UPLINK

Status

Ongoing
Status date

2025-09-15
Activity Code

6C.069

Objectives

A large number of cost-effective Optical Ground Stations (OGS) is needed globally, to deliver the future expansion of free-space optical ground-to-space communications.

The UPLINK project has the main objective of developing a platform of high-power (>20-Watts) Erbium-doped fibre laser amplifiers that can be seamlessly integrated into any OGS.

Seamless integration includes having “plug-and-play” capability of laser amplifiers to enable simplified installation as well as service, repair, maintenance, and upgrades throughout the lifetime of the OGS asset.

Challenges

There are currently no optical connectors that allow “plug-and-play” connections and disconnections of fibre amplifiers at the 20 Watt power level.
Delivery of 20-Watt average power (up to 40 Watts peak power) in optical fibre can exceed nonlinear thresholds causing signal distortion.

Benefits

UPLINK laser amplifier systems provide OGS integrators with benefits over existing laser-amplifier and beacon lasers:

Having flexibility in the location of high-power laser-amplifiers and BEACONs, meaning they can be located at a distance from the telescope.
Having ability to integrate, remove, replace and upgrade high amplifiers and Beacon lasers into the OGS without needing to re-align the aperture(s) in the telescope.

Features

UPLINK laser amplifier is configured to operate in a regime where the threshold for deleterious optical nonlinear effects in the delivery cable is higher than the peak powers that can be delivered by the laser amplifier. This feature means that long delivery cables can be used, enabling UPLINK amplifiers to be located several tens of metres from the OGS telescope.
New, high-power connectors and connection procedures are developed, enabling 20 Watt UPLINK laser amplifiers to be connected and disconnected from delivery cables, enabling pre-installation and alignment of the delivery cable within the OGS.

System Architecture

UPLINK laser systems are based on a Master Oscillator Power Amplifier (MOPA) configuration, where a low-power seed laser is amplified in a multi-stage Erbium-doped fibre amplifier, with the final stage customised to deliver powers in excess of 20 Watts at wavelengths in the C-Band and/or L-Band.

UPLINK laser systems have a unique ability to be “Modulated-on-Demand” meaning that the amplitude of the 20 Watt laser output can be modulated at frequencies from 0 Hz. up to 10 MHz.

The output of the UPLINK laser system is optically isolated and delivered in a long length, more than 20 metres of single-mode delivery cable, having input connection (to the laser output) that can be disconnected in the field for installation and service/maintenance.

Plan

UPLINK is spread over two Phases with the following key activities and target milestones.

Technology Phase

Simulation of nonlinear fibre delivery;
Development of the UPLINK amplifier;
Demonstration of 20 Watts “Plug-and-Play” fibre delivery in 20-metre length UPLINK cables.

Product Phase

Production engineered UPLINK laser and delivery system;
Qualification;
- CE-Marked Solution;
- Qualified for >2000 hours MTTF.

Current status

Status as of summer 2025

The Technology Phase of the project is coming to completion, with successful demonstration of:

20 Watts average power UPLINK lasers at C-Band wavelengths;
Delivery of 20 Watts average power (40 Watts peak power optical on/off-keyed modulation) through UPLINK cables of >20 metres in length;
Demonstration of “fieldable” connection;
Packaged Uplink delivery cable within mechanically-robust conduit for field installation.