriber end through the circulator 103.

In the case where a reflective semiconductor optical amplifier (RSOA) is used as shown in FIG. 1B, the operation thereof is the same as in the case of using FP-LD. First, the light output from the broadband light source (BLS) 104 is demultiplexed by a 1 × N waveguide type wavelength division multiplexer (1 × N AWG) 102 through the circulator 103. The RSOAs 105-1 to 105-N are spectrally divided, and the divided light is amplified by the wavelength of the light source injected by the RSOAs 105-1 to 105-N, and then modulated and output. The modulated signals at each RSOA 105-1 to 105-N are then multiplexed into a single signal in the 1xN waveguide type wavelength division multiplexer 102 and transmitted to the subscriber end through the circulator 103.

By the way, it is known that FP-LD and RSOA, which are light sources used above, have a limit of maximum modulation rate. That is, the experiment result considering the power intensity, transmission distance and temperature environment of the broadband light source, the optimal modulation rate of FP-LD is less than 622Mbps, RSOA is less than 1.25Gbps. In the case of an optical signal in the data transmission rate, the transmission rate depends on the modulation rate because the ratio of the optical signal is high.

Therefore, when the light source of the optical subscriber network is configured using only FP-LD or RSOA, there is a problem that it is not suitable to be applied to the optical subscriber network requiring a different transmission speed according to the wavelength.

It is an object of the present invention to provide a wavelength division multiplexing optical subscriber network device capable of simultaneously utilizing light sources having different optimal modulation rates in optical subscriber networks requiring different transmission rates for each channel.

In order to achieve the above object, the present invention provides a wavelength division multiplexing passive optical subscriber network comprising a central base station, a local base station connected to the central base station by a single ray, and a plurality of subscriber devices connected to the local base station. A broadband light source (BLS) for outputting an optical signal of a wide wavelength range to a base station; A 1 × N waveguide type wavelength division multiplexing device which demultiplexes and transmits an optical signal having a wide wavelength range from the broadband light source to a light source for each subscriber device, and multiplexes and outputs a modulated optical signal from the light source for each subscriber device. 1 × N AWG); An optical path for inputting an optical signal having a wide wavelength range from the broadband light source to the 1 × N waveguide type wavelength division multiplexing device and transferring the multiplexed optical signal from the 1 × N waveguide type wavelength division multiplexing device to a subscriber end; An optical circulator for setting the; And a plurality of light sources for each subscriber device connected to the 1 × N waveguide type wavelength division multiplexing device to optically modulate and transmit data to be transmitted to an optical signal having a wavelength allocated to each subscriber device. The light source for each subscriber device of the apparatus accommodates various modulation rates, characterized in that the modulation rate is different in the optical modulation.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the same components in the drawings are represented by the same reference numerals and symbols as much as possible even if shown in different drawings. In addition, in describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

2A to 2C are diagrams illustrating an embodiment of a wavelength division multiplexing optical subscriber network device to which light sources of different modulation rates are applied according to the present invention.

First, in order to apply to an optical subscriber network requiring a different modulation rate according to the wavelength, as shown in FIGS. 2A to 2C, when the optimum modulation rate of each light source is experimentally examined, the optimum modulation rate is between 155 Mbps and 622 Mbps. FP-LD is used to request an RSOA when the optimal modulation rate is between 622Mbps and 1.25Gbps, and a distributed feedback laser (DFB-LD) is required when the optimal modulation rate is between 1.25Gbps and 10Gbps. do.

An optical subscriber network device using light sources having characteristics at such a modulation rate is as follows.

2A is an exemplary diagram of a wavelength division multiplexing optical subscriber network device using a light source of a different modulation rate according to the present invention using RSOA as a light source based on FP-LD.

In FIG. 2A, the wideband optical signal output from the wideband light source (BLS) 204 is input to the 1 × N waveguide type wavelength division multiplexer (1 × N AWG) 202 through the circulator 203 and 1 × N. The waveguide-type wavelength division multiplexer (1 × N AWG) 202 is demultiplexed to perform spectral division for each wavelength. The spectral-divided optical signal for each wavelength is modulated after being locked or amplified by the same wavelength as the light source injected by the FP-LD 201-1 or 201-N or RSOA 201-i. It is output to the 占 N waveguide type wavelength division multiplexer (1 占 N AWG) 202. The modulated optical signals output from the respective light sources are multiplexed into a single signal in a 1 × N waveguide multiplexer (1 × N AWG) 202 and transmitted to the subscriber end through the circulator 203.

Figure 2b is an illustration of a wavelength division multiplexing optical subscriber network device applying a light source of different modulation rate according to the present invention using FP-LD, RSOA and DFB-LD as a light source.

In FIG. 2B, the wideband optical signal output from the wideband light source (BLS) 204 is input to the 1 × N waveguide type wavelength division multiplexer (1 × N AWG) 202 through the circulator 203, and 1 × N. The waveguide-type wavelength division multiplexer (1 × N AWG) 202 is demultiplexed to perform spectral division for each wavelength. The spectral-divided optical signal for each wavelength is modulated after being locked or amplified by the same wavelength as the light source injected by the FP-LD 205 or the RSOA 205-i. Output to a multiplexer (1 × N AWG) 202. In addition, the DFB-LD 205 -N outputs a modulated signal having a unique wavelength regardless of the broadband light source 204. The modulated optical signals output from the respective light sources are multiplexed into a single signal in a 1 × N waveguide multiplexer (1 × N AWG) 202 and transmitted to the subscriber end through the circulator 203. do.

On the other hand, in the wavelength division multiplex optical subscriber network considering the commercially available conditions, the FP-LD is limited to 622Mbps or less when the operating temperature is not kept constant (Uncooled FP-LD). However, if the operating temperature is kept constant (Cooled FP-LD), the modulation rate can be extended to 1.25Gbps in a wavelength division multiplex optical subscriber network.

Therefore, Uncooled FP-LD or Cooled FP-LD can be selectively used depending on the modulation rate. Therefore, as shown in FIG. 2C, the role of the RSOA 201-i in FIG. 2A may be substituted by the cooled FP-LD 206-i.

In FIG. 2C, the wideband optical signal output from the wideband light source (BLS) 204 is input to the 1 × N waveguide type wavelength division multiplexer (1 × N AWG) 202 through the circulator 203 and 1 × N. The waveguide-type wavelength division multiplexer (1 × N AWG) 202 is demultiplexed to perform spectral division for each wavelength. The spectral split optical signal is modulated after the wavelength is locked to the same wavelength as that of the light source injected by the Uncooled FP-LD 201-1 or 201-N or Cooled FP-LD 201-i. And a 1 × N waveguide type wavelength division multiplexer (1 × N AWG) 202. The modulated optical signals output from the respective light sources are multiplexed into a single signal in a 1 × N waveguide multiplexer (1 × N AWG) 202 and transmitted to the subscriber end through the circulator 203.

3 is a configuration diagram of an optical link using a wavelength division multiplexing optical subscriber network device according to the present invention.

The optical link using the wavelength division multiplexing optical subscriber network device according to the present invention includes a central base station 31, a local base station 32 and a subscriber device 33.

The central base station 31 is provided with a wavelength division multiplexing optical subscriber network device to which light sources of different modulation rates according to the present invention are applied, and use them as respective downward light sources. That is, Tx ₁ (301-1) and Tx _i (301-i) used as the downward light source And Tx _N (301-N) As shown in FIGS. 2A to 2C, light sources having different modulation rates are configured. The downlink optical signal of each of the light sources is Rx ₁ 306-1, Rx _i 306-i of the subscriber device 33. And Rx _N 306 -N.

In addition, each subscriber device 33 is provided with a wavelength division multiplexing optical subscriber network device to which light sources of different modulation rates according to the present invention are applied, and use them as respective upward light sources. That is, Tx ₁ (307-1), Tx _i (307-i) used as an upward light source And Tx _N 307 -N includes light sources having different modulation rates as described with reference to FIGS. 2A through 2C. The uplink optical signal of each of the light sources is Rx ₁ (312-1) and Rx _i (312-i) of the central base station 31. And Rx _N 312-N.

 The operation principle of the optical link having the wavelength division multiplexing optical subscriber network device to which the light sources of different modulation rates according to the present invention are applied is as follows.

In the downlink transmission, the wideband signal generated by the wideband light source (BLS) 304 of the central base station is input to the 1xN waveguide type diffraction grating 302 through the circulator 303 and then spectrum-divided. In addition, the optical signals for each channel of the spectral division are respectively downlink light sources Tx ₁ (301-1) and Tx _i (301-i). And Tx _N (301-N). In addition, the downward light sources Tx ₁ (301-1) and Tx _i (301-i) And Tx _N 301-N have the same wavelength as the injected spectral divided channel-specific optical signal and output an optical signal directly modulated according to downlink data to be transmitted. Each downlink optical signal output is multiplexed into one optical signal in the 1xN waveguide diffraction grating 302. The multiplexed downlink signal is transmitted to the local base station 32 through the circulator 303. The transmitted signals are then demultiplexed in the 1 × N waveguide diffraction grating 305 of the local base station 32, and then the optical receivers Rx ₁ 306-1 and Rx _i 306- of the subscriber device 33, respectively. i) And Rx _N 306-N, which is detected as an electrical signal.

Similarly, in uplink transmission, the wideband signal generated by the broadband light source 310 of the central base station 31 is input to the 1 × N waveguide type diffraction grating 308 of the local base station 32 through the circulator 309 and then divided into spectral segments. do. Each spectrum-split channel is a light source (Tx ₁ (307-1), Tx _i (307-i) of the subscriber device 33, respectively And Tx _N (307-N). In addition, the upward light sources Tx ₁ (307-1) and Tx _i (307-i) And Tx _N 307 -N have the same wavelength as the injected spectral divided channel, and output an optical signal directly modulated with uplink data to be transmitted. Each of the outputted uplink optical signals is inputted into the 1xN waveguide diffraction grating 308 of the local base station 32 and multiplexed. The multiplexed uplink signal is transmitted to the central base station 31, passed through the circulator 309, demultiplexed in the 1xN waveguide diffraction grating 311, and then receivers Rx ₁ (312-1) and Rx, respectively. _i (312-i) And Rx _N 312-N, which is detected as an electrical signal.

4, 5, and 6 are exemplary embodiments of an optical subscriber network using a wavelength division multiplex optical subscriber network apparatus using a light source having a different modulation rate according to the present invention. Only the downward operation will be described.

4 is a block diagram of an embodiment of a wavelength division multiplexing optical subscriber network using an active optical subscriber network using an optical subscriber network device using a light source of a different modulation rate according to the present invention.

In the case of an active optical network (AON), for example, the central base station 41 converts an optical signal modulated at 2.5 Gbps to an electrical signal. The converted electrical signals are divided into time periods so as to provide 155Mbps to each subscriber by using electrical switches in the central base station 41, and then converted into optical signals and transmitted to the local base station 42. The local base station 42 converts the signal back into an electrical signal and finally detects the signal.

As shown in FIG. 4, the WDM-PON OLT (WDM-PON Optical Line Terminal) (401-1, 401-N) and the optical end station of the active optical subscriber network (WDM-PON OLT) The electrical signals received from the AON OLT) 401-i are converted into optical signals using direct modulation schemes of the FP-LDs 402-1 and 402-N and DFB-LD 402-i, respectively.

The converted optical signals are input to the 1 × N waveguide diffraction grating 403, multiplexed, and then transmitted through the circulator 404 to the local base station 42. The transmitted optical signal is then demultiplexed in the 1 × N waveguide diffraction grating 406 of the local base station 42.

Each demultiplexed signal can be a WDM-PON ONT (WDM-PON Optical Network Terminal) (407-1, 407-N) or an active optical subscriber network terminator (AON ONU). AON Optical Network Unit (407-i) is converted into a signal type for each protocol and then delivered to each subscriber.

FIG. 5 is a block diagram of an embodiment of a wavelength division multiplexing optical subscriber network using an Ethernet-based passive optical subscriber network using an optical subscriber network device to which light sources of different modulation rates are applied according to the present invention.

In the case of the Ethernet based Passive Optical Network (EPON), for example, an optical signal modulated at 1.25Gbps at the central base station is demultiplexed at the local base station, branched by a power splitter, and then converted into an electrical signal. do. The converted electrical signal is selected to take only information necessary for each subscriber according to a given algorithm.

As shown in FIG. 5, the WDM-PON OLT (WDM-PON Optical Line Terminal) (501-1, 501-N) and the Ethernet-based passive optical subscriber network of the wavelength division multiplexing passive optical subscriber network are shown. The electrical signals received from the optical end stations (EPON OLT) 501-i are converted into optical signals using the direct modulation schemes of the FP-LD 502-1 and 502-N and the RSOA 502-i, respectively.

The converted optical signals are input to the 1 × N waveguide diffraction grating 503, multiplexed, and then passed through the circulator 504 to the local base station 52. The transmitted optical signal is then demultiplexed in the 1 × N waveguide diffraction grating 506 of the local base station 52.

Each demultiplexed signal can be a WDM-PON ONT (WDM-PON Optical Network Terminal) (507-1, 507-N) or an Ethernet-based passive optical subscriber station (WDM-PON ONT). EPON ONU (EPON Optical Network Unit) 507-i is converted into a signal type for each protocol and then delivered to each subscriber.

FIG. 6 is a diagram illustrating an embodiment of a wavelength division multiple access optical subscriber network mixed with an active optical subscriber network and an Ethernet-based passive optical subscriber network using an optical subscriber network device using a light source having a different modulation rate according to the present invention.

As shown in FIG. 6, an optical end station (WDM-PON OLT; WDM-PON Optical Line Terminal) 601-1 of an wavelength division multiplexing passive optical subscriber network, an optical end station of an Ethernet-based passive optical subscriber network (EPON) Electrical signals received from the OLT) 601-i and the AON OLT 601-N of the active optical subscriber network, respectively, FP-LD (602-1), RSOA (602-i) and DFB-LD. The signal is converted into an optical signal using the direct modulation method of (602-N).

The converted optical signals are input to the 1 × N waveguide diffraction grating 603, multiplexed, and then transmitted through the circulator 604 to the local base station 62. The transmitted optical signal is then demultiplexed in the 1 × N waveguide diffraction grating 606 of the local base station 62.

Each demultiplexed signal is a WDM-PON ONT (WDM-PON Optical Network Terminal) (607-1), an Ethernet-based passive optical subscriber network (EPON ONU; EPON). The optical network unit (607-i) and the active unit of the optical subscriber network (AON OLT) (607-N) is converted into a signal type for each protocol and then delivered to each subscriber.

4, 5, and 6 are suitable for simultaneously using an active optical subscriber network (AON) requiring power in a dense residential area such as an apartment, and a passive optical subscriber network without a power source in a Hansan area such as a single house. Do. It is apparent that such an optical subscriber network can be used not only in two stranded wavelength division multiplex optical subscriber networks but also in one strand of bidirectional wavelength division multiplex optical subscriber networks.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

As described above, the present invention provides a wavelength division multiplex optical subscriber network device capable of simultaneously utilizing light sources having different optimal transmission rates in optical subscriber networks having different transmission rates for each channel, and an optical subscriber network structure using the same. At the same time, there is an effect that the economical network configuration is possible by being acceptable.

1A to 1B are diagrams illustrating an embodiment of a light source device in a wavelength division multiplex optical subscriber network;

2a to 2c is a configuration diagram of an embodiment of a wavelength division multiplexing optical subscriber network device to which light sources of different modulation rates are applied according to the present invention.

Figure 3 is an embodiment configuration of an optical link using a wavelength division multiplexing optical subscriber network device according to the present invention.

4 is a block diagram of an embodiment of a wavelength division multiplexing optical subscriber network using an active optical subscriber network using an optical subscriber network device to which light sources of different modulation rates are applied according to the present invention.

FIG. 5 is a diagram illustrating an embodiment of a wavelength division multiplexing optical subscriber network using an Ethernet-based passive optical subscriber network using an optical subscriber network device to which light sources of different modulation rates are applied according to the present invention. FIG.

FIG. 6 is a block diagram of an embodiment of a wavelength division multiplex optical subscriber network mixed with an active optical subscriber network and an Ethernet-based passive optical subscriber network using an optical subscriber network device using a light source having a different modulation rate according to the present invention. FIG.

Claims (7)

A wavelength division multiplexing passive optical subscriber network comprising a central base station, a local base station connected by a single optical path to the central base station, and a plurality of subscriber devices connected to the local base station, wherein the central base station includes: A broadband light source (BLS) for outputting an optical signal in a wide wavelength range; A 1 × N waveguide type wavelength division multiplexing device which demultiplexes and transmits an optical signal having a wide wavelength range from the broadband light source to a light source for each subscriber device, and multiplexes and outputs a modulated optical signal from the light source for each subscriber device. 1 × N AWG); An optical path for inputting an optical signal having a wide wavelength range from the broadband light source to the 1 × N waveguide type wavelength division multiplexing device and transferring the multiplexed optical signal from the 1 × N waveguide type wavelength division multiplexing device to a subscriber end; An optical circulator for setting the; And A plurality of light sources for each subscriber device connected to the 1 × N waveguide type wavelength division multiplexing device to optically modulate and transmit data to be transmitted to an optical signal having a wavelength allocated to each subscriber device; A plurality of light source for each subscriber device is a wavelength division multiplex passive optical network that accommodates a variety of modulation rates, characterized in that the modulation rate is configured to differ in the optical modulation. The method of claim 1, The light source for each subscriber device, Wavelengths that accommodate various modulation rates, comprising a Febri-Perot laser diode (FP-LD) with an optimal modulation rate of 155 Mbps to 622 Mbps and a reflective optical amplifier (RSOA) with an optimal modulation rate of 622 Mbps to 1.25 Gbps Split Multiple Passive Optical Subscriber Network. The method of claim 1, The light source for each subscriber device, It is composed of a Febri-Perot laser diode (FP-LD) with an optimum modulation rate of 155 Mbps to 622 Mbps and a distributed feedback laser (DFB-LD) with an optimum modulation rate of 1.25 Gbps to 10 Gbps. Wavelength Division Multiplexing Passive Optical Subscriber Network. The method of claim 1, The light source for each subscriber device, Fabry-Perot laser diode (FP-LD) with an optimal modulation rate of 155 Mbps to 622 Mbps, a reflective optical amplifier (RSOA) with an optimal modulation rate of 622 Mbps to 1.25 Gbps, and a distributed feedback laser with an optimal modulation rate of 1.25 Gbps to 10 Gbps ( DFB-LD) is a wavelength division multiplex passive optical network that accommodates a variety of modulation rates. The method of claim 1, The light source for each subscriber device, An uncooled FP-LD that does not maintain a constant operating temperature with an optimal modulation rate of 155 Mbps to 622 Mbps, and a Fabry-Perot laser that maintains a constant operating temperature with an optimal modulation rate of 622 Mbps to 1.25 Gbps Wavelength division multiplexing passive optical network that accommodates various modulation rates, characterized by a diode (Cooled FP-LD). The method according to any one of claims 2 to 5, The Fabry-Perot laser diode, And a wavelength-division multiplexing passive optical subscriber network accommodating various modulation rates, characterized by outputting a signal modulated by wavelength-locking the same wavelength as an optical signal transmitted from the 1 × N waveguide type wavelength division multiplexing device. The method according to claim 2 or 4, The reflective optical amplifier (RSOA), And a wavelength division multiplex passive optical network for accommodating various modulation rates, wherein the signal is amplified and modulated by the same wavelength as the optical signal transmitted from the 1 × N waveguide type wavelength division multiplexing device.