Spotted Custom Lenses to Tailor the Divergence of Vertical-Cavity Surface-Emitting Lasers

Abstract

International audienceWe demonstrate the output beam collimation of GaAs-based vertical-cavity surface-emitting lasers by means of self-aligned polymer microlenses deposited on SU-8 pedestals using a cantilever-based spotter. We show that this fabrication technique ensures a reproducible lens shape because the contact angle and the deposited volume are constant for a given surface. Device properties are presented and compared to optical beam propagation modeling results. We demonstrate that the final beam divergence is only controlled by pedestal design parameters and can be reduced with this method by a factor 10 (to 1.2° for single-mode devices) with no significant lasing performance modification

Comparative study of soft thermal printing and lamination of dry thick photoresist films for the uniform fabrication of polymer MOEMS on small-sized samples

“…Although these solutions significantly reduce the diffraction effects, they do not provide sufficient control of the SU-8 final thickness. For example, for direct fabrication of SU-8-based static or movable lenses on VCSEL wafers, the tolerance error on the distance between the VCSEL and the lens is less than 8 µm (for a target value of 100 µm) [10][1]. Other well-known solutions are based on manual or automatic elimination of edge beads during spinning, but this process significantly reduces the usable surface.…”

Vertical optical power delivery and inter-chip interconnect concept based on surface-normal MQW modulators

“…Micro-lenses are fabricated lithographically on the top of the tapered couplers and the VCSELs. The micro-lenses can be fabricated using methods similar to [5]. With the collimating micro-lenses also being lithographicallydefined from another polymer layer, the optical fabric minimizes the degrees of misalignment of such a free-space OI system.…”

Surface-normal electro-aborption MQW modulator-based chip-scale optical interconnects

“…Microlenses are fabricated lithographically on the top of the tapered couplers and the VCSELs. The micro-lenses can be fabricated using methods similar to [5]. Due to a refractive index difference between the coupler and micro-lens layer, the incident light focused by the lens is first refracted into the waveguide via the facet towards a mirror at the bottom of the coupler; the reflected beam then undergoes a total internal reflection (TIR) at the same facet and subsequently propagates into the waveguide.…”