DFC BC / DFC MD
Beam combiner and monochromatic beat detector
• Flexible beat detection units • Designed for use with DFC and DL pro
• Stable and compact • DFC BC mounted directly to DL pro • DFC MD: versatile monochromator
TOPTICA's beat detection consists of two flexible modules: DFC BC and DFC MD. Separating beam combination and beat detection into two units allows for placing them at different locations. This increases the flexibility when minimizing loop delays in the laboratory. Both units are as versatile as possible and machined out of one block. Only high quality optics and mechanics are used for a reliable operation. The DFC BC and DFC MD units are specifically designed for a combination of the DFC with TOPTICA's DL pro tunable diode laser series, but can also be used with other cw lasers.
DFC BC
The DFC BC (beam combiner) spatially overlaps the DFC output with a cw laser. The relative intensities between both beams can be adjusted internally. If a fixed splitting ratio is acceptable the DFC BC can be replaced by an all-fiber combiner. The unit can also be used individually as an ultra-stable combiner and fiber coupler for any pair of laser beams.
DFC MD
The DFC MD (monochromatic detector) detects a beat-note between the DFC and a cw laser with the highest possible signal to noise ratio. Using a grating-based adjustable filter with a bandwidth of 10 GHz and a tuning range of several 10 nm, it filters a narrow spectral component of the combined cw laser and DFC. The unit also includes a low-noise photodetector and amplifier to detect the RF beat-note signal. It enables three different operation modes:
• Measurement of the beat frequency using the beat monitoring unit of the DFC CORE module
• Active locking of the cw laser to the DFC (requires additional locking electronics for the cw laser)
• Locking of the DFC to the cw laser (requires DFC CORE+ version)
The photodetector can be detached from the DFC MD unit to convert it into a monochromator serving as narrow band frequency filter. The output of the monochromator can be fiber-coupled or attached with slits of different sizes defining the filtering bandwidth.
Applications
• Optical Clocks • Microwave Generation • High-resolution Spectroscopy • Laser Reference
• Dual-comb Spectroscopy • Direct Frequency Comb Spectroscopy • CEP-stable Seeders
Options
Modular DFC Extensions: Various extension modules are available that convert the offset-free fundamental output of the DFC CORE / DFC CORE+ from 1560 nm to any desired wavelength between 420 nm and 2200 nm
DFC BC and DFC MD units for beam combining and monochromatic beat detection
Specifications
DFC BC
DFC MD Inputs
1. Frequency comb: Fiber-coupled (FC/APC fiber
coupler included), > 0.25 mW/nm recommended
2. cw laser > 100 μW recommended, 1 mW ideal(fiber-coupled, fiber coupler included)
Frequency comb + cw laser: Fiber-coupled
(fiber coupler included)Outputs
1. Frequency comb + cw laser: Fiber-coupled,
(fiber coupler and SM/PM fiber included)
2. cw laser: Free beam (fiber coupling optional)RF signal, amplified for use with mFALC
Wavelength
420 nm - 2200 nm
Spectral width of
operating rangeapprox. 50 nm (depends on central wavelength)
50 nm (depends on central wavelength)
Filter element
n.a.
• 10 GHz bandwidth grating (other bandwidths on request)
• Optical resolution > 50.000
• Tuning via manual adjustment of µm-screw incl. scale reading
• Tuning resolution < 1 GHz (typ.)
Dimensions (H x W x D)
49 x 100 x 100 mm
64 x 60 x 120 mm