JPH11174381A - Multiwavelength light source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actualize a desired multiwavelength light output system of a simple and small-sized constitution for optical device evaluation which has an output intensity and a light spectrum stable in nonpolarization characteristics, and also has respective uniform wavelength output powers. SOLUTION: Spectral light (b) corresponding to transmission characteristics which is outputted by a Fabri-Perot etalon optical filter 3 through a 1st optical circulator 2a for the light emitted by a natural light emitting source 1 is amplified by an optical amplifier 4 through a 2nd optical circulator 2b and the spectral light (c) which is cut more sharply by a Fabri-Perot etalon optical filter 3 through an optical fiber 5 and a 2nd optical circulator 2b is outputted from an output port 6 through the 1st optical circulator 2a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a multi-wavelength light source that outputs multi-wavelength light simultaneously.

[0002]

2. Description of the Related Art For example, in the literature (Mitsuta et al .: Gain characteristics of low-input / high-output multi-wavelength optical amplifiers, 1995 IEEJ, B-
As shown in FIG. 5, the multi-wavelength light source 1095) couples the output light from the independently driven semiconductor laser diodes 10a to 10e to different optical fibers 5a to 5e, propagates the light, and The light is coupled to the optical fiber 5f and output from the output port 6.

The above-described conventional multi-wavelength light source employs a system in which a desired number of semiconductor laser diodes having a desired wavelength are arranged and multi-wavelength light is output simultaneously (a desired multi-wavelength light output system using a semiconductor laser diode).

In general, a multi-wavelength light source that actually outputs multi-wavelength light is used in a wavelength-division multiplexing transmission system in which different signals are put on light of different wavelengths to communicate with one optical fiber in order to increase the transmission capacity. This is necessary when evaluating the amplification characteristics of the optical amplifier used.

[0005]

The above-mentioned conventional multi-wavelength light source employs a multi-wavelength light output system using a semiconductor laser diode of a desired wavelength. It is difficult to control a desired wavelength, and it is necessary to select from a large number of semiconductor laser diodes. In addition, there is a problem that the wavelength and the number of signals used for each wavelength division multiplex transmission system are different, and the wavelength division multiplex transmission system can be used only for a specific wavelength division multiplex transmission system.

An object of the present invention is to provide a multi-wavelength light source which solves the above-mentioned problems, has a simple and compact configuration, has a stable output intensity and an optical spectrum of non-polarization characteristics, and has an output power of each wavelength. To easily and simultaneously output light of desired multi-wavelength uniform (desired multi-wavelength light output system with a simple and small configuration).

[0007]

A multi-wavelength light source according to the present invention is characterized in that the following means are provided to solve the above-mentioned problems, and a desired multi-wavelength light output system having a simple and small configuration is adopted.

The first optical circulator is provided with a light emitting element (for example, a spontaneous emission light source or a light emitting diode comprising an optical fiber having a rare earth element doped core and the rare earth element excitation light source) for the first and second ports. An output port and a first optical filter that transmits multiple wavelengths (eg, a Fabry-Perot etalon optical filter or first and second arrayed waveguide grating optical filters or Fabry-Perot etalon optical filters having the same optical filter characteristics and bandpass light); Filter or Fabry-Perot etalon optical filter, low-pass optical filter, and high-pass optical filter).

The second optical circulator connects the first, second and third ports to the second port of the first optical filter and the input and output ports of the optical amplifier, respectively.

The multi-wavelength light source is a second optical filter (for example, a fiber grating optical filter, a dielectric multilayer optical filter, or a Fabry-Perot etalon optical filter) for making the light intensity of each wavelength uniform with respect to the output port.
To the third port of the first optical circulator.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A multi-wavelength light source according to an embodiment of the present invention, as shown in FIG. 1 (a), comprises a spontaneous emission light source comprising an optical fiber having a rare earth element doped core and a rare earth element excitation light source. FIG. 1 shows a Fabry-Perot etalon optical filter 3 that transmits multiple wavelengths through a first optical circulator 2a that transmits light generated by an optical light source 1 (which may be downsized using a light emitting diode).
Output as the spectrum light shown in (b). Next, the spectrum light is amplified by an optical amplifier 4 which enters through a transmitting second optical circulator 2b and cut out more sharply by an optical fiber 5 and a Fabry-Perot etalon optical filter 3 which passes through the second optical circulator 2b. FIG.
Output as the spectrum light shown in (c). Further, the spectrum light is output from the output port 6 via the first optical circulator 2a. Since the laser beam does not oscillate after passing through the optical amplifier 4 only once, light with stable optical power and optical spectrum can be output without being affected by the phase disturbance of the optical components constituting the loop. Further, since the light is amplified by the optical amplifier 4 and passes twice through the Fabry-Perot etalon optical filter 3, the light output from the spontaneous emission light source 1 is cut out sharply with higher output characteristics and spectrum than the configuration in which the Fabry-Perot etalon optical filter 3 only cuts out the generated light. And obtained characteristics. In addition, a non-polarized spontaneous emission light source 1 is used as a light emitting element, and the light from the output port has a non-polarized characteristic, so that there is no error due to the polarization dependence of the measuring device when evaluating an optical device (such as an optical amplifier) and the evaluation is performed with high accuracy. it can.

The multi-wavelength light source according to the above-described embodiment has a simple and compact configuration, has a stable output intensity and optical spectrum with non-polarization characteristics, and can easily output simultaneously desired multi-wavelength lights having uniform output powers at each wavelength. (A desired multi-wavelength optical output system with a simple and compact configuration).

In the embodiment of the present invention shown in FIG. 1A, as shown in FIG. 2A, a band pass band-passing between the Fabry-Perot etalon optical filter 3 and the second optical circulator 2b. An optical filter 7 (a low-pass and high-pass optical filter may be used, or a wavelength-tunable band-pass / low-pass and high-pass optical filter may be used to vary the wavelength of light from the output port 6) may be separately provided. The same effect as described above can be obtained, and light of an unnecessary wavelength in the transmission wavelength of the Fabry-Perot etalon optical filter 3 can be removed. First, the transmission spectrum of a light emitted from a spontaneous emission light source 1 is combined by a band-pass optical filter 7 into which a spectrum light output from a Fabry-Perot etalon optical filter 3 via a first optical circulator 2a enters. Output as the spectrum light shown in FIG. Next, the spectrum light is amplified by an optical amplifier 4 which enters through a second optical circulator 2b, and the optical fiber 5, a band-pass optical filter 7 via a second optical circulator 2b, and a Fabry-Perot etalon optical filter 3
Then, the light is cut out more sharply and output as spectrum light shown in FIG. Further, the spectrum light is output from the output port 6 via the first optical circulator 2a.

In the embodiment of the invention shown in FIG. 1A, as shown in FIG. 3A, the first and second arrays having the same optical filter characteristics are used instead of the Fabry-Perot etalon optical filter 3. Waveguide grating optical filters 8a and 8b may be provided. The same effect as above is obtained, and the output port 6
From which light at an arbitrary wavelength interval is obtained. First, with respect to the light generated by the spontaneous emission light source 1, light of a desired wavelength is input to the first to n-th light beams (n is positive) at an input port of a first arrayed waveguide grating optical filter 8a which is incident via a first optical circulator 2a. Integer, Figure 3
(A) shows a case where n = 6) is output from the output port of the second array waveguide grating optical filter 8b.
3 to the n-th input port, and
It is output as the spectrum light shown in FIG. Next, the spectrum light is amplified by the optical amplifier 4 which enters through the second optical circulator 2b, and the optical fiber 5 and the second
The first and second array waveguide grating optical filters 8b and 8a, which are incident through the optical circulator 2b, cut out more sharply and output as spectral light shown in FIG. 3 (c).
Further, the spectrum light is output from the output port 6 via the first optical circulator 2a.

In the embodiment of the invention shown in FIG. 1A, as shown in FIG. 4A, a first optical circulator 2a
A fiber grating optical filter 9 (using a dielectric multilayer optical filter or a Fabry-Perot etalon optical filter) having a desired optical filter characteristic (which may be any section from the spontaneous emission light source 1 to the output port) May be separately provided, and the light intensity of each wavelength is made uniform by the fiber grating optical filter 9 which passes through the first optical circulator 2a with respect to the spectrum light shown in FIG. 1C, and is shown in FIG. The light may be output from the output port 6 as spectrum light. The same effect as described above is obtained, and light with uniform light intensity of each wavelength is easily obtained from the output port 6.

[0016]

The multi-wavelength light source of the present invention as described above employs a desired multi-wavelength light output system with a simple and compact configuration, so that the output from the optical circulator is higher than that of the conventional system using a desired wavelength semiconductor laser diode. In addition to obtaining light of a desired multi-wavelength by using an optical filter that transmits appropriate multi-wavelengths in which a large number of light wavelengths coincide with the transmission wavelength, the invention has the following effects. (1) A non-polarized spontaneous emission light source is used as the light-emitting element, and the light from the output port has non-polarized characteristics, so that there is no error due to the polarization dependence of the measuring device when evaluating an optical device (such as an optical amplifier) and high accuracy. Can be evaluated. Alternatively, the size can be reduced by using a light emitting diode. (2) A Fabry-Perot etalon optical filter can be used as an optical filter that transmits multiple wavelengths to easily output light of multiple wavelengths. Alternatively, by using a Fabry-Perot etalon optical filter and a band-pass optical filter or a low-pass optical filter and a high-pass optical filter, light having an unnecessary wavelength at the transmission wavelength of the Fabry-Perot etalon optical filter can be removed. Alternatively, light at an arbitrary wavelength interval is obtained by using two array waveguide grating optical filters. (3) Light having a uniform light intensity at each wavelength can be easily obtained using a dielectric multilayer optical filter or a Fabry-Perot etalon optical filter having desired optical filter characteristics, for example, a fiber grating optical filter.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a multi-wavelength light source showing an embodiment of the present invention, an optical spectrum diagram after transmission through a first optical circulator, and an optical spectrum diagram obtained from an output port.

FIG. 2 is a configuration diagram showing another embodiment of the present invention, an optical spectrum diagram after passing through the bandpass optical filter, and an optical spectrum diagram obtained from the output port.

FIG. 3 is a configuration diagram showing another embodiment of the present invention, an optical spectrum diagram after passing through the second array waveguide grating optical filter, and an optical spectrum diagram obtained from the output port.

FIG. 4 is a configuration diagram showing another embodiment of the present invention, and an optical spectrum diagram obtained from the output port.

FIG. 5 is a configuration diagram of a multi-wavelength light source showing a conventional technique.

[Explanation of symbols]

1 Spontaneous emission light source, 2a, 2b optical circulator,
3 Fabry-Perot etalon optical filter, 4 optical amplifier, 5 optical fiber, 6 output port, 7 bandpass optical filter, 8a, 8b array waveguide grating optical filter, 9 fiber grating optical filter. In the drawings, the same reference numerals indicate the same or corresponding parts.

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Claims (5)

[Claims] 1. An output port of a light emitting element for the first and second ports and a first optical filter of a first optical filter transmitting multiple wavelengths.
A first optical circulator for connecting to each of the ports, and a second optical circulator for connecting to the second port of the first optical filter and the input port and the output port of the optical amplifier for the first, second and third ports, respectively. A multi-wavelength light source including two optical circulators. 2. The multi-wavelength light source according to claim 1, wherein a spontaneous emission light source or a light emitting diode comprising a light emitting element having an optical fiber having a rare earth element doped core and said rare earth element excitation light source is used. 3. A first optical filter having a Fabry-Perot etalon optical filter, a Fabry-Perot etalon optical filter, a band-pass optical filter, a Fabry-Perot etalon optical filter, a low-pass optical filter, a high-pass optical filter, or a filter having the same optical filter characteristics. 1st and 2nd
2. The multi-wavelength light source according to claim 1, wherein said array waveguide grating optical filter is used. 4. The output port is connected to the third port of the first optical circulator via a second optical filter having a desired optical filter characteristic and making the light intensity of each wavelength uniform. The multi-wavelength light source according to claim 1, wherein 5. The multi-wavelength light source according to claim 4, wherein a fiber grating optical filter, a dielectric multilayer optical filter, or a Fabry-Perot etalon optical filter is used as the second optical filter.