LD101 1550 nm low-noise DFB laser
Koheron LD101 is a 1550 nm, low-noise, DFB laser with integrated current driver, photodetector and RF modulation. It works on a single 3.3V power supply and is designed to be mounted on a standard M6 metric breadboard. Laser current is adjusted with a precision trimmer ranging from 0 to 55 mA. The LD101 features an AC-coupled modulation input for current modulation. The internal photodetector includes a transimpedance amplifier with a gain of 2 V/mA and 40 MHz bandwidth. The LD101 has a typical spectral linewidth of 5 MHz.
Resources
Specifications
| LD101 | |
|---|---|
| Laser diode | |
| Wavelength | 1550 nm |
| Optical power30 mA current | 3 mW |
| Spectral linewidth | typ. 5 MHz, ≤ 8 MHz |
| Integrated optical isolation | 30 dB |
| Fiber output | 1 m SM fiber with FC/APC connector |
| Current | |
| Current monitor gain | 40 V/A |
| Current limit | 55 mA |
| Modulation | |
| AC modulation cutoff frequency | 1.6 kHz |
| Gain | 20 mA/V above 100 kHz |
| Internal photodetector | |
| 3 dB bandwidth | 40 MHz |
| Gain | 2000 V/A |
| Output impedance | 50 Ω |
| Other | |
| Supply voltage | 3.3 V to 5 V |
| I/O | SMA for modulation and internal photodetector |
| Outside dimensionsexcl. fiber | 64 mm x 45 mm x 14 mm |
| Weight | 21 g |
| Operating temperature | 0 °C to 50 °C |
Functional diagram
Characterization
Relative intensity noise
We characterized the laser relative intensity noise (RIN) for different operating currents. In all measurements, the same optical power (1 mW) was sent to the photodetector to maintain the same shot-noise floor.
Spectral linewidth
We measured the LD101 spectral linewidth using the self-homodyne method with a 10 km fiber delay. The figure below shows the power spectral density of the interference signal:
Modulation input
The graph below shows the frequency response of the AC-coupled modulation input at 40 mA current and 1 Vpp modulation.
Example: 100 kHz triangle
We modulated the laser current with a 100 kHz triangle wave. The graph below shows in yellow the modulation signal, in blue the monitoring output and in green the laser output observed with a PD100-DC photodetector.
Internal photodetector output
The graph below shows the frequency response of the internal photodetector output. Bandwidth at 3 dB is about 40 MHz.
