JPH0846297A - Light source device - Google Patents

Abstract

PURPOSE:To enable perfectly unpolarized light to be emitted by a method wherein the specific values of an optical filter, an optical attenuator and an optical switch are decided making reference to a wavelength memory table, power value memory table and on/off memory table using a central control unit (CPU) for operation control. CONSTITUTION:A CPU 73 reads in the set up values of an optical attenuator 7 for the corresponding amounts from a power value memory table 15 so as to set up the values in the optical attenuator 7. A specific value specifying either one direction out of two directions of an optical switch 8 is externally inputted in on/off memory 13 to be stored. Next, the CPU 73 reads in the on time state in the optical switch 8 from the on/off memory table 16 so as to transfer the optical switch 8. Through these procedures, light is externally outputted out of a light source device through the intermediary of an optical connector 9. Furthermore, the spectrum line width of an output light 21 of an optical filter 6 can be decided by the characteristic value of the applicable optical filter 6, thereby enabling the required line width to be decided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device for use as a light source when evaluating an optical component.

[0002]

2. Description of the Related Art As a conventional light source device for use as a light source when evaluating optical parts, a high-bandwidth tunable LD light source manufactured by Suntec Co., Ltd. is known. Figure 5
FIG. 1 is a block diagram showing an example of such a conventional light source device.

In FIG. 5, laser light (light) emitted from a semiconductor laser light emitting element (excitation laser) 62.
Enters the diffraction grating 61 after passing through the lens 68. The laser light having the desired wavelength selected by the diffraction grating 61 passes through the lens 69 and enters the isolator 64. The laser light output from the isolator 64 passes through the lens 70 and is input to the condenser 65. Light collector 65
From the optical fiber cable passes through the optical fiber cable and enters the coupler 66. The light is output from the coupler 66 in two directions, and one light is output to the optical connector 6 for output to the outside.
7 and the other light is input to the light receiving unit 71. The intensity of the light input to the light receiving unit 71 is determined by the CPU 73, and the output of the excitation laser 62 is controlled. Also,
By attaching an oscillator 74 to the outside and inputting it to the isolator 64 via the bias tee 72, the line width of the spectrum of light from the excitation laser 62 can be expanded.

[0004]

The output light of a conventional light source device having a variable wavelength and an APC function for evaluating the above-mentioned optical components is generally a deflected light, Moreover, the line width of the spectrum of the oscillated light is often narrow. If the line width of the spectrum is narrow, even if the output of the light source device itself is stable, interference in the fiber occurs due to slight reflection by the fiber end face or switching part of the optical component to be connected to be evaluated. It has the disadvantage that the evaluation results may vary. In addition, there is also a problem that since the optical component to be evaluated is affected by the polarization dependence, it is necessary to generate pseudo-all-polarized light (non-polarized light) using a depolarizer or the like.

[0005]

A first light source device of the present invention is a semiconductor laser light emitting element, a direct current power source for driving the semiconductor laser light emitting element, and an eribium-doped light in which an eribem is added to an optical fiber. A fiber, an optical multiplexer / demultiplexer that applies the output light of the semiconductor laser light-emitting device to the eribume-doped fiber, and an output light of the eribume-doped optical fiber is input to block reflected return light to the eribume-doped optical fiber. An isolator, an optical filter for inputting the output light of the isolator and selecting and outputting light of a specified wavelength, and an optical attenuation for inputting the output light of the optical filter and adjusting the power value of the output light And an optical switch for inputting the output light of the optical attenuator and switching the output light in two directions and outputting the output light from the first direction of the optical switch. And a non-reflecting terminator, an optical connector that outputs the output light from the second direction of the optical switch to the outside, and a plurality of wavelength values selected in the optical filter are input and stored from the outside. Wavelength memory,
A power value memory for externally inputting and storing a plurality of power values of the output light of the optical attenuator, and an ON / ON for externally inputting and storing a value designating one of two directions of the optical switch. An off memory, a wavelength memory table in which the selected value of the optical filter corresponding to the wavelength value written in the wavelength memory is written, and a power value written in the power value memory A power value memory table in which the corresponding adjustment value of the optical attenuator is written, and an on / off state in which the operating position of the optical switch corresponding to the state written in the on / off memory is written. Memory table, the wavelength memory, the power value memory, and the values stored in the on / off memory to read the wavelength memory table and the power value memory Buru and with reference to the memory table for the on / off and a central control unit for controlling the operation to determine the optical filter and the optical attenuator and the set value of the optical switch.

According to a second light source device of the present invention, there is provided a semiconductor laser light emitting device, a DC power supply for driving the semiconductor laser light emitting device, an erbium-doped optical fiber obtained by adding an erbium to an optical fiber, An optical multiplexer / demultiplexer that applies the output light of the semiconductor laser light emitting element to the erbium-doped fiber, and an isolator that receives the output light of the erbium-doped optical fiber and blocks reflected return light to the erbium-doped optical fiber; An optical filter that receives the output light of the isolator, selects and outputs light having a designated wavelength, a coupler that receives the output light of the optical filter and branches in two directions, and a first output of the coupler. An optical power meter for inputting light and monitoring its power value, and inputting the second output light of the coupler and switching the output in two directions to output the light A switch, a terminator for inputting output light from the first direction of the optical switch into a non-reflecting state, and an optical connector for outputting output light from the second direction of the optical switch to the outside, A wavelength memory for inputting and storing a plurality of wavelength values to be selected in the optical filter from the outside, and a plurality of power values serving as a reference for comparing the output light from the coupler monitored by the optical power meter in the determination unit. To the power value memory for externally inputting and storing the value, an on / off memory for externally inputting and storing a value that specifies one of the two directions of the optical switch, and the wavelength memory. The wavelength memory table in which the selected value of the optical filter corresponding to the entered wavelength value is written, and the adjustment of the DC power source corresponding to the power value written in the power value memory. A power value memory table in which a value is written, an on / off memory table in which an operating position of the optical switch corresponding to a state written in the on / off memory is written, and an output power Power fine adjustment memory table in which the adjustment data of the DC power supply for fine adjustment is written, and the power value of the output light from the coupler monitored by the optical power meter and the power value memory are written. And a power adjustment direction determination unit that determines the difference and the direction of fine power adjustment when the monitor value does not match the set value as the determination result of the determination unit. Reading the wavelength memory, the power value memory, and the on / off memory, the wavelength memory table and the power value memory table And a central control unit for making fine adjustments to the DC power source and controlling the overall operation with reference to the on / off memory table and the power fine adjustment memory table.

[0007]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of the present invention, FIG. 2 is a waveform diagram showing a light waveform in the embodiment of FIG. 1, and FIG. 1 (a) is a waveform of an output light from an erbium-doped optical fiber. And (b) is a waveform diagram showing a waveform of output light of the optical filter. FIG. 3 is a block diagram showing the operation of calibrating the memory table in the embodiment of FIG.

In the embodiment shown in FIG. 1, a semiconductor laser light emitting element (excitation laser) 1, a direct current power source (PS) 2 for driving an excitation laser (LD) 1, and an elifem-doped fiber (EDF). 3 and the output light of the excitation laser 1
An optical multiplexer / demultiplexer 4 input to the DF 3, an isolator 5 for inputting the output light of the EDF 3 and blocking the reflected return light to the EDF 3, and a light of a designated wavelength by inputting the output light of the isolator 5 An optical filter 6 for output, an optical attenuator 7 for inputting output light of the optical filter 6 and adjusting the power value of the output light, and an optical attenuator 7 for inputting output light of the optical attenuator 7
Optical switch 8 for switching to different directions for output, and optical switch 8
Of the optical switch 7 for outputting the output light from the second direction of the optical switch 7 to the outside of the light source device, and the optical filter. 6, a wavelength memory 11 for externally inputting and storing a plurality of wavelength values selected, a power value memory 12 for externally inputting and storing a plurality of power values of the output light of the optical attenuator 7, An on / off memory 13 for externally inputting and storing a value designating one of two directions of the switch 8 and an adjustment value of the optical filter 6 corresponding to the wavelength value written in the wavelength memory 11 are written. ON / OFF of the rare wavelength memory table 14, the power value memory table 15 in which the adjustment value of the optical attenuator 6 corresponding to the power value written in the power value memory 12 is written, Write to memory 13 An on / off memory table 16 are written to the operating position of the optical switch 8 corresponding to the condition, a memory 12 for the wavelength memory 11 and the power value
And a CPU 73 for reading the on / off memory 13 and referring to the wavelength memory table 14, the power value memory table 15, and the on / off memory table 16 to control the overall operation.

Next, the operation of this embodiment will be described with reference to FIGS.

Each of the wavelength memory table 14, the power value memory table 15, and the on / off memory table 16 has an optical filter 6
In addition, a wavelength value and an attenuation amount to be set for each device of the optical attenuator 7 and the optical switch 8, a designated value for designating the terminator 9 or the optical connector 10, and a set value for designating them are written in advance. .

The output light from the pumping laser 1 is input via the optical multiplexer / demultiplexer 4 and is pumped from the EDF 3 as shown in FIG.
As shown in (a), the spontaneous emission light (A
SE) EDF output light 20 is output.

The wavelength memory 11 stores a plurality of wavelength values to be selected in the optical filter 6 by inputting them from outside (for example, a keyboard). The CPU 73 reads the set value for the optical filter 6 corresponding to the wavelength value to be selected from the wavelength memory table 14, and sets the value in the optical filter 6. In addition, the power value memory 12 stores a plurality of attenuation amounts (power values) of the output light to be adjusted in the optical attenuator 7, which are input from the outside.

The CPU 73 reads a set value for the optical attenuator 7 corresponding to the corresponding attenuation amount from the power value memory table 15 and sets the value in the optical attenuator 7. A designated value for designating one of the two directions of the optical switch 8 is externally input and stored in the on / off memory 13. The CPU 73 controls the on / off memory table 1
The state when the optical switch 8 is on is read from 6 and the optical switch 8 is switched. As a result, light is output to the outside of the light source device via the optical connector 9. When the light source output is turned off in the on / off memory 13, the CPU 73
Is the optical switch 8 from the on / off memory table 16.
The state when the switch is turned off is read and the optical switch 8 is switched.
As a result, the output of the light source device ends at the terminator 9 and is not output outside the light source device.

As shown in FIG. 2B, the line width D of the spectrum of the optical filter output light 21 which is the output light of the optical filter 6 is determined by the characteristic value (cut width) of the optical filter 6 used. By selecting the optical filter 6 having an appropriate characteristic value, the line width D can be set to a required width.

The calibration method for each of the wavelength memory table 14 and the power value memory table 15 is performed as shown in FIG.

FIG. 3 is a block diagram showing a state when the wavelength memory table 14 is calibrated. In FIG.
The output light of the optical connector 10 is input to the wavelength meter 17, the value input to the calibration wavelength input memory 19 and the value measured by the wavelength meter 17 are compared by the comparator 18, and the result is stored in the CPU.
Enter 73. If the comparison results do not match, C
The PU 73 changes the set value of the wavelength for the optical filter 6, and repeats this until the comparison results match. When the comparison results match, the set value for the optical filter 6 at that time is written in the wavelength memory table 14. In the case of the power value memory table 15, an optical power meter is connected to the optical connector 10 instead of the wavelength meter 17, and calibration is performed by the same operation.

FIG. 4 is a block diagram showing a second embodiment of the present invention.

The embodiment shown in FIG. 4 shows a semiconductor laser light emitting element (excitation laser) 31, a DC power supply (PS) 32 as a power supply for driving an excitation laser (LD) 31, and an erbium-doped fiber (EDF). 33, an optical multiplexer / demultiplexer 34 for inputting the output light of the pumping laser 31 to the EDF 3,
33, an optical filter 36 for receiving the output light of the EDF 33 and blocking the reflected return light to the EDF 33, inputting the output light of the isolator 35, selecting and outputting light of a designated wavelength, and an optical filter 36. A coupler 37 for inputting output light and branching in two directions, an optical power meter 38 for inputting first output light of the coupler 37 and monitoring its power value, and a second output light of the coupler 37 are input. An optical switch 43 for switching between two directions for output and an optical switch 4
3, a terminator 44 for inputting output light from the first direction to make it a non-reflective state, an optical connector 45 for outputting output light from the second direction of the optical switch 43 to the outside of the light source device, A wavelength memory 40 for externally inputting and storing a plurality of wavelength values selected in the filter 36 and a plurality of wavelengths serving as a reference for comparing in the determination unit 42 output light from the coupler 37 monitored by the optical power meter 38. Power value memory 39 for externally inputting and storing a power value
And an on / off memory 41 for externally inputting and storing a value designating one of the two directions of the optical switch 43.
A wavelength memory table 47 in which the adjustment value of the optical filter 36 corresponding to the wavelength value written in the wavelength memory 40 is written, and a direct current corresponding to the power value written in the power value memory 39. The power value memory table 46 in which the adjustment value of the power supply (PS) 32 is written, and the ON / OFF state in which the operating position of the optical switch 38 corresponding to the state written in the ON / OFF memory 13 is written. The off memory table 48, the power fine adjustment memory table 49 in which the adjustment data of the DC power supply 32 for finely adjusting the output power is written, and the power of the output light from the coupler 37 monitored by the optical power meter 38. Value and the power value written in the power value memory 47. As a determination result in the determination unit 42, the monitor value = the set power value If not, the power adjustment to the direction determination unit 50, reads the wavelength memory 40 and the power value memory 39 and the on / off memory 41, the memory table 4 wavelength to determine the direction of the power fine adjustment seeking the difference
7 and a CPU 73 for performing fine adjustment on the DC power supply 32 and control of the entire operation with reference to the power value memory table 46, the on / off memory table 48, and the power fine adjustment memory table 49.

Next, the operation of the light source of this embodiment will be described.

Each of the wavelength memory table 47, the power value memory table 46, the on / off memory table 48, and the power fine adjustment memory table 49 has an optical filter 36, a DC power source 32, and an optical switch 43, respectively. The wavelength value and the adjustment value to be set, the specified value for specifying the terminator 9 or the optical connector 10, the adjustment value for fine adjustment with respect to the DC power supply 32, and the set value for specifying them are written in advance.

The output light from the pumping laser 31 is input via the optical multiplexer / demultiplexer 34 and is excited by the EDF 33 from the EDF 33.
EDF output light 20 of spontaneous emission light (ASE), which is unpolarized light, is output (see FIG. 2A).

When the wavelength setting value is written in the wavelength memory 40 in the input waiting state, the CPU 73 reads the setting value for the optical filter 36 corresponding to the wavelength value from the wavelength memory table 47, and sets the value. Optical filter 36
Set to. In addition, the power value memory 39 in the input waiting state
When the set value of the power value is written into the DC power supply 32, the CPU 73 reads the set value for the DC power supply 32 corresponding to the power value from the power value memory table 46, and sets the value in the DC power supply 32. The output from the optical filter 36 is branched by the coupler 37 and monitored by the optical power meter 38, and the result is compared with the value written in the power value memory 39 in the judging section 42.

The CPU 73 refers to the power fine adjustment memory table 49, and if the result determined by the power adjustment direction determination unit 50 is shifted in the (+) direction, the DC power supply 32
Is decreased, and if it is deviated in the (-) direction, the setting value for the DC power source 32 is increased, and the above-mentioned value is set until the set value and the monitor value match or the difference between them is within the allowable range. Repeat the operation.

When the light source output ON is set in the ON / OFF memory 41 in the input waiting state, the CPU 73
The optical switch 43 is switched by reading the state when the optical switch 43 is on from the on / off memory table 48.
Thus, light is output to the outside of the light source device via the optical connector 45. When the light source output OFF is set in the ON / OFF memory 41, the CPU 73 reads the OFF state of the optical switch 43 from the ON / OFF memory table 41 and switches the optical switch 43. Thus, the output of the light source device ends at the terminator 44 and is not output outside the light source device.

[0026]

As described above, the light source device according to the present invention uses the spontaneous emission light (ASE) of the eribium-doped fiber (EDF) excited by the laser light, so that the light in the completely unpolarized state can be obtained. Can be generated, and the polarization dependence unique to the optical components and each device included in the system to be evaluated can be ignored, so that the polarization dependence and the like to be evaluated can be accurately measured. Also, since the line width of the spectrum can be widened (thickened), it is possible to suppress the influence of reflection at each optical component and each device included in the system to be evaluated and their connection points, and to perform stable evaluation. In addition to being able to perform it, there is also an effect that an accurate output can be guaranteed by performing calibration.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIGS. 2A and 2B are waveform diagrams showing light waveforms in the embodiment of FIG. 1, wherein FIG. 2A shows a waveform diagram of output light from an erbium-doped optical fiber and FIG. 2B shows a waveform of output light from an optical filter; It is a waveform diagram.

FIG. 3 is a block diagram showing a calibration operation of a memory table in the embodiment of FIG. 1;

FIG. 4 is a block diagram showing a second embodiment of the present invention.

FIG. 5 is a block diagram illustrating an example of a conventional light source device.

[Explanation of symbols]

 1,31 Excitation laser 2,32 DC power supply 3,33 EDF 4,34 Optical multiplexer / demultiplexer 5,35,64 Isolator 6,36 Optical filter 7 Optical attenuator 8,43 Optical switch 9,44 Terminator 10,45 , 67 Optical connector 11, 40 Wavelength memory 12, 39 Power value memory 13, 41 ON / OFF memory 14, 47 Wavelength memory table 15, 46 Power value memory table 16, 48 ON / OFF memory table 17 Wavelength meter 18 Comparator 19 Calibration wavelength input memory 20 EDF output light 21 Optical filter output light 37, 66 Coupler 38 Optical power meter 42 Judgment unit 49 Power fine adjustment memory table 50 Power adjustment direction determination unit 61 Diffraction grating 62 Laser light 65 Condenser 68, 69, 70 Lens 71 Light receiver 72 Bias tee 73 CP 74 oscillator

Claims (2)

[Claims] 1. A semiconductor laser light emitting device, a DC power supply for driving the semiconductor laser light emitting device, an erbium-doped optical fiber obtained by adding an erbium to an optical fiber, and an output light from the semiconductor laser light emitting device. An optical multiplexer / demultiplexer for inputting to the ellibium-doped fiber, an isolator for inputting output light of the ellibium-doped optical fiber and blocking reflected return light to the ellibium-doped optical fiber, and inputting and specifying output light of the isolator An optical filter that selects and outputs the light of the given wavelength, an optical attenuator that receives the output light of the optical filter and adjusts the power value of the output light, and that receives the output light of the optical attenuator. 2
An optical switch that switches to and outputs a direction, a terminator that receives the output light from the first direction of the optical switch and enters a non-reflection state, and outputs the output light of the optical switch from the second direction to the outside. An optical connector for outputting, a wavelength memory for externally inputting and storing a plurality of wavelength values selected in the optical filter, and a power for externally inputting and storing a plurality of power values of output light of the optical attenuator. A value memory, an on / off memory for externally inputting and storing a value designating one of the two directions of the optical switch, and the light corresponding to the wavelength value written in the wavelength memory. A wavelength memory table in which a filter selection value is written, and a power value memory table in which adjustment values of the optical attenuator corresponding to the power values written in the power value memory are written. , Said on An on / off memory table in which the operation position of the optical switch corresponding to the state written in the off memory is written, and stored in the wavelength memory, the power value memory, and the on / off memory. The values are read, and the set values of the optical filter, the optical attenuator, and the optical switch are determined with reference to the wavelength memory table, the power value memory table, and the on / off memory table to operate. A light source device comprising: a central control unit that performs control of the light source. 2. A semiconductor laser light emitting device, a DC power supply for driving the semiconductor laser light emitting device, an erbium-doped optical fiber obtained by adding an erbium to an optical fiber, and output light of the semiconductor laser light emitting device. An optical multiplexer / demultiplexer that applies the output light of the ellibium-doped fiber, an isolator that inputs the output light of the erbium-doped optical fiber and blocks the reflected return light to the ellibium-doped optical fiber, and an output light of the isolator. An optical filter for selecting and outputting light of the specified wavelength,
A coupler that inputs the output light of the optical filter and branches in two directions; an optical power meter that inputs the first output light of the coupler and monitors the power value; and a second output light of the coupler. An optical switch for inputting and switching to two directions and outputting; a terminator for inputting output light from the first direction of the optical switch to a non-reflection state; and an output of the optical switch from a second direction An optical connector that outputs light to the outside, a wavelength memory that inputs and stores a plurality of wavelength values selected in the optical filter from the outside, and an output light from the coupler monitored by the optical power meter in a determination unit. A power value memory for externally inputting and storing a plurality of power values serving as a reference for comparison, and an ON / OFF for externally inputting and storing a value designating one of two directions of the optical switch. Memory, a wavelength memory table in which the selected value of the optical filter corresponding to the wavelength value written in the wavelength memory is written, and a power value written in the power value memory. And a power value memory table in which an adjustment value of the DC power supply corresponding to the ON / OFF state is written, and an ON / OFF state in which an operation position of the optical switch corresponding to a state written in the ON / OFF memory is written.
An off memory table, a power fine adjustment memory table in which adjustment data of the DC power supply for fine adjustment of output power is written, and a power value of output light from the coupler monitored in the optical power meter. The determination unit that compares the power value written in the power value memory, and the determination result of the determination unit, if the monitor value does not match the set value, the difference and the direction of the power fine adjustment. A power adjustment direction determining unit for determining, a memory for wavelength, a memory for power value, and a memory for on / off to read the wavelength memory table, the power value memory table, and the on / off memory table, Central for fine adjustment of the DC power source and control of the overall operation by referring to the power fine adjustment memory table A light source device characterized in that it comprises a control unit.