KR100758106B1 - Wavelength-tunable transceiver having wavelength independent light-source - Google Patents

Abstract

An optical transceiving device employing a wavelength independent light source is provided to use an access structure with a WDM(Wavelength Division Multiplexing) system of an existing optical transceiving device, as it is, thereby employing the wavelength independent light source as maintaining compatibility with the existing optical transceiving device. A wavelength independent light source(12) varies a wavelength of light according to injection light to output the varied light. A transmission light detector(14) measures transmission light output of the light source(12), and outputs the measured value. A light source driver(11) drives the light source(12) according to the measured value and a differential signal received from a WDM system. A temperature controller(15) controls so that temperature of the light source(12) is regularly maintained. An external power monitor(16) monitors changes of external power supplied for operation of the controller(15) apart from internal power supplied through a standard interface. A controller(22) receives information on an output state of the light source(12) from the driver(11) as receiving information on a supplied state of the external power from the monitor(16), and sends the state information to the WDM system through the standard interface.

Description

Wavelength-tunable transceiver having wavelength independent light-source

1 is a block diagram showing the configuration of an optical transmitting and receiving device according to the standards of conventional GBIC and SFP.

2 is a block diagram showing the configuration of an optical transmission / reception apparatus employing a wavelength independent light source according to the present invention.

Figure 3 is a memory map for the external power monitoring parameters added in the optical transmission and reception apparatus of the present invention.

<Description of Symbols for Main Parts of Drawings>

11 light source driver 12 wavelength independent light source

13 optical splitter 14 transmission light detector

15: temperature control unit 16: external power monitoring unit

17: memory 18: temperature sensor

19: internal power monitoring unit 20: receiving light detector

21: limited amplifier 22: control unit

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an optical transmission / reception device used in a wavelength independent multiplexing (WDM) optical network. More specifically, the present invention employs a wavelength independent light source while maintaining compatibility with an existing optical transmission / reception device. It relates to an optical transmitting and receiving device that can be used.

Recently, due to the growth of applications related to the Internet, the required bandwidth of the network is rapidly increasing. Therefore, the WDM technique is actively applied to provide the required bandwidth in a limited optical fiber infrastructure.

WDM is a method of simultaneously transmitting optical signals having several different wavelengths through one optical fiber, and is a transmission method that can stably increase transmission capacity without additionally installing optical fiber.

Currently, most WDM transmission systems use a fixed wavelength light source in which a wavelength of a light source for generating an optical signal is fixedly assigned to each WDM channel. However, in the conventional WDM transmission system using multiple wavelengths, as the concept of high density WDM (DWDM: Dense WDM) is introduced, the number of light wavelengths used per fiber increases to several tens or hundreds, so the wavelength of the light source is individually increased. Management puts a big burden on network operation and maintenance.

Accordingly, in the case of the WDM network construction method such as WDM passive optical network (WDM-PON), which is expected to be widely deployed in large quantities, the wavelength-independent light source or wavelength-independent light source is used to pursue the wavelength-independent WDM optical network. The approach offers great convenience in the operation of the network.

In order to configure such a WDM optical network, an optical transmission / reception device for transmitting and receiving optical signals should be installed in optical termination devices at both ends of an optical fiber. The optical transmission and reception device adopts a standardized structure and interface to improve field applicability and to reduce cost. For example, SFF-8053 defines Gigabit Interface Converter (GBIC), and SFF-8075 defines Small Form-factor Pluggable (SFP).

1 is a block diagram showing the configuration of an optical transmission and reception apparatus according to the standards of the conventional GBIC and SFP.

The transmission data (differential signal) received from the WDM system (not shown) is first input to the light source driver 1, and the light source driver 1 drives the fixed wavelength light source 3 according to the input differential signal so that the optical signal is used to transmit the transmission fiber. Through the optical transmission receiver (not shown) on the other side (OLT). In this case, as the fixed wavelength light source 3, a Fabry-Perot laser, a distributed feedback laser, or the like is used. The transmission light detector 2 detects the intensity of the optical signal output from the fixed wavelength light source 3 to the transmission optical fiber and feeds back the information to the light source driver 1. The optical signal received through the receiving optical fiber is converted into an electrical signal by the receiving optical detector 4, and then amplified by the limiting amplifier 5 and transmitted to the WDM system (not shown) as received data (differential signal). At this time, the transmitting optical fiber and the receiving optical fiber are separated, but in the case of the bidirectional optical transceiver, since one optical fiber is used in both directions, optical connection may be made with one optical fiber.

The light source driver (1) and the limiting amplifier (5) provide monitoring and management functions, such as detection and interruption of transmission and reception, as standard, and the optical transmission / reception device uses a WDM system (not shown) and a memory through a two-wire serial interface. It transmits the information on the specification of the module stored in (6) to the WDM system (not shown).

The SFF-8472 standard, which extends the optical transmission / reception monitoring function of the optical transmission / reception apparatus of FIG. 1, can be commonly applied to existing GBICs and SFPs, and has a controller added when compared to SFF-8053 or SFF-8075. Additional monitoring functions such as light output monitoring, module temperature monitoring and internal power voltage monitoring are provided and the information is provided to the WDM system via a standard interface. That is, the light source driver 1 transmits information on transmission power and transmission failure to the WDM system through the controller, instead of directly receiving the differential signal (transmission data). The limiting amplifier 5 also transmits information on reception power and reception failure other than the differential signal (reception data) output to the WDM system through the controller. In addition, the controller provides the WDM system with information stored in memory, module temperature monitoring, internal power supply voltage monitoring, etc. via a 2-wire serial interface.

However, all of these optical transmission and reception devices such as SFF-8053, SFF-8075, and SFF-8472 are based on the assumption of using a fixed wavelength light source, and there is a problem in that it is impossible to implement a monitoring and management control function required for a wavelength independent light source. have. In other words, the conventional optical transceiver has a structure in which a wavelength independent light source cannot be adopted.

Moreover, since the conventional optical transmission / reception apparatus presupposes the use of a fixed wavelength light source, the power (internal power) provided from the WDM system is also limited accordingly. That is, the conventional optical transmitter and receiver is designed to use a fixed wavelength light source, so the WDM system is also designed to supply only a limited size of power to the optical transmitter and receiver. Therefore, in order to maintain compatibility with the existing optical transmission and reception apparatus, since the standardized interface with the WDM system should not be changed, the internal power source is used as it is, but as described above, the size of the internal power source is limited so that only the internal power source There is a problem that can not implement the monitoring and management control function required for the wavelength independent light source.

Accordingly, an object of the present invention for solving the above problems is to improve the structure of the optical transmission and reception device to maintain the compatibility with the existing optical transmission and reception device and to adopt a wavelength independent light source in the optical transmission and reception device.

Optical transmitting and receiving device employing the wavelength independent light source of the present invention for achieving the above object is a wavelength independent light source that is output by varying the wavelength of the light in accordance with the injection light; A transmission light detector which measures the transmission light output of the wavelength independent light source and outputs the measured value; A light source driver for driving the wavelength independent light source in accordance with the differential signal from the WDM system and the measured value from the transmission light detector; A temperature controller which senses a temperature of the wavelength independent light source and controls the temperature of the wavelength independent light source to be kept constant; An external power monitoring unit for monitoring a change in external power supplied for operation of the temperature control unit separately from the internal power supplied through the standard interface; And control the operation of the optical transmission and reception device as a whole, and receive information on the output state of the wavelength independent light source from the light source driver and receive information on the supply state of the external power from the external power monitoring unit. It is provided with a control unit for transmitting the state information to the WDM system through.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

2 is a block diagram showing the configuration of an optical transmitting and receiving apparatus employing a wavelength independent light source according to the present invention.

2 is a light source driver 11, a wavelength independent light source 12, an optical splitter 13, a transmission light detector 14, a temperature controller 15, an external power monitor 16, and a memory ( 17), a temperature sensor 18, an internal power supply monitoring unit 19, a reception light detector 20, a limiting amplifier 21 and a control unit 22.

The light source driver 11 receives the transmission data (differential signal) from the WDM system (part of the ONU or OLT except the optical transmission / reception apparatus of the present invention) through a standard interface, and feeds back the received differential signal and the transmission light detection unit 14. The wavelength independent light source 13 is driven in accordance with the information on the transmitted power. The light source driver 11 receives the state (power) information of the light output from the wavelength independent light source 13 to the transmission optical fiber from the transmission light detector 14 and detects the transmission power and the transmission failure of the output light. The information is transmitted to the control unit 22. The light source driver 11 stops driving the wavelength independent light source 13 when the transmission stop command is applied from the controller 22.

The wavelength independent light source 12 generates an optical signal having a predetermined wavelength according to the drive signal from the light source driver 11 and outputs the optical signal to the transmission optical fiber. An example of the wavelength independent light source 13 of the present invention is injection locking for injecting an auxiliary light (BLS), which is a broadband light source (BLS), to a Fabry-Perot laser diode (FP-LD). Through the process it is possible to selectively output the light of a specific wavelength desired. That is, when a light source having a specific light wavelength is injected into the FP-LD, only the mode corresponding to the wavelength is oscillated greatly and other modes are suppressed. Therefore, the FP-LD can output an optical signal close to a single mode instead of a multi-mode output, and the injection locked light source is used as a wavelength independent light source because the wavelength is determined according to the wavelength of the external injection light (auxiliary light). It is possible to do In addition, the wavelength independent light source 12 may be a semiconductor optical amplifier (SOA) for amplifying and modulating an auxiliary light source or a reflective semiconductor optical amplifier (RSOA) for reflecting, amplifying and modulating an auxiliary light source. have. In addition, the auxiliary light source may be configured separately to inject into the wavelength independent light source 12, may branch a portion of the received optical signal applied to the transceiver device and make it as an auxiliary light to be injected into the wavelength independent light source 12. have.

The optical splitter 13 splits a part of the light output from the wavelength independent light source 12 and outputs it to the transmission light detector 14.

The transmission light detector 14 measures the intensity of light branched from the optical splitter 13 and feeds back the measured value (optical power) to the light source driver 11.

The temperature controller 15 keeps the temperature of the wavelength independent light source 12 constant so that the output wavelength of the wavelength independent light source 12 is maintained at the same wavelength as that of the injected light source. The general characteristic of the wavelength independent light source 12 such as FP-LD, SOA, and RSOA described above is that it provides a relatively uniform wideband amplification band, which is output from the wavelength independent light source 12 through this characteristic. The wavelength of the optical signal has the same wavelength as that of the injected light source. However, since the amplification band of the wavelength independent light source 12 moves in accordance with the temperature of the light source, the performance of the optical link may be degraded under certain environmental conditions. Therefore, in order to prevent this, a temperature controller such as a heater or a thermoelectric cooler is attached to the wavelength independent light source 12 to maintain a constant temperature of the light source 12.

The external power monitoring unit 16 detects the voltage value of the external power applied to the optical transmission and reception apparatus separately from the internal power applied through the standard interface with the WDM system and transmits the voltage value to the control unit 22. That is, a large amount of power is consumed when the temperature controller 15 is used to keep the temperature of the wavelength independent light source 12 constant. However, since the conventional optical transmission and reception device presupposes the use of a fixed wavelength light source that does not require a temperature controller, the size of the power to which the optical transmission and reception device is applied through the standard interface with the WDM system is limited. Therefore, the optical transmission and reception apparatus of the present invention is external to receive external power separately from the power applied through the standard interface with the WDM system to operate the temperature control unit 15 while maintaining compatibility with the conventional optical transmission and reception apparatus. It is provided with a power terminal (not shown) through which additional external power is supplied. Accordingly, the external power monitoring unit 16 detects the voltage value and transmits the voltage value to the control unit 22 to monitor whether the voltage value of the external power source is stably maintained.

The memory 17 stores data for driving the optical transmitting and receiving device and information on the standard of the optical transmitting and receiving device, and provides the corresponding information to the controller 22 at the request of the controller 22. In particular, as shown in FIG. 3, the memory 17 stores the voltage value of the external power supply separately supplied to drive the temperature controller 15, reference values for determining whether the external power supply is abnormal, and abnormality of the external power supply. Stores flags for notifying the system.

The temperature sensor 18 senses the temperature in the optical transceiver and transmits the result to the controller 22.

The internal power monitor 19 detects a voltage value of a power (internal power) received from the WDM system through a standard interface with the WDM system and transmits the voltage value to the control unit 22.

The reception light detector 20 converts the optical signal received through the reception optical fiber into an electrical signal and transmits the signal to the limiting amplifier 21.

The limiting amplifier 21 amplifies the received data from the receiving light detector 20 and transmits the received data to the WDM system as a differential signal through a standard interface. The limited amplifier 21 detects the reception power and the reception failure by comparing the magnitude of the received signal with a preset threshold and transmits the detection result to the controller 22.

The control unit 22 controls the data transmission and reception operation of the optical transmission and reception device as a whole, and transmits the failure information from the light source driver 11 and the limiting amplifier 21 to the WDM system through the standard interface during data transmission and reception. In particular, the controller 22 stores the voltage value of the external power provided from the external power monitor 16 in the memory 17 and compares the voltage value with the preset reference values as shown in FIG. If it is higher or lower than these thresholds, the status is notified to the WDM system using the flag of FIG. 3C. At this time, the control unit 22 transmits a flag to the WDM system through the two-wire serial interface of the standard interface.

Although FIG. 2 illustrates a case in which a transmitting optical fiber for transmitting an optical signal and a receiving optical fiber for receiving an optical signal are respectively separated, it is also possible to use one optical fiber in both directions.

The operation of the optical transmission and reception apparatus according to the present invention having the above-described configuration will be briefly described as follows. In the following description, since the processing for the optical signal received through the receiving optical fiber is substantially the same as in the conventional optical transmitting and receiving apparatus, description thereof will be omitted.

When the transmission data (differential signal) is received from the WDM system, the light source driver 11 drives the wavelength independent light source 12 in accordance with the received differential signal. At this time, the wavelength independent light source 12 is injected with a narrow band of spectral divided auxiliary light having a specific light wavelength (not shown), so that the wavelength of the optical signal output from the wavelength independent light source 12 is determined by the auxiliary light injected. .

The optical signal output from the wavelength independent light source 12 is partially branched from the optical splitter 13 and applied to the transmission light detector 14.

The transmission light detector 14 measures the power of the light branched from the optical splitter 13 to sense the power of the transmission light and feeds back the detected value to the light source driver 11.

The light source driver 11 compares the value fed back from the transmission light detector 14 with a preset reference value to compensate for the difference and drives the wavelength independent light source 12 by compensating for the difference. It stabilizes the intensity of the light output from the constant. Then, the light source driver 11 transmits the information about the transmission power and transmission failure to the controller 22 based on the value fed back from the transmission light detector 14.

As described above, the temperature controller 15 detects the temperature of the wavelength independent light source 12 and compares the value with a preset reference value as shown in FIG. As a result of comparison, when the temperature of the wavelength independent light source 12 is higher or lower than the reference value, the temperature controller 15 drives a temperature control device such as a heater or a thermoelectric cooler to set the temperature of the wavelength independent light source 12 to a predetermined level. By adjusting so as to be maintained, the wavelength of the light output from the wavelength independent light source 12 is stabilized. At this time, the power required for the operation of the temperature control unit 15 is applied through an external power terminal (not shown) provided separately from the standard interface. Therefore, the controller 22 continuously monitors the voltage value of the external power supplied to the temperature controller 15 through the external power monitor 16.

The controller 22 compares the voltage value of the external power provided from the temperature controller 15 with the preset reference value (FIG. 3B) and displays the situation when the voltage value of the external power becomes higher or lower than the reference value. Notify the WDM system via the serial interface. That is, the controller transmits a flag (warning or caution flag) of FIG. 3C indicating a voltage value of an external power supply and an abnormal supply of an external power supply to a WDM system through a two-wire serial interface.

As described above, the optical transmission / reception apparatus of the present invention has a connection structure (standard interface) with the WDM system of the conventional optical transmission / reception apparatus as it is, while maintaining compatibility with the existing optical transmission / reception apparatus, while simultaneously providing a wavelength to the optical transmission / reception apparatus. Adopts independent light source.

Claims (5)

In the optical transmission and reception apparatus having a standard interface structure for connection with a WDM system, A wavelength independent light source outputting a variable wavelength of light according to the injected light; A transmission light detector which measures the transmission light output of the wavelength independent light source and outputs the measured value; A light source driver for driving the wavelength independent light source in accordance with the differential signal from the WDM system and the measured value from the transmission light detector; A temperature controller which senses a temperature of the wavelength independent light source and controls the temperature of the wavelength independent light source to be kept constant; An external power monitoring unit that monitors a change in external power supplied for operation of the temperature controller separately from the internal power supplied through the standard interface; And It controls the operation of the optical transmission and reception device as a whole, and receives the information on the output state of the wavelength independent light source from the light source driver and the information on the supply state of the external power from the external power monitoring unit to receive the standard interface. And a wavelength independent light source having a control unit for transmitting the state information to the WDM system. The method of claim 1, And a light splitter for dividing a part of the light output from the wavelength independent light source and transmitting it to the transmission light detecting unit. The method of claim 1, wherein the wavelength independent light source An implant-locked Fabry-Perot laser diode, a semiconductor amplifier for amplifying and modulating the injection light, and a reflective semiconductor optical amplifier for reflecting and amplifying and modulating the injection light are employed. One optical transmitter and receiver. The method of claim 1, wherein the control unit And a wavelength independent light source, which transmits status information on the external power source to the WDM system via a two-wire serial interface of the standard interface. The method of claim 4, wherein the control unit Optical transmission and reception device employing a wavelength independent light source, characterized in that for transmitting the voltage value of the external power supply currently supplied as the status information for the external power and warning or warning information indicating the abnormality of the external power supply to the WDM system. .

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