- Center Wavelengths on 100 GHz ITU Grid
- Wavelengths in C, and L Bands
- Output Power: 20 mW
- Wavelength Stability:< 2 pm / 24 hrs
- Extremely Stable Output Power < 0.01dB / 24 hrs
- Precise Wavelength Tuning: over ± 0.85 nm
- Direct Display of Wavelength During Tuning
- Precise Power Attenuation: over 6 dB, typ. 10 dB
- Variable Coherence Control, Linewidths Adjustable up to 1 GHz
- Instrument Drivers for LabVIEW™ & LabWindows/CVI™
- FC/APC Connector
The PRO8 WDM Laser Modules are distributed feedback (DFB) laser sources for the PRO8 Test & Measurement Platform with precise tunability as well as long-term wavelength and power stability. Provided with adjustable coherence control, these laser modules are ideally suited for all dense wavelength division multiplexing (DWDM) applications such as test systems for fiber optic DWDM components, EDFA manufacturing, and multi-laser optical sources for DWDM transmission experiments. For detailed information about the PRO8 test and measurement platform, please see PRO8 Platform.
Stability, Accuracy, and Dependability
This DWDM laser platform is the ideal choice for demanding DWDM test and measurement applications with laser linewidths of less than 10 MHz, center wavelength stability of better than 0.002 nm per 24 hours, and wavelength accuracy of better than ±0.025 nm. We use only telecom-rated, butterfly packaged DFB lasers with integrated TEC elements, optical isolators, and low back-reflection fiber pigtails. When combined with our sophisticated drive circuits, the result is an extremely stable, low-noise laser source that exhibits optical power stability better than 0.005 dB per 15 minutes and a relative intensity noise RIN figure of typ. -145 dB/Hz. All Thorlabs' instruments are backed by an extensive two-year warranty on materials and workmanship.
Thorlabs' DWDM sources cover the ITU-T DWDM grid containing 100 wavelengths (100 GHz channels) spanning the C, and L Bands. Many of these lasers ship directly from stock. Wavelengths on the 50 GHz and 25GHz grid are available on request. Thorlabs also offers the service of incorporating user-supplied lasers into our modules. Please contact Thorlabs for details. Our laser sources are supplied with PM fiber and a non-orientated FC/APC connector. For details on customized options, please contact Thorlabs.
Coherence Control, Internal Modulation
For high-precision power measurements, the narrow linewidth of a DFB laser can lead to interference effects caused by reflections from the multiple surfaces that are present in most optical systems. These multiple reflections, while extremely small, can accumulate due to the long coherence length of the laser light. Brillouin scattering is another effect that can lead to significant errors when making optical power measurements in fiber-based systems.
The magnitude of these effects can be significantly reduced by increasing the linewidths of the source. Therefore, all the DWDM-series laser sources provide an adjustable coherence length control. Here a small signal modulation on the laser current is used to broaden the DFB laser linewidth from a few MHz up to more than 1GHz. The PRO8 provides continuous adjustment of the linewidth over this entire range. An internal broadband noise source or an internal, freely running, sine wave/square wave generator is used to modulate the laser current. The modulation frequency range of the function generator is 20 Hz to 50 kHz with up to 100% modulation depths. Using these features, an ideal non-discrete Gaussian-shaped distribution or a discrete spectral distribution is generated.
External Digital Modulation, DC to 10 kHz
All laser modules within a chassis can be modulated synchronously by an external TTL signal. The modulation bandwidth ranges from DC to 10 kHz. The modulation signal input is on the back panel of the chassis and operates simultaneously on all laser modules of the chassis.
External Analog LF Modulation, DC to 50 kHz (Optional)
For applications where a precise LF modulation up to 50 kHz is required, the DWDM modules are available with an LF modulation option. With this option, the output power can be modulated via an optional SMA input. The laser remains fully protected due to a precise limit circuit located inside the module. To order the source with the external analog LF modulation option, please contact Tech Support.
Precision Wavelength Tuning
The wavelength is displayed with a resolution of 0.001 nm on the PRO8 front panel or can be read through the IEEE-488 interface with a resolution of 0.001 nm. By precisely controlling the temperature of the laser chip, the emitted wavelength can be tuned over a range of ±0.85 nm (approximately ±100 GHz). This range allows the central wavelength of the source to be shifted from one transmission channel to either of the adjacent channels for dense WDM systems with 100 GHz channel spacing or tuning over up to 8 channels for systems with 25 GHz channel spacing. This feature is useful for simulating crosstalk between channels. It can also be used to measure the profile of narrow band DWDM filters. Manual polarization controllers can be supplied as accessories for laser modules. They can be used to adapt the state of polarization in the fiber to polarizationdependant external modulators.
For further information, please contact Tech Support.
|Technical Data PRO8 DWDM Laser Modules
||100 Wavelengths within 100 GHz ITU Grid in C and L-Band a
||±0.025 nm, typ.<±0.01 nm
||<0.002 nm over 24 hrs
|Accuracy (abs / rel)
||0.6 dB / 0.4 dB
|Stability (Coherence Control active)
||<0.002 dB over 15 s,
<0.005 dB over 15 minutes,
<0.01 dB over 24 hours
||>6 dB; 10 dB typ. (continuously variable)
|Side Mode Suppression Ratio (SMSR)
||>40 dB typ. (>36 dB min.) at max. power
|Relative Intensity Noise (RIN)
||-145 dB/Hz typ.
|Coherence Control (Standard Feature, All Models)
||Up to 1 GHz (Adjustable)
||Noise, Sine & Square (Triangle upon request)
||~ 0.2 to 5 kHz
|Frequency (Sine, Square)
||0.02 to up to 50 kHz
|Modulation Depth (Noise)
||0.1 to 10 %
|Modulation Depth (Sine, Square)
||0.1 to 100 %
||0.02 to up to 50 kHz
||0 to 10 kHz (all lasers within mainframe simultaneously via common BNC input)
|Analog LF Modulation
||DC to 50 kHz (Option, via SMA input at the module)
|Optical Output (Standard)
||0 to +35 °C (non condensing)
||-40 to +60 °C
|Warm-Up Time for Rated Accuracy
||1 PRO8 Slot
|Laser Safety Class
The following parts are included together with each of our PRO8 WDM Sources:
- WDM8000 Laser Source Module DWDM (WDM8-X-XXX-20-NM)
- Operating Manual