Photodigm DBR Laser Diodes ranging 730-1100 nm

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Case Study, Field Deployable Atomic Clocks


Research laboratories have been given responsibility for successfully contributing to national and global timing accuracy and stability. They ascertain national reference time inputs for the globalized coordinated universal time (UTC) and International Atomic Time (TAI). This is accomplished through averaging several atomic clock schemes and sophisticated error minimization protocols.


Smaller, less massive, high-performance atomic clocks are desired for field deployment outside laboratory environments. Cesium (Cs, 55) and Rubidium (Rb, 37) are suitable candidate elements. The motion of these atoms can be slowed down by exposure to very specific single-frequency light, a process known as laser cooling. Using precise energy to probe these transitions allows physicists to obtain a universal reference. The result is very accurate timing with errors of approximately one (1) second every 100 million years. How can physicists best probe this information with a very specific single-wavelength/frequency electromagnetic radiation field while employing small form factor lasers useful for those in non-laboratory environments?

The DBR is an Ideal Laser Source for Atomic Clocks


The Photodigm Distributed Bragg Reflector (DBR) laser diode delivers the requisite wavelength, output power, and spectral linewidth, all while exhibiting totally deterministic wavelength tuning with injection current. By current and thermally controlling the laser diode to the Cs atomic transition line, the lasing mode maintains a fixed position relative to adjacent cavity modes, suppressing any mode discontinuities. The result: the laser diode is permanently locked to the atomic transition line without any mode hopping over its entire lifetime.


      • Deterministic and invariant wavelength, which can maintain a lifetime lock to the atomic line

      • High output power and high efficiency

      • Narrow laser linewidth and stable polarization

      • Monolithic structure for ruggedness and scalability

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    ABOUT PHOTODIGM, INC: For over 20 years Photodigm, Inc. has been the only 100% U.S.-based semiconductor manufacturer of single spatial and longitudinal mode Distributed Bragg Reflector (DBR) laser diodes. DBR lasers are essential to quantum sensing and atomic clock manufacturers, optical metrology and sensing, and laser spectroscopy. Headquartered in Richardson, Texas, they design and produce fixed wavelength diode lasers best known for their accuracy and reliability. Learn more at

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