Thorlabs' single-frequency, turnkey, low-noise laser systems are ready-to-use laser systems that integrate their ULN15PC or DFB1550P diodes with a low-noise driver and temperature stabilization inside of a benchtop housing. To minimize the laser linewidth and relative intensity noise (RIN), these lasers include drive electronics that are designed to minimize the current noise. An isolator is integrated at the output of the lasers to minimize the impact of any back-reflected light on the lasers.
- Low-Noise, Narrow-Linewidth Laser Systems, 1550 nm
- High-Power, Turnkey, Single-Frequency Laser Systems at 1550 nm
- Low-Noise Drive Electronics to Minimize RIN and Linewidth
- 20 MHz Current Modulation Bandwidth
- Linewidths as Low as 100 Hz Available
The ULN15TK is an ultra-low-noise (ULN) laser system based on a hybrid external-cavity semiconductor laser employing a fiber Bragg grating (FBG) for feedback to the laser cavity. This patented design enables exceptionally narrow Lorentzian linewidths of 100 Hz and record low RIN below -160 dBc/Hz. When factory-set for optimized performance, this laser offers typical optical output powers of 120 mW with an SMSR of 70 dB. As a result of this unique design, the mode-hop-free single-frequency regions are not continuous as the laser current is adjusted, typically limited to 20 mA to 50 mA wide current regions. The temperature of the laser case is stabilized through a third temperature stabilization circuit to provide long-term power and wavelength stability when the system is used in standard laboratory environments.
The DFB15TK is based on a distributed feedback (DFB) cavity on the laser chip, providing single-frequency emission with typical relative intensity noise (RIN) of -150 dBc/Hz and typical linewidths of 50 kHz. Factory-set for optimized performance, this laser offers a minimum output power of 100 mW with a side-mode suppression ratio (SMSR) of 50 dB. This design allows for a broad, mode-hop-free, single-frequency operation range (350 mA to 1000 mA). The DFB15TK laser system can also be tuned by adjusting the current or the temperature of the laser chip, with a mode-hop-free temperature tuning range of up to 2 nm.
These lasers are designed with laser frequency locking applications in mind. The systems come equipped with two analog current modulation ports (DC and AC coupled) and an analog temperature modulation port. These modulation inputs can be used to lock the laser frequencies to optical cavities or referenced using servo electronics in order to build stable laser systems.
Single-Frequency Operation and Wavelength Tuning
Factory-set for single-frequency operation, these lasers have a preset drive current and temperature. When the laser is enabled using the push-button switch on the front panel (see Front & Back Panels tab), the laser operates at the preset current level. Each laser is shipped with a test data sheet taken at the preset operating conditions; click here for a sample data sheet. The user can adjust the operating current either by sending a command through USB communication (see Remote Operation below) or by applying small modulation to the current through one of the modulation ports on the front panel of the system (see Analog Modulation below). Adjusting the operating current results in both a change in the output power but also a change in the laser wavelength. In addition to the operating current, the laser chip or FBG temperature is also adjustable either through the command-line interface (USB) or the front-panel modulation port. The temperature changes are primarily useful for tuning the laser wavelength while maintaining a relatively constant output power.
This graph shows the typical single mode operating regions for a ULN15TK laser system operated at a fiber Bragg grating temperature (TFBG) of 27 °C. Multimode regions have been removed.
Features
- High-Power Turnkey Single-Frequency Laser Systems in the C-Band
- Ultra-Low-Noise (ULN), Narrow-Linewidth Laser System:
- 100 Hz Typical Linewidth, 70 dB typical SMSR
- RIN of -160 dBc/Hz
- Discontinuous Mode-Hop-Free Regions 20 mA to 50 mA Wide
- Temperature Tuning Range of 0.32 nm with Simultaneous Current Tuning
- Distributed Feedback (DFB) Laser System:
- 50 kHz Typical Linewidth, 50 dB Typical Side-Mode Suppression Ratio (SMSR)
- Relative Intensity Noise (RIN) of -150 dBc/Hz
- Continuous Mode-Hop-Free Operating Current Region
- Temperature Tuning Range of 2 nm
- Low-Noise Drive Electronics to Minimize RIN and Linewidth
- Analog Modulation Inputs for DC Current, AC Current, and Laser Temperature
- Integrated Isolator with to Minimize Effects of Back-Reflected Light
- Remote Operation and Set-Point Adjustment with Command-Line Interface via USB 2.0
Applications
- Optical Reference Laser
- LIDAR/LADAR
- Fiber Optic Sensing
- Quantum Optics
- Atomic Clocks
- Rubidium Cooling
Read more here.