Introduction
The LS5000 Series Modules are DWDM DFB Laser Sources for the TXP platform . These laser source modules cover the 1530.33 – 1611.79 nm wavelength range, on the 100 GHz ITU grid, and provide 20 mW optical power. The optical power can be tuned over 6 dB, and the wavelength over ± 0.85 nm. These light source modules have been designed for excellent stability in power and wavelength, providing reliable measurement results for test setups characterizing BER link performance and EDFA parameters. The modules feature internal modulation capabilities for flexible coherence control, especially the triangular modulation format for efficient suppression of Stimulated Brillouin Scattering in fibers.

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 0.005 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 60 minutes and a relative intensity noise RIN figure of typ. -145dB/Hz. All Thorlabs' instruments are backed by an extensive two-year warranty on materials and workmanship.

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 1 GHz. The LS5000 Series provides continuous adjustment of the linewidth over this entire range. An internal, freely running, sine wave/square/triangle wave generator is used to modulate the laser current. The modulation frequency range of the function generator is 20 Hz to 20 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 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.

Precision Wavelength Tuning
The wavelength is displayed with a resolution of 0.001 nm on the LS5000 GUI or can be read through the data interface of the TXP-Chassis (USB or Ethernet) 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.

Operation
A TXP chassis is required for the operation of the LS5000 Series modules . The modules are hot-pluggable; they can be inserted or removed during the operation of other modules. An intuitive graphical user interface (GUI) for the LS5000 Series modules is delivered with the TXP chassis, as well as drivers for LabVIEW™, LabWindows/CVI™, MSVC and Borland C.

For further information, please contact our Tech Support Team.

The Software Package for the TXP5000 Platform contains the Software Modules for the LS5000

Use this link to download the following software packages:

The available software is organized into the following categories:

1. Applications: Standard application software packages and graphical user interfaces. This is what most users need to operate the device for typical applications.
2. Drivers: Instrument drivers for the National Instruments™, LabWindows™/CVI, and LabVIEW™ development environments. These are intended for developers who want to extend or adapt the functionality of the device to their special requirements.
3. Firmware: Low level software for the internal operation of the device. This should be updated to the newest version available to guarantee optimal performance. Please see the Operating Manual for information on how to update the firmware of your device.