FALC 110 and mFALC 110 – Modules for Fast Analog Laser Linewidth Control and Phase Locking
- PID regulator with less than 15 ns signal delay
- Additional analog mixer for phase detection (mFALC)
- Two high-speed differential inputs
- Low-voltage output for fast current control
- Slow integrator for drift cancellation (piezo or laser temperature)
- For TOPTICA’s tunable diode lasers (DL pro, DL DFB, DL 100)
- High-bandwidth stabilization, linewidth reduction, phase locking
- Sub-Hz laser linewidths demonstrated
The Fast Analog Linewidth Control (FALC 110) is a module for advanced laser frequency stabilization tasks, such as linewidth reduction and high-bandwidth frequency locking. Due to an optimized circuit layout, the -3 dB bandwidth of the fastest signal path reaches 100 MHz. - The Mixing FALC (mFALC) additionally comprises an analog mixer for phase detection, and is designed for fast phase locking of two lasers to an external RF reference.
Technical Information
Technical Information
| Concept | Module of DC 110 series, for high-bandwidth frequency locking (FALC) or phase locking of two lasers to an external reference (mFALC) |
|---|---|
| Input section | |
| Inputs | Two high-speed differential inputs, adjustable input offset |
| Fast circuit branch | |
| PID regulator | < 15 ns signal delay |
| Phase delay | < 45° @ 10 MHz ∼ 90° @ 45 MHz |
| DC gain | 15 dB to 80 dB |
| Output voltage range | Max. +/- 2 V @ 50 Ω |
| Slow integrator | |
| Bandwidth | 10 kHz (for grating piezo or laser temperature control) |
| DC gain | Typ. 110 dB |
| Output voltage range | Max. +/- 5 V, high-impedance load |
| RF input (beat signal of two lasers, mFALC only) | |
| Frequency range | 10 MHz .. 200 MHz |
| Max. input voltage, DC | 5 V |
| Max. input voltage, AC | 4.5 V pp |
| LO input (local oscillator, to be mixed with RF input, mFALC only) | |
| Frequency range | 10 MHz .. 200 MHz, sine wave preferred |
| Max. input voltage, DC | 2 V |
| Max. input voltage, AC | 2.8 V pp |
For use with TOPTICA’s tunable diode lasers, an AC modulation input is required on the laser head (DL-MOD PCB).
Beat signal of two DL DFB lasers at 855 nm. Grey: free running lasers; blue: phase lock with mixing FALC to an external 10 MHz reference.
Options & Related Products
Options & Related Products
Related Products:
| PID 110 | LIR 110 | PDD 110 | FALC 110 | DigiLock 110 | LaseLock | Wavelength Meter | Iscan | |
|---|---|---|---|---|---|---|---|---|
| Description / type | Analog PID | Analog Lock-In Regulator | Pound-Drever- Hall Signal Generation | Fast Analog 2-Channel PID | Versatile Digital Locking Solution | Suited for third party lasers | Wavelength meter with PID option | Low finesse etalons as reference with Lock-Electronics |
| Side-of-fringe | • | • | • | • | Not applicable | |||
| Top-of-fringe | With PDD | • | • | With PDD | • | • | ||
| Locking bandwidth* | kHz .. MHz | kHz range | ≈ 45 MHz | ≈ 10 MHz | 1 MHz | < 100 Hz | kHz range | |
| Modulation frequency | 0.6 Hz .. 14 kHz | 20 MHz ** | 17 Hz .. 25 MHz | 33 Hz .. 1 MHz | Not applicable | |||
| Accuracy | Depends on reference (can be very good) | > 10 MHz | 1 MHz (relative) | |||||
| Signal analysis | • | |||||||
| Relock mechanisms | • | • | • | • | • | |||
| Computer control | • | • | • | |||||
| High voltage output | • | • | • | • | ||||
| High bandwidth output | • | • | ||||||
| Two channel version | • | |||||||
| SYS DC 110 module | • | • | • | • | • | |||
| Stand-alone | • | • | • | |||||
| Catalog page | 35 | 36 | 36 | 35 | 37 | 40 | 55 | 42 |
| low budget | high end & preferrable | |||||||
*Estimated bandwidth depends on gain and PID settings **5- 40 MHz versions available
- Tunable diode lasers: DL pro, DL 100 / pro design, DL DFB, DL 100
- High power diode lasers, and frequency converted diode lasers
- PID 110: PID regulator with HV output
- PDD 110: Pound-Drever-Hall detector
- DigiLock 110: Versatile digital module for computerized locking tasks
- LCC: Modulation source for laser linewidth broadening
- Wavelength meters
Technical Drawings
Applications
Applications
Beat measurement of two ECDLs, locked to two high-finesse cavities. One of the locks was realized with a FALC 110. The beat width was less than 0.5 Hz over 8 s. The inset shows the phase stability of the beat note (J. Alnis, MPQ Garching).
Oscilloscope traces of the beat signal of two DL DFB lasers. Upper trace: free running lasers, lower trace: Phase lock with mFALC.
Applications of the FALC 110 and mFALC 110 include
- High-bandwidth laser frequency stabilization
- Linewidth reduction of ECDL and selected DFB lasers
- Phase locking of two lasers
- Difference frequency stabilization
- Precision frequency control (BEC, quantum optics, metrology)
TOPTICA offers a wide portfolio of modules for laser linewidth manipulation: High-bandwidth regulators like FALC 110 and DigiLock 110 have been shown to achieve sub-Hertz linewidth values, whilst the LCC broadens the spectral profile to Gigahertz levels. The range of laser coherence control thus spans more than nine orders of magnitude (coherence length 130000 km .. 4 cm).
Application Note
