Greater than 50% inversion in Erbium doped Chalcogenide waveguides.

Kunlun Yan,Rongping Wang,Steve Madden,Khu Vu

doi:10.1364/oe.24.023304

Abstract

We report Er-doped Ge-Ga-Se films and waveguides deposited using co-thermal evaporation and patterned with plasma etching. Strong photoluminescence at 1.54 µm with intrinsic lifetime of 1 ms was obtained from deposited films with 1490 nm excitation. Erbium population inversion up to 50% was achieved, with a maximum of ~55% possible at saturation for the first time to the author's knowledge, approaching the theoretical maximum of 65%. Whilst gain was not achieved due to the presence of upconversion pumped photoinduced absorption, this nonetheless represents a further important step towards the realization of future chalcogenide Erbium doped waveguide amplifiers at 1550 nm and in the Mid-infrared.

Highlights

Chalcogenide glasses (ChGs) are of great interest for planar photonics on account of the many interesting optical properties they possess
The low phonon energy of chalcogenide glasses is advantageous for rare-earth doped devices to enable transitions unavailable in common high phonon energy hosts like silica [3]
The possibility of having both high gain and outstanding nonlinear optical performance in a single device could lead to practical low pump power all-optical signal processing devices

Summary

Introduction

Chalcogenide glasses (ChGs) are of great interest for planar photonics on account of the many interesting optical properties they possess Their transparency deep into the infrared region (which includes most of the important range for vibrational spectroscopy) makes them very attractive for applications in chemical and biosensing [1]. The total Erbium ion population inversion was estimated at 30% limited by clustering of the Erbium even with concentrations as low as 0.15 mol% (~4.5 × 1019 ion/cm3) This is essentially the minimum usable doping level for a planar waveguide device, as at this concentration, the peak absorption (at 1540 nm) is 1.7 dB/cm. Only a few reports on rare-earth doped Ga-containing chalcogenide films exist and none on the use of such materials in waveguide amplifiers. A large part of the difficulty in film/waveguide amplifier experiments, in Gallium containing ChGs, relates to the difficulties in fabricating high quality Erbium doped films. The performance of the waveguides under resonant pumping was investigated and high inversion levels demonstrated

Experiments

Findings

Conclusions