Optical Multi-Format Transmitter (OMFT) for Defence & Secure Communication

Secure defence communication has moved decisively toward coherent optical links, and that shift changes what a laboratory needs on the transmit side. Once information is carried in the phase and polarisation of light rather than in intensity alone, a link can no longer be validated with a simple modulated source. The transmitter itself becomes a reference instrument: it must produce advanced modulation formats with known, repeatable quality, so that any impairment observed at the far end belongs to the channel or the receiver under test rather than to the signal that was launched. That is the role the Optical Multi-Format Transmitter fills in defence photonics work. It generates reference-grade modulated optical signals across the formats these programmes care about, giving a group a trusted transmit-side benchmark for developing and qualifying secure high-capacity links, Radio Frequency over Glass transport and terahertz communication research. The value of a multi-format instrument is that a programme rarely settles on one scheme at the outset. Format selection in secure links is a trade among spectral efficiency, receiver sensitivity, tolerance to channel impairments and processing burden, and the only honest way to resolve it is to generate several candidates through the same transmit chain and compare results measured under identical conditions. Being able to switch format without swapping hardware keeps that comparison clean, and it keeps a single instrument relevant as a programme’s requirements move from early feasibility studies toward a specification that has to be defended.

The pairing with the CORX Coherent Optical IQ Receiver is what makes the arrangement genuinely useful, because a coherent link can only be characterised end to end when both ends are trustworthy. With the OMFT generating a known signal and the CORX recovering in-phase and quadrature components through calibrated coherent detection, a laboratory can close the loop on its own bench: launch a defined modulation format, impose the channel conditions it wants to study, and measure exactly how the signal degraded. A prototype transmitter can then be evaluated against the CORX, and a prototype receiver against the OMFT, so an unexplained error-rate rise is localised to one side instead of being argued over. A Narrow Linewidth Tunable Laser Source supplies the optical carrier for that chain, keeping phase noise low enough that constellation quality reflects the modulator and the link rather than the laser, and the Automatic Bias Control System holds Mach-Zehnder modulators at their correct operating points over temperature and time — without it, bias drift slowly degrades extinction ratio and constellation shape during exactly the long unattended runs that qualification campaigns depend on. For terahertz work the same reference discipline applies, since a terahertz carrier synthesised optically inherits the quality of the optical signals that produced it. Polarisation-multiplexed formats make this doubly important, since the receiver front end has to split and mix polarisations in a defined state before any of the digital recovery can work.

Defence programmes also value being able to keep this work in house. Sensitive hardware frequently cannot leave the laboratory for external measurement, and qualification gates expect documented, repeatable evidence produced under controlled conditions over a campaign that may run for years. A transmit-and-receive reference chain assembled from one instrument family supports that: consistent control interfaces, consistent calibration practice, and measurements taken at feasibility that remain directly comparable with measurements taken at field trial. In India, United Spectrum Instruments, based in Chennai, is the authorised distributor for ID Photonics GmbH and supplies the OMFT to defence research laboratories, strategic-sector organisations and academic institutions supporting defence-related photonics. USI also supplies the CORX receiver, the Narrow Linewidth Tunable Laser Source and the Automatic Bias Control System, so compatibility, calibration, documentation and post-installation support rest with a single accountable supplier rather than being split across import channels — which matters when procurement is staged across a multi-year programme. To discuss a configuration, download the brochure on this page and use the Enquire Now button, write to sales@unitedspectrum.in, or call +91 97899 04948 or +91 93631 83748, describing the modulation formats and symbol rates you need, whether the work is RFoG, terahertz or secure coherent link validation, and which receiver and carrier hardware you already have on the bench. For a laboratory building capability, this reference chain also serves adjacent investigations — sensing, distributed fibre monitoring and coherent link emulation over installed cable — so bench investment is not confined to one project. Stating the programme stage you have reached helps the team recommend a configuration that will still fit when the work reaches field trial.