Transverse Coupled Cavity VCSEL: Making 100 GHz Bandwidth Achievable

TL;DR

This paper introduces a novel transverse coupled cavity VCSEL design that significantly enhances modulation bandwidth, achieving over 170 GHz, through strong slow-light feedback and photon-photon resonance effects.

Contribution

The study proposes a new MTCC-VCSEL structure with multiple feedback cavities, enabling ultra-high bandwidth operation exceeding 170 GHz, which is a substantial improvement over traditional designs.

Findings

Achieves 3-dB bandwidth of 170 GHz

Photon-photon resonance occurs above 145 GHz

Multiple feedback cavities improve bandwidth enhancement

Abstract

Enhancing the modulation bandwidth (MBW) of semiconductor lasers has been the challenge of research and technology to meet the need of high-speed photonic applications. In this paper, we propose the design of vertical-cavity surface-emitting laser integrated with multiple transverse coupled cavities (MTCCs) as a promising device with ultra-high 3-dB bandwidth. The laser features high modulation performance because of the accumulated strong coupling of the slow-light feedback from the surrounding lateral TCCs into the VCSEL cavity. Photon-photon resonance (PPR) is predicted to occur at ultra-high frequencies exceeding 145 GHz due to the optical feedback from short TCCs, which achieves 3-dB MBW reaching 170 GHz. The study is based on the modeling of the VCSEL dynamics under multiple transverse slow-light feedback from the surrounding TCCs. We show that the integration of the VCSEL with four or six feedback cavities is advantageous over the TCC-VCSEL in achieving much higher MBW enhancement under weaker coupling of slow-light into the VCSEL cavity. We also characterize the noise properties of the promising MTCC-VCSEL in the regime of ultra-high bandwidth in terms of the Fourier spectrum of the relative intensity noise (RIN).