KR100547721B1 - Optical amplifier module and optical transmission system using same - Google Patents

Abstract

The present invention relates to an optical amplifier module for amplifying each optical signal having a different wavelength by using a semiconductor optical amplifier, and an optical transmission system using the same.

An optical amplifier module of the present invention comprises: a first wavelength division multiplexer for separating optical signals into respective wavelength bands; And at least two semiconductor optical amplifiers for amplifying each of the optical signals separated into the respective wavelength bands, and respective optical branch taps for dividing a part of the optical signals amplified by the respective semiconductor optical amplifiers.

According to the present invention, there is provided an optical amplifier module suitable for bidirectional communication using different wavelength bands, can be integrated in a small size, and has an excellent cost competitiveness, and an optical transmission system using the same.

Semiconductor Optical Amplifiers, Wavelength Division Multiplexers, Optical Branch Taps, Optical Isolators

Description

Optical amplifier module and optical transmission system using same {OPTICAL AMPLIFIER MODULE AND OPTICAL TRANSMITTING SYSTEM USING THE SAME}             

1 is a diagram showing the configuration of a bidirectional semiconductor optical amplifier module according to a first embodiment of the present invention;

2 is a view showing the configuration of a bidirectional semiconductor optical amplifier module according to a second embodiment of the present invention;

3 is a view showing the configuration of a bidirectional semiconductor optical amplifier module according to a third embodiment of the present invention;

4 is a view showing an example of the configuration when the semiconductor optical amplifier module of the present invention is applied to a PON network,

5 is a view showing the configuration of a bidirectional semiconductor optical amplifier module according to a fourth embodiment of the present invention;

FIG. 6 is a diagram illustrating an example of a configuration in which the semiconductor optical amplifier module of FIG. 5 is applied to a bidirectional optical communication network. FIG.

The present invention relates to an optical amplifier, and more particularly, to an optical amplifier module for amplifying each of the optical signals of different wavelengths using a semiconductor optical amplifier and an optical transmission system using the same.

In recent years, WDM (Wavelength Division Multiplexing) optical communication systems have been widely applied to subscriber networks and local area networks. At this point, in order to further evolve into an optical subscriber system such as fiber to the home (FTTH), low cost and miniaturized functional optical modules are needed.

Paper [Three-waveguide two-grating codirectional coupler for 1.3- / 1.3 + / 1.5㎛ demultiplexing in transceiver, A. Lupu et al, Vol. 36, No. 24, Electronics Letters, 2000], the Passive Optical Network (PON) network is an optical network unit (ONU) installed in several subscriber premises in an optical line terminal (OLT) of a central office. The connection is made via 1 XN passive optical splitter. In general, the uplink transmission signal from the ONU to the OLT is transmitted through the 1.3 μm band, and the downlink transmission signal from the OLT to the ONU is bidirectionally transmitted using the 1.5 μm band. At this time, the signal transmitted downward from the OLT is received by the ONU of each subscriber's premises with optical signal power reduced by 1 / N times while passing through the 1 XN passive optical splitter. Optical signal power is received at the OLT. This optical loss requires expensive, high-performance 1.3µm / 1.5µm transmit and receive optical modules in the OLT and ONU, and typically limits the number of ONUs connected to one OLT to about 16. Accordingly, there is a problem in that the cost burden for installing and maintaining the subscriber network is greatly increased.

In order to solve the optical loss problem, an optical amplifier module for amplifying and outputting an input optical signal is used.

In general, an optical amplifier module uses an Erbium Doped Fiber Amplifier (EDFA), a Raman Amplifier, or a semiconductor optical amplifier (SOA).

EDFA has the advantage of having a high gain characteristic and excellent noise figure (NF), but has a problem that the operating wavelength is limited to the 1.5㎛ band.

Raman amplifier has the advantage of having a wide operating bandwidth of 1.3㎛ to 1.6㎛ band, but optical pumping (optical pumping) is required to add additional optical components such as expensive light pumping light source and WDM wavelength combiner need. Accordingly, there is a problem in that the overall size of the optical amplifier module is increased and the price of the optical module is increased.

The semiconductor optical amplifier (SOA) uses the gain characteristics of the semiconductor and operates in the 1.3 μm band and the 1.5 μm band and has a high gain characteristic of approximately 28 dB or more. The size of the device is small, within a few mm, and has the advantage of not requiring an expensive pumping light source. However, a problem has been pointed out to simultaneously amplify the optical signals in the 1.3 μm band and the 1.5 μm band by separately configuring the SOA in the 1.3 μm band and the SOA in the 1.5 μm band.

Accordingly, it is an object of the present invention to provide an optical amplifier module suitable for bidirectional communication using different wavelength bands, which can be integrated in a small size, and has a high cost and an optical transmission system using the same.

In order to achieve the above object, the optical amplifier module of the present invention comprises a first wavelength division multiplexer for separating the optical signal into each wavelength band; And at least two semiconductor optical amplifiers for amplifying each of the optical signals separated into the respective wavelength bands, and respective optical branch taps for dividing a part of the optical signals amplified by the respective semiconductor optical amplifiers.

Preferably, the method further comprises a second wavelength division multiplexer for multiplexing and outputting the optical signal amplified by the semiconductor optical amplifier.

In addition, the optical transmission system of the present invention in a passive optical network of a tree structure in which an optical line termination (OLT) and a plurality of optical network units (ONU) are connected through an optical splitter, the OLT to ONU To amplify the downlink signal transmitted and the uplink signal transmitted from the ONU to the OLT

First and second wavelength division multiplexers for separating and combining the downlink signal and the uplink signal; A plurality of semiconductor optical amplifiers and the semiconductor optical amplifiers disposed between the first and second wavelength division multiplexers, respectively, for amplifying optical signals separated into respective wavelength bands by the first and second wavelength division multiplexers; And a bidirectional semiconductor optical amplifier module disposed between the two wavelength division multiplexers, the bidirectional semiconductor optical amplifier module having respective optical branch tabs for dividing some of the optical signals amplified by the respective semiconductor optical amplifiers.

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 though they are 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.

1 is a diagram showing the configuration of a bidirectional semiconductor optical amplifier module according to a first embodiment of the present invention.

Referring to FIG. 1, the bidirectional semiconductor optical amplifier module 100 includes a wavelength division multiplexer 10 and first and second semiconductor optical amplifiers 20 and 30 connected to respective channels of the wavelength division multiplexer 10. It is configured to include.

The wavelength division multiplexer 10 separates an input optical signal of 1.3 μm / 1.5 μm band into a 1.3 μm band optical signal and a 1.5 μm band optical signal, respectively.

The first semiconductor optical amplifier 20 is a semiconductor optical amplifier operating in a 1.5 μm band, and amplifies an optical signal input from a 1.5 μm band channel of the wavelength division multiplexer 10.

The second semiconductor optical amplifier 30 is a semiconductor optical amplifier operating in a 1.3 μm band, and amplifies an optical signal input from a 1.3 μm band channel of the wavelength division multiplexer 10.

2 is a diagram illustrating a configuration of a bidirectional semiconductor optical amplifier module according to a second embodiment of the present invention. FIG. 2A illustrates a case in which the traveling directions of the 1.5 μm band and 1.3 μm band optical signals are the same. 2 (b) shows a case where the traveling directions of the 1.5 μm band and 1.3 μm band optical signals are different from each other.

Referring to FIG. 2, the bidirectional semiconductor optical amplifier module 200 may include a wavelength division multiplexer 10 and first and second semiconductor optical amplifiers 20 and 30 connected to respective channels of the wavelength division multiplexer 10. And an optical isolator 40 to 45 connected to the input and output terminals of the first and second semiconductor optical amplifiers 20 and 30, respectively. Differences from FIG. 1 are in the optical isolators 40 to 45, and other configurations and operations are the same as those in FIG. 1, and thus only the optical isolators 40 to 45 will be described in the description of this embodiment in order to avoid overlapping materials. .

The optical signals input to the semiconductor optical amplifiers 20 and 30 reflect some optical signals at both facets of the semiconductor optical amplifiers 20 and 30, and the reflected optical signals cause interference with the input optical signals. do. Such interference phenomenon is one cause of deterioration of characteristics of the optical signal amplified by the semiconductor optical amplifier. Therefore, the amplification characteristics of the semiconductor optical amplifier are reduced by inserting the optical isolators 40 to 45 at the input and output ends of the semiconductor optical amplifiers 20 and 30, respectively, as in the present embodiment, thereby blocking the reverse of the optical signal. It can be improved. In this case, the optical isolators 40 to 45 may be disposed at either of the input or output terminals of the semiconductor optical amplifiers 20 and 30 as necessary, but are preferably disposed at both ends to minimize reflection of the optical signal. Do.

3 is a view showing the configuration of a bidirectional semiconductor optical amplifier module according to a third embodiment of the present invention, this embodiment transmits a 1.5㎛ band optical signal and 1.3㎛ band optical signal in both directions through one transmission path If it is.

Referring to FIG. 3, the bidirectional semiconductor optical amplifier module 300 includes first and second wavelength division multiplexers 10 and 50 and first and second signals connected to respective channels of the first wavelength division multiplexer 10. 2 includes a semiconductor optical amplifier 20, 30, which is a second wavelength division multiplexer 50 is further included in the configuration of FIG.

The second wavelength division multiplexer 50 serves to multiplex optical signals for each channel amplified by the first and second semiconductor optical amplifiers 20 and 30 and transmit them through one optical fiber. As such, the first and second wavelength division multiplexers 10 and 50 may be provided to enable bidirectional signal transmission through one optical fiber.

4 illustrates an example of a configuration in which the semiconductor optical amplifier module of the present invention is applied to a PON network.

PON connects one Optical Line Termination (OLT) 1 and a plurality of ONUs (Optical Network Units 3a to 3c) using a 1 × N optical splitter (2). It is an optical subscriber network structure forming a distributed topology.

The OLT (1) and ONU (3a, 3b, 3c) comprises a laser diode (LD), a photodiode (PD) and a wavelength division multiplexer (WDM), respectively, the laser diode (LD) has a transmission function The photodiode PD performs a reception function. The communication signal between the OLT and the ONU uses a 1.5 μm band for downlink transmission from the OLT to the ONU, and the uplink transmission from the ONU to the OLT uses a 1.3 μm band for bidirectional transmission.

The semiconductor optical amplifier module 300 is disposed between the OLT 1 and the 1xN passive optical splitter 2 and amplifies uplink and downlink optical signals for respective bands, and then multiplexes them to output them. In this case, the semiconductor optical amplifier module 300 may be installed in the link between the OLT 1 and the 1xN passive optical splitter 2 or disposed in the OLT 1 as in the present embodiment.

FIG. 5 is a diagram illustrating a configuration of a bidirectional semiconductor optical amplifier module according to a fourth exemplary embodiment of the present invention, in which the optical power monitoring function is added.

Referring to FIG. 5, the bidirectional semiconductor optical amplifier module 400 includes first and second wavelength division multiplexers 10 and 50, first and second semiconductor optical amplifiers 20 and 30, and a monitoring optical branch tap. And 60, 70.

The monitoring optical branch tabs 60 and 70 are disposed between the semiconductor optical amplifiers 20 and 30 and the second wavelength division multiplexer 50, and the power of the optical signal reduced in the 1.5 µm / 1.3 µm bidirectional optical transmission network. It extracts a portion of the optical signal by branching the transmission optical signal to monitor (61, 71).

6 illustrates an example in which the semiconductor optical amplifier module of FIG. 5 is applied to a bidirectional optical communication network. The bidirectional semiconductor optical amplifier module 400 including the monitoring optical branch tabs may include a first diode and a second transceiver 4 including a laser diode LD, a photo diode PD, and a wavelength division multiplexer WDM, respectively. 5) is placed between.

The operation of this embodiment having the above configuration is as follows.

5 and 6, a 1.5 μm band optical signal transmitted downward from the first transceiving unit 4 and a 1.3 μm band optical signal transmitted upward from the second transceiving unit 5 are divided into a first wavelength division multiplex. The firearm 10 separates the 1.5 μm band optical signal and the 1.3 μm band optical signal. The 1.5 탆 band optical signal is amplified by the first semiconductor optical amplifier 20 for the 1.5 탆 band. The amplified optical signal is partially extracted by the monitoring optical branch tap 60 (61) and monitored by the optical signal monitoring device 6, and the remaining optical signal is transmitted as it is by the second wavelength division multiplexer 50. Multiplexed and transmitted to the second transceiver 5 through one optical fiber. Similarly, the 1.3 μm band optical signal transmitted upward from the second transceiver 5 is also amplified by the second semiconductor optical amplifier 30 for the 1.3 μm band and partially extracted by the monitoring optical branch tap 70 ( 71) is monitored by the optical signal monitoring device 6, the remaining optical signal is transmitted as it is, multiplexed by the first wavelength division multiplexer 10 and transmitted to the first transceiver 4 through one optical fiber.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

As described above, the optical amplifier module of the present invention can compensate for the attenuation of the optical signal at a low cost by amplifying and outputting the transmission optical signal for each band by using a semiconductor optical amplifier operating in the band used for the transmission optical signal.

Therefore, when the optical amplifier module of the present invention is applied to a subscriber network such as a PON, the number of ONUs connected to the OLT can be increased than before, thereby reducing network management and installation costs.

In addition, it is expected that the installation of the 1.5 μm / 1.3 μm bidirectional optical communication network will be widely performed, and thus, it is expected to move forward toward the FTTH (Fiber to the Home) as well as the activation of the 1.5 μm / 1.3 μm bidirectional optical transceiver market.

Claims (8)

An optical amplifier module for amplifying an optical signal, A first wavelength division multiplexer for separating the optical signal into respective wavelength bands; At least two semiconductor optical amplifiers for amplifying each of the optical signals separated into each wavelength band; Respective optical branch taps for branching a portion of the optical signal amplified by each of the semiconductor optical amplifiers Optical amplifier module, characterized in that configured to include. The optical amplifier module of claim 1, further comprising a second wavelength division multiplexer for multiplexing and outputting an optical signal amplified by the semiconductor optical amplifier. The optical amplifier module according to claim 1 or 2, further comprising an optical isolator connected to at least one of an input or an output terminal of the semiconductor optical amplifier. delete In a passive optical network having a tree structure in which an optical line termination (OLT) and a plurality of optical network units (ONUs) are connected through an optical splitter, a downlink signal transmitted from the OLT to the ONU and an OLT in the ONU To amplify the uplink signal First and second wavelength division multiplexers for separating and combining the downlink signal and the uplink signal; A plurality of semiconductor optical amplifiers and the semiconductor optical amplifiers disposed between the first and second wavelength division multiplexers, respectively, for amplifying optical signals separated into respective wavelength bands by the first and second wavelength division multiplexers; And a bidirectional semiconductor optical amplifier module disposed between two wavelength division multiplexers, each bidirectional semiconductor optical amplifier module having a respective optical branch tab for dividing a portion of the optical signal amplified by each semiconductor optical amplifier. 6. The bidirectional semiconductor optical amplifier module of claim 5, wherein And a link installed between the OLT and the optical splitter. 6. The bidirectional semiconductor optical amplifier module of claim 5, wherein And disposed in the OLT. 6. The optical transmission system according to claim 5, further comprising an optical isolator connected to at least one of an input or an output terminal of the semiconductor optical amplifier.

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