# Tunable MEMS VCSEL on Silicon substrate

## TL;DR

This paper reports the design, fabrication, and characterization of a tunable MEMS VCSEL on a silicon substrate, demonstrating a 40 nm tuning range and high mechanical resonance frequency, with improved robustness and bidirectional tuning capabilities.

## Contribution

It introduces a novel fabrication process using silicon-on-insulator and direct InP wafer bonding for a more robust, tunable MEMS VCSEL with enhanced spectral range and bidirectional tuning.

## Key findings

- 40 nm tuning range achieved
- Mechanical resonance frequency exceeds 2 MHz
- Robust fabrication process demonstrated

## Abstract

We present design, fabrication and characterization of a MEMS VCSEL which utilizes a silicon-on-insulator wafer for the microelectromechanical system and encapsulates the MEMS by direct InP wafer bonding, which improves the protection and control of the tuning element. This procedure enables a more robust fabrication, a larger free spectral range and facilitates bidirectional tuning of the MEMS element. The MEMS VCSEL device uses a high contrast grating mirror on a MEMS stage as the bottom mirror, a wafer bonded InP with quantum wells for amplification and a deposited dielectric DBR as the top mirror. A 40 nm tuning range and a mechanical resonance frequency in excess of 2 MHz are demonstrated.