KR20040043210A - High-power broadband light source - Google Patents

Abstract

PURPOSE: A light source with a high power optical bandwidth is provided to implement the light source having a high power optical bandwidth with two outputs at a low cost. CONSTITUTION: A light source with a high power optical bandwidth includes a common gain terminal(206), a first output terminal(205) and a second output terminal(207). The common gain terminal(206) is provided with a first output end and a second output end to bidirectionally output the amplified spontaneous emission(ASE) with A bandwidth. The first output terminal(205) is connected to the first end of the common gain terminal(206) to output the high power optical bandwidth light of the A-bandwidth by amplifying the ASE of the A-bandwidth. And, the second output terminal(207) is connected to the second output end of the common gain terminal(206) to output the high power optical bandwidth light of B bandwidth by using the ASE of the A-bandwidth as a pumping light.

Description

High-power broadband light source

The present invention relates to a broadband light source, and more particularly to a high output broadband light source having two output terminals. The broadband light source of the present invention outputs two broadband lights of the same band or two broadband lights of different bands.

The broadband light source is mainly used to measure the operating characteristics according to the wavelength of the optical device. The characteristics of the optical device must be operated in a wide wavelength range for measurement, and high power optical power is required to reduce measurement errors. Due to the recent development of the wavelength division multiplexing optical communication system, the C-band (1530 nm to 1560 nm) band and the L-band (1570 nm to 1600 nm) band are actively utilized.

In addition, the broadband light source is also used as the light source for the wavelength division multiplexing optical subscriber network. This is described in US Pat. No. 5,440,417 and in the international journal “IEEE Photonic Technology Letters, vol. 12, no. 8, pp. 1067-1069 ”. In order to implement a wavelength division multiple access optical network, two high power broadband light sources for uplink and downlink signal allocation are required.

In order to obtain a high power broadband light source, a method using a semiconductor optical amplifier and a rare earth-doped optical fiber was mainly used. 1 is a block diagram of a broadband light source using a rare earth-added optical fiber, which is shown in US Pat. No. 6,424,762. Referring to Figure 1 as follows.

When optically pumping optical fibers containing rare earth elements such as Er (Erbium), Pr (Praseodymium), and Yb (Ytterbium), amplified spontaneous emitted light (ASE) is generated. In particular, Er-added optical fiber emits C-band and L-band ASE. When the rare earth addition optical fiber 103 is used to excite the pump light 109 using the wavelength division multiplexer 104, the ASE generated in the rare earth addition optical fiber 103 propagates in both directions 107 and 108. ASE proceeding in the opposite direction of the dual-optical output terminal 110 has a disadvantage that can not be used. In order to improve this, the optical power of the light output terminal 110 is maximized by reflecting using the light reflector 101. The second wavelength division multiplexer 102 and the light absorber 106 were used to prevent the reflection of the pump light.

Conventional broadband light source is a way to obtain a high power in one band. That is, when two high power broadband light sources of the same band or high power light sources of two different bands are required, there is a limit to be manufactured independently.

The present invention has been made to solve the above problems of the prior art, an object of the present invention to provide a high power light source for wavelength division multiplex optical communication and optical measurement.

Another object of the present invention is to provide a high output broadband light source having a simple structure with two outputs. In addition, a simple structure provides a high power broadband light source operating in different wavelength bands.

As a technical idea for achieving the above object of the present invention, the present invention proposes a low cost implementation of a high power broadband light source of two bands using a rare earth-added fiber amplifier, a semiconductor optical amplifier, or a nonlinear fiber amplifier.

The present invention is an efficient structure using both directions of the ASE generated in the common gain stage.

1 is a schematic block diagram illustrating a broadband light source using a rare earth-added optical fiber according to the related art.

Figure 2 is a schematic block diagram showing a broadband light source according to an embodiment of the present invention

3 is a schematic block diagram showing a broadband light source using a erbium-doped optical fiber according to the present invention.

4 is a graph showing bidirectional optical output characteristics of a common gain stage using an erbium-doped optical fiber

5 is a graph illustrating output characteristics of a C-band output stage having a gain flattening filter.

6 is a graph illustrating output characteristics of a C-band output stage having a Fabry-Parrot filter.

7 is a graph illustrating output characteristics of an L-band output terminal.

Fig. 1 is a schematic block diagram of a public gain stage of a wideband light source according to the present invention.

Hereinafter, with reference to the accompanying drawings, the configuration and operation of the embodiment of the present invention will be described in detail.

2 is a block diagram of a high power broadband light source according to the present invention. The broadband light source includes a common gain stage 206, a first output stage 205, and a second output stage 207. Arrows 201-204 represent light paths. The common gain stage has two output terminals 210 and 211. One output terminal 210 of the common gain terminal is connected to the input terminal 209 of the first output terminal, and the other output terminal 211 is connected to the input terminal 212 of the second output terminal.

As a preferred embodiment for implementing a high power broadband light source, a common gain stage having a first output terminal and a second output terminal for outputting the ASE of the A band in both directions, and an A band connected to and input to the first output terminal of the common gain terminal; A-band high-power wideband light is output by using a first output stage for amplifying the ASE of the A band and outputting high-bandwidth broadband light in the A band, and an ASE in the A band, which is connected to and inputted to a second output terminal of the common gain stage, as a pumping light. And a second output stage.

In the above embodiment, the common gain stage is a semiconductor optical amplifier or a rare earth-doped optical fiber. As the first output terminal and the second output terminal, a semiconductor optical amplifier, a rare earth-added optical fiber amplifier, and an optical fiber amplifier using a nonlinear phenomenon are used.

3 is a block diagram of a two-band high power broadband light source according to the preferred embodiment described above. This embodiment aims to implement different high power broadband light sources of C-band (1530 nm to 1560 nm) in the A band and L-band (1570 nm to 1600 nm) in the B band. In addition, the embodiment using only the rare earth addition fiber amplifier.

ASE is emitted when optically pumping a rare earth-doped optical fiber. In particular, when erbium is added, ASE can be obtained in C-band and L-band. C-band ASE can be obtained by optical pumping of 980 nm or 1480 nm in erbium-doped fiber. If the length of the erbium-doped fiber is longer, the C-band ASE is again acting as a pumping light to emit the L-band ASE.

The common gain stage 301 of this embodiment emits a C-band ASE, the first output stage 300 is a C-band output stage, and the second output stage 302 is an L-band output stage.

The common gain stage 301 is composed of a pump light source 315, a wavelength division multiplexer 310, an erbium-doped optical fiber 304, and optical deflector tubes 309 and 311. The pumping light source 310 may be a high power laser diode, a fiber laser, or the like in the 980 nm or 1480 nm band. The wavelength division multiplexer 310 delivers the pumped light to the erbium-doped optical fiber. When pumping light is incident on the erbium fiber, C-band ASE is generated and output in both directions.

4 is a light output graph (400, 401) of the ASE direction occurs in the common gain stage according to the above embodiment. The 9.8 m Erbium-doped optical fiber was optically pumped using a 1480 nm pump laser diode. The ASE 401 delivered to the C-band output terminal and the ASE 402 delivered to the L-band output terminal are both ASEs in the C-band region. The common gain stage can be used as a C-band broadband light source with two output stages. However, the common gain stage alone is difficult to implement a high power C-band broadband light source of more than 20 dBm, and there is a limit in flattening the output spectrum.

The C-band output stage 300 amplifies the input ASE 401 of the common gain stage. The C-band output stage includes a pumping light source 314, an erbium-doped optical fiber 303, a wavelength division multiplexer 307, an optical deflector tube 306, and an optical wavelength filter 308. The optical wavelength filter 308 may be a band-pass filter, a Fabry-Parot filter, an optical interleaver, or a flat output to obtain an output of only a certain portion of the C-band region. It is a gain flattening filter for obtaining a characteristic or a combination thereof. By adjusting the intensity of the pumping light source at the C-band output stage, broadband light of desired intensity can be obtained.

5 is an optical output spectrum of a C-band output stage using the gain flattening filter according to the embodiment as the optical wavelength filter 308. A 6.5 m Erbium-doped fiber and a 1480 nm pumped laser diode were used for the C-band output stage. The output optical power was flattened through a gain flattening filter. Measurements were taken at a resolution of 0.2 nm. Flatness is within 1.5 dB within 30 nm, and the total output optical power is 20 dBm or more high power C-band broadband light source.

6 is an optical output spectrum of a C-band output stage using a Fabry-Perot filter and a gain flattening filter as the optical wavelength filter 308 according to the embodiment. A Fabry-Parrot filter with a period of 100 GHz was used. When the Fabry-Perot filter is inserted, it is possible to realize a high power light source having periodic output characteristics. In addition, since it shows output characteristics similar to those of the wavelength division multiplexed optical signal, it can be used to measure the characteristics of the optical amplifier and the optical passive element required for the wavelength division multiplexing method.

Meanwhile, in FIG. 3, the L-band output terminal 302 includes a pumping light source 316, a wavelength division multiplexer 312, an erbium-doped optical fiber 305, and an optical deflective tube 313. The L-band output stage can be realized by extending the length of the erbium-doped fiber. As the length of the erbium-doped fiber increases, the pumping light source of 980 nm or 1480 nm is absorbed by all part of the erbium-doped fiber, which causes the C-band pumped light to propagate deep into the erbium-doped fiber and To gain.

Efficiency can be greatly improved by inserting C-band light from the outside rather than using only C-band pumping light generated by the L-band output stage itself. The externally applied C-band ASE is amplified by 980 nm or 1480 nm pumped light at the L-band output stage and used as a pumping light for generating L-band ASE in the erbium-doped optical fiber.

7 is an output spectrum of an L-band output terminal according to an embodiment of the present invention. An 57 m erbium-doped fiber and a 1480 nm pump laser diode were used. When the common gain stage is not connected (701) and the C-band ASE is injected (700), it can be seen that the output power is significantly different. In the embodiment of the present invention, the L-band output stage had flatness within 2 dB in a region of 30 nm or more without using a gain flattening filter.

In the embodiment of FIG. 3, only one-way optical pumping is used for the gain medium of the C-band output stage, the common gain stage, and the L-band gain stage to realize a low cost light source. Light output can be improved by bidirectional optical pumping of the gain medium.

3 is an embodiment for configuring a high power broadband light source of two bands using a rare earth fiber amplifier. In the above embodiments, a semiconductor optical amplifier may be used as the common gain stage. In addition, a semiconductor optical amplifier or a nonlinear fiber amplifier may be used as the first output terminal and the second output terminal.

In another preferred embodiment of implementing the high power broadband light source of the present invention, a common gain terminal having a first output terminal and a second output terminal and outputting an ASE in the A band in both directions is connected to a first output terminal of the common gain terminal. A first output stage for amplifying the input ASE and outputting high-bandwidth wideband light of A band, and a second output stage connected to a second output terminal of the common gain stage and amplifying the input ASE for outputting A-band high-power wideband light; It is a broadband light source characterized in that.

In another preferred embodiment of implementing the high power broadband light source of the present invention, a common gain terminal having a first output terminal and a second output terminal and outputting an ASE in the A band in both directions is connected to a first output terminal of the common gain terminal. The first output stage outputting the high output broadband light of the B band by using the inputted ASE of the A band as the pumping light source, and the ASE of the A band which is connected to the second output terminal of the common gain terminal and used as the pumping light B And a second output stage for outputting high-bandwidth broadband light in a band.

In another preferred embodiment of the high power broadband light source of the present invention, the first output terminal and the second output terminal have a first output and emit an AS1 band that is part of the A band, and the second output terminal is a part of the rest of the A band. A public gain stage that emits an ASE in the A2 band, a first output stage that amplifies the ASE in the A1 band that is connected to the first output terminal of the common gain stage and outputs the high output light of the A1 band, and a second of the common gain stage; And a second output terminal for amplifying the ASE of the A2 band inputted to the output terminal and outputting the high output broadband light of the A2 band. The A1 output stage and the 2nd output stage can be used with an A-band optical amplifier.

Fig. 8 is a configuration example of a public gain stage that emits AASE of A1 band to the first output stage and emits AASE of A2 band to the second output stage according to the preferred embodiment described above. Two-way optical amplifiers are used. Two-way optical amplifiers are implemented as rare-earth-added optical fiber amplifiers, semiconductor optical amplifiers, or non-linear optical fiber amplifiers, without the use of optical deflectors.

The A-band ASE is generated in both directions by the bidirectional optical amplifier. The light in the A2 band during the ASE proceeding to the left in Fig. (A) is reflected by the first A1 and A2 band wavelength division multiplexer (06) and the reflector (901), and then enters the optical amplifier (70). The re-entry light in the A2 band is amplified by the optical amplifier (07) and passed through the second A1 and A2 band wavelength division multiplexers (90) and the optical deflector (90) to output to the second output stage (90). The light in the A1 band of the ASE, which proceeded to the right, is reflected by the wavelength-division multiplexer (90) and the reflector (90) in the second A1 and A2 bands and then enters the optical amplifier (90). The light of the A1 band, which has been reentered, is amplified by the optical amplifier (07) and passed through the first A1 and A2 band wavelength division multiplexers (90) and the optical deflector tube (90) to the first output stage (90). (110, 80) has light reflection characteristics independent of wavelength.

Fig. (B) shows the optical power coupler (14, 16) and the wavelength of the optical power coupler (14, 16) that separate and separate the optical power instead of the wavelength-divided multiplexers (06, 0, 0) and wavelength independent optical reflectors (10, 0, 0) for the A1 and A2 bands. This embodiment is implemented by using reflectors (110 and 11). The principle of operation is the same as in Figure (a).

While the invention has been described above based on the preferred embodiments thereof, these embodiments are intended to illustrate rather than limit the invention. It will be apparent to those skilled in the art that various changes, modifications, or adjustments to the above embodiments can be made without departing from the spirit of the invention.

As described above, according to the present invention, a common gain stage is provided so that the first output stage and the second output stage are shared, so that the bidirectional ASE of the common gain stage can be used. Therefore, a simple structure and low cost, high power broadband light source having two outputs can be realized. Improved output optical power enables precise measurement of optical devices. Also, it is used as a broadband light source for wavelength division multiplexing optical subscriber network and as a light source for up and down signals.

Claims (27)

In the method of implementing a high power broadband light source, A common gain terminal having a first output terminal and a second output terminal and outputting the ASE of the A band in both directions; A first output terminal connected to the first output terminal of the common gain stage and amplifying the ASE of the A band to be input to output high-power wideband light of the A band; And a second output terminal connected to the second output terminal of the common gain stage and outputting the high output broadband light of the B band by using the ASE of the A band as the pumping light. The method of claim 1, The common gain stage includes a rare earth-doped fiber amplifier and a semiconductor optical amplifier that output ASEs in the A band in both directions. The method of claim 1, The first output terminal is a high-power broadband light source, characterized in that the rare earth-added optical fiber amplifier, a semiconductor optical amplifier, a non-linear optical fiber amplifier for amplifying the input A-band broadband light. The method of claim 1, The second output stage is a high-power broadband light source, characterized in that the rare earth-added optical fiber amplifier, semiconductor optical amplifier, nonlinear optical fiber amplifier for outputting the B-band high-power broadband light by using the input A-band broadband light as the pumping light. In the method of implementing a high power broadband light source, A common gain terminal having a first output terminal and a second output terminal and outputting the ASE of the A band in both directions; A first output terminal connected to the first output terminal of the common gain stage and amplifying the ASE of the A band to be input to output high-power wideband light of the A band; And a second output terminal connected to the second output terminal of the common gain stage and amplifying the ASE of the A band to be input to output the high output broadband light of the A band. The method of claim 5, The common gain stage includes a rare earth-doped fiber amplifier and a semiconductor optical amplifier that output ASEs in the A band in both directions. The method of claim 5, The first output stage is a high power broadband light source, characterized in that the rare-earth-added optical fiber amplifier, semiconductor optical amplifier, nonlinear optical fiber amplifier for amplifying the input A band ASE. The method of claim 5, The second output terminal is a high power broadband light source, characterized in that the rare earth-added optical fiber amplifier, semiconductor optical amplifier, nonlinear optical fiber amplifier for amplifying the input A-band ASE. In the method of implementing a high power broadband light source, A common gain terminal having a first output terminal and a second output terminal and outputting the ASE of the A band in both directions; A first output terminal connected to the first output terminal of the common gain stage and outputting high-power wideband light of the B band by using an ASE in the A band as pumping light; And a second output terminal connected to the second output terminal of the common gain stage and outputting the high output broadband light of the B band by using the ASE of the A band as the pumping light. The method of claim 9, The common gain stage includes a rare earth-doped fiber amplifier and a semiconductor optical amplifier that output ASEs in the A band in both directions. The method of claim 9, The first output stage is a high-power broadband light source, characterized in that the rare-earth-added optical fiber amplifier, semiconductor optical amplifier, nonlinear optical fiber amplifier for outputting the B-band high-power broadband light by using the input A-band broadband light as the pumping light. The method of claim 9, The first output stage is a high-power broadband light source, characterized in that the rare-earth-added optical fiber amplifier, semiconductor optical amplifier, nonlinear optical fiber amplifier for outputting the B-band high-power broadband light by using the input A-band broadband light as the pumping light. In the method for simultaneously implementing a C-band broadband light source and an L-band broadband light source using an erbium-doped optical fiber, A common gain stage having a first output terminal and a second output terminal and outputting a C-band ASE to two output terminals; A C-band output stage connected to the first output terminal of the common gain stage and amplifying the C-band ASE input to output C-band high-power wideband light; And a L-band output stage connected to a second output terminal of the common gain stage and outputting L-band high power wideband light using a C-band ASE input thereto. The method of claim 13, Common gain stage is erbium-doped optical fiber, An optical deflecting tube connected to the first terminal of the erbium-doped optical fiber and allowing light to pass in the direction of the first output terminal of the common gain terminal; A wavelength division multiplexer connected to the second terminal of the erbium-doped optical fiber, A pumping light source connected to one terminal of the wavelength division multiplexer, A two-band broadband light source, characterized in that it comprises an optical deflector which is connected to the other terminal of the wavelength division multiplexer and passes light to the second output terminal of the common gain stage. The method of claim 13, C-band output terminal is Erbium-doped optical fiber, A wavelength division multiplexer connected to the first terminal of the erbium-doped optical fiber, A pumping light source connected to one terminal of the wavelength division multiplexer, An optical deflector which is connected to the other terminal of the wavelength division multiplexer and passes light to the output terminal of the C-band output terminal, A two-band broadband light source comprising an optical wavelength filter connecting between the second terminal of the erbium-doped fiber and the input terminal of the C-band output terminal The method of claim 15, An optical wavelength filter is a two-band broadband light source, characterized in that the bandpass filter for obtaining the light output of a specific wavelength range. The method of claim 15, The optical wavelength filter is a two-band broadband light source characterized by a Fabry-Parrot filter and an optical interleaver to obtain periodic output characteristics. The method of claim 15, The optical wavelength filter is a two band wideband light source characterized by a gain flattening filter for obtaining flat output characteristics. The method of claim 13, L-band output terminal is Erbium-doped optical fiber, A wavelength division multiplexer connected to the first terminal of the erbium-doped optical fiber, A pumping light source connected to one terminal of the wavelength division multiplexer, The other terminal of the wavelength division multiplexer is the input terminal of the L-band output terminal, A two-band broadband light source, characterized by an optical deflector tube connected to the second terminal of the erbium-doped optical fiber and transmitting light to the output terminal of the L-band output terminal. The method according to claim 14,15,19, Pumped light source is a two-band broadband light source characterized by a high power laser diode or a fiber laser The method according to claim 14,15,19, Pumped light source is a two-band broadband light source characterized by a high power laser diode or a fiber laser The method of claim 13, The C-band ASE applied to the L-band output terminal through the second output terminal of the common gain stage is amplified in the front part of the rare earth-added optical fiber of the L-band output terminal and propagated along the rare earth-added optical fiber to generate L-band high power broadband light. Two-band broadband light source, characterized in that. In the method for implementing a high power broadband light source, A public gain terminal having a first output terminal and a second output terminal, emitting a ASE of the A1 band which is part of the A band as a first output terminal, and emitting an ASE of the A2 band which is a part of the A band as the second output terminal; A first output terminal connected to the first output terminal of the common gain terminal and amplifying the ASE of the A1 band to be input to output the high output light of the A1 band; And a second output terminal connected to a second output terminal of the common gain stage and amplifying the ASE of the A2 band input to output high output broadband light of the A2 band. In paragraph 23, the public gain group is A-band bidirectional optical amplifier with two outputs A first wavelength division multiplexer, which is connected to the output terminal of the A-band bidirectional optical amplifier and separates / combines the A1 and A2 bands. Wavelength-independent optical reflector connected to the A2-band output terminal of the first wavelength-division multiplexer, An optical deflector tube which passes light from the A1 band output terminal of the first wavelength multiplexer to the first output terminal of the public gain terminal; A second wavelength division multiplexer connected to the other output terminals of the A-band bidirectional optical amplifier and separating / combining the A1 and A2 bands; Wavelength independent light reflector connected to the A1 band output terminal of the second wavelength division multiplexer, High power wideband light source, characterized by including an optical deflector which passes light from the A2 band output terminal of the second wavelength division multiplexer to the second output terminal of the common gain stage. In paragraph 23, the public gain group is A-band bidirectional optical amplifier with two outputs The first optical coupler, which is connected to a certain output terminal of the A-band bidirectional optical amplifier and separates and couples the optical power, A2 band optical reflector connected to one terminal of the first optical coupler, An optical deflector tube, which passes light from the other terminal of the first optical coupler to the first output terminal of the public gain terminal, A second coupler, which is connected to the other output terminals of the A-band bidirectional optical amplifier and separates and couples the optical power. A1-band optical reflector, which is connected to the other terminal of the second optical coupler, High power wideband light source, characterized by including an optical deflector which passes light from the other terminal of the second optical coupler to the second output terminal of the public gain stage. Paragraphs A and B of the public gain stages in paragraphs 24 and 25 are two-way optical amplifiers that use a rare earth additive optical fiber amplifier, a semiconductor optical amplifier, and a nonlinear optical fiber amplifier. The high-output wide-band light source described in paragraph 23 is characterized by the characteristics of the A-band optical amplifier using the rare earth-added optical fiber amplifier, the semiconductor optical amplifier, and the nonlinear optical fiber amplifier.