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# Tunable III-V Hybrid Laser Source on Si for LiDAR Applications

Guillaume Bruel

► To cite this version:

Guillaume Bruel. Tunable III-V Hybrid Laser Source on Si for LiDAR Applications. Journée des thèses DOPT, Jun 2023, Grenoble, France. hal-04127491

HAL Id: hal-04127491

https://hal.science/hal-04127491

Submitted on 13 Jun 2023

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# Tunable III-V Hybrid Laser Source on Si for LiDAR Applications

**By:** Guillaume Bruel, DOPT/SNAP/LIPS + STM, CIFRE

**Supervision:** Frédéric Boeuf (ST), Sylvain Guerber (LIPS) and Leopold Virot (LIPS) + Johan Rothman (LIR)

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## Context

Silicon photonic platform still lacks laser function

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### New market applications:

**LiDAR:** **Light** Detection and Ranging

For autonomous driving:

* Long range & High resolution 3D scanning

* Small size & Low cost

* Eye-safety @1550nm

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### Avoid massive and expensive solutions:

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Don't use
mechanical
MEMS mirrors

Use Optical Phased Array
(OPA)

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Need of a **high-power** Laser source

## Goals

High power: 100 mW

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**Spectral purity:**

High **SMSR**: 40/50dB

Small **linewidth**: 100 kHz

**FMCW**

detection:

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Heterodyne detection: High SNR

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High range & Velocity measurement

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$f_{\text{modulation}} \approx 10 \text{ kHz}, \Delta\lambda \approx 1 \text{ nm}$

## Integration

Silicon Laser
cavity using
CMOS processes

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Wafer Bonding:
III-V on Silicon

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III-V
direct
bandgap
materials

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## Challenges

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High optical power
→ **Heat management** ?

**Spectral
purity**

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Single
mode
operation ?

## Theory and modelling: optimization of the **Laser design**

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## References:

1. B. Szelag et al., "Hybrid III-V/Silicon Technology for Laser Integration on a 200-mm Fully CMOS-Compatible Silicon Photonics Platform".

2. L. Coldren and S. Corzine, Diode Lasers and Photonic Integrated Circuits, (New York, Wiley 1995).

3. Yariv, Amnon, Quantum Electronics, Wiley, 1989.

4. Gaudy Josserand et al., Modulation of C-band III-V/Si hybrid Lasers for FMCW LiDAR Applications", SSDM 2022, A-10-07, p.74-75.

N₀: Carriers density

T₀: Laser Temperature

N_c (N₀): Effective DOS in conduction band (in valence band)

Mᵢ: reduced effective mass

E_g: Gap energy

τ: relaxation time accross the gap

ηᵢ: internal quantum efficiency

αᵢ (αₘ): Internal loss (mirror loss)

Tₜp: Adiabatic taper transmission

Zτ: Thermal impedance

nₐff: Effective index