Optical spectrum measurement program, optical spectrum measurement method, and optical spectrum analyzer

Abstract

To provide an optical spectrum measurement program, optical spectrum measurement method, and optical spectrum analyzer for reducing a difference between respective measurement conditions for a plurality of measured lights.SOLUTION: An optical spectrum measurement program for measuring an optical spectrum of a plurality of measured lights during one sweeping allows a processor to perform: acquiring a measurement result of intensity of the measured light selected one by one from the measured lights; and generating the optical spectrum of each one of the measured lights by associating the measured light selected in performing measurement with the acquired measurement result.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to an optical spectrum measurement program, an optical spectrum measurement method, and an optical spectrum analyzer. [Background technology]

[0002] As described in Patent Document 1, a spectrometer equipped with a rotatable grating is known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5339027 Summary of the Invention [Problem to be solved by the invention]

[0004] When measuring an optical spectrum, an optical spectrum analyzer rotates a grating by an angle corresponding to each wavelength from the start wavelength to the end wavelength of the measurement wavelength range, and measures the optical spectrum, which is the light intensity of each wavelength. Optical spectrum analyzers sometimes measure the optical spectra of multiple light beams under measurement. After measuring the optical spectrum of one light beam under measurement, an optical spectrum analyzer switches to measure the optical spectrum of the next light beam under measurement. In this case, a time lag occurs between the measurements of the multiple light beams under measurement. The time lag between the measurements of each light beam under measurement can cause fluctuations in the measurement conditions for each light beam under measurement. Fluctuations in the measurement conditions for each light beam under measurement can make it impossible to accurately compare the measurement results of each light beam under measurement. To accurately compare the measurement results of each light beam under measurement, it is necessary to minimize the differences in the measurement conditions for each light beam under measurement.

[0005] The present disclosure has been made in consideration of the above-mentioned points, and aims to provide an optical spectrum measurement program, an optical spectrum measurement method, and an optical spectrum analyzer that can reduce differences in measurement conditions for multiple light beams under measurement. [Means for solving the problem]

[0006] (1) An optical spectrum measurement program according to some embodiments is a program for measuring the optical spectra of multiple light beams under measurement during a single sweep. The optical spectrum measurement program causes a processor to acquire measurement results of the intensities of the multiple light beams under measurement selected one by one from the multiple light beams under measurement, and generate an optical spectrum for each of the multiple light beams under measurement by associating the acquired measurement results with the light beams under measurement selected at the time of measurement. This reduces the time difference between measuring the intensities of the multiple light beams under measurement at the same measurement wavelength. As a result, the difference in measurement conditions for each of the multiple light beams under measurement is reduced.

[0007] (2) The optical spectrum measurement program according to (1) above may cause the processor to select a light beam to be measured from the plurality of light beams to be measured. By selecting the light beam to be measured, the processor does not need to acquire information for identifying the input light beam to be measured.

[0008] (3) The optical spectrum measurement program described in (2) above may cause the processor to acquire a measurement result of the optical intensity of the first wavelength of at least one light under measurement selected one by one from the plurality of light under measurement during a first period in which the optical intensity of the first wavelength is measured during a sweep. In this way, the switching frequency of each light under measurement is weighted. As a result, the switching frequency of the light under measurement is reduced.

[0009] (4) The optical spectrum measurement program according to (3) above may cause the processor to acquire, during the first period, measurement results of the optical intensities of the first wavelengths of all of the plurality of light beams under measurement. This makes it possible to compare the optical intensities of the first wavelengths of all of the light beams under measurement. As a result, user convenience is improved.

[0010] (5) The optical spectrum measurement program according to (3) or (4) above may cause the processor to select the light under measurement so that the number of light under measurement selected in a second period during which the optical intensity of a second wavelength is measured during the sweep is different from the number of light under measurement selected in the first period. This weights the switching frequency of each light under measurement. As a result, the switching frequency of the light under measurement is reduced.

[0011] (6) The optical spectrum measurement program according to any one of (3) to (5) above may cause the processor to determine the number of light beams under measurement to be selected in each period for measuring the optical intensity of each wavelength during a sweep, based on the accuracy required for measuring each of the light beams under measurement. This reduces the frequency of switching between light beams under measurement while maintaining the required measurement accuracy.

[0012] (7) The optical spectrum measurement program according to any one of (1) to (6) above may cause the processor to acquire a measurement result after an invalid period has elapsed since selecting and switching one of the plurality of light beams under measurement, thereby maintaining or improving the measurement accuracy of the optical spectrum.

[0013] (8) The optical spectrum measurement program according to any one of (1) to (7) above may cause the processor to, when multiple measurements of the light intensity at a measurement wavelength are performed, acquire a calculated value by performing statistical processing on the multiple measurement values ​​obtained in each of the multiple measurements as the measurement result of the light intensity at the measurement wavelength. By using the statistical value, the influence of disturbances such as noise is reduced.

[0014] According to some embodiments, an optical spectrum measurement method (9) is a method for measuring the optical spectrum of a plurality of light beams under measurement during a single sweep. The optical spectrum measurement method includes acquiring a measurement result of the intensity of each light beam under measurement selected from the plurality of light beams under measurement, and generating an optical spectrum for each light beam under measurement by associating the acquired measurement result with the light beam under measurement selected at the time of measurement. This reduces the time difference between measuring the intensity of the same measurement wavelength of the plurality of light beams under measurement. As a result, the difference in measurement conditions for each of the plurality of light beams under measurement is reduced.

[0015] (10) An optical spectrum analyzer according to some embodiments generates optical spectra of multiple light beams under measurement during a single sweep. The optical spectrum analyzer includes at least one measurement unit that measures the intensity of each light beam under measurement selected from the multiple light beams under measurement, and a control unit that generates an optical spectrum of each light beam under measurement by associating the light beam under measurement selected at the time of the measurement by the measurement unit with the measurement result of the light intensity by the measurement unit. This reduces the time difference between measuring the intensity of the multiple light beams under measurement at the same measurement wavelength. As a result, the difference in measurement conditions for each of the multiple light beams under measurement is reduced.

[0016] (11) The optical spectrum analyzer described in (10) above may further include a switching unit that switches a connection so that one light under measurement selected from the plurality of light under measurement is input to the measurement unit. The control unit may control the switching unit to select one light under measurement to be input to the measurement unit from the plurality of light under measurement. By the control unit selecting the light under measurement, it is not necessary to obtain information that identifies the light under measurement to be input.

[0017] (12) In the optical spectrum analyzer described in (11) above, the switching unit may be configured to receive a trigger signal and switch the light under measurement to be input to the measurement unit in response to the trigger signal. By switching the light under measurement to be input to the measurement unit in response to the trigger signal from an external device, the light under measurement can be switched in response to the operation of a user program in the external device. As a result, user convenience is improved.

[0018] (13) In the optical spectrum analyzer according to any one of (10) to (12) above, when the number of the measurement units is two or more, each of the two or more measurement units may measure the optical intensity of a light under measurement selected one by one from the plurality of light under measurement. By providing the optical spectrum analyzer with two or more measurement units, the optical spectra of a plurality of light under measurement can be measured in parallel. [Effects of the Invention]

[0019] According to the optical spectrum measurement program, the optical spectrum measurement method, and the optical spectrum analyzer according to the present disclosure, the difference in measurement conditions among a plurality of light beams to be measured is reduced. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 10 is a block diagram showing the configuration of a device according to a comparative example. [Figure 2] 10 is a graph showing a measured waveform obtained by a method according to a comparative example. [Figure 3] FIG. 1 is a block diagram illustrating an example configuration of an optical spectrum analyzer according to the present disclosure. [Figure 4] 1 is a flowchart illustrating an example of a procedure for an optical spectrum measurement method according to the present disclosure. [Figure 5] 5 is a timing chart of a sweep in the optical spectrum measurement method of FIG. 4. [Figure 6] 6 is an example of the measured waveforms of the first and second light beams under measurement generated based on the measurement results of the light intensity of each wavelength obtained by executing the sweep of FIG. 5. [Figure 7A] 10 is an example of a measured waveform obtained by performing an optical spectrum measurement method. [Figure 7B] 7B is a differential waveform between the measured waveforms of the first measured light and the second measured light in FIG. 7A. [Figure 8A] 10 is an example of a measured waveform obtained by performing a method according to a comparative example. [Figure 8B] 8B is a differential waveform between the measured waveforms of the first measured light and the second measured light in FIG. 8A. [Figure 9] FIG. 1 is a block diagram showing an example of the configuration of an optical spectrum analyzer that switches the light under measurement in response to an input of a trigger signal. [Figure 10] 10 is a flowchart illustrating an example of a procedure of an optical spectrum measuring method including a procedure of switching the light under measurement in response to an input of a trigger signal. [Figure 11] 11 is a timing chart of a sweep in the optical spectrum measurement method of FIG. 10. [Figure 12] FIG. 1 is a block diagram showing an example of the configuration of an optical spectrum analyzer equipped with two measurement units. [Figure 13] FIG. 10 is a block diagram showing an example of the configuration of an optical spectrum analyzer to which an optical switch is externally connected. DETAILED DESCRIPTION OF THE INVENTION

[0021] The present disclosure relates to an optical spectrum analyzer, an optical spectrum measurement program, and an optical spectrum measurement method for measuring the optical spectra of multiple light beams under measurement. In this disclosure, a grating-based measurement method is adopted. When measuring the optical spectrum of each light beam under measurement, a grating-based optical spectrum analyzer rotates a grating by an angle corresponding to each wavelength from the start wavelength to the end wavelength of a measurement wavelength range, and measures the optical spectrum, which is the light intensity for each wavelength. The operation of measuring the optical spectrum by rotating the grating by an angle corresponding to each wavelength is also called sweeping.

[0022] Hereinafter, an embodiment according to the present disclosure will be described in comparison with a comparative example.

[0023] (Comparative Example) 1, an apparatus 90 according to the comparative example includes an optical input port 91, a measurement unit 92, and a control unit 93. In the comparative example, a first light under measurement, a second light under measurement, and an N-th light under measurement are input to the optical input port 91 in order as a plurality of light under measurement.

[0024] First, a fiber transmitting the first light under measurement is connected to the optical input port 91. The measurement unit 92 performs a sweep while the first light under measurement is input to the optical input port 91, and measures the intensity of each wavelength in the measurement wavelength range of the first light under measurement. The control unit 93 obtains the measured values ​​of the intensity of each wavelength from the measurement unit 92 and generates an optical spectrum of the first light under measurement.

[0025] After the sweep of the first light under measurement is completed, the fiber transmitting the second light under measurement is connected to the optical input port 91. In other words, the fiber is switched to the optical input port 91. The measurement unit 92 performs a sweep while the second light under measurement is input to the optical input port 91, and measures the intensity of each wavelength in the measurement wavelength range of the second light under measurement. The control unit 93 obtains the measured values ​​of the intensity of each wavelength from the measurement unit 92 and generates an optical spectrum of the second light under measurement.

[0026] After the sweep of the second light under measurement is completed, a fiber transmitting the next light under measurement is connected to the optical input port 91. Finally, a fiber transmitting the Nth light under measurement is connected to the optical input port 91. The measurement unit 92 performs a sweep while the Nth light under measurement is input to the optical input port 91, and measures the intensity of each wavelength in the measurement wavelength range of the Nth light under measurement. The control unit 93 obtains the measured values ​​of the intensity of each wavelength from the measurement unit 92 and generates an optical spectrum of the Nth light under measurement.

[0027] The device 90 according to the comparative example can measure the optical spectra of N light beams under measurement from the first light beam under measurement to the Nth light beam under measurement by performing the above operations.

[0028] FIG. 2 shows the results of measuring the optical spectrum of the first measured light and the optical spectrum of the second measured light by an apparatus 90 according to a comparative example. When measurement values ​​at m points are acquired in one sweep, the measurement value of the intensity of the measurement start wavelength of the first measured light corresponds to the measurement value at the first point, and the measurement value of the intensity of the measurement start wavelength of the second measured light corresponds to the measurement value at the (m+1)th point. It takes longer for the apparatus 90 to acquire the measurement value at the (m+1)th point from the time it takes for the apparatus 90 to complete one sweep. The same applies to the time it takes for the apparatus 90 to acquire the measurement value at the second point of the first measured light from the time it takes for the apparatus 90 to acquire the measurement value at the (m+2)th point corresponding to the same wavelength of the second measured light. The same applies to the time it takes for the apparatus 90 to acquire the measurement value at the (m+m)th point corresponding to the measurement end wavelength of the first measured light from the time it takes for the apparatus 90 to acquire the measurement value at the (2m+m)th point corresponding to the measurement end wavelength of the second measured light.

[0029] In this case, in the comparative example, the conditions for measuring the intensity of each wavelength change over time, and the conditions for measuring the intensity of each wavelength of the first light under measurement may differ from the conditions for measuring the intensity of each wavelength of the second light under measurement. It is therefore impossible to accurately compare the measurement results of the optical spectrum under different measurement conditions. Therefore, when measuring the optical spectra of multiple light under measurement, it is necessary to minimize the fluctuations in the measurement conditions.

[0030] In the present disclosure, an optical spectrum measurement program, an optical spectrum measurement method, and an optical spectrum analyzer 10 (see FIG. 3) that can reduce fluctuations in the measurement conditions of an optical spectrum will be described below.

[0031] (Configuration example of optical spectrum analyzer 10) As shown in FIG. 3, an optical spectrum analyzer 10 according to one embodiment of the present disclosure includes a measurement unit 20, a control unit 31, a display unit 32, an optical switch 40, and an optical input unit including N ports from a first port 51 to an Nth port 5N.

[0032] Each of the N ports from the first port 51 to the Nth port 5N of the optical input unit is configured to accept input of light under measurement to be measured by the optical spectrum analyzer 10. A fiber transmitting the first light under measurement is connected to the first port 51. A fiber transmitting the Nth light under measurement is connected to the Nth port 5N.

[0033] The optical switch 40 includes terminals 411 to 41N and a terminal 42. The terminals 411 to 41N are connected to the first port 51 to the Nth port 5N, respectively. The terminal 42 is configured to be switchable so as to be connected to any of the terminals 411 to 41N. When the terminal 42 in the optical switch 40 is switched to be connected to any of the terminals 411 to 41N, the light under measurement input to the measurement unit 20 is switched from the first light under measurement to any of the Nth light under measurement. The optical switch 40 is also referred to as a switching unit.

[0034] The terminal 42 may select a terminal to be connected from among the terminals 411 to 41N based on a control instruction from the control unit 31. In other words, the control unit 31 may control which terminal among the terminals 411 to 41N the terminal 42 is to be connected to. The terminal 42 may select a terminal among the terminals 411 to 41N to be connected to based on a control instruction from a device connected externally to the optical spectrum analyzer 10. When the control unit 31 does not control the connection destination of the terminal 42, the control unit 31 may obtain information specifying the connection destination of the terminal 42 from the optical switch 40.

[0035] The measurement unit 20 includes a spectrometer 21, a light receiving element 22, an amplifier 23, and a data acquisition circuit 24. The spectrometer 21 separates the light to be measured into light of each wavelength, and passes the light of the wavelength to be detected, causing it to be incident on the light receiving element 22. In the present disclosure, it is assumed that a grating is used as the spectrometer 21. The light receiving element 22 detects the light that has passed through the spectrometer 21 and is incident thereon, and outputs a signal corresponding to the intensity of the incident light. The amplifier 23 amplifies the signal output from the light receiving element 22 and outputs it to the data acquisition circuit 24. The data acquisition circuit 24 synchronizes the wavelength of the light that has passed through the spectrometer 21 with the amplified signal, and acquires measured values ​​of the intensity of each wavelength.

[0036] The control unit 31 acquires the measured values ​​of the intensity of each wavelength of the light under measurement from the measurement unit 20 and generates an optical spectrum of the light under measurement. The control unit 31 may control the sweeping operation of the measurement unit 20. The measurement unit 20 may perform a sweep by moving the grating in response to a control instruction from the control unit 31, and measure the optical intensity of each wavelength in the measurement wavelength range.

[0037] The control unit 31 may be configured to include a processor such as a CPU (Central Processing Unit). The control unit 31 may realize a predetermined function by causing the processor to execute a predetermined program. The control unit 31 may be configured to include a dedicated circuit such as an FPGA (Field Programmable Gate Array).

[0038] The control unit 31 may include a storage unit. The storage unit stores various information used in the operation of the optical spectrum analyzer 10, or programs for realizing the functions of the optical spectrum analyzer 10. The storage unit may function as a work memory for the control unit 31. The storage unit may be configured, for example, as a semiconductor memory. The storage unit may include a volatile memory or a non-volatile memory. At least a part of the storage unit may be configured as a storage device connected to the outside of the optical spectrum analyzer 10.

[0039] The control unit 31 may be realized as a computer such as a desktop personal computer (PC) or a notebook PC that is connected to the outside of the optical spectrum analyzer 10.

[0040] The display unit 32 displays the waveform of the optical spectrum of the light under measurement. The display unit 32 may be configured to include various displays such as a liquid crystal display. The display unit 32 may be configured as a touch panel display that displays a GUI (Graphical User Interface) that functions as an input device and accepts input from a user. In other words, the display unit 32 may be configured integrally with the input device.

[0041] The optical spectrum analyzer 10 may include an input device that accepts operational inputs from a user. The input device may include, for example, a keyboard or physical keys, a touch panel or touch sensor, or a pointing device such as a mouse. The input device may be configured as a touch panel display integrated with the display unit 32, as described above.

[0042] (Example of operation of the optical spectrum analyzer 10) A specific example of the operation of the optical spectrum analyzer 10 according to the present disclosure will be described below.

[0043] The optical spectrum analyzer 10 may execute an optical spectrum measurement method including the steps of the flowchart illustrated in Fig. 4. The optical spectrum measurement method may be realized as an optical spectrum measurement program executed by the optical spectrum analyzer 10. The optical spectrum measurement program may be stored in a non-transitory computer-readable medium.

[0044] The control unit 31 of the optical spectrum analyzer 10 sets a measurement wavelength, which is a wavelength whose intensity is to be measured, in order to measure the intensity of each wavelength as the optical spectrum of the light under measurement (step S1). The control unit 31 first sets the measurement start wavelength in the measurement wavelength range as the measurement wavelength. The control unit 31 controls the grating of the spectroscope 21 according to the set value of the measurement wavelength.

[0045] The optical spectrum analyzer 10 switches the light under measurement to be input to the measurement unit 20 (step S2). The light under measurement to be input to the measurement unit 20 is determined depending on the connection destination of the terminal 42 of the optical switch 40. The control unit 31 of the optical spectrum analyzer 10 may control the optical switch 40 to switch the light under measurement to be input to the measurement unit 20. That is, the control unit 31 may select the light under measurement to be input to the measurement unit 20 one by one from the multiple lights under measurement input to the optical switch 40, and control the optical switch 40 to switch the connection of the optical switch 40 so that the selected light under measurement is input to the measurement unit 20. When the control unit 31 controls the optical switch 40 itself, it can recognize which light under measurement is input to the measurement unit 20. As a result, the control unit 31 does not need to acquire information identifying the light under measurement to be input.

[0046] When the control unit 31 does not control the connection destination of the optical switch 40, the control unit 31 may recognize which light under measurement is input to the measurement unit 20 by acquiring information specifying the connection destination of the terminal 42 of the optical switch 40 from the optical switch 40. In other words, the control unit 31 may confirm whether the light under measurement input to the measurement unit 20 has been switched by a device connected externally to the optical spectrum analyzer 10 by acquiring information specifying the connection destination of the terminal 42.

[0047] The measurement unit 20 of the optical spectrum analyzer 10 measures the light intensity of the measurement wavelength set in the procedure of step S1 for the light to be measured input to the measurement unit 20 (step S3).

[0048] The control unit 31 determines whether the condition for changing the measurement wavelength is satisfied (step S4). The condition for changing the measurement wavelength may be that measurement of the light intensity of the light to be measured at the set measurement wavelength is completed. Completion of measurement of the light intensity of the light to be measured at the set measurement wavelength may be associated with the number of pulses sent to the motor to drive the motor that rotates the grating reaching a specified number, i.e., the rotation angle of the grating reaching a specified angle. The condition for changing the measurement wavelength may be that a trigger signal is input to the optical spectrum analyzer 10 to instruct it to change the measurement wavelength.

[0049] The condition for changing the measurement wavelength may be, for example, the elapse of a time set as the time for changing the measurement wavelength. The time for changing the measurement wavelength may be set to the time required for the rotation angle of the grating to reach a specified angle. The time for changing the measurement wavelength may be set according to the time for executing the sweep. For example, the time for executing the sweep divided by the number of wavelengths set as the measurement wavelength may be set to the time for changing the measurement wavelength. The time for changing the measurement wavelength may also be set to the time required to complete measurement of the light intensity of each of the multiple measurement wavelengths of the measurement light. The control unit 31 may determine that the time since setting the measurement wavelength has arrived when measurement of the light intensity of the measurement light to be measured at the set measurement wavelength has been completed.

[0050] If the conditions for changing the measurement wavelength are not met (step S4: NO), the control unit 31 returns to the procedure of step S2 and switches the measured light to be input to the measurement unit 20 so as to measure the intensities of multiple measured lights at the set measurement wavelength.

[0051] When the condition for changing the measurement wavelength is satisfied (step S4: YES), the control unit 31 completes the measurement of the light intensity at the set measurement wavelength and updates the measurement data at the set measurement wavelength (step S5). The optical spectrum analyzer 10 can acquire measurement results of the intensity of the light under measurement selected one by one from the plurality of light under measurement by executing the procedures from steps S1 to S5. The optical spectrum analyzer 10 can also associate the light under measurement selected at the time of measurement by the measurement unit 20 with the intensity measurement results acquired by the measurement unit 20. When executing the measurement data update procedure of step S5, the control unit 31 may generate measurement data of the optical spectrum of each of the plurality of light under measurement based on the data acquired up to this point that associates the light under measurement selected at the time of measurement by the measurement unit 20 with the intensity measurement results acquired by the measurement unit 20, and display the generated data on the display unit 32.

[0052] The control unit 31 determines whether acquisition of data in the measurement wavelength range has been completed (step S6). When the measurement end wavelength in the measurement wavelength range is set as the measurement wavelength and measurement of the light intensity at the measurement end wavelength has been completed, the control unit 31 determines that acquisition of data in the measurement wavelength range has been completed.

[0053] If the control unit 31 has not completed acquiring data for the measurement wavelength range (step S6: NO), it returns to the procedure of step S1, resets the measurement wavelength to the next wavelength within the measurement wavelength range, and measures the intensities of multiple measured lights at the reset measurement wavelength.

[0054] When the control unit 31 has completed acquisition of data in the measurement wavelength range (step S6: YES), it generates measurement data of the optical spectra of the plurality of light beams under measurement and displays it on the display unit 32 (step S7). By executing the procedure of step S7, the optical spectrum analyzer 10 can generate an optical spectrum for each of the plurality of light beams under measurement based on data correlating the light beam under measurement selected during measurement by the measurement unit 20 with the intensity measurement results acquired by the measurement unit 20. After executing the procedure of step S7, the control unit 31 ends execution of the flowchart in FIG. 4. Even while acquiring data in the measurement wavelength range, the control unit 31 may generate measurement data of the optical spectra of each of the plurality of light beams under measurement based on the data acquired up to that time, and display it on the display unit 32 at any time, for example, when the measurement data update procedure of step S5 is executed.

[0055] An example of the operation of acquiring measurement data by performing the above-described operations will be described with reference to Figures 5 and 6. In this operation example, the optical spectrum analyzer 10 measures the optical spectra of two light beams under measurement, namely, the first light beam under measurement and the second light beam under measurement, in one sweep.

[0056] As shown in the timing chart of Fig. 5, it is assumed that the measurement wavelength is set to x0, x1, and x2 in order. Setting the measurement wavelength corresponds to the procedure of step S1 in Fig. 4. Meanwhile, it is assumed that the light (input light) input to the measurement unit 20 is switched to either the first light to be measured (#1) or the second light to be measured (#2). Switching the light input to the measurement unit 20 corresponds to the procedure of step S2 in Fig. 4.

[0057] During the period in which the measurement wavelength is set to x0, the light input to the measurement unit 20 is first switched to the first measured light. The measurement unit 20 measures the intensity (y0) of the wavelength component of x0 in the first measured light. Measuring the intensity of the wavelength component of x0 in the first measured light corresponds to the procedure of step S3 in FIG. 4. The measurement data of the first measured light is expressed as first measured light acquisition data. Furthermore, x0 corresponds to the measurement start wavelength.

[0058] Here, the first measured light acquisition data includes data represented by a rectangle with diagonal hatching before the data represented by y0. This data is data measured during the period until the switching of the light input to the measurement unit 20 is completed. The period until the switching of the light input to the measurement unit 20 is completed may be set as a period during which the intensity of the light input to the measurement unit 20 is unstable. Measurement data during the period during which the intensity of the light input to the measurement unit 20 is unstable reduces the measurement accuracy of the optical spectrum. Therefore, data during the period during which the intensity of the light input to the measurement unit 20 is unstable is treated as invalid data. A period during which measurement data is invalid, i.e., a period during which the intensity of the light input to the measurement unit 20 is unstable, is also referred to as an invalid period. The control unit 31 may acquire a measurement result after the invalid period has elapsed since selecting and switching one measured light from the multiple measured light sources. In this way, the measurement accuracy of the optical spectrum is maintained or improved.

[0059] When the measurement unit 20 completes measurement of the data represented by y0, the time after setting the measurement wavelength to x0 has not yet come to change the measurement wavelength. This case corresponds to the case of NO in step S4 of FIG. 4. Therefore, corresponding to the procedure of step S2 of FIG. 4, the light input to the measurement unit 20 is switched to the second measured light. The measurement unit 20 measures the intensity (y1) of the wavelength component of x0 for the second measured light. The measurement of the intensity of the wavelength component of x0 for the second measured light corresponds to the procedure of step S3 of FIG. 4. The measurement data of the second measured light is represented as second measured light acquired data. The second measured light acquired data also includes invalid data.

[0060] When the measurement unit 20 completes measurement of the data represented by y1, the time after setting the measurement wavelength to x0 has not yet come to change the measurement wavelength. This case corresponds to the case of NO in step S4 of FIG. 4. Therefore, corresponding to the procedure of step S2 of FIG. 4, the light input to the measurement unit 20 is switched back to the first light under measurement. The measurement unit 20 measures the intensity (y2) of the wavelength component of x0 for the first light under measurement. Furthermore, the light input to the measurement unit 20 is switched to the second light under measurement. The measurement unit 20 measures the intensity (y3) of the wavelength component of x0 for the second light under measurement.

[0061] Suppose that while measuring the intensity of the wavelength component of x0 for the second light under measurement, the time after setting the measurement wavelength to x0 has come to change the measurement wavelength. This case corresponds to the case of YES in step S4 of Fig. 4. The control unit 31 updates the measurement data of the intensity of the measurement wavelength (x0) of the first light under measurement and the second light under measurement based on the measurement data measured up to this point with the measurement wavelength set to x0, in accordance with the procedure of step S5 of Fig. 4.

[0062] 6, the intensity of the first measured light component having a wavelength x0 is calculated and plotted based on a set of measurement data having elements y0 and y2, while the intensity of the second measured light component having a wavelength x0 is calculated and plotted based on a set of measurement data having elements y1 and y3.

[0063] When the number of elements in the light intensity measurement data is one, the value of that element may be directly adopted as the light intensity measurement data. When the number of elements in the light intensity measurement data is two or more, a statistical value calculated by performing statistical processing on the values ​​of each element may be adopted as the light intensity measurement data. The statistical value may be, for example, the average value of multiple elements, or the maximum or minimum value among the multiple elements. By adopting the statistical value, the influence of disturbances such as noise is reduced. Furthermore, the maximum or minimum value can be easily calculated by holding the measurement value at the maximum or minimum value. Therefore, by adopting the maximum or minimum value as the statistical value, the calculation load is reduced.

[0064] Returning to the timing chart of Figure 5, since the set measurement wavelength is x0, acquisition of data in the measurement wavelength range has not yet been completed. This case corresponds to the case of NO in step S6 of Figure 4. Therefore, the measurement wavelength is reset to x1, corresponding to the procedure of step S1 of Figure 4.

[0065] While the second light under measurement is still being input, the measurement unit 20 measures the intensity (y4) of the wavelength component x1 of the second light under measurement. The measurement of the intensity of the wavelength component x1 of the second light under measurement corresponds to the procedure of step S3 in FIG. 4. Thereafter, similar to the period when the set wavelength was set to x0, the light input to the measurement unit 20 is switched between the first light under measurement and the second light under measurement even during the period when the set wavelength is set to x1. The measurement unit 20 measures the intensity (y5 and y7) of the wavelength component x1 of the first light under measurement. The measurement unit 20 measures the intensity (y4, y6, and y8) of the wavelength component x1 of the second light under measurement.

[0066] The control unit 31 updates the measurement data of the intensity of the measurement wavelength (x1) of the first and second measured lights based on the measurement data measured when the measurement wavelength is set to x1. As shown in Fig. 6, the intensity of the first measured light component having wavelength x1 is calculated and plotted based on a set of measurement data having elements y5 and y7. Furthermore, the intensity of the second measured light component having wavelength x1 is calculated and plotted based on a set of measurement data having elements y4, y6, and y8.

[0067] Returning to the timing chart of FIG. 5, the measurement wavelength is reset to x2. Even during the period in which the set wavelength is set to x1, the light input to the measurement unit 20 is switched between the first light under measurement and the second light under measurement. The measurement unit 20 measures the intensity (y 10 The measurement unit 20 measures the intensity of the wavelength component x2 (y9 and y 11 ) is measured.

[0068] The control unit 31 updates the measurement data of the intensity of the measurement wavelength (x2) of the first and second light beams under measurement based on the measurement data measured when the measurement wavelength is set to x2. As shown in FIG. 6, the intensity of the first light beam under measurement with the wavelength x2 is expressed as y 10 The intensity of the second measured light component having a wavelength of x2 is calculated and plotted based on a set of measurement data having elements y9 and y 11 It is calculated and plotted based on a set of measurement data having elements.

[0069] The operation of resetting the measurement wavelength and measuring the intensity of the light to be measured at each measurement wavelength is to set the measurement wavelength to the measurement end wavelength x m and set the measurement wavelength (x m ) is updated, that is, until one sweep is completed. By measuring the intensities of both the first and second light under measurement until one sweep is completed, the measured waveforms of the optical spectra of the first and second light under measurement are generated in one sweep, as shown in FIG.

[0070] In the above-described operation example, the measurement wavelength is changed during the measurement of the intensity of the second measured light. The control unit 31 may switch the measured light when changing the measurement wavelength. The control unit 31 may wait until the measurement of the measured light is completed before changing the measurement wavelength. In other words, the control unit 31 may synchronize the change of the measurement wavelength with the switching of the measured light.

[0071] As described above, by performing the optical spectrum measurement method according to the present disclosure, the intensities of multiple light beams under measurement are measured for one measurement wavelength during one sweep. Also, the optical spectra of multiple light beams under measurement are measured during one sweep. By being able to measure the optical spectra of multiple light beams under measurement in one sweep, the time difference between measuring the intensity of one measurement wavelength for each light beam under measurement is shortened.

[0072] For example, assume that the measurement of the light intensity is affected by a disturbance during the execution of a sweep, as shown in Fig. 7A. In the optical spectrum measurement method according to the present disclosure, the time difference between measuring the intensities of the same measurement wavelength for the first light under measurement and the second light under measurement is short, so when the measurement is affected by the disturbance, the effect of the disturbance appears in both the measurement waveforms of the first light under measurement and the second light under measurement.

[0073] Also, assume that the output of the light source of the light under measurement fluctuates due to drift or the like during the execution of the sweep, and the light intensity is affected by the fluctuation in the light source output. In this case, too, since the time difference between measuring the intensities of the same measurement wavelength for the first light under measurement and the second light under measurement is short, when the measurement is affected by the fluctuation in the light source output, the influence of the fluctuation in the light source output appears in common in the measurement waveforms of both the first light under measurement and the second light under measurement.

[0074] 7B, when a differential waveform between the measured waveforms of the first and second light under measurement is generated, the influence of disturbances and fluctuations in the light source output appears in both the measured waveforms of the first and second light under measurement, i.e., the difference between the measurement conditions for the optical spectrum of the first and second light under measurement becomes small.

[0075] Then, waveforms that appear in common in the measurement waveforms of both the first and second measured lights are canceled out in the differential waveform. By canceling out the waveforms that appear in common in the differential waveform, the differential waveform contains only waveforms that represent the characteristics that are desired to be observed when comparing the first and second measured lights. As a result, the optical spectrum of the first and second measured lights is correctly compared.

[0076] In the comparative example, a first sweep was performed to measure the optical spectrum of a first light under measurement and a second sweep was performed to measure the optical spectrum of a second light under measurement. In the comparative example, the time difference between the first and second sweeps was large, resulting in a larger time difference between measuring the intensity of the same wavelength than the time difference between measuring the intensity of the same wavelength in the optical spectrum measurement method according to the present disclosure. In the comparative example, the large time difference between measuring the intensity of the same wavelength resulted in the influence of disturbances appearing only in the measured waveform of the first light under measurement, as shown in FIG. 8A . Furthermore, the influence of fluctuations in the light source output was appearing only in the measured waveform of the second light under measurement.

[0077] 8B, when a differential waveform between the measured waveforms of the first and second light sources is generated, the differential waveform includes not only a waveform representing the desired characteristics but also a waveform resulting from disturbances or fluctuations in the light source output. In other words, the method according to the comparative example increases the difference between the measurement conditions for the optical spectrum of the first and second light sources. As a result, the method according to the comparative example makes it difficult to accurately compare the optical spectrum of the first and second light sources.

[0078] As described above, the optical spectrum measurement method according to the present disclosure can reduce the difference in measurement conditions among multiple light beams under measurement compared to the method according to the comparative example, thereby improving the accuracy of comparison of the optical spectra of multiple light beams under measurement compared to the method according to the comparative example.

[0079] (Other embodiments) Other embodiments of the optical spectrum analyzer 10 and the optical spectrum measuring method according to the present disclosure will be described below.

[0080] <Switching frequency of multiple light sources under test> The number of light beams to be measured while one measurement wavelength is set may be the same or different. That is, the number of light beams to be measured for each measurement wavelength may be the same or different. For example, if the multiple light beams to be measured by the optical spectrum analyzer 10 include light that needs to be measured with high accuracy and reference light that does not need to be measured with high accuracy, the control unit 31 may switch the light that needs to be measured with high accuracy to be input to the measurement unit 20 more frequently than the light that does not need to be measured with high accuracy to be input to the measurement unit 20. In other words, the control unit 31 may weight the switching frequency of each light beam to be measured depending on the purpose of measuring each light beam.

[0081] During one sweep, the control unit 31 may, for example, set the first wavelength as the measurement wavelength and measure the light intensity of the first wavelength. The period during which the first wavelength is set as the measurement wavelength is also referred to as the first period. During the first period, the control unit 31 may select at least one light beam under measurement one by one from the multiple light beams under measurement input to the optical switch 40, and obtain from the measurement unit 20 the measurement result of the light intensity of the first wavelength for the at least one selected light beam under measurement. For example, during the first period, the control unit 31 may select light beams that need to be measured with high accuracy and not select light beams that do not need to be measured with high accuracy. In this way, the switching frequency of each light beam under measurement is weighted.

[0082] The control unit 31 may select all of the light beams under measurement at least once during the first period and measure the light intensity of the first wavelength for all of the light beams under measurement. This makes it possible to compare the light intensity of the first wavelength for all of the light beams under measurement. As a result, user convenience is improved.

[0083] The control unit 31 may set a second wavelength different from the first wavelength as the measurement wavelength and measure the light intensity of the second wavelength. The period during which the second wavelength is set as the measurement wavelength is also referred to as a second period. During the second period, the control unit 31 may also select at least one light beam under measurement from the multiple light beams under measurement and obtain from the measurement unit 20 the measurement result of the light intensity of the second wavelength for the selected at least one light beam under measurement.

[0084] Also in the second period, the control unit 31 may select all of the light beams under measurement from among the plurality of light beams under measurement at least once and measure the light intensity of the second wavelength for all of the light beams under measurement.

[0085] The control unit 31 may select the light beams under measurement in each of the first and second periods so that the number of light beams under measurement selected to measure the light intensity of a first wavelength in the first period is different from the number of light beams under measurement selected to measure the light intensity of a second wavelength in the second period. For example, the control unit 31 may select light beams that need to be measured with high accuracy in both the first and second periods, and select light beams that do not need to be measured with high accuracy in only one of the first and second periods. In other words, the control unit 31 may determine the number of light beams under measurement selected in each period for measuring the light intensity of each wavelength during the sweep based on the accuracy required for measuring each measurement light. In this way, the frequency of switching the light beams under measurement is reduced while maintaining the required measurement accuracy.

[0086] By weighting the switching frequency of the light under measurement, the switching frequency of the light under measurement in one sweep is reduced. As a result, the time required for one sweep is shortened. In addition, while suppressing the total number of times the light under measurement is switched in one sweep, it is possible to perform measurement by dividing the measurement wavelength into smaller sections only for the light under measurement that needs to be measured with high accuracy.

[0087] <Switching of the optical switch 40 by a trigger signal> As shown in FIG. 9 , the optical switch 40 may be configured to receive a trigger signal from a device connected externally to the optical spectrum analyzer 10. The optical switch 40 may be configured to switch the light input to the measurement unit 20 in response to the trigger signal. For example, when the first light under measurement and the second light under measurement are input to the optical switch 40, the optical switch 40 switches the light input to the measurement unit 20 between the first light under measurement and the second light under measurement in response to the trigger signal. The trigger signal may be a pulse signal. The optical switch 40 may switch the light input to the measurement unit 20 between the first light under measurement and the second light under measurement at the rising edge of the trigger signal. The optical switch 40 may switch the light input to the measurement unit 20 between the first light under measurement and the second light under measurement at the falling edge of the trigger signal.

[0088] When the optical switch 40 is configured to switch the light input to the measurement unit 20 in response to the input of a trigger signal, the optical spectrum analyzer 10 may execute an optical spectrum measurement method including the steps of the flowchart illustrated in Fig. 10. The optical spectrum measurement method may be realized as an optical spectrum measurement program executed by the optical spectrum analyzer 10. The optical spectrum measurement program may be stored in a non-transitory computer-readable medium.

[0089] The control unit 31 of the optical spectrum analyzer 10 sets a measurement wavelength (step S11). The measurement wavelength may be set in the same manner as in step S1 of FIG.

[0090] The optical switch 40 of the optical spectrum analyzer 10 determines whether a trigger signal has been input (step S12). If a trigger signal has been input (step S12: YES), the optical switch 40 switches the light under measurement to be input to the measurement unit 20 (step S13). The switching of the light under measurement to be input to the measurement unit 20 may be performed in the same manner as in step S2 of Fig. 4. If a trigger signal has not been input (step S12: NO), the optical switch 40 does not perform the procedure of switching the light under measurement in step S13, and proceeds to step S14.

[0091] The measurement unit 20 of the optical spectrum analyzer 10 measures the light intensity of the measurement wavelength set in the procedure of step S11 for the light under measurement input to the measurement unit 20 (step S14). The measurement of the light intensity of the measurement wavelength may be performed in the same manner as the procedure of step S3 in FIG.

[0092] The control unit 31 determines whether the conditions for changing the measurement wavelength are satisfied (step S15). The determination may be performed in the same manner as in the procedure of step S4 in Fig. 4. If the conditions for changing the measurement wavelength are not satisfied (step S15: NO), the control unit 31 returns to the procedure of step S12, and switches the measured light to be input to the measurement unit 20 when a trigger signal is input.

[0093] When the condition for changing the measurement wavelength is satisfied (step S15: YES), the control unit 31 completes the measurement of the light intensity at the set measurement wavelength and updates the measurement data at the set measurement wavelength (step S16). The measurement data update may be performed in the same manner as the procedure of step S5 in Fig. 4. When performing the measurement data update procedure of step S16, the control unit 31 may generate measurement data of the optical spectrum of each of the multiple light beams to be measured based on the data obtained up to this point that associates the light beams to be measured selected during measurement by the measurement unit 20 with the intensity measurement results obtained by the measurement unit 20, and display the generated measurement data on the display unit 32.

[0094] The control unit 31 determines whether acquisition of data in the measurement wavelength range has been completed (step S17). This determination may be performed in the same manner as in step S6 of Fig. 4. If acquisition of data in the measurement wavelength range has not been completed (step S17: NO), the control unit 31 returns to the procedure of step S11, resets the measurement wavelength to the next wavelength in the measurement wavelength range, and measures the intensities of the multiple light beams to be measured at the reset measurement wavelength.

[0095] When the control unit 31 has completed acquisition of data in the measurement wavelength range (step S17: YES), it displays the measurement data of the optical spectra of the plurality of light beams under measurement on the display unit 32 (step S18). The display of the measurement data may be executed in the same manner as the procedure in step S7 of Fig. 4. After executing the procedure in step S18, the control unit 31 ends execution of the flowchart in Fig. 10. Even while acquiring data in the measurement wavelength range, the control unit 31 may generate measurement data of the optical spectra of each of the plurality of light beams under measurement based on the data acquired up to that time, and display the generated measurement data on the display unit 32 at any time, for example, when the measurement data update procedure in step S16 is executed.

[0096] An example of an operation for acquiring measurement data by switching the light under measurement input to the measurement unit 20 by inputting a trigger signal to the optical switch 40 will be described with reference to the timing chart of Fig. 11. In this operation example, the optical spectrum analyzer 10 measures the optical spectra of two light under measurement, namely, the first light under measurement and the second light under measurement, in one sweep.

[0097] As shown in Fig. 11, it is assumed that the measurement wavelength is set to x0 and x1 in order. Setting the measurement wavelength corresponds to the procedure of step S11 in Fig. 10. Meanwhile, it is assumed that the light (input light) input to the measurement unit 20 is switched to either the first light under measurement (#1) or the second light under measurement (#2) at the rising edge of the trigger signal. Inputting the trigger signal corresponds to the procedure of step S12 in Fig. 10. Switching the light input to the measurement unit 20 corresponds to the procedure of step S13 in Fig. 10.

[0098] During the period in which the measurement wavelength is set to x0, the light input to the measurement unit 20 is switched to each of the first measured light and the second measured light. The measurement unit 20 measures the intensity (y0 and y2) of the wavelength component of x0 for the first measured light. The measurement unit 20 measures the intensity (y1) of the wavelength component of x0 for the second measured light. The measurement of the intensities of the first measured light and the second measured light corresponds to the procedure of step S14 in FIG. 10. The measurement data of the first measured light is represented as first measured light acquisition data. The measurement data of the second measured light is represented as second measured light acquisition data.

[0099] After measuring the intensity (y2), the measurement wavelength is reset to x1. The intensity (y4) of the wavelength component of x1 for the first light under measurement is measured. The measurement unit 20 measures the intensities (y3 and y5) of the wavelength components of x1 for the second light under measurement.

[0100] The operation of resetting the measurement wavelength and measuring the intensity of the light under measurement at each measurement wavelength is repeated until the measurement wavelength is set to the measurement end wavelength and the measurement data of the intensity of each wavelength in the measurement wavelength range is updated, that is, until one sweep is completed. By measuring the intensities of both the first and second light under measurement until one sweep is completed, measurement waveforms of the optical spectra of the first and second light under measurement are generated in one sweep.

[0101] As described above, the optical spectrum analyzer 10 may be configured to switch the light under measurement input to the measurement unit 20 in response to a trigger signal input from an external device. The external device may be a computer used by a user of the optical spectrum analyzer 10. For example, the user of the optical spectrum analyzer 10 may run a user program on the external device that changes the light under measurement input to the optical spectrum analyzer 10 and generates a trigger signal that switches the light under measurement to be input to the measurement unit 20. The user program outputs a trigger signal, allowing the light under measurement to be switched in response to the operation of the user program. This makes it easy to switch the light under measurement to be input to the measurement unit 20 in accordance with changes in the light under measurement. As a result, user convenience is improved.

[0102] The optical switch 40 may be configured to receive an input of a single trigger signal and sequentially switch among a plurality of light beams under measurement at the rising or falling edge of the single trigger signal. For example, when switching among N light beams under measurement from the first light beam under measurement to the Nth light beam under measurement, the optical switch 40 may switch from the first light beam under measurement to the second light beam under measurement in response to an input of a trigger signal, switch from the second light beam under measurement to the third light beam under measurement in response to the next trigger signal, and switch from the Nth light beam under measurement to the first light beam under measurement.

[0103] The optical switch 40 may be configured to receive multiple trigger signals and switch to any one of multiple light beams under measurement in response to a combination of the multiple trigger signals. For example, when switching between 2^K-1 light beams under measurement, from the first light beam under measurement to the 2^K-1 light beam under measurement, the optical switch 40 may switch the light beams under measurement in response to K trigger signals. Specifically, the number of combinations of the K trigger signals is 2^K-1. Therefore, the optical switch 40 may switch to any one of the light beams under measurement corresponding to the 2^K-1 inputs obtained by combining the K trigger signals. In this way, even if the number of light beams under measurement to be switched by the optical switch 40 increases, the optical switch 40 can quickly switch to any one of the light beams under measurement.

[0104] <Configuration with Multiple Measurement Units 20> 12, the optical spectrum analyzer 10 may include a first measuring unit 20A and a second measuring unit 20B as the measuring unit 20. The first measuring unit 20A and the second measuring unit 20B may have the same configuration as the measuring unit 20.

[0105] The optical spectrum analyzer 10 may further include a first optical switch 40A for switching the light under measurement to input to the first measuring unit 20A. The first optical switch 40A includes terminals 411A to 41NA and a terminal 42A. The terminals 411A to 41NA are connected to the first port 51 to the Nth port 5N, respectively. The terminal 42A is configured to be switchable so as to be connected to any of the terminals 411A to 41NA. The first optical switch 40A switches the light to be input to the first measuring unit 20A to any of the light under measurement from the first light under measurement input to the first port 51 to the Nth light under measurement input to the Nth port 5N.

[0106] The optical spectrum analyzer 10 may further include a second optical switch 40B for switching the light under measurement to input to the second measurement unit 20B. The second optical switch 40B includes terminals 411B to 41NB and a terminal 42B. The terminals 411B to 41NB are connected to the (N+1)th port 61 to the (N+M)th port 6M, respectively. The terminal 42B is configured to be switchable so as to be connected to any of the terminals 411B to 41NB. The second optical switch 40B switches the light to be input to the second measurement unit 20B to any of the (N+1)th light under measurement input to the (N+1)th port 61 to the (N+M)th light under measurement input to the (N+M)th port 6M.

[0107] The optical spectrum analyzer 10 can measure the optical spectra of multiple light beams under measurement in parallel by including multiple measuring units 20. Also, the optical spectrum analyzer 10 can increase the number of light beams under measurement that can be connected by including multiple optical switches 40.

[0108] <Configuration in which the optical switch 40 is connected to the outside> 13 , the optical spectrum analyzer 10 may not have a built-in optical switch 40, but may instead have an optical input port 50 connectable to an externally installed optical switch 40. The control unit 31 acquires information specifying the light under measurement to be input to the optical input port 50 from the external optical switch 40. Based on the information specifying the light under measurement to be input to the optical input port 50, the control unit 31 can measure the optical spectrum of each of the multiple light under measurement that are switched and input from the optical switch 40.

[0109] By configuring the optical spectrum analyzer 10 to be connectable to an external optical switch 40 without incorporating an optical switch 40, the optical spectrum measurement method according to the present disclosure can be executed by the optical spectrum analyzer 10 that does not originally incorporate an optical switch 40. As a result, user convenience is improved.

[0110] Although the embodiments of the present disclosure have been described based on the drawings and examples, it should be noted that those skilled in the art can make various modifications or alterations based on the present disclosure. Therefore, it should be noted that these modifications or alterations are included in the scope of the present disclosure. For example, the functions included in each component can be rearranged so as not to cause logical inconsistencies, and multiple components can be combined or divided into one. [Explanation of symbols]

[0111] 10 Optical Spectrum Analyzer 20 Measuring part (20A: 1st measuring part, 20B: 2nd measuring part) 21 Spectrometer 22 Photodetector 23 Amplifier 24 Data acquisition circuit 31 Control Unit 32 Display section 40 Optical switch (40A: first optical switch, 40B: second optical switch) 411~41N (411A~41NA, 411B~41NB) terminal 42(42A, 42B) terminal 50 optical input ports 51~5N 1st to Nth ports 61~6M N+1st~N+Mth ports

Claims

1. A program for measuring optical spectra of a plurality of light beams under measurement during one sweep, acquiring a measurement result of the intensity of light under measurement selected one by one from the plurality of light under measurement; generating an optical spectrum of each of the light beams to be measured by associating the light beams to be measured selected at the time of measurement with the acquired measurement results; an optical spectrum measurement program that causes a processor to execute the above;

2. 2. The optical spectrum measurement program according to claim 1, which causes the processor to select a light beam to be measured from the plurality of light beams to be measured.

3. 3. The optical spectrum measurement program according to claim 2, wherein the program causes the processor to acquire a measurement result of the optical intensity of the first wavelength of at least one measured light beam selected one by one from the plurality of measured light beams during a first period in which the optical intensity of the first wavelength is measured during a sweep.

4. 4. The optical spectrum measurement program according to claim 3, wherein the program causes the processor to acquire, during the first period, measurement results of the optical intensities of the first wavelengths of all of the plurality of light beams under measurement.

5. 4. The optical spectrum measurement program according to claim 3, wherein the program causes the processor to select the light under measurement so that the number of light under measurement selected in a second period during which the light intensity of a second wavelength is measured during a sweep is different from the number of light under measurement selected in the first period.

6. 4. The optical spectrum measurement program according to claim 3, wherein the program causes the processor to determine the number of light beams to be measured in each period during which the light intensity of each wavelength is measured during a sweep, based on the accuracy required for measuring each of the light beams to be measured.

7. 7. The optical spectrum measurement program according to claim 1, further comprising: acquiring a measurement result after an invalid period has elapsed since selecting and switching one of the plurality of light beams under measurement.

8. 7. The optical spectrum measurement program according to claim 1, wherein the program causes the processor to execute the following: when multiple measurements of the light intensity at a measurement wavelength are performed, perform statistical processing on multiple measurement values ​​obtained in each of the multiple measurements, and acquire the calculated value as the measurement result of the light intensity at the measurement wavelength.

9. 1. A method for generating a plurality of optical spectra of light under test during a single sweep, comprising: acquiring a measurement result of the intensity of light under measurement selected one by one from the plurality of light under measurement; generating an optical spectrum of each of the light beams to be measured by associating the light beams to be measured selected at the time of measurement with the acquired measurement results; An optical spectrum measurement method comprising:

10. An optical spectrum analyzer that generates a plurality of optical spectra of light under test during one sweep, at least one measurement unit that measures the intensity of light beams to be measured that are selected one by one from the plurality of light beams to be measured; a control unit that generates an optical spectrum of each of the lights under measurement by associating the lights under measurement selected when the measurement unit measures the light intensity with the measurement result of the light intensity by the measurement unit; An optical spectrum analyzer comprising:

11. a switching unit that switches a connection so that one light beam under measurement selected from the plurality of light beams under measurement is input to the measurement unit; the control unit controls the switching unit to select one of the plurality of light beams under measurement to be input to the measurement unit.

11. The optical spectrum analyzer of claim 10.

12. 12. The optical spectrum analyzer according to claim 11, wherein the switching unit is configured to receive an input of a trigger signal, and switches the light under measurement to be input to the measuring unit in response to the input of the trigger signal.

13. 13. The optical spectrum analyzer according to claim 10, wherein when the number of the measurement units is two or more, each of the two or more measurement units measures the optical intensity of a light under measurement selected one by one from the plurality of light under measurement.

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