Addressing the two most vexing characteristics of laser diodes – mode hops and beam divergence – the Photodigm PreciseMode™ delivers a nearly circular, weakly divergent beam with a >2nm mode-hop-free tuning range. Both OEMs and researchers alike will find significantly improved user-friendliness with the same high performance specifications that they have come to expect from all Photodigm DBR Lasers.
Since their commercial introduction over 10 years ago, Photodigm DBR lasers have come to define the standard of performance for single spatial mode, single longitudinal mode semiconductor lasers. Technologists and engineers worldwide have come to rely on the precision of the Photodigm DBR laser. Photodigm DBR lasers are critical elements in both scientific research and precision commercial instruments.
Despite their superior performance features, Photodigm DBR lasers are edge emitting quantum well laser diodes and share common characteristics with all laser diodes at the chip level. Light is emitted from the 1 µm by 3 µm intersection of the quantum well with the edge facet. As a result, the output beam is divergent and astigmatic. Furthermore, the resonator design acts to ensure lasing at maximum gain, which varies with temperature and current. This results in deterministic wavelength discontinuities as the laser is tuned by either temperature or current.
Photodigm listened to our customers as we developed the PreciseMode™ DBR.
Beam correction followed straightforward optical design principles. We designed a virtual point source (VPS) microlens, aligned on the submount, to correct the beam at the submount level, so that it can be focused with a simple asphere selected by the user according to specific requirements.
The extended mode hop feature is the result of extensive engineering to understand the origin of mode hops and how to minimize their occurrence. The novelty of Photodigm’s invention was recognized in early 2017 with the acceptance of our claims in a US patent application.
Photodigm PreciseMode™ DBR lasers are available now in several free space package options including Mercury™ TOSA, TO8, and COS.