JP6385795B2 - Optical device simulation method - Google Patents

Description

The present invention relates to an optical device simulation method in which the characteristics of an optical device can be simulated using an electronic circuit simulator.
In particular, the present invention has been devised so that the characteristics of an optical device whose response varies depending on the polarization state of an input optical signal can be simulated using an electronic circuit simulator. Polarization Multiplexing The present invention is useful for simulating the characteristics of an optical device that processes an optical signal modulated by.

In recent years, in optical communication, an attempt has been made to overcome each performance limit by co-designing an electronic circuit and an optical circuit. In the cooperative design of an electronic circuit and an optical circuit, a simulation environment that verifies the validity of the design is required.
For this reason, active research has been carried out to create a simulation environment that verifies the validity of collaborative design by using an electronic circuit simulator with a high integration density as the base and realizing optical circuit simulation in this electronic circuit simulator. ing.

Since the light (optical signal) used in optical communication is an electromagnetic wave, it is considered that the optical circuit can be simulated by driving the electronic circuit simulator at the carrier frequency of the optical signal. However, the carrier frequency used in optical communication is as high as several tens to several hundreds THz, and cannot be handled by a normal electronic circuit simulator.
Even if it can be handled, the maximum frequency handled by the electronic circuit is about the modulation frequency of the optical signal (about several tens of GHz), and there is a difference of three digits or more from the carrier frequency of the optical signal. Requires resources and computation time. Therefore, in practice, it has been very difficult to simulate an optical circuit using an electronic circuit simulator.

  For this reason, conventionally, when an optical circuit (optical device) is simulated using an electronic circuit simulator, the target optical device to be simulated is accompanied by photoelectric conversion or electro-optical conversion without considering the extremely high carrier frequency. Only the response to the modulation frequency of the signal has been simulated for an optical device (see Non-Patent Document 1).

In contrast, when simulating an optical device with an electronic circuit simulator, a method has been proposed that enables simulation with realistic computer resources and calculation time by reducing the optical carrier frequency to a pseudo carrier frequency. (See Non-Patent Document 2).
In this method, the response characteristic of the optical device at the carrier frequency is obtained in advance by measurement or calculation, and is made to correspond to the response characteristic of the optical device at the pseudo carrier frequency. In the electronic circuit simulator, the optical device model having response characteristics at the pseudo carrier frequency is driven at the pseudo carrier frequency to realize the simulation of the optical device. This method (the method of Non-Patent Document 2) is different from the method of Non-Patent Document 1 described above, and can simulate the response to the modulation frequency and the response to the carrier frequency of the optical device.

Here, an outline of the technique disclosed in Non-Patent Document 2 will be described with reference to FIGS. 7, 8, and 9.
An optical signal L that is a modulated wave shown in FIG. 7A is obtained by modulating the optical carrier signal C with the optical modulation signal M. The frequency of the optical signal L is obtained by superimposing the modulation frequency F2 (about several tens GHz) of the optical modulation signal M on the carrier frequency F1 (several tens to several hundreds THz) of the optical carrier signal C.

Some optical devices have a response characteristic (response function) at a carrier frequency as shown in FIG.
In order to simulate the characteristics of such an optical device with an electronic circuit simulator, a relatively low pseudo carrier frequency F3, which is approximately 10 times the modulation frequency F2, is employed instead of the carrier frequency F1. Then, in the pseudo carrier frequency F3, the response specification is set so that the input / output characteristics equivalent to the input / output characteristics of the optical device at the carrier frequency F1 (FIG. 8A) can be obtained also in the pseudo carrier frequency F2. The response characteristic of the optical device (FIG. 8B) is set.

  In the electronic circuit simulator, a carrier frequency conversion step S1 and an optical device simulation step S2 are set as shown in FIG. The electronic circuit simulator is realized by hardware resources and a program for controlling the hardware resources.

  In the carrier frequency conversion step S1, the pseudo optical signal Lf is output by multiplying the pseudo optical carrier signal Cf having the pseudo carrier frequency F3 by the mixer model 1 and the optical modulation signal M having the modulation frequency F2. The frequency of the pseudo optical signal Lf is obtained by superimposing the modulation frequency F2 on the pseudo carrier frequency F3 (from baseband to several hundred GHz).

The optical device model 2 is set in the optical device simulation step S2. This optical device model 2 has the response characteristics of the optical device at the pseudo carrier frequency F3 shown in FIG. 8B. Then, by inputting the pseudo optical signal Lf to the optical device model 2, the optical output signal R is output. The response characteristic of the optical output signal R corresponds to the response characteristic when the optical signal L is input to an optical device having a response characteristic (response function) with respect to the carrier frequency as shown in FIG. It has become.
Therefore, by examining the characteristics of the optical output signal R, the characteristics of the optical device can be simulated.

  7A shows the optical signal L, FIG. 7B shows the response characteristic of the optical device at the pseudo carrier frequency F3 as in FIG. 8B, and FIG. 7C shows the electronic circuit. An optical output signal R output from the optical device model 2 in the simulator is shown.

J.-W. Shi, et al., "Dynamic Analysis of a Si / SiGe-Based Impact Ionization Avalanche Transit Time Photodiode With an Ultrahigh Gain-Bandwidth Product", IEEE ELECTRON DEVICE LETTERS, VOL. 30, NO. 11, p .1164-1166, 2009 Kotaro Takeda and three others, “Verification of equivalent circuit model of silicon photonics wavelength filter circuit”, Electronics Society Conference 2014, IEICE Electronics Conference, September 23-26, 2014, p.217

On the other hand, in order to cope with the explosive increase in the information distribution amount in recent years, the polarization multiplexing method has become the mainstream as a modulation method.
In the polarization multiplexing method, paying attention to the fact that there are two electromagnetic waves (vertically polarized electromagnetic waves and horizontally polarized electromagnetic waves) in electromagnetic waves (light), the vertically polarized electromagnetic waves and the horizontal polarized waves The polarized electromagnetic wave is individually modulated.

However, many optical devices have different responses due to different polarization states.
For example, in an optical device, as shown in FIG. 10, the response characteristics differ depending on the polarization state.
The response characteristic shown in FIG. 10A is a response characteristic in which a TE-polarized optical signal is input and a TE-polarized optical output signal is output, and the response characteristic shown in FIG. 10 (c) is a response characteristic in which a wave optical signal is input and a TM polarized light output signal is output. The response characteristic shown in FIG. The response characteristic shown in FIG. 10D is a response characteristic in which a TM-polarized optical signal is input and a TE-polarized optical output signal is output.

  As described above, in an optical device having different responses due to different polarization states, it is indispensable to consider the polarization state when simulating.

  However, not only the method shown in Non-Patent Document 1 but also the method shown in Non-Patent Document 2 does not assume that the response of the optical device to each polarization state is simulated.

Thus, in the technique of Non-Patent Document 2, since the response to the polarization state is not distinguished, the polarization is always fixed and has been treated as not changing.
Therefore, as shown in FIGS. 10A, 10 </ b> B, 10 </ b> C, and 10 </ b> D, simulation of an optical device having different response characteristics due to different polarization states is performed using the technique of Non-Patent Document 2. When an attempt is made, any one of the response characteristics shown in FIGS. 10A, 10B, 10C, and 10D is selected, and the selected response characteristic is selected as the optical device model shown in FIG. It was necessary to set a response characteristic of 2 and perform a simulation. In other words, it was not possible to perform a simulation according to each polarization state.

  In view of the above circumstances, the present invention considers the difference between the carrier frequency and the polarization state within a realistic calculation time using a realistic computer resource when simulating an optical device using an electronic circuit simulator. It is an object of the present invention to provide an optical device simulation method capable of obtaining the response characteristics of

The present invention for solving the above problems
An optical device simulation method for simulating the characteristics of an optical device having different response characteristics every time the polarization state of an input polarization multiplexed optical signal is different by a computer,
A carrier frequency conversion step, an optical signal distribution step, an optical device simulation step, and a multiplexing step,
The carrier frequency conversion step includes
Having a first mixer model and a second mixer model;
The first mixer model multiplies the pseudo optical carrier signal having a pseudo carrier frequency lower than the carrier frequency of the optical carrier signal of the optical signal by the TE optical modulation signal having TE polarization. To output a pseudo optical signal that is TE polarized,
The second mixer model multiplies the pseudo optical carrier signal by a TM optical modulation signal that is TM polarized, and outputs a pseudo optical signal that is TM polarized,
The optical signal distribution step includes:
Having a first power splitter model and a second power splitter model;
The first power splitter model bifurcates the pseudo optical signal that is TE polarized,
The second power splitter model bifurcates the pseudo optical signal that is TM polarized,
The optical device simulation step includes
An optical device model comprising a first optical device response model, a second optical device response model, a third optical device response model, and a fourth optical device response model;
The first optical device response model has an input / output characteristic equivalent to an input / output characteristic in which a TE-polarized optical output is output when a TE-polarized optical signal is input to the optical device at the carrier frequency. A TE-TE in which a response characteristic is set so as to be obtained even at the pseudo carrier frequency, and a TE polarized light output is output when a TE polarized light signal is input to the optical device at the pseudo carrier frequency. Having a response characteristic, the TE-polarized pseudo optical signal is inputted, and a TE-TE optical output signal corresponding to the TE-TE response characteristic is output,
The second optical device response model has an input / output characteristic equivalent to an input / output characteristic in which a TM polarized optical output is output when a TM polarized optical signal is input to the optical device at the carrier frequency. TM-TM, which has a response characteristic set so as to be obtained even at the pseudo carrier frequency, and outputs a TM polarized light output when a TM polarized optical signal is input to the optical device at the pseudo carrier frequency. Having a response characteristic, the TM-polarized pseudo optical signal is input, and a TM-polarized optical output signal corresponding to the TM-TM response characteristic is output;
The third optical device response model has an input / output characteristic equivalent to an input / output characteristic in which a TM polarized optical output is output when a TE polarized optical signal is input to the optical device at the carrier frequency. A TE-TM in which a response characteristic is set so as to be obtained even at the pseudo carrier frequency, and a TM polarized light output is output when a TE polarized light signal is input to the optical device at the pseudo carrier frequency. Having a response characteristic, the TE-polarized pseudo optical signal is input, and a TM-polarized optical output signal corresponding to the TE-TM response characteristic is output;
The fourth optical device response model has an input / output characteristic equivalent to an input / output characteristic in which a TE-polarized optical output is output when a TM-polarized optical signal is input to the optical device at the carrier frequency. TM-TE, which has a response characteristic set so as to be obtained even at the pseudo carrier frequency, and outputs a TE polarized light output when a TM polarized optical signal is input to the optical device at the pseudo carrier frequency. It has a response characteristic, and the pseudo optical signal of TM polarization is input to output an optical output signal of TE polarization corresponding to the TM-TE response characteristic,
The combining step includes
Having a first coupler model and a second coupler model;
The first coupler model includes a TE-polarized optical output signal output from the first optical device response model and a TE-polarized optical output signal output from the fourth optical device response model. In addition, output a TE-polarized total optical output signal,
The second coupler model includes a TM-polarized optical output signal output from the second optical device response model and a TM-polarized optical output signal output from the third optical device response model. In addition, a total optical output signal of TM polarization is output.

The present invention also provides
The optical device is any one of an optical filter, a polarization rotation element, an optical waveguide, an optical termination element, an optical amplifier, and an optical variable attenuator.

The present invention also provides
And further comprises a demodulation step,
The demodulation step includes
Having a first demodulator model and a second demodulator model;
The first demodulator model demodulates the total optical output signal of TE polarization output from the first coupler model, and outputs a demodulation signal of TE polarization,
The second demodulator model demodulates the TM polarized optical output signal output from the second coupler model and outputs a TM polarized demodulated signal.

The present invention also provides
The optical device is either an optical receiver or an optical modulator.

The present invention also provides
An optical device simulation method for simulating the characteristics of an optical device having different response characteristics every time the polarization state of an input polarization multiplexed optical signal is different by a computer,
A carrier frequency conversion step and an optical device simulation step,
The carrier frequency conversion step includes
Having a first mixer model and a second mixer model;
The first mixer model multiplies the pseudo optical carrier signal having a pseudo carrier frequency lower than the carrier frequency of the optical carrier signal of the optical signal by the TE optical modulation signal having TE polarization. To output a pseudo optical signal that is TE polarized,
The second mixer model multiplies the pseudo optical carrier signal by a TM optical modulation signal that is TM polarized, and outputs a pseudo optical signal that is TM polarized,
The optical device simulation step includes
A response function matrix,
The response function matrix includes
An input / output characteristic equivalent to an input / output characteristic that outputs a TE-polarized light output when a TE-polarized optical signal is input to the optical device at the carrier frequency is also obtained at the pseudo carrier frequency. A TE-TE response characteristic in which a TE-polarized optical output is output when a TE-polarized optical signal is input to the optical device at the pseudo carrier frequency with the response characteristic set;
An input / output characteristic equivalent to an input / output characteristic in which a TM polarized light output is output when a TM polarized light signal is input to the optical device at the carrier frequency is also obtained at the pseudo carrier frequency. A TM-TM response characteristic in which a TM-polarized light output is output when a TM-polarized light signal is input to the optical device at the pseudo-carrier frequency with a response characteristic set;
An input / output characteristic equivalent to an input / output characteristic in which a TM polarized light output is output when a TE polarized light signal is input to the optical device at the carrier frequency is also obtained at the pseudo carrier frequency. A TE-TM response characteristic in which a TM-polarized optical output is output when a TE-polarized optical signal is input to the optical device at the pseudo carrier frequency with a response characteristic set;
An input / output characteristic equivalent to an input / output characteristic in which a TE-polarized optical output is output when a TM-polarized optical signal is input to the optical device at the carrier frequency is also obtained at the pseudo carrier frequency. A TM-TE response characteristic in which a TE-polarized optical output is output when a TM-polarized optical signal is input to the optical device at the pseudo carrier frequency with a response characteristic set;
Is incorporated as a 2-by-2 matrix,
By calculating using the response function matrix,
When the TE-polarized pseudo optical signal is input, a TE-polarized optical output signal is obtained according to the TE-TE response characteristic, and a TM-polarized optical output signal is determined according to the TE-TM response characteristic. Seeking
When the TM-polarized pseudo optical signal is input, a TM-polarized optical output signal is obtained according to the TM-TM response characteristic, and a TE-polarized optical output signal is determined according to the TM-TE response characteristic. Seeking
Further, the TE polarized light output signal obtained in accordance with the TE-TE response characteristic and the TE polarized light output signal obtained in accordance with the TM-TE response characteristic are added to obtain the TE polarized light. Output as a total optical output signal
The TM-polarized light output signal obtained according to the TM-TM response characteristics and the TM-polarized light output signal obtained according to the TE-TM response characteristics are added to obtain a TM-polarized total light. It outputs as an output signal, It is characterized by the above-mentioned.

According to the present invention, it is possible to simulate an optical device that exhibits different responses depending on the polarization state on an electronic circuit simulator.
In addition, the application destination of the electronic circuit simulator is expanded, and the person who performs the cooperative design of the electronic circuit and the optical circuit (optical device) does not need to have a plurality of simulators, thereby reducing the design cost.

FIG. 4A is a characteristic diagram showing response characteristics of an optical device, and FIG. 4A is a TE-TE response characteristic chart in which a TE-polarized optical output signal is output when a TE-polarized optical signal is input at a pseudo carrier frequency; b) TM-TM response characteristic diagram in which a TM-polarized optical output signal is output when a TM-polarized optical signal is input at the pseudo-carrier frequency, and (c) is a TE-polarized optical signal at the pseudo-carrier frequency. FIG. 4D is a TE-TM response characteristic diagram in which a TM polarized optical output signal is output when a TM polarized optical signal is input at a pseudo carrier frequency. It is a TM-TE response characteristic figure outputted. It is a characteristic view which shows the optical signal input, (a) shows TE polarization component, (b) shows TM polarization component. FIG. 4A is a characteristic diagram showing response characteristics of an optical device, and FIG. 4A is a TE-TE response characteristic chart in which a TE-polarized optical output signal is output when a TE-polarized optical signal is input at a pseudo carrier frequency; b) TM-TM response characteristic diagram in which a TM-polarized optical output signal is output when a TM-polarized optical signal is input at the pseudo-carrier frequency, and (c) is a TE-polarized optical signal at the pseudo-carrier frequency. FIG. 4D is a TE-TM response characteristic diagram in which a TM polarized optical output signal is output when a TM polarized optical signal is input at a pseudo carrier frequency. It is a TM-TE response characteristic figure outputted. It is a characteristic figure which shows a synthetic | combination optical output signal, (a) shows the component of TE polarization, (b) shows TM polarization component. It is a functional block diagram which shows the electronic circuit simulator which concerns on Example 1 of this invention. It is a block diagram which shows the apparatus which determines the response characteristic of an optical device by measurement. It is a functional block diagram which shows the electronic circuit simulator which concerns on Example 2 of this invention. It is a functional block diagram which shows the electronic circuit simulator which concerns on Example 3 of this invention. (A) is a characteristic diagram showing the optical signal L, (b) is a characteristic diagram showing the response characteristic of the optical device at the pseudo carrier frequency, and (c) is an optical output signal output from the optical device model in the electronic circuit simulator. FIG. It is a characteristic view which shows the response characteristic of an optical device, (a) is a characteristic figure in a carrier wave frequency, (b) is a characteristic figure in a pseudo carrier wave frequency. It is a functional block diagram which shows the conventional electronic circuit simulator. FIG. 4 is a characteristic diagram showing response characteristics of an optical device, in which (a) is a response characteristic diagram in which a TE-polarized optical signal is input at a carrier frequency and a TE-polarized optical output signal is output, and (b) is a carrier frequency. (C) is a response characteristic diagram in which a TM polarized optical signal is input and a TM polarized optical output signal is output. FIG. (D) is a response characteristic diagram in which a TM polarized optical signal is input and a TE polarized optical output signal is output at the carrier frequency.

  Hereinafter, an optical device simulation method according to the present invention will be described in detail.

[Principle of the Invention]
First, when the response characteristic at the carrier frequency F1 of the optical device to be inspected varies depending on the polarization state, the response characteristic for each polarization state at the carrier frequency F1 is obtained by measurement or calculation.
For example, as shown in FIG. 10 described above, response characteristics due to the difference in polarization state at the carrier frequency F1 are obtained. That is, the following response characteristics (1) to (4) are obtained.
(1) TE-TE response characteristics in which a TE-polarized optical output signal is output when a TE-polarized optical signal is input at the carrier frequency F1 shown in FIG.
(2) TM-TM response characteristics in which a TM-polarized light output signal is output when a TM-polarized light signal is input at the carrier frequency F1 shown in FIG.
(3) TE-TM response characteristics in which a TM-polarized optical output signal is output when a TE-polarized optical signal is input at the carrier frequency F1 shown in FIG.
(4) TM-TE response characteristics in which a TE-polarized optical output signal is output when a TM-polarized optical signal is input at the carrier frequency F1 shown in FIG.

Next, in order to simulate the characteristics of such an optical device using an electronic circuit simulator, a relatively low pseudo carrier frequency F3, which is approximately 10 times the modulation frequency F2, is employed instead of the carrier frequency F1. The pseudo carrier wave in which the response specification is set so that the input / output characteristic for each polarization state equivalent to the input / output characteristic for the polarization state of the optical device at the carrier wave frequency F1 is also obtained at the pseudo carrier frequency F3. Response characteristics (FIGS. 1A, 1B, 1C, and 1D) for each polarization state of the optical device at the frequency F3 are set.
The four response characteristics shown in FIGS. 1A, 1B, 1C, and 1D are determined by simulation, calculation, or actual measurement.

(1) FIG. 1A shows TE-TE response characteristics in which a TE-polarized optical output signal is output when a TE-polarized optical signal is input at the pseudo carrier frequency F3.
(2) FIG. 1B shows a TM-TM response characteristic in which a TM-polarized light output signal is output when a TM-polarized light signal is input at the pseudo carrier frequency F3.
(3) FIG. 1C shows a TE-TM response characteristic in which a TM-polarized optical output signal is output when a TE-polarized optical signal is input at the pseudo carrier frequency F3.
(4) FIG. 1 (d) shows a TM-TE response characteristic in which a TE-polarized optical output signal is output when a TM-polarized optical signal is input at the pseudo carrier frequency F3.

Four optical device models having response characteristics shown in FIGS. 1A, 1B, 1C, and 1D are set in the electronic circuit simulator.
Next, the optical modulation signal M is divided into a TE polarized TE optical modulation signal M _TE and a TM polarized TM optical modulation signal M _TM . That is, the input signal for simulating the optical device in the electronic circuit simulator is divided into two. Note that the frequencies of the TE-polarized TE optical modulation signal M _TE and the TM-polarized TM optical modulation signal M _TM are the modulation frequency F 2, similar to the frequency of the optical modulation signal M.
Instead of the optical carrier signal C, a pseudo optical carrier signal Cf whose frequency is the pseudo carrier frequency F3 is employed.

The pseudo optical signal Lf _TE obtained by modulating the pseudo optical carrier signal Cf with the TE optical modulation signal M _{TE is} converted into an optical device model having a TE-TE response characteristic shown in FIG. 1A and a TE− shown in FIG. Input to an optical device model with TM response characteristics.
A pseudo optical signal Lf _TM obtained by modulating the pseudo optical carrier signal Cf with the TM optical modulation signal M _{TM is} converted into an optical device model having a TM-TM response characteristic shown in FIG. 1B and a TM− shown in FIG. Input to an optical device model with TE response characteristics.

Next, the TE polarized optical output signal r _TE-TE output from the optical device model having the TE-TE response characteristic shown in FIG. 1A and the TM-TE response characteristic shown in FIG. The TE-polarized optical output signal r _TM-TE output from the optical device model is added to obtain a TE-polarized total optical output signal R _TE .
Also, the TM polarized optical output signal r _TM-TM output from the optical device model having the TM-TM response characteristic shown in FIG. 1B and the TE-TM response characteristic shown in FIG. The TM polarized optical output signal r _TE-TM output from the optical device model is added to obtain a TM polarized total optical output signal R _TM .
That is, there are two output signals (total optical output signals) when the optical device is simulated in the electronic circuit simulator.

By examining the characteristics of the TE-polarized total optical output signal R _TE and the TM-polarized total optical output signal R _TM thus obtained, the characteristics of the optical signal for each polarization state can be simulated. .

2A (a) and 2 (b) show an input optical signal L. The optical signal L has a TE polarization component but does not include a TM polarization component.
2B (a), (b), (c), and (d) are the same as in FIGS. 1 (a), (b), (c), and (d), for each polarization state of the optical device at the pseudo carrier frequency F3. The response characteristics are shown.
FIG. 2C (a) shows the TE-polarized total optical output signal R _TE, and FIG. 2C (b) shows the TM-polarized total optical output signal R _TM . As shown in FIGS. 2C (a) and 2 (b), TE polarization output characteristics and TM polarization output characteristics in accordance with the polarization state can be obtained, so that the simulation according to the polarization state of the optical device is performed. Can do.

[Example 1]
An optical device simulation method according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 3 represents a simulation process performed by a simulation apparatus (electronic circuit simulator) realized using a computer using functional blocks. The first embodiment is an example in which the optical device simulation method of the present invention is applied to an optical filter, for example.

  The first embodiment includes a carrier frequency conversion step S11, an optical signal distribution step S12, an optical device simulation step S13, and a multiplexing step S14.

In the carrier frequency conversion step S11, the pseudo optical signal Lf _TE is output by multiplying the pseudo optical carrier signal Cf having the pseudo carrier frequency F3 and the TE optical modulation signal M _TE having the modulation frequency F2 by the mixer model 11a. . The frequency of the pseudo optical signal Lf _TE is obtained by superimposing the modulation frequency F2 on the pseudo carrier frequency F3 (from baseband to several hundred GHz).
Further, the pseudo optical signal Lf _TM is output by multiplying the pseudo optical carrier signal Cf having the pseudo carrier frequency F3 and the TM optical modulation signal M _TM having the modulation frequency F2 by the mixer model 11b. The frequency of the pseudo optical signal Lf _TM is obtained by superimposing the modulation frequency F2 on the pseudo carrier frequency F3 (several hundred GHz from the baseband).

In the optical signal distribution step S12, by the power splitter model 12a, a pseudo optical signals Lf _TE 2 branches and outputs to the optical device model 13. Further, the pseudo optical signal Lf _TM is branched into two by the power splitter model 12 b and output to the optical device model 13.

In the optical device simulation step S13, the optical device model 13 is set. This optical device model 13 has a plurality of optical device response models 13-1, 13-2, 13-3, 13-4.
The optical device response model 13-1 has a TE-TE response characteristic in which a TE-polarized optical output signal is output when a TE-polarized optical signal is input to the optical filter at the pseudo carrier frequency F3. Yes.
The optical device response model 13-2 has a TM-TM response characteristic in which a TM-polarized optical output signal is output when a TM-polarized optical signal is input to the optical filter at the pseudo carrier frequency F3. Yes.
The optical device response model 13-3 has a TE-TM response characteristic in which a TM-polarized optical output signal is output when a TE-polarized optical signal is input to the optical filter at the pseudo carrier frequency F3. Yes.
The optical device response model 13-4 has a TM-TE response characteristic in which a TE-polarized optical output signal is output when a TM-polarized optical signal is input to the optical filter at the pseudo carrier frequency F3. Yes.

  Each response characteristic set in each of the optical device response models 13-1, 13-2, 13-3, and 13-4 is a response characteristic at the pseudo carrier frequency for both the real part and the imaginary part. Each response characteristic set in each optical device response model 13-1, 13-2, 13-3, 13-4 is determined by measurement or a simulator. The determination method will be described later.

The optical device response model 13-1, the pseudo optical signal Lf _TE is input, and outputs an optical output signal r _TE-TE of TE polarized waves according to TE-TE response.
When the pseudo optical signal Lf _TM is input, the optical device response model 13-2 outputs a TM polarized optical output signal r _TM-TM according to the TM-TM response characteristics.
When the pseudo optical signal Lf _TE is input, the optical device response model 13-3 outputs a TM-polarized optical output signal r _TE-TM according to the TE-TM response characteristics.
When the pseudo optical signal Lf _TM is input, the optical device response model 13-4 outputs a TE-polarized optical output signal r _TM-TE according to the TM-TE response characteristics.

In the combining step S14, the coupler model 14a determines that the TE polarized light output signal r _TE-TE output from the optical device response model 13-1 and the TE polarized light output from the optical device response model 13-4. The optical output signal r _TM-TE is added and output as a TE-polarized total optical output signal R _TE .
Further, the coupler model 14b includes a TM polarized light output signal r _TM-TM output from the optical device response model 13-2 and a TM polarized light output signal r output from the optical device response model 13-3. Add _TE-TM and output as TM-polarized total optical output signal _RTM .

The characteristics of the optical device (optical filter) can be simulated by examining the characteristics of the TE polarized total optical output signal R _TE and the TM polarized total optical output signal R _TM thus obtained. . That is, it is possible to simulate the characteristics of an optical device (optical filter) having a response that depends on the carrier frequency and the polarization state.

  Here, a determination method for determining each response characteristic of each of the optical device response models 13-1, 13-2, 13-3, and 13-4 by measurement will be described with reference to FIG.

  The light source 101 in FIG. 4 outputs light. The polarization controller 102 receives light from the light source 101 and is adjusted so that TE-mode light or TM-mode light enters the device under test (optical device) 103. The analyzer 104 is adjusted to an angle at which only TE mode light or TM mode light output from the DUT 103 is detected. The detector 105 detects the light output from the analyzer 104. The device 106 is a device with a clear polarization response.

At the time of measurement, the device under test (optical device) 103 is sandwiched between the polarization controller 102 and the analyzer 104 and measured.
When obtaining the TE-TE response characteristic, the polarization controller 102 adjusts the TE mode light to enter the DUT 103 and the analyzer 104 detects the TE mode light. In order to see the polarization response of only the device under test 103, the device 106 with a clear polarization response is measured first, then the device under test 103 is measured, and the difference in the response is observed to measure the device under test 103. Measure the polarization dependent response. The real part imaginary part of the response is determined from the intensity change and the phase change. These responses are measured around the necessary carrier frequency, then processed to move to the vicinity of the pseudo carrier frequency and applied to the simulation on the electronic circuit simulator.

When obtaining the TM-TM response characteristic, the polarization controller 102 adjusts so that the TM mode light is incident on the DUT 103 and the analyzer 104 detects the TM mode light.
When obtaining the TE-TM response characteristic, the polarization controller 102 makes an adjustment so that the TE mode light is incident on the DUT 103 and the analyzer 104 detects the TM mode light.
When obtaining the TM-TE response characteristic, the polarization controller 102 adjusts so that the TM mode light is incident on the DUT 103 and the analyzer 104 detects the TE mode light.

  As a method for determining each response characteristic of the optical device response models 13-1, 13-2, 13-3, and 13-4 by a simulator, calculation by an eigenmode expansion method of electromagnetic field analysis is given as an example. Simulate TE / TM input, TE / TM output intensity, and phase change near the carrier frequency to determine device response. These responses are calculated around the necessary carrier frequency, then processed to move to the vicinity of the pseudo carrier frequency and applied to the simulation on the electronic circuit simulator.

In the embodiment shown in FIG. 3, an optical filter is shown as the optical device. However, the simulation of the polarization rotation element, the optical waveguide, the optical termination element, the optical amplifier, and the optical variable attenuator is performed in the same manner as the optical filter. Can be done.
Of course, in this case, the response characteristics of the optical device response models 13-1, 13-2, 13-3, 13-4 (TE-TE response characteristics, TM-TM response characteristics, TE-TM response characteristics, TM- The TE response characteristic is determined for each optical device by measurement or simulation.

[Example 2]
An optical device simulation method according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 5 represents a simulation process performed by a simulation apparatus (electronic circuit simulator) realized using a computer using functional blocks.

  The second embodiment includes a carrier frequency conversion step S21 and an optical device simulation step S22.

The carrier frequency conversion step S21 is the same as the carrier frequency conversion step S11 of the first embodiment shown in FIG.
That is, the pseudo optical signal Lf _TE is output by multiplying the pseudo optical carrier signal Cf having the pseudo carrier frequency F3 and the TE optical modulation signal M _TE having the modulation frequency F2 by the mixer model 11a. The frequency of the pseudo optical signal Lf _TE is obtained by superimposing the modulation frequency F2 on the pseudo carrier frequency F3 (from baseband to several hundred GHz).
Further, the pseudo optical signal Lf _TM is output by multiplying the pseudo optical carrier signal Cf having the pseudo carrier frequency F3 and the TM optical modulation signal M _TM having the modulation frequency F2 by the mixer model 11b. The frequency of the pseudo optical signal Lf _TM is obtained by superimposing the modulation frequency F2 on the pseudo carrier frequency F3 (several hundred GHz from the baseband).

In the optical device simulation step S22, the response function matrix 20 is set. In the response function matrix 20, the following four response characteristics (a), (b), (c), and (d) are incorporated in the circuit as a matrix S of 2 rows and 2 columns.
(A) TE-TE response characteristic in which a TE-polarized optical output signal is output when a TE-polarized optical signal is input to the optical device at the pseudo carrier frequency F3.
(B) TM-TM response characteristics in which a TM-polarized optical output signal is output when a TM-polarized optical signal is input to the optical device at the pseudo carrier frequency F3.
(C) TE-TM response characteristics in which a TM-polarized optical output signal is output when a TE-polarized optical signal is input to the optical device at the pseudo carrier frequency F3.
(D) TM-TE response characteristic in which a TE-polarized optical output signal is output when a TM-polarized optical signal is input to the optical device at the pseudo carrier frequency F3.

Further, the following calculation process is performed by calculating using the response function matrix 20.
When the pseudo optical signal Lf _TE is input, an optical output signal r _TE-TE of TE polarization is obtained according to the TE-TE response characteristic.
When the pseudo optical signal Lf _TM is input, a TM polarized optical output signal r _TM-TM is obtained according to the TM-TM response characteristic.
When the pseudo optical signal Lf _TE is input, an optical output signal r _TE-TM of TM polarization is obtained according to the TE-TM response characteristic.
When the pseudo optical signal Lf _TM is input, a TE polarized optical output signal r _TM-TE is obtained according to the TM-TE response characteristic.

Further, the TE-polarized optical output signal r _TE-TE and the TE-polarized optical output signal r _TM-TE are added and output as a TE-polarized total optical output signal R _TE .
Also, the TM-polarized optical output signal r _TM-TM and the TM-polarized optical output signal r _TE-TM are added and output as a TM-polarized total optical output signal R _TM .

  The circuit configuration of the second embodiment is simpler than that of the first embodiment. However, since the matrix calculation is performed by the calculation engine of the electronic circuit simulator, more calculation resources are required than in the first embodiment.

[Example 3]
An optical device simulation method according to Example 3 of the present invention will be described with reference to FIG. FIG. 6 represents a simulation process performed by a simulation apparatus (electronic circuit simulator) realized using a computer using functional blocks.
As an optical device to be simulated according to the third embodiment, there are an optical receiver and an optical modulator.

In the third embodiment, a demodulation step S15 is further provided after the multiplexing step S14. That is, the AM demodulation models 15a and 15b are provided at the subsequent stage of the coupler models 14a and 14b.
The response characteristics (TE-TE response characteristics, TM-TM response characteristics, TE-TM response characteristics, TM-TE response characteristics) of the optical device response models 13-1, 13-2, 13-3, 13-4 are as follows. These are determined for each optical device to be measured by measurement or simulation.
The other steps are the same as those of the first embodiment shown in FIG. Therefore, description of the same part as Example 1 is abbreviate | omitted, and only the part peculiar to Example 3 is demonstrated.

In the demodulation step S15, the AM demodulator model 15a AM-demodulates the TE-polarized total optical output signal _RTE output from the coupler model 14a, and outputs a TE-polarized demodulated signal. The demodulated signal is to the total optical output signal R _TE were cut pseudo optical carrier signal Cf.
Moreover, AM demodulator model 15b has a total optical output signal R _TM of TM polarized wave output from the mosquito Model 14b by AM demodulation, and outputs a demodulated signal of the TM polarization. The demodulated signal is to the total optical output signal R _TM was cut pseudo optical carrier signal Cf.

  A simulation apparatus (electronic circuit simulator) according to the first to third embodiments controls a computer having a CPU (Central Processing Unit), a storage device, and an interface with the outside, and hardware resources thereof. It can be realized by a program. The CPU executes the arithmetic processing described in each embodiment in accordance with a program stored in the storage device.

  The present invention can be applied to a technique for simulating an optical device using an electronic circuit simulator.

DESCRIPTION OF SYMBOLS 1 Mixer model 2 Optical device model 11a, 11b Mixer model 12a, 12b Power splitter model 13 Optical device model 13-1, 13-2, 13-3, 13-4 Optical device response model 14a, 14b Coupler model 15a, 15b AM Demodulator model S1 Carrier frequency conversion step S2 Optical device simulation step S11 Carrier frequency conversion step S12 Optical signal distribution step S13 Optical device simulation step S14 Multiplexing step S15 Demodulation step L Optical signal C Optical carrier signal F1 Carrier frequency M Optical modulation signal F2 modulation frequency Lf pseudo optical signal Lf _TE pseudo optical signal Lf _TM pseudo optical signal Cf pseudo optical carrier signal F3 suspected carrier frequency M _TE TE light modulation signal M _TM TM light modulation signal R optical output signal r _TE-TE T Optical output signal of the polarization r _TM-TE TE polarization of the optical output signal R _TE overall optical output signal of the TE polarized r _TM-TM TM polarization of the optical output signal r _TE-TM TM polarization of the optical output signal R _TM TM polarized optical output signal

Claims (5)

An optical device simulation method for simulating the characteristics of an optical device having different response characteristics every time the polarization state of an input polarization multiplexed optical signal is different by a computer,
A carrier frequency conversion step, an optical signal distribution step, an optical device simulation step, and a multiplexing step,
The carrier frequency conversion step includes
Having a first mixer model and a second mixer model;
The first mixer model multiplies the pseudo optical carrier signal having a pseudo carrier frequency lower than the carrier frequency of the optical carrier signal of the optical signal by the TE optical modulation signal having TE polarization. To output a pseudo optical signal that is TE polarized,
The second mixer model multiplies the pseudo optical carrier signal by a TM optical modulation signal that is TM polarized, and outputs a pseudo optical signal that is TM polarized,
The optical signal distribution step includes:
Having a first power splitter model and a second power splitter model;
The first power splitter model bifurcates the pseudo optical signal that is TE polarized,
The second power splitter model bifurcates the pseudo optical signal that is TM polarized,
The optical device simulation step includes
An optical device model comprising a first optical device response model, a second optical device response model, a third optical device response model, and a fourth optical device response model;
The first optical device response model has an input / output characteristic equivalent to an input / output characteristic in which a TE-polarized optical output is output when a TE-polarized optical signal is input to the optical device at the carrier frequency. A TE-TE in which a response characteristic is set so as to be obtained even at the pseudo carrier frequency, and a TE polarized light output is output when a TE polarized light signal is input to the optical device at the pseudo carrier frequency. Having a response characteristic, the TE-polarized pseudo optical signal is inputted, and a TE-TE optical output signal corresponding to the TE-TE response characteristic is output,
The second optical device response model has an input / output characteristic equivalent to an input / output characteristic in which a TM polarized optical output is output when a TM polarized optical signal is input to the optical device at the carrier frequency. TM-TM, which has a response characteristic set so as to be obtained even at the pseudo carrier frequency, and outputs a TM polarized light output when a TM polarized optical signal is input to the optical device at the pseudo carrier frequency. Having a response characteristic, the TM-polarized pseudo optical signal is input, and a TM-polarized optical output signal corresponding to the TM-TM response characteristic is output;
The third optical device response model has an input / output characteristic equivalent to an input / output characteristic in which a TM polarized optical output is output when a TE polarized optical signal is input to the optical device at the carrier frequency. A TE-TM in which a response characteristic is set so as to be obtained even at the pseudo carrier frequency, and a TM polarized light output is output when a TE polarized light signal is input to the optical device at the pseudo carrier frequency. Having a response characteristic, the TE-polarized pseudo optical signal is input, and a TM-polarized optical output signal corresponding to the TE-TM response characteristic is output;
The fourth optical device response model has an input / output characteristic equivalent to an input / output characteristic in which a TE-polarized optical output is output when a TM-polarized optical signal is input to the optical device at the carrier frequency. TM-TE, which has a response characteristic set so as to be obtained even at the pseudo carrier frequency, and outputs a TE polarized light output when a TM polarized optical signal is input to the optical device at the pseudo carrier frequency. It has a response characteristic, and the pseudo optical signal of TM polarization is input to output an optical output signal of TE polarization corresponding to the TM-TE response characteristic,
The combining step includes
Having a first coupler model and a second coupler model;
The first coupler model includes a TE-polarized optical output signal output from the first optical device response model and a TE-polarized optical output signal output from the fourth optical device response model. In addition, output a TE-polarized total optical output signal,
The second coupler model includes a TM-polarized optical output signal output from the second optical device response model and a TM-polarized optical output signal output from the third optical device response model. In addition, output a TM polarization total optical output signal,
An optical device simulation method. In claim 1,
The optical device simulation method, wherein the optical device is any one of an optical filter, a polarization rotation element, an optical waveguide, an optical termination element, an optical amplifier, and an optical variable attenuator. In claim 1,
And further comprises a demodulation step,
The demodulation step includes
Having a first demodulator model and a second demodulator model;
The first demodulator model demodulates the total optical output signal of TE polarization output from the first coupler model, and outputs a demodulation signal of TE polarization,
The second demodulator model demodulates the TM polarized optical output signal output from the second coupler model, and outputs a TM polarized demodulated signal.
An optical device simulation method. In claim 3,
The optical device simulation method, wherein the optical device is either an optical receiver or an optical modulator. An optical device simulation method for simulating the characteristics of an optical device having different response characteristics every time the polarization state of an input polarization multiplexed optical signal is different by a computer,
A carrier frequency conversion step and an optical device simulation step,
The carrier frequency conversion step includes
Having a first mixer model and a second mixer model;
The first mixer model multiplies the pseudo optical carrier signal having a pseudo carrier frequency lower than the carrier frequency of the optical carrier signal of the optical signal by the TE optical modulation signal having TE polarization. To output a pseudo optical signal that is TE polarized,
The second mixer model multiplies the pseudo optical carrier signal by a TM optical modulation signal that is TM polarized, and outputs a pseudo optical signal that is TM polarized,
The optical device simulation step includes
A response function matrix,
The response function matrix includes
An input / output characteristic equivalent to an input / output characteristic that outputs a TE-polarized light output when a TE-polarized optical signal is input to the optical device at the carrier frequency is also obtained at the pseudo carrier frequency. A TE-TE response characteristic in which a TE-polarized optical output is output when a TE-polarized optical signal is input to the optical device at the pseudo carrier frequency with the response characteristic set;
An input / output characteristic equivalent to an input / output characteristic in which a TM polarized light output is output when a TM polarized light signal is input to the optical device at the carrier frequency is also obtained at the pseudo carrier frequency. A TM-TM response characteristic in which a TM-polarized light output is output when a TM-polarized light signal is input to the optical device at the pseudo-carrier frequency with a response characteristic set;
An input / output characteristic equivalent to an input / output characteristic in which a TM polarized light output is output when a TE polarized light signal is input to the optical device at the carrier frequency is also obtained at the pseudo carrier frequency. A TE-TM response characteristic in which a TM-polarized optical output is output when a TE-polarized optical signal is input to the optical device at the pseudo carrier frequency with a response characteristic set;
An input / output characteristic equivalent to an input / output characteristic in which a TE-polarized optical output is output when a TM-polarized optical signal is input to the optical device at the carrier frequency is also obtained at the pseudo carrier frequency. A TM-TE response characteristic in which a TE-polarized optical output is output when a TM-polarized optical signal is input to the optical device at the pseudo carrier frequency with a response characteristic set;
Is incorporated as a 2-by-2 matrix,
By calculating using the response function matrix,
When the TE-polarized pseudo optical signal is input, a TE-polarized optical output signal is obtained according to the TE-TE response characteristic, and a TM-polarized optical output signal is determined according to the TE-TM response characteristic. Seeking
When the TM-polarized pseudo optical signal is input, a TM-polarized optical output signal is obtained according to the TM-TM response characteristic, and a TE-polarized optical output signal is determined according to the TM-TE response characteristic. Seeking
Further, the TE polarized light output signal obtained in accordance with the TE-TE response characteristic and the TE polarized light output signal obtained in accordance with the TM-TE response characteristic are added to obtain the TE polarized light. Output as a total optical output signal
The TM-polarized light output signal obtained according to the TM-TM response characteristics and the TM-polarized light output signal obtained according to the TE-TM response characteristics are added to obtain a TM-polarized total light. Output as an output signal,
An optical device simulation method.

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