Pulse Width Control Based on Blumlein Pulse Forming Line and SI-GaAs PCSS
Round 1
Reviewer 1 Report
The output pulse width of high power nonlinear Gallium Arsenide Photoconductive Semi-conductor Switch (GaAs PCSS) cannot be controlled due to Lock-on effect, usually in the order of microseconds or even larger. In this manuscript, the output pulse width is effectively controlled by using the characteristics of Blumlein pulse formation line. It lays the experimental foundation for the practical application of nonlinear GaAs PCSS. In general, this work is quite interesting and I would like to recommend the acceptance of this work after minor revision.
(1) When the bias voltage is 28kV, the triggered optical energy is 78 mJ, the optical pulse width is 9.5ns, and the output pulse width of SI-GaAs PCSS is 10ns. How can it be seen that SI-GaAs PCSS works in a nonlinear mode?
(2) What is “the photon-activated charge domain(PACD)”? Please give a simple explanation in the article.
Author Response
Response to Reviewer 1 Comments
Point1：When the bias voltage is 28kV, the triggered optical energy is 78 mJ, the optical pulse width is 9.5ns, and the output pulse width of SI-GaAs PCSS is 10ns. How can it be seen that SI-GaAs PCSS works in a nonlinear mode?
Response 1：The main feature of SI-GaAs PCSS into nonlinear mode of operation is the multiplication rate of carriers. The linear mode absorbs one photon to produce one electron-hole pair, and the nonlinear mode absorbs one photon to produce multiple electron-hole pairs. In the manuscript, when the bias voltage is 28kv, the multiplication rate of the carriers is 58.2. Therefore, it can be determined that the SI-GaAs PCSS enters the nonlinear operation mode.
Point2：What is “the photon-activated charge domain (PACD)”? Please give a simple explanation in the article.
Response 2：The laser triggers the SI-GaAs PCSS, the high carrier concentration triggers the electron transfer effect of the material, causing the formation of charge domains inside the switch. After meeting a certain photoelectric threshold, the electric field in the domain reaches the intrinsic breakdown strength, thus impact ionization occurs. The avalanche impact ionization under the strong electric field occurs in the domain, which makes the carriers multiply. And the radiation compounded by the impact ionization becomes a new light source and is reabsorbed by the material. This phenomenon is called photon-activated charge domain (PACD).
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The mechanism of pulse width modulation by Blumlein pulse formation line is analyzed experimentally and theoretically. This work is both important and novel. The paper is well organized. It is suggested to publish with a slight modification.
Q1: Lines 59and 69 in the manuscript, trigger optical energy description is inconsistent.
Q2:In the Figure 4, The two figures are the same, you do not need to display both figures.
Q3: In the introduction, there are a number of controversial claims without a basis (no references), for example, the authors claim that “Compared with other types of switches, PCSS have the advantages of simple structure, fast response, litter jitter and low parasitic inductance". But there are no references to studies where these characteristics are demonstrated.
Author Response
Response to Reviewer 2 Comments
Point1：Lines 59and 69 in the manuscript, trigger optical energy description is inconsistent.
Response 1：I am very sorry, due to my mistake caused two writing optical energy inconsistency. The trigger optical energy in the manuscript should both be 78 mJ. In the page2 line 59, 76 mJ revised to 78 mJ.
Point2：In the Figure 4, the two figures are the same, you do not need to display both figures.
Response 2：I have modified the two diagrams in Figure 4 into one, as shown below. In the page3 Figure 4 has been replaced.
Figure4
Point3：In the introduction, there are a number of controversial claims without a basis (no references), for example, the authors claim that “Compared with other types of switches, PCSS have the advantages of simple structure, fast response, litter jitter and low parasitic inductance". But there are no references to studies where these characteristics are demonstrated.
Response 3：I have added references to the manuscript that demonstrate the switching characteristics, as shown below.
[3]. B. Vergne, V. Couderc, A. Barthelemy, D. Gontier, M. Lalande, and V. Bertrand, “High voltage rectifier diodes used as photoconductive device for microwave pulse generation,” IEEE Trans. Plasma Sci., vol. 34, no. 5, pp. 1806–1813, Oct. 2006,
doi: 10.1109/TPS.2006.883403.
[4]. W. Wei et al., “Research on synchronization of 15 parallel high gain photoconductive semiconductor switches triggered by high power pulse laser diodes,” Appl. Phys. Lett., vol. 106, no. 2, 2015, Art. no. 022108, doi: 10.1063/1.4906035.
[5]. W. Shi, L. Zhang, H. Gui, L. Hou, M. Xu, and G. Qu, “Accurate measurement of the jitter time of GaAs photoconductive semiconductor switches triggered by a one-to-two optical fiber,” Appl. Phys. Lett., vol.102, no.15, Apr. 2013, Art. no. 154106, doi: 10.1063/1.4802755.
In the page1 line 17, “Compared with other types of switches, PCSS have the advantages of simple structure, fast response, litter jitter and low parasitic inductance.” revised to “Compared with other types of switches, PCSS have the advantages of simple structure, fast response, litter jitter and low parasitic inductance[3],[4],[5].”
Author Response File: Author Response.pdf
Reviewer 3 Report
The authors present a system for the generation of ultra-short high voltage pulses as those required in ultra-wideband radar transmitters. In this setup a pulse-forming network (Blumlein implementation) is connected to a gallium arsenide photoconductive semiconductor switch.
While there may be novelty in the implementation this is not clearly highlighted in the manuscript. Author presented a very limited description of their implementation using simplified diagrams of switch and the pulse-forming network. As a single result, authors show the 10 ns-23 kV output voltage pulse but other relevant performance parameters, such as power efficiency and lifetime of the switch, were not addressed in the manuscript. I recommend authors highlight the novelty in the design and physics of the switch and driver as well as provide a more comprehensive analysis of their circuit performance considering other competitive technologies.
Author Response
Response to Reviewer 3 Comments
Point1：The authors present a system for the generation of ultra-short high voltage pulses as those required in ultra-wideband radar transmitters. In this setup a pulse-forming network (Blumlein implementation) is connected to a gallium arsenide photoconductive semiconductor switch. While there may be novelty in the implementation this is not clearly highlighted in the manuscript. Author presented a very limited description of their implementation using simplified diagrams of switch and the pulse-forming network. As a single result, authors show the 10 ns-23 kV output voltage pulse but other relevant performance parameters, such as power efficiency and lifetime of the switch, were not addressed in the manuscript. I recommend authors highlight the novelty in the design and physics of the switch and driver as well as provide a more comprehensive analysis of their circuit performance considering other competitive technologies.
Response 1：A system for generating the ultra-short high-voltage pulses required for ultra-wideband radar transmitters is presented in this manuscript. Ultra-wideband electromagnetic radiation technology is a frontier research field under development, which has been widely used in civil fields such as target identification, target detection, and medicine, and has very important application potential in military fields such as ultra-wideband communications and ultra-wideband impact radar and electronic jamming. From the development trend of recent years, the research in the field of ultra-wideband electromagnetic pulse focuses on the pursuit of high power, high efficiency, high repetition rate of the pulse source and miniaturization of the device. The key to the ultra-wideband electromagnetic pulse technology is the high-voltage fast response switch and ultra-wideband pulse antenna.
The main advantages of the PCSS are fast response to the repetition rate of picosecond rise and fall times, small parasitic inductance and capacitance and high voltage resistance. It is easy to form an array and can be made into a large volume proportionally, and has the possibility of integrating with microelectronic devices in a single block. The ultra-wideband antenna is to radiate the ultra-wideband electromagnetic pulse with high efficiency, forming the ultra-wideband electromagnetic microwave propagating in space.
The basic principle of operation is to apply the photoconductivity effect of semiconductor, using ultrashort laser pulses to modulate the electrical conductivity of semi-insulation with bias voltage, and finally produce sub-magnitude ultrashort electromagnetic pulses at the output of the switch, compressing large energy in space and time in a very small area, generating extremely high instantaneous energy, and finally providing it to the load.
There is also a PCSS device called a thyristor. The thyristor always turns on at the inner edge of the cathode near the gate, which is called partial conduction. By the time the entire device is fully on, the current has grown to a large value. The current is concentrated in a very small area, so the high current density can easily cause the conductor to heat up strongly and thus damage the device. Due to its inherent turn-on mechanism which limits its development in the field of pulsed power.
Therefore, it can be seen that the characteristics of GaAs PCSS are more suitable for the needs of the pulsed power field.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Manuscript was not improved. Comment by this reviewer was not addressed by the authors.
Author Response
Response to Reviewer Comments
Dear Editor and Reviewer,
We gratefully appreciate for the precious time the reviewer spent making constructive remarks. These comments are all valuable and very helpful for revising and improving our manuscript, as well as the important guiding significance to our research. We gave detailed answers all comments raised by reviewer and improved contents in the manuscript. The explanation and answers for the questions of reviewers are as follows.
Thank you for allowing a resubmission of our manuscript, with an opportunity to address the reviewers’ comments.
Best regards,
<Meilin Wu> et al.
Reviewer#3, Concern # 1: The authors present a system for the generation of ultra-short high voltage pulses as those required in ultra-wideband radar transmitters. In this setup a pulse-forming network (Blumlein implementation) is connected to a gallium arsenide photoconductive semiconductor switch. While there may be novelty in the implementation this is not clearly highlighted in the manuscript. Author presented a very limited description of their implementation using simplified diagrams of switch and the pulse-forming network. As a single result, authors show the 10 ns-23 kV output voltage pulse but other relevant performance parameters, such as power efficiency and lifetime of the switch, were not addressed in the manuscript. I recommend authors highlight the novelty in the design and physics of the switch and driver as well as provide a more comprehensive analysis of their circuit performance considering other competitive technologies.
Author response:
Point 1: While there may be novelty in the implementation this is not clearly highlighted in the manuscript.
Response1: Energy storage devices are an important component in pulsed power technology, and this paper adopts an energy storage method based on Blumlein pulse forming lines. The Blumlein pulse forming lines is designed to control the impedance well, and when it is combined with SI-GaAs PCSS, it can control the width of the output electric pulse well.
Point 2: Author presented a very limited description of their implementation using simplified diagrams of switch and the pulse-forming network.
Response2: In response to the reviewer's suggestion I revised the SI-GaAs PCSS schematic and added a cross-sectional schematic of the SI-GaAs PCSS and a top view of the SI-GaAs PCSS electrodes. Figure 1 shows the Schematic diagram of SI-GaAs PCSS. Figure 2 shows the Top view of the GaAs PCSS electrodes. Figure 3 shows the Cross- section of the SI-GaAs PCSS.
Fig.1 Schematic diagram of SI-GaAs PCSS
Fig. 2 Top view of SI-GaAs PCSS electrodes
Fig.3 Cross-section of the SI-GaAs PCSS
Point 3: As a single result, authors show the 10 ns-23 kV output voltage pulse but other relevant performance parameters, such as power efficiency and lifetime of the switch, were not addressed in the manuscript.
Response 3: The SI-GaAs PCSS enters nonlinear operating mode at a bias voltage of 28 kV and a trigger optical energy of 78 mJ. The output electrical pulse is obtained by an oscilloscope with an electrical pulse width of 10 ns, an output voltage amplitude of 23 kV, and a transmission efficiency is
（1）
—output voltage, bias voltage. From equation (1), the transmission efficiency of the peak voltage of the waveform is 82.14%. The SI-GaAs PCSS ON-state resistance is a time-dependent quantity during the process of switch conduction. And the highest point of the output electrical pulse waveform is the minimum value of the switch ON-state resistance. The smaller the SI-GaAs PCSS ON-state resistance, the higher the voltage transfer efficiency after the switch circuit is turned on.
The ON-state resistance of SI-GaAs PCSS in nonlinear mode can be expressed as
(2)
n—carriers concentration, —carriers mobility, V—SI-GaAs PCSS volume, and L—SI-GaAs PCSS length. As can be seen from equation (2), under the condition of constant trigger optical energy, the ON-state resistance of SI-GaAs PCSS in nonlinear mode is related to the carrier mobility. SI-GaAs semiconductor material is a two-energy valley material, SI-GaAs PCSS in meeting the conditions of certain photoelectric field threshold, SI-GaAs PCSS reaches the intrinsic breakdown strength after the collision ionization, carriers move towards the electrodes under the action of a strong electric field.
In this paper, SI-GaAs PCSS in nonlinear mode, the triggering process of the switch is accompanied by current ablation of the electrodes, and the switch was eventually damaged due to electrodes breakage. 3-mm electrodes gap can withstand 4888 pulses triggered by Nd:YAG laser. In the experiment, the same batch of SI-GaAs PCSS with 5 mm electrodes gap was used under the same triggering optical energy condition. After the electrodes is triggered continuously, local ablation occurs, and eventually the ablation begins to run through the entire electrode, resulting in device failure.
Table 1 Blumlein pulse forming lines test parameters and results
|
The gap of PCSS |
3mm |
5mm |
|
Input voltage |
28kV |
28kV |
|
Bias electric field |
93.3kV/cm |
56kV/cm |
|
Pulse width |
10ns |
11.1ns |
|
Lifetime |
4888 pulses |
5600 pulses |
When the SI-GaAs PCSS is operated in nonlinear mode, the current pulse rises rapidly. In this paper, the rise time of the output electrical pulse is 2 ns under the bias voltage of 28 kV with a pulse width of 9.5 ns, a wavelength of 1064 nm, and an energy of 78 mJ. The rise time of the output electrical pulse of the switch is related to the trigger optical pulse width, the bias electric field strength, and the incident optical energy.
The main feature of SI-GaAs PCSS into nonlinear mode of operation is the multiplication rate of carriers. The linear mode absorbs one photon to produce one electron-hole pair, and the nonlinear mode absorbs one photon to produce multiple electron-hole pairs. The carrier multiplication rate is calculated by using the ratio of absorbed photons to output carriers in the nonlinear mode of operation of the PCSS, which reflects the depth of the nonlinear mode of the PCSS, and the multiplication rate is calculated as shown in equation (3).
(3)
—carrier multiplication rate.
—the number of carriers generated.
—the number of absorbed photons.
In the paper, the multiplication rate of carriers is 58.2 for a bias voltage of 28 kV.
In the pursuit of system optimization, the lower time jitter of SI-GaAs PCSS plays a critical role in enhancing the stability and the capacity of any system. The jitter value can be used to quantitatively describe the avalanche stability. The repetitive waveform of SI-GaAs PCSS triggered 10 times continuously at a bias voltage of 28 kV is shown in Figure 4.
Fig.4 Ten repetitive output waveforms of the SI-GaAs PCSS biased at 28 kV
The SI-GaAs PCSS jitter can be calculated by
(4)
Where is the number of triggers, is the average value of delay times of multiple triggers, denotes the delay time between the laser pulse and the output current waveform of trigger i. The jitter value of SI-GaAs PCSS under 28 kV is 47.9 ps.
Point 4: I recommend authors highlight the novelty in the design and physics of the switch and driver as well as provide a more comprehensive analysis of their circuit performance considering other competitive technologies.
Response 4: Solid-state semiconductor switches have the advantages of long service life, high repetitive operating frequency, compact structure, and high reliability. According to the classification of the principle of voltage resistance, power semiconductor devices mainly rely on the reverse bias of the pn junction resistance to high voltage. Optoelectronic semiconductor switch is a body device, is dependent on the semi-insulation of the material resistance to high voltage.
As shown in Figure 5, compared with Back Lighted Thyratron (BLT), Silicon Controlled Rectifier (SCR), Gate Turn-Off Thyristor (GTO), MOS Controll Thyristor (MCT) and Insulated Gate Bipolar Transistor (IGBT), compared to Metallic Oxide Semiconductor Field Effect Transistor (MOSFET). MOSFET have the fastest response and low switching losses among power electronics devices and are widely used in high-frequency devices with frequencies up to MHz level, but MOSFET have small current capacity, low withstand voltage, and the power of a single tube generally does not exceed 10 kW. If applied in arrays, their parasitic capacitance is not negligible, which affects the transient characteristics [1], [2]. The IGBT successfully developed by GE and RCA in 1983 and the Injection Enhanced Gate Transistor (IEGT) developed by Toshiba in 1993 have a fast turn-on speed of up to sub-ns magnitude, and IGBT with a withstand voltage of 6.5 kV are now commercialized. At voltages above 1000 V, IGBT switching losses are 1/10 that of GTR and comparable to MOSFET when compared to power MOSFET and Giant Transistors (GTR). As a result, they have difficulty combining high repetition frequencies and power capacities, such as kilowatt-scale silicon IGBT with maximum operating frequencies in the 100 kHz range.
Fig.5 Comparison of switching power and switching Rate of PCSS and several commonly used power switching devices
PCSS have excellent characteristics in terms of both bandwidth and power, and are particularly prominent in the field of high-power electromagnetic pulse generation, where a few tens of grams of switching devices can produce hundreds of megawatts of power capacity within tens of picoseconds of time accuracy, power rise times of less than picoseconds, repetition frequencies of up to megahertz. As can be seen from Figure 5, PCSS have the largest repetition frequency and dynamic range, and also have a large switching power. In addition to the above advantages, the PCSS also has a nonlinear working mode, which makes the trigger optical energy of the switch a smaller amount than the original, so that the laser diode can be used to conduction the switch. So the size of the trigger optical source is greatly reduced, making the PCSS more effective, convenient and flexible in the field of power pulse applications. Figure 5 shows the best technical specifications obtained for high-multiplier photoconductive switches in recent years [3], [4], [5].
References
[1] Jiang W., Fast High Voltage Switching Using Stacked MOSFETs, Dielectrics and Electrical Insulation, IEEE Transactions on, 14(4):947-950, 2007.
[2] O’Brien H, Shaheen W, THOMAS R L, Evaluation of Advanced Si and SiC Switching Components for Army Pulsed Power Applications, IEEE Transactions on magneticsmag, 43(1): 259, 2007.
[3] Nunally, W.C., Hammond, R.B., 80-mw photoconductor power switch, Applied Physics Letters, 44(10): 980-982, 1984.
[4] Maksimchuk, A., Kim, M., Signal averaging x-ray streak camera with picosecond jitter Review of Scientific Instruments, 67(10): 697-699, 1996.
[5] Brussaard, G.J.H., Hendriks, J., Photoconductive operation of a laser triggered spark gap, IEEE Transactions on Dielectrics and Electrical Insulation, 14(4): 976-979, 2007.
Author Response File: Author Response.pdf
