Dynamics of high-contrast grating vertical-cavity surface-emitting laser with lateral optical feedback by a heterostructure interface

Abstract

We investigate the dynamics of high-contrast grating vertical-cavity surface-emitting laser (HCG-VCSEL) with a lateral optical feedback cavity. The lateral optical feedback is realized by the reflection at the heterostructure interface between two different HCGs. The lateral optical feedback cavity possesses slow light which can be tuned by changing HCG parameters, and can control the dynamics of the HCG-VCSEL. The optical feedback can enhance the -3-dB bandwidth and enlarge the eye openings of diagrams of the HCG-VCSEL, and can also reduce the frequency chirp. The HCG-VCSEL with a lateral optical feedback cavity can achieve a -3-dB bandwidth of 37.7 GHz at 12 mA and eye diagrams at 60 Gbps (non-return to zero format) and 50 GBaud (4-level pulse amplitude modulation format) with sufficient openings.

Dynamics and feedback sensitivity of vertical-cavity surface-emitting lasers with arbitrary optical feedback intensity

“…where n L is the refractive index of the VCSEL cavity, n ext is the refractive index of the optical feedback cavity. In the real devices, the reflection and transmission coefficients can be tuned by introducing the heterostructure interface composed of the high-contrast gratings with different widths of the grating bar [15]. The relationship between the reflection phase and transmission phase at the interface between the VCSEL cavity and the optical feedback cavity is [32]…”

“…The optical interconnect technology has been proved to be the efficient solution to solve the bandwidth thirsty in HPCs and DCs, because the fiber-based optical interconnect has advantages like larger bandwidth, quantum wells for a high differential gain, tuning the photon lifetime, employing a short cavity and a small oxide aperture, relieving the thermal effect, and reducing the parasitic resistances and capacitances [8][9][10]. The methods of further improving the −3 dB bandwidth of the VCSEL including injection locking [11,12], composite-resonator [13], optical feedback [14,15], modulator integration [16,17], and so on. Among them, the optical feedback is proved to be a low-cost and effective way to enhance the modulation bandwidth of the VCSELs, which has attracted extensive attention [18][19][20][21].…”

Spiking Behaviour in Laterally-Coupled Pairs of VCSELs With Applications in Neuromorphic Photonics

“…Laterally-coupled VCSELs are formed by designing a structure such that there is overlap of the lateral optical fields between two adjacent VC-SELs. Previously, laterally coupled VCSELs with integrated passive cavities have shown promise for enhancing modulation bandwidth, an approach which has been reported for single VCSEL-passive cavity devices [27]- [29] as well as multiple coupled cavities in two-dimensional hexagonal 'superstructure' [30]. In this work, we assume an array of homogeneous, laterally coupled VCSELs (active devices) forming a set of coupled oscillators, with spiking in mixed active-active and active-passive coupled elements representing an interesting future research direction.…”

70 Gbps PAM-4 850-nm oxide-confined VCSEL without equalization and pre-emphasis

“…The spectral width can be reduced by reducing the strength of the optical confinement. The size of the oxide aperture is estimated to be about 6 μm in diameter, deduced from the mode spacing between the fundamental mode and the first higher-order mode [22] .…”