# Design of High Peak Power Pulsed Laser Diode Driver

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*Green Photonics Networks: From*

*VCSELs to Nanophotonics*’)

## Abstract

**:**

_{oss}difference between turn-on and turn-off states. The analysis is according to a laser diode model that is adjusted to match the VCSEL, made in National Yang Ming Chiao Tung University (NYCU). A design guide is summarized from the derivations and analysis of the proposed laser diode driver. According to the design guide, we selected the capacitor, resistor, and diode components to achieve 10 ns to 100 ns pulse duration for laser lighting. The experiment demonstrated that the maximum power-to-light efficiency can be as high as 86% and the maximum peak power can be 150 W, which matches the specifications of certain applications such as light detection and ranging (LiDAR).

## 1. Introduction

## 2. Laser Diode

_{b}denotes band gap potential of the semiconductor in volts, n denotes temperature exponent, and A is a constant independent of the temperature T. It is modelled into a similar form as a normal PN diode as follows.

_{b}denotes the band gap potential of the laser diode in volts. This capacitance named the space-charge capacitance, C

_{SC}, of the active region is given as follows.

_{sc}

_{(0)}is the zero-bias space-charge capacitance and V

_{J}is the heterojunction built-in potential. The active layer diffusion capacitance of the laser diode is C

_{i}. The inductance L

_{i}arises from the small signal analysis of the rate equations and represents the resonance phenomenon of the laser diode with capacitance C

_{i}. The resistance R

_{i}includes the differential resistance of the laser diode model damping due to the spontaneous and stimulated recombination terms in the rate equations. The resistance R

_{se}models damping due to spontaneous emission coupled into the lasing mode. In the equivalent circuit we model both R

_{i}and R

_{se}together into R

_{i,se}; R

_{c}is the contact resistance, which includes the semiconductor bulk resistance. The main contribution to R

_{c}comes from the contacts because the bulk resistance of semiconductors is very low. The inductance L

_{1}arises from the circuit parasitic inductance, which is always preferred to be as low as possible.

## 3. VCSEL Laser Diode Driver

_{b}is 1 nF, which serves as a line filter. When v

_{GS}is high, the transistor M

_{1}turns on, and the current flows from the voltage source through a very small resistance R

_{1}to the laser diode. The reverse saturation current I

_{ss}on the laser diode is a function of temperature when the temperature of the laser diode increases the diode current i

_{LD}derived in Equation (1) and cannot be ignored [27] at a constant temperature operation. The moment when v

_{DS}goes to zero is the time when the laser diode goes into the stimulated emission mode, and the rest of the oscillating response is the resonance phenomenon of the laser diode when the laser diode is likely to be in the spontaneous emission mode. The signals are taken from the transistor as shown in Figure 3b. When the gate-source voltage is operated with an on-time duration 10 ns at a pulse repetition rate 10 kHz, the transistor M

_{1}turns on and v

_{DS}drops to low voltage. The actual i

_{LD}can be roughly estimated through dividing the voltage difference V

_{DD}− v

_{DS}by the dynamic R

_{on}resistance of the GaN HEMT.

_{1}must be high enough to reduce the voltage ringing, as shown in Figure 3b, when the transistor M

_{1}turns off. The high resistance R

_{1}limits the current i

_{LD}flowing through the diode, which is typically ten times higher than the contact resistance R

_{c}. For the high peak laser power application, the circuit must be reconsidered.

#### 3.1. The Proposed VCSEL Laser Diode Driver

#### 3.2. Power Supply

_{DD}for the laser driver circuit from a low voltage, such as V

_{in}= 4 V from Li-ion battery. The boost power supply is used to boost the low voltage into a high voltage for the laser. The input voltage v

_{DD}is then subsequently charging the capacitor C

_{1}, which is the main voltage source in the laser lighting loop. On the power supply side, the boost converter circuit consists of an inductor L

_{b}, diode D

_{b}, transistor M

_{b}, and capacitor C

_{b}. The diode D

_{b}comes into the reverse bias when the transistor M

_{b}is switched on. During the M

_{b}turn-on period δ

_{b}T

_{b}, the inductor L

_{b}increases its magnetic energy with a current rise as follows.

_{b}during its M

_{b}turn-off period. Because the output current from the power supply to the laser driver is very low, the boost converter working in the discontinuous current mode is assumed. On the path of the current flowing from the inductor L

_{b}to the capacitor C

_{1}, the diode D

_{b}is forced into a forward bias. The charging current of the capacitor C

_{b}is derived in the steady state as follows.

_{b}turn-off period $\left(1-{\delta}_{b}\right){T}_{b}$. During the M

_{b}turn-off period, the current i

_{Db}flows into the capacitor C

_{b}through the diode D

_{b}.

_{DD}denotes the average voltage across the capacitor C

_{b}; I

_{R1}denotes the average current flow through resistor R

_{1}; P

_{L}denotes the power loss in the laser diode driver including the resistor R

_{1}. Substituting Equation (7) into (6) and comparing Equations (5) and (6), we have the capacitor voltage v

_{DD}as follows.

_{R1}from R

_{1}, the capacitor voltage v

_{DD}is charged/discharged by two sources, and the total voltage can be calculated from the superposition theorem as follows.

_{b}and the charge withdrawn ΔQ from the capacitor. On the laser driver side, the capacitor C

_{1}obtains the charges from capacitor C

_{b}when transistor M

_{1}turns off. The charge redistribution between two capacitors occurs when transistor M

_{b}turns on, and the diode D

_{b}is under reverse bias.

_{C1}is obtained when the charge redistribution is completed. The time constant may be seen as the capacitor C

_{b}to charge the C

_{1}, which, relatively, has a very small capacitance. The governing equation for the charge redistribution is derived as follows.

_{1}of capacitor C

_{1}. The capacitor loses electrical energy ΔE each time when the laser diode is powered up within the pulse train period T

_{pp}. Assuming that ${V}_{C1}={V}_{DD}$ at steady state, we can derive the power loss from the laser diode driver circuit as follows.

_{b}is proportional to the square root of the voltage drop Δv

_{C1}in capacitor C

_{1}.

#### 3.3. Laser Circuit Response

_{spd}, the switch on-time t

_{on}, the switching parasitic charge time t

_{spc}, and the laser diode resonant time t

_{lr}. The entire cycle between two consecutive gate turn-on signals is a pulse period time T

_{pp}, which is the reciprocal of the laser repetition rate.

_{pp}is the reciprocal of the repetition rate f

_{LD}, that is

_{p}, which consists of the switch parasitic capacitor discharge time t

_{spd}, the switch on-time t

_{on}.

_{i}with capacitance C

_{i}. The resonance mechanism of a true laser diode may be more sophisticated than the circuit model, however, it is simplified into the circuit as shown in Figure 2 and analyzed only for circuit control purposes.

#### 3.3.1. Switch Parasitic Capacitor Discharge Time t_{spd}

_{s}turns to high voltage for switching on the transistor M

_{1}, the parasitic capacitors in C

_{oss}are discharged in order to bring the transistor M

_{1}to the linear ohmic state. The capacitors C

_{oss}discharge through the laser diode D

_{L}and the inductor L

_{1}with the governing equation as follows.

_{spd}is a function of inductor L

_{1}and capacitor C

_{oss}as follows.

_{2}can be ignored because the on-resistance of the GaN device is much smaller than R

_{2}. However, the parallel resistance R

_{2}may yield a current path when the laser diode starts to flow and thus weaken the laser diode current. Therefore, we may add an extra diode to prevent R

_{2}current from flowing in the same direction as the laser diode. The damping ratio of the current oscillation is as follows.

_{c}is the contact resistance of the laser diode. The discharging is under a very light damping, hence the rise time of the current response, i.e., the discharging time, is estimated as follows.

_{spd}forms a barrier for the laser current to flow; that is, the pulse duration shall not be smaller than t

_{r,spd}in order to have the laser diode come to its stimulated emission.

#### 3.3.2. Switch On-Time t_{on}

_{1}through the laser diode D

_{L}and the inductor L

_{1}to the transistor M

_{1}with the governing equation as follows. It is assumed that the diode holds a constant voltage V

_{LD,on}depending on the I

_{SS}of the laser diode. It may also be considered that the capacitor C

_{1}charges both the inductor and the on-resistance of the transistor R

_{D}. Assuming the on-resistance of the transistor R

_{D}is small and the damping ratio ${\xi}_{on}$ is negligibly small, the governing equation is derived as follows.

_{on}is a function of inductor L

_{1}and capacitor C

_{1}as follows.

_{C1}as ${V}_{C1}={V}_{DD}$ into Equation (22), we obtain

_{C1}is reducing along the time when the transistor M

_{1}is on, and the lost voltage of the capacitor will be refilled during the M

_{1}turn-off time. The capacitor voltage drop when ignoring V

_{LD,on}is derived as follows.

_{1}is mainly consumed by the laser diode, hence the power transferred to the laser diode for the lighting pulse is then derived as follows.

_{on}= π/ω

_{on}, that is, the electrical energy stored in the capacitor is used up during each pulse of laser switching. The inductor current i

_{L1}is then derived in terms of the capacitor voltage as follows.

_{L}flows through the laser diode, only a portion of the current becomes the lighting current i

_{LD}stated in Equation (1). The fraction between i

_{LD}and i

_{L}during the on-time is mainly a function of the resistance R

_{i}, including the differential resistance of the laser diode model damping due to the spontaneous and stimulated recombination terms in the rate equations. The larger the resistance R

_{i}, the higher the lighting current i

_{LD}is. The other current branch of the laser diode includes the current path through the inductance L

_{i}, representing the resonance phenomenon of the laser diode, the resistance R

_{se}, representing damping due to spontaneous emission coupled into the lasing mode, and the current through the active layer diffusion capacitance of the laser diode C

_{i}. The resonance phenomenon and the active layer diffusion will prolong the current of i

_{L}after the lighting current i

_{LD}cuts off from the diode equation.

_{1}. When the on-resistance R

_{D}of the transistor is made very small, the maximum light current is proportional to the V

_{DD}and not limited by the resistance in the current loop.

#### 3.3.3. Transistor Parasitic Capacitor Charge Time t_{spc}

_{s}turns to low voltage for switching off the transistor M

_{1}, the parasitic capacitors in C

_{oss}shall be charged in order to bring the transistor M

_{1}to the off-state. The capacitors C

_{oss}are charged through the laser diode D

_{L}and the inductor L

_{1}with the governing equation as follows.

_{spc}and ${\xi}_{spc}$ are the same as ω

_{spd}and ${\xi}_{spd}$ derived in Equations (19) and (20), respectively. The charging is under a very light damping, hence the rise time of the current response, the charging time, is the same as derived in Equation (21). The only difference between charging and discharging of the parasitic capacitors is that the laser diode is conducting current i

_{LD}during the charging time only.

#### 3.3.4. Laser Diode Resonant Time t_{lr}

_{1}turns off at the time t

_{r,spc}passed the v

_{s}turn-off time, then the output parasitic capacitor C

_{oss}of the transistor M

_{1}has been filled up; however, the resonance through the same capacitor as the current in the inductor has no zero first-derivative.

_{2}is mapped into the dynamic impedance Z

_{2}from the parallel connection with L

_{1}and C

_{oss}into a series connection as follows.

_{1}turns off, the parallel resistance R

_{2}can contribute to the damping ratio. The damping ratio ${\xi}_{lr}$ when R

_{C}+ R

_{se}= Z

_{2}is then written as follows.

_{DS}. Table 3 shows the R

_{2}adjusted according to the damping desired.

#### 3.3.5. C_{1} Recovery Time

_{1}recovery time. The recovery time is critical when the repetition rate increases, thus for the same pulse duration, the duty of the transistor switching increases. The supply of charges from resistor R

_{1}through the path from R

_{1}to C

_{1}and then to R

_{2}is activated only when the transistor turns off. The loss of charges from C

_{1}during the transistor turn-on time must be refilled through its turn off time in order to maintain the capacitor C

_{1}at the same voltage as the voltage source v

_{s}. The time constant for the charging T

_{c1}can be obtained from the RC charging equation as follows.

_{1}recovery time t

_{c1r}may be estimated as four times the time constant T

_{c1}, which is nearly 98% of the full voltage to V

_{DD}.

#### 3.4. Sensing the Laser Diode Current

_{D}or the voltage v

_{DS}without interfering with the laser driver circuit. However, the state sensing is of extreme importance during the feedback control of the laser power. In Figure 7, we simplified the laser driver circuit from the view of resistor R

_{1}. The resistor voltage is labeled in the opposite way such that it matches the wave form of the supposed v

_{DS}. In Figure 7a, the total laser diode current i

_{L}can be obtained from the branch current solution as follows when ${R}_{1}>>{R}_{D,on}$ is assumed.

_{DD}is controlled through the power supply, the voltage v

_{R1}is sensed, and the dynamic-on resistance of the transistor is assumed. In Figure 7b, the supplement voltage to the capacitor C

_{1}is estimated.

_{1}can be estimated by taking the average of the integration.

_{1}. With the voltage response, we can easily label the timing of the individual states of the laser driving process. The anomaly cases include:

- (a)
- Due to either the resistance of R
_{1}being too high or the capacitance C_{1}being too small, the voltage of v_{R1}is below zero voltage all the time during the high repetition rate operation. - (b)
- The voltage of v
_{R1}does not fall to ─V_{DD}during the short pulse duration operation. - (c)
- Due to either the damping of the laser driver circuit being too high or the charge pump gate drive being subjected to high gate resistance, the voltage of v
_{R1}does not oscillate during the laser diode resonant time t_{lr}.

## 4. Design Guide

_{DD}, which is controlled by the power supply, as stated previously. In order to maintain the correct voltage, the duty cycle (δ

_{b}) is controlled as stated in Equation (13). The other parameters, including the resistor R

_{1}for both experimental sensing and the charging of capacitor C

_{1}and the capacitance C

_{1}, are critical to the power efficiency, maximum pulse duration, and peak laser lighting power.

#### 4.1. Power to Light Efficiency

_{1}as follows. The first session of power loss is due to the current conducting through R

_{1}to M

_{1}during the transistor M

_{1}turn-on time. The joule loss from R

_{1}is estimated by assuming the on-resistance of the transistor R

_{D}is small as follows.

_{1}to again reach the voltage V

_{C1}. The joule loss from R

_{1}during the transistor M

_{1}turn-off time is derived from the integration of the exponential current charging of the capacitor C

_{1}.

_{C1}in capacitor C

_{1}is due to the lighting, and the remaining voltage is derived in Equation (25), which is proportional to V

_{C1}. The electrical power loss of the laser diode driver is then derived as follows.

_{pp}is defined previously as the repetition period, which is the reciprocal of the repetition rate f

_{LD}. The electrical power loss is proportional to the repletion rate as well as the square of the voltage V

_{C1}. In order to reduce the electrical power loss, we will need to (a) reduce the capacitance C

_{1}and (b) increase the resistance R

_{1}. The lighting current i

_{LD}is proportional to V

_{C1}and the laser diode voltage holds constant V

_{LD,on}. Therefore, the power to light efficiency is in proportion to the product of the repetition rate and the V

_{DD}.

#### 4.2. Maximum Pulse Duration and Repetition Rate f_{LD}

_{LD}of the laser diode will turn off when the current reverses, as shown in Figure 6, the maximum pulse duration t

_{p,max}is restrained by Equation (28) and i

_{L}> 0 as follows.

_{1}or the capacitance C

_{oss(GaN,on)}+ C

_{i}. It will need four times the time constant R

_{1}C

_{1}to recover the capacitor C

_{1}back into V

_{DD}; therefore, the repetition rate is limited by the reciprocal of R

_{1}C

_{1}as follows.

_{1}and C

_{1}.

#### 4.3. Peak Power

_{p}as its maximum value t

_{p,max}from Equation (41), we obtain the P

_{LD}follows.

_{DD}and C

_{1}as well; however, we can also decrease L

_{1}to increase the peak power.

_{1}is to be minimized. Except for the high peak power of laser output, the capacitance C

_{1}is preferred to be small. In order to increase the repetition rate, we will have to choose a low resistance R

_{1}. In order to increase peak power of the laser output, we will need to increase the input voltage V

_{DD}.

## 5. Simulation and Experiment

_{DD}shown in capacitor C

_{b}is 15 V while the simulation result for t

_{p}= 50 ns at its steady state is shown in Figure 9b. There is a parasitic inductance due to bonding connected in series with the transistor M

_{1}. The parameters used in the simulation as experiment as well are shown in Table 5. The ω

_{on}derived in Equation (23) is also calculated and converted to 5 MHz, as shown Table 5. The maximum pulse duration t

_{p,max}is calculated from Equation (41) as 100 ns. The pulse duration t

_{p}= 50 ns is half of t

_{p,max}= 100 ns; one half of total electrical energy previously stored in the capacitor C

_{1}was released during the laser light process. Therefore, the Δv

_{C1}is calculated as 0.3V

_{DD}= 4.5 V from Equation (25) when the switch parasitic capacitor discharge time t

_{spd}is negligibly small and t

_{on}≈ t

_{p}. The simulation result shows, in Figure 9b, the voltage v

_{R1}(purple curve line) measured on the resistor R

_{1}goes from 0 V at 0 s representing the M

_{1}turn-off state, immediately drops down to −V

_{DD}representing when the transistor M

_{1}turns on, then jumps to 0 V again at 50 ns, indicating the transistor has been turned off again, and later falls back to the voltage −(V

_{DD}− Δv

_{C1}) = −10 V at 150 ns, which is inconsistent with the result predicted in Equation (25). For a shorter pulse duration, say, one-tenth of 100 ns (t

_{p,max}), the repetition rate can be as high as 10 MHz.

_{OUT}) and the responsivity based upon the incident light.

_{PD}/P is the ratio of generated photocurrent I

_{PD}to the incident light power P at a given wavelength λ. According to the response curve, the photodiode responsivity R(λ) is around 0.6 A/W at wavelength 940 nm. Ignoring the dark current (I

_{DARK}), junction capacitance (C

_{J}), and the other electric characters in the circuit, the received power can be carried out via measured photocurrent (I

_{PD}) at wavelength 940 nm.

_{DD}in this experiment is 15 V. The prototyping board is used in the experiment, and the parasitic inductance L

_{1}is approximately 100 nH according to the model fitting of the frequency response using Equation (22). The thickness of the prototyping board is 1.55 mm. The spacing between the VCSEL and the photodiode detector is 5 mm, which can also be observed from the Figure 11a side view to compare the thickness with the distance. The active area diameter of the DET08CL(/M) InGaAs junction photodiode is Ø80 µm, and its received solid angle was calculated as follows when $\theta \cong {\mathrm{sin}}^{-1}\left(80\mu m/5mm\right)\approx 0.016rad$.

_{1}. We used a 10 nF capacitor C

_{1}to produce a t

_{p,max}= 100 ns pulse, which is inconsistent with the simulation. The result is shown in Figure 12. In Figure 12, there are four curves. The first curve, in blue, is the gate-source voltage v

_{GS}of the D-mode GaN HEMT. Because the D-mode GaN HEMT is a normally on device and the turn-on voltage of the D-mode GaN HEMT is −7 V, a charge pump gate drive is used, as shown in Figure 6. The second curve, in green, is the drain-source voltage v

_{DS}response of the D-mode GaN HEMT. We directly measured the v

_{DS}using a difference voltage probe that has very low capacitance. The third curve, in purple, is the v

_{R1}. As stated in Section 3.4, the voltage response of v

_{R1}is similar to v

_{DS}, with the only difference being in voltage shift. Comparing v

_{R1}in 4 V/div and v

_{DS}in 10 V/div from the experimental result, we actually found the v

_{R1}is oscillating more than v

_{DS}and with some amount of delay. The fourth curve, in cyan is the current taken from the photodetector, and the peak ampere is 165 mA. According to the power correcting factor calculated from 5 mm distance according to Equation (48) and the power conversion according to Equation (46), the peak power is calculated to be 81 W. It is also observed from Figure 12 that there is still some amount of residual laser light showing on the photodetector, which may be due to the VCSEL resonance.

_{on}, which should be no less than the pulse duration t

_{p,max}. In Figure 12, it is observed that when t

_{on}is larger than t

_{p,max}, the pulse duration remained at t

_{p,max}= 100 ns when ignoring the residual light.

## 6. Discussion

_{oss}difference between turn-on and turn-off states, and which is used to drive the VCSEL made in NYCU. There are still areas for improvement, such as circuit fabrication, SiP (system in a package) IC design, and VCSEL efficiency, to be achieved in order to catch up with those state-of-the-art products.

_{iss}of the GaN HEMT, and the cooling of the circuit board. Among these factors, the stray inductance is most critical factor. Extra stray inductance may result in reduction of the maximum output current and the maximum laser output power, which can be improved through shortening the current path from the laser to the capacitor C

_{1}and to the transistor M

_{1.}Thus, flip-chip bonding instead of wire bonding is recommended for future work. The input parasitic capacitance is critical to achieve shorter pulse duration as well as higher repetition rate, which can be reduced by fabricating the GaN HEMT with a smaller gate width. A 20 mm GaN HEMT device will be introduced to replace the 120 mm device used in this paper, of which the differences between the devices and the laser output characteristics will be reported in future work. The copper pours, the clip bond, and the ribbon bond are solutions to enhance the heat dissipation of the laser diode driver circuit, which actually help the laser output stability.

## 7. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## Appendix A

**Table A1.**The specifications of electronic components in Figure 9.

Designator | Part Description | Manufacturer | Manufacturer Part # |
---|---|---|---|

IC, Gate driver | Texas Instruments | LM5114BMF/NOPB | |

L_{b} | Inductor, 47 µH | TDK | SLF12575T-470M2R7-PF |

M_{2} | Transistor, Cascode GaN Type 2B | NYCU [17] | |

D_{b} | Fast recovery diode, 200 V, 10 A | ROHM semiconductor | RFN10T2D |

C_{b} | Capacitor, 10 µF, 50 V, X5R 0805 | Murata | GRM21BR61H106KE43L |

R_{1} | Resistor, 100Ω, ±1%, 1/8W, 0805 | Yageo | RC0805FR-07100RL |

M_{1} | Transistor, depletion mode GaN HEMT with charge pump circuit | NYCU [16,17] | |

C_{1} | Capacitor, 100 nF, 50 V, X7R 0805 | Murata | GCD21BR71H104KA01L |

D_{2} | Fast recovery diode, 200 V, 0.5 A | ROHM semiconductor | RF05VYM2SFHTR |

R_{2} | Resistor, 2Ω, ±5%, 1/8 W, 0805 | Yageo | RC0805JR-072RL |

D_{L} | VCSEL, 940 nm 2 W | Egismos | V3-7-2000-S |

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**Figure 2.**Circuit model for (

**a**) diode and (

**b**) VCSEL (940 nm by NYCU or V3-7-2000-S by EGISMOS) laser diode.

**Figure 3.**EPC9144 (

**a**) schematic and (

**b**) waveforms with repetition rate 10 kHz and time duration 10 ns.

**Figure 12.**Result of Appendix A: the experiment with 50 ns pulse duration.

**Figure 13.**The performance indices: (

**a**) electrical power input, (

**b**) average laser power output, (

**c**) laser peak power, and (

**d**) efficiency with waveforms (green: v

_{DS}, cyan: i

_{PD}, blue: v

_{GS}, purple: v

_{R1}).

Symbol | Unit | Value | |
---|---|---|---|

V_{J} | V | 1.9 | |

C_{sc(o)} | pF | 0.6 | |

C_{i} | pF | 400 | |

R_{i} | Ω | 3.0 | |

L_{i} | nH | 30 | |

L_{1} | nH | Matrix board | 100 |

PCB | 20 | ||

R_{se} | mΩ | 100 | |

M | 0.5 | ||

N | 1 | ||

E_{b} | V | 1.9 | |

I_{ss} | A | 1 × 10^{−18} | |

C_{1} | µF | 220 | |

R_{1} | Ω | 100 | |

R_{2} | Ω | 100 | |

T_{1} | µs | 44 |

Symbol | Unit | Value | |
---|---|---|---|

C_{oss(GaN)} | On | pF | 70 |

Off | 250 | ||

R_{C} (Laser Diode) | mΩ | 100 | |

R_{se} (Laser Diode) | mΩ | 50 | |

L_{1} + L_{i} | nH | 130 | |

ω_{spd} | Mrad/sec | 332 | |

${\xi}_{spd}$ | 0.001 | ||

t_{r,spd} | ns | 9.5 |

Symbol | Unit | Value | |
---|---|---|---|

L_{1} | nH | 100 | |

L_{i} | nH | 30 | |

C_{oss(GaN,off)} + C_{i} | $\mathrm{pF}$ | 500 | |

R_{c} + R_{se} | $m\mathsf{\Omega}$ | 200 | |

R_{2} | $\mathsf{\Omega}$ | 8 | 100 |

${\xi}_{lr}$ | 2 | 0.16 |

Task | Preference | |||
---|---|---|---|---|

V_{DD} | R_{1} | C_{1} | L_{1} | |

Increase repetition rate f_{LD} | decrease | decrease | ||

Decrease pulse duration t_{p,max} | decrease | decrease | ||

Increase peak power P_{LD} | increase | increase | decrease | |

Increase power to light efficiency η | decrease | increase |

Symbol | Unit | Value |
---|---|---|

L_{1} | nH | 100 |

C_{1} | nF | 10 |

R_{1} | Ω | 100 |

ω_{on} | Mrad/s | 31.6 |

t_{p,max} | ns | 100 |

${f}_{on}={\omega}_{on}/2\pi $ | MHz | 5 |

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## Share and Cite

**MDPI and ACS Style**

Liu, C.-Y.; Wu, C.-C.; Tang, L.-C.; Chieng, W.-H.; Chang, E.-Y.; Peng, C.-Y.; Kuo, H.-C.
Design of High Peak Power Pulsed Laser Diode Driver. *Photonics* **2022**, *9*, 652.
https://doi.org/10.3390/photonics9090652

**AMA Style**

Liu C-Y, Wu C-C, Tang L-C, Chieng W-H, Chang E-Y, Peng C-Y, Kuo H-C.
Design of High Peak Power Pulsed Laser Diode Driver. *Photonics*. 2022; 9(9):652.
https://doi.org/10.3390/photonics9090652

**Chicago/Turabian Style**

Liu, Ching-Yao, Chih-Chiang Wu, Li-Chuan Tang, Wei-Hua Chieng, Edward-Yi Chang, Chun-Yen Peng, and Hao-Chung Kuo.
2022. "Design of High Peak Power Pulsed Laser Diode Driver" *Photonics* 9, no. 9: 652.
https://doi.org/10.3390/photonics9090652