Review Reports - Equivalent Circuit Establishments of a GaN High-Electron-Mobility Transistor and 635 nm Laser Diode for a Short-Pulsed Rising Current Simulation

Round 1

Reviewer 1 Report

In this work, the authors developed a dynamic operational linear-regulator (DOLR) based on a GaN high-electron-mobility transistor (HEMT) and wide-bandwidth operational amplifier. Using the developed DOLR porotype, the three 635-nm laser diodes were controlled to achieve the short-pulsed and continuous-wave lasers. Overall, the article is well organized and the presentation is appropriate. In the view of my point, before the consideration for publication, the following issues needs to be addressed:

1) In introduction, the authors write: “…light-emitting diodes (LEDs) were used as the light source, and a bipolar junction transistor (BJT) and metal-oxide-semiconductor field-effect transistor (MOSFET) were used respectively as the linear regulator…” I recommend the authors to add some statement about the knowledge of GaN-based LED. Several important references related to GaN-based LEDs, such as Nano Energy 2020, 69, 104427; Optics Express 27, A669 (2019); Optics Express 25, 26615 (2017); Japanese Journal of Applied Physics 56, 111001 (2017), etc. should be added, so that the readers can be clear about the state-of-the-art of this topic.

2) In Figure 3(a), “Gate termainal” should be revised to be “Gate terminal”.

3) In Table 4, “Micro-controller unin” should be revised to be “Micro-controller unit”.

4) There are some grammatical errors in the manuscript, although most of them do not obscure the understanding of the technical contents. However, I believe that the paper should be proof-read for English before it is submitted. For example:

--“The drain–source channel resistance of the GaN HEMT can be regulate by the DOLR to control the drain terminal current.” should be corrected to be “The drain–source channel resistance of the GaN HEMT can be regulated by the DOLR to control the drain terminal current.”

--“Moreover, the parasitic inductance Lpp inside the Vcc is also be considered.” should be corrected to be “Moreover, the parasitic inductance Lpp inside the Vcc is also considered.”

--“The simulation circuit using the PSIM, as shown in Figure 6.” should be corrected to be “The simulation circuit using the PSIM is shown in Figure 6.”

--“Using the developed DOLR porotype” should be corrected to be “Using the developed DOLR prototype”

Author Response

Response: Thank you for considering my manuscript and for your positive evaluation.

Please see pages 3 and 13. The suggested four papers have been cited in the new manuscript.

2) In Figure 3(a), “Gate termainal” should be revised to be “Gate terminal”.

Response: Please see page 5. The wrong spelling “termainal” has been modified as “terminal”.

3) In Table 4, “Micro-controller unin” should be revised to be “Micro-controller unit”.

Response: Please see page 6. The wrong spelling “unin” has been modified as “unit”.

Response: Please see page 6. The wrong grammar has been modified.

--“Moreover, the parasitic inductance Lpp inside the Vcc is also be considered.” should be corrected to be “Moreover, the parasitic inductance Lpp inside the Vcc is also considered.”

Response: Response: Please see page 8. The wrong grammar has been modified.

--“The simulation circuit using the PSIM, as shown in Figure 6.” should be corrected to be “The simulation circuit using the PSIM is shown in Figure 6.”

Response: Please see page 8. The wrong grammar has been modified.

--“Using the developed DOLR porotype” should be corrected to be “Using the developed DOLR prototype”

Response: Please see page 12. The wrong grammar has been modified.

Author Response File: Author Response.docx

Reviewer 2 Report

This work deals with the demonstration and simulation of the dynamic operational linear-regulator featuring GaN HEMT device and wide-bandwidth operational amplifier for the 632-nm laser diode applition. The experimental waveform measurements verify the DOLR simulation and operation. I think the method and results in the work will be interesting to the readers. It can be published in this journal after a minor revision. In the introduction part, the authors are suggested to further emphasize the role of wide-bandgap semiconductor device in the high-performance semiconductor laser and related systems. Besides, the GaN device nowadays can sustain over 900 V (not below 600 V mentioned by the authors).

Author Response

This work deals with the demonstration and simulation of the dynamic operational linear-regulator featuring GaN HEMT device and wide-bandwidth operational amplifier for the 632-nm laser diode application. The experimental waveform measurements verify the DOLR simulation and operation. I think the method and results in the work will be interesting to the readers. It can be published in this journal after a minor revision. In the introduction part, the authors are suggested to further emphasize the role of wide-bandgap semiconductor device in the high-performance semiconductor laser and related systems. Besides, the GaN device nowadays can sustain over 900 V (not below 600 V mentioned by the authors).

Response: Thank you for considering my manuscript and for your positive evaluation.

To answer the first question: please see page 1. According to the reviewer’s suggestion, some research literature has been cited in the new manuscript.

To answer the second question: please see page 3. Due to GaN layers are epitaxial growth on Si, SiC, or sapphire substrates, the electric field occurs on the surface of a lateral active layer; therefore, the lateral configuration of the GaN semiconductor device can withstand a rating voltage, which is lower than 650 V; however, a new cascode GaN-FET (field-effect transistor) can raise the withstand voltage to 900 V.

Author Response File: Author Response.docx