Optical Multi-Format Transmitter (OMFT) for Satellite & Space Communication

Why Space Communication Teams Settle the Format on the Ground

In optical space communication, the modulation format is one of the few link parameters a team can still change late in design. Aperture, transmit power and pointing accuracy are fixed early by the spacecraft’s mass, power and thermal limits.

That makes the format the lever for data rate. Simple on-off keying is robust but wasteful; DP-QPSK and higher-order QAM carry more bits per symbol but ask more of the receiver and the link margin.

Once a terminal is in orbit, the choice cannot be revisited. Teams need hardware-generated signals on the ground to compare formats fairly, under matched conditions, before the design is frozen.

The Optical Multi-Format Transmitter’s Role: One Source for Every Candidate

The optical multi-format transmitter (OMFT) from ID Photonics turns I and Q signals from an AWG or pulse pattern generator into a modulated optical signal. In a satellite programme it acts as the single reference transmitter for format trade studies: one instrument produces each candidate format at the same wavelength, power and symbol rate, so every result shares one baseline.

It is laboratory test equipment for ground work, not flight hardware.

Why Format-Independent Bias Control Matters for Satellite Link Trade Studies

A trade study switches formats again and again. On an ordinary IQ modulator, each switch means a manual bias search, and a slightly different bias point shows up as a penalty that belongs to the setup, not the format.

The OMFT’s built-in bias control works independently of the RF format and amplitude, and relocks within milliseconds.

• Fair comparisons: differences between QPSK and 16-QAM results reflect the formats, not drift in the transmitter.
• Faster studies: no recalibration between formats, so a full sweep fits into one session.
• Defensible reviews: one locked baseline gives design reviews numbers that can be repeated later.

Built for Long Space Communication Test Campaigns

Space communication programmes run for years and pass through many gated reviews, so the reference transmitter has to give the same answer at every stage.

Sweep formats and rates together

Format and symbol rate can be stepped on the same unit, building a curve of spectral efficiency against receiver complexity rather than a few isolated points. Each point then feeds the link budget directly.

Match the bandwidth class to the mission

Class 40, 60 and 80 share one chassis and control interface; only the modulator differs. The class is chosen by the highest symbol rate the programme expects to test.

Keep the spectrum free of pilot tones

Zero-noise mode mutes the bias-control dither after lock. Spectral and EVM measurements then show the format itself, with no pilot tone in the optical spectrum.

Run unattended in the test facility

USB, Ethernet and a browser-based GUI let scripts set up and log long fading and loss sweeps overnight. Device-specific calibration files support pre-distortion for cleaner constellations.

Closing a Satellite Optical Link on the Ground Bench

A typical bench feeds the OMFT from the Narrow Linewidth Tunable Laser Source, whose sub-1 kHz linewidth keeps carrier phase noise out of the format comparison. After emulated free-space loss and fading, the CORX Coherent Optical IQ Receiver recovers the signal for bit-error-rate and EVM analysis, and the ID OSA Optical Spectrum Analyser records channel placement and spectral occupancy for each format.

The standalone Automatic Bias Control System brings the same bias locking to the discrete modulators in a team’s own prototype terminal transmitter. With reference and prototype locked the same way, the step from trade study to terminal design stays traceable.

Who Uses It

• Space research institutions and their optical communication groups
• Satellite payload and optical terminal developers
• Ground-station and optical ground terminal teams
• Free-space optics laboratories at IITs and research institutes
• Coherent DSP and modem developers working on space links

Supply and Support in India

United Spectrum Instruments (USI), Chennai, supplies this optical multi-format transmitter in India as the distributor for ID Photonics, together with the narrow linewidth laser, CORX receiver, ID OSA and standalone Automatic Bias Control System.

Sourcing the full ground bench from one supplier gives a single point of accountability for bandwidth class, laser option, AWG compatibility, installation and after-sales support. Pre-sales guidance helps match the class to the mission without over-specifying.

Request a Configuration

Download the brochure from this page, use the Enquire Now button, write to sales@unitedspectrum.in, or call +91 93631 83748 / +91 97899 04948. Please mention:

• Link type: inter-satellite, satellite-to-ground or both
• Candidate modulation formats and target symbol rates
• Single or dual polarisation, and wavelength
• Laser option: built-in or external, and your AWG or PPG model