Optical
Communications

The Drive to Faster Data Transmission

Communications companies have traditionally relied on radio-frequency (RF) communication to transmit data signals. Today, however, these same companies are looking to laser-based communications for uplink, downlink, and data transfer.

Optical communications can provide thousands of times more data capability than RF systems. Additionally, laser-based systems offer dramatic cost reductions  and are far less susceptible to detection, interception, jamming, and frequency interference than RF systems.

 NASA’s Laser Communications Relay Demonstration communicating with the International Space Station over laser links. Credit: NASA’s Goddard Space Flight Center. 

Metrology to Meet Optical Communication Challenges

The optical components and systems involved in transmitting, relaying, and receiving these signals must be held to rigorous controls at every functional wavelength.

4D Technology has been leading the development of metrology for space-based optics since its inception over 20 years ago. 4D offers multiple solutions to measure surface quality, transmitted wavefront quality, and surface roughness of these critical optics and systems.

NASA’s Low-Cost Optical Terminal (LCOT) prototype ground telescope. Credit: NASA.

 Surface Shape and Wavefront Quality

The AccuFiz SWIR Fizeau Interferometer and PhaseCam Twyman-Green SWIR Interferometer both operate around the 1550 nm wavelength. Their advantages for optical measurements include:

• unique capability to accept external sources at wavelengths throughout the C-Band, enabling manufacturers to test optical components and systems at every operational wavelength
• vibration immunity to measure in challenging environments, without isolation
• compact, lightweight design that simplifies test setups
• highly accurate measurement of focal and afocal optics, aspheres, optical systems and telescopes, prisms, corner cubes, etc.
• Real-time optical system alignment and collimation.

AccuFiz Fizeau and PhaseCam Twyman-Green interferometers for vibration-insensitive testing throughout the C-Band.

 Surface Roughness

Excessive surface roughness can scatter the beam, leading to signal loss, reduced data transfer rates, and crosstalk.

The NanoCam HD optical profiler measures roughness on optical grade surfaces. Robot-mounted or handheld, the NanoCam measures rapidly at multiple locations around an optic to ensure that roughness falls within specifications.

NanoCam HD mounted on robot for production roughness measurements.