Application of 660 nm high power DBR tapered laser based on diamond wafer

The FBH has developed a red-emitting DBR tapered laser at a wavelength of 660 nm.  With an almost single-mode emission and more than 1 W optical output power, this laser is suitable to generate entangled photons for quantum-OCT.

Optical coherence tomography (OCT) in the mid-infrared (MIR) is in strong demand for non-destructive testing of thin films that are opaque at visible wavelengths.  However, detecting MIR photons is challenging, as common silicon-based detectors are blind in this spectral region, and MIR detectors are not available with the needed performance.  Fortunately, the growing sophistication of quantum entanglement offers the perfect solution. Specifically, FBH scientists have been able to entangle (critical, but undetected) MIR photons with (detectable) near-infrared photons that act as “witness” photons.  As a result, measurements such as OCT in the MIR are now possible, by detecting the entangled near-infrared photons using common Si detectors [1].  The necessary entanglement for this quantum-OCT is created using the well-established spontaneous parametric down conversion (SPDC) technique.  The SPDC process requires a high optical power pump source at visible wavelengths with very good coherence properties.  Previously, the FBH had already developed a suitable laser source at 660 nm that used two chips in a master-oscillator power-amplifier configuration with an optical output power of up to 500 mW .The laser structure is shown below :

To further miniaturize the pump source, FBH scientists now realized a dedicated single-chip solution based on a tapered laser with internal distributed Bragg reflector (DBR-TPL) for the wavelength of 660 nm .  The chips were mounted p-side down on dedicated diamond heat spreaders and on screening submounts .  This enables optimized heat extraction and future module integration.

With the aid of the laser, scientists could make quantum tomography devices smaller and more portable in the future for non-contact scanning of ceramic thin film materials.

CSMH focuses on the research and production of diamond wafers. At present, it has diamond wafers, diamond heat sinks, GaN on diamond, AlN on diamond and other products. Among them, high-power semiconductor lasers packaged by diamond heat sinks have been used in optical communications. In the fields of laser diodes, power transistors, and electronic packaging materials, it can provide customers with diamond thermal management solutions.