Optical Time Transfer

We require the delivery of two optical terminals to DSTG Edinburgh by the end of Q4 2025 that can establish a point-to-point optical link. These terminals will have the following nominal specifications:

Performance:

Carry optical timing signals at 1550 nm at eye-safe power levels (Class 1 or 1M) as per the AS/NZS IEC 60825.12:2023 standard (required)
Carry optical timing signals at 810 nm at the single-photon-level (desired)
Average optical link loss of less than 30 dB across a 1.5 km link, including coupling out of, and in to, single-mode fibre (SMF) for monostatic operation, or into SMF or multi-mode fibre (MMF) for bi-static operation
Have sufficient pointing bandwidth to track angle-of-arrival fluctuations in high turbulence environments (Cn2 > 10-14 m-2/3), including SMF coupling

Size <50 L per terminal, not including the mount
Weight <30 kg per terminal, not including the mount
Acquisition and tracking:

The terminals should be able to acquire and stabilise a stationary optical point-to-point link between themselves autonomously, and maintain the link for significant periods of time (hours to days) without physical intervention from an operator (required)
The terminals should be able to track each other if one is moving relative to the other (desired)

Inputs/outputs:

1550 nm SMF fibre in/out in either monostatic (SMF fibre) or bi-static (SMF Tx, SMF or MMF Rx) arrangement. Connector type (i.e., FC/APC, FC/PC) and arrangement (i.e., one fibre for Tx and Rx, or separate Tx and Rx fibres) to be agreed upon
If applicable, 810 nm fibre in/out in either monostatic (SMF fibre) or bi-static (SMF Tx, SMF or MMF Rx) arrangement. Connector type (i.e., FC/APC, FC/PC) and arrangement to be agreed upon.
SMF in/out. Connector type (i.e., FC/APC, FC/PC) and arrangement (i.e., one fibre for Tx and Rx, or separate Tx and Rx fibres) to be agreed upon

Technical Readiness Level (TRL): 5 or above