# An Organic Microcavity Laser Amplifier Integrated on the End Facet of an Optical Fiber

## TL;DR

Researchers developed a tiny laser amplifier attached to an optical fiber, which could improve optical communication and miniaturized devices.

## Contribution

A novel integration of a polymer-coated DFB microcavity amplifier on a fiber tip with a flexible transfer technique is introduced.

## Key findings

- An amplification factor of 4.33 at 578.57 nm was achieved using supercontinuum pulses.
- The device shows a larger amplification spectral range and reduced polarization dependence due to random grating distortions.
- The compact size and integration ease suggest potential for optical communication and miniaturized optical systems.

## Abstract

We report a thin-film optical amplifier integrated on a fiber facet based on polymer-coated distributed feedback (DFB) microcavities, which are fabricated on a planar substrate and then transferred onto fiber tips by means of a flexible transfer technique. The amplified light directly couples into the fiber and is detected when coupled out at the other end after propagating along the fiber for about 20 cm. A prominently amplification factor of about 4.33 at 578.57 nm is achieved by sending supercontinuum pulses into the hundreds of micrometers’ DFB microcavities along the normal direction, which is also the axis direction of the fiber. The random distortions of grating lines generated during the transfer process result in a larger amplification spectral range and a less strict polarization dependence for injected light. Benefitting from the device size of hundreds of micrometers and the ease of integration, polymer amplifiers based on DFB microcavities demonstrate significant application potentials in optical communication systems and miniaturized optical devices.