1. What is the ROUSB Series designed for in OEM systems?

 

The SureLock™ ROUSB Series is designed as a compact, single‑frequency, wavelength‑stabilized laser module for OEM integration into cost‑sensitive instruments that require high coherence, such as particle sensing, interferometry, metrology, and HeNe replacement systems. The module integrates the laser diode, TEC temperature control, and constant‑current driver into a single cylindrical package, minimizing external electronics and integration effort.

 

2. Why is the ROUSB suitable for interferometry and particle sensing?

 

The lower cost ROUSB Series provides more limited functionality:

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• Single‑frequency operation with narrow linewidth (typically 150–300 MHz) depending on diode

• Excellent wavelength stability using SureLock™ external‑cavity stabilization

   

These characteristics support long coherence length, stable interference fringes, and repeatable phase measurements required in interferometric and particle characterization systems. 

 

3. How does SureLock™ wavelength stabilization benefit OEM designs?

 

SureLock™ technology uses an external cavity with a stabilizing element to lock the laser wavelength, maintaining spectral performance across 0–100% operating power and over temperature. For OEM systems, this means:

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• Reduced calibration drift over time

• Improved unit‑to‑unit consistency

• Stable fringe spacing in interferometric measurements

 

This stability is especially valuable in unattended or embedded systems.

 

4. What wavelengths and power levels are available?

 

Standard ROUSB wavelengths include:

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• 633 nm (40–70 mW)

• 638 nm (up to 120 mW)

• 658–660 nm (≈35 mW)

• 785 nm (80–100 mW)

 

Multiple OEM SKUs are available, including variants with optical isolators or single‑mode fiber pigtails, depending on system requirements.

 

5. How does the ROUSB help reduce system cost?

 

For low‑cost OEM instruments, the RO‑USB reduces BOM and integration cost by:

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• Eliminating the need for external laser drivers and TEC controllers

• Providing USB‑based digital control instead of custom analog electronics

• Offering HeNe‑like performance in a compact diode‑based solution

 

This makes it well‑suited for scalable manufacturing and cost‑optimized designs.

 

6. What optical output configurations are available?

 

OEMs can select from:

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• Free‑space collimated output

• Single‑mode PM fiber‑coupled output

• Optional built‑in optical isolator

 

Fiber‑coupled versions are recommended when beam delivery, alignment stability, or modular optical layouts are required.

 

7. Is optical feedback a concern in interferometric systems?

 

Yes. Optical feedback is a critical consideration for interferometry and particle sensing. Wavelength‑stabilized diode lasers are particularly sensitive to back‑reflections, which can:

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• Unlock the stabilized cavity

• Shift wavelength or broaden linewidth

• Cause latent or permanent diode damage

 

For systems with potential back reflection, we strongly recommends:

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• Using optical isolators

• Angling reflective surfaces

• Avoiding normal‑incidence alignment

• Using AR‑coated or angle‑polished fiber tips

 

These precautions are essential for long‑term reliability

 

8. What electrical interfaces are required for OEM integration?

 

The ROUSB Series operates from:

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• 3.3–5 VDC input (model‑dependent)

• <3 A operating current (max)

 

Control options include:

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• USB virtual COM port for digital control and monitoring

• TTL on/off input for simple modulation or safety control

 

This allows easy integration with embedded controllers, SBCs, or industrial PCs.

 

9. Can the laser be controlled without USB?

 

Yes. The ROUSB can operate in stand‑alone mode using stored current and temperature setpoints. USB communication is optional and typically used during:

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• Factory configuration

• Calibration

• Advanced diagnostics

 

Once programmed, the module can operate autonomously in an embedded system.

 

10. What thermal management is required?

 

Proper thermal integration is critical. The module:

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• Must be mounted to a suitable heat sink

• Relies on conduction cooling through the housing

• Is sensitive to thermal runaway if improperly mounted

 

OEMs should ensure good thermal contact and avoid excessive airflow near the optical aperture, which can degrade wavelength stability.

 

11. Is the ROUSB compliant as a standalone laser product?

 

No. In its OEM configuration, the RO‑USB Series is intended solely as an OEM component and does not comply with CDRH 21 CFR requirements when operated as a standalone product. Regulatory compliance is the responsibility of the final instrument manufacturer.

 

An optional configuration with keyswitch is available for CDRH 21 CFR 11 requirements.

 

12. How does the ROUSB support high‑volume OEM production?

 

The ROUSB Series is well‑suited for volume deployment due to:

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• Fixed, factory‑aligned optics

• Digitally repeatable settings

• Stable wavelength performance across units

• Availability of OEM SKUs without keyswitches

 

This supports consistent performance across large production runs.

 

13. What are the most common OEM integration risks?

 

The most common integration pitfalls are:

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1. Optical feedback due to reflective optics

2. Inadequate heat sinking

3. Improper power supply selection

4. Contaminated fiber or optical surfaces

5. Overdriving via USB commands without safeguards

 

Addressing these early in the design phase significantly improves lifetime and reliability

 

14. Where does the ROUSB fit best in an OEM portfolio?

 

The ROUSB Series is ideal for:

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• Low‑cost interferometers

• Particle sizing and counting systems

• Compact metrology tools

• Embedded HeNe replacement platforms

• OEM sensing and analytical instruments

 

It bridges the gap between simple diode modules and higher‑cost stabilized laser systems, offering coherence where it matters most.

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15. What is the difference between vacuum and air-referenced wavelengths?

 

Because we tightly control wavelength accuracy and tolerance, it is important to specify the reference medium used for wavelength measurement.

 

Light travels slightly more slowly in air than in vacuum, causing the wavelength in air to be marginally shorter. To avoid ambiguity and ensure consistency, wavelengths in our datasheets are vacuum‑referenced, which is also the convention used by many spectroscopy databases.  As an example, a HeNe laser specified at 632.991 nm in vacuum corresponds to 632.816 nm in air. This difference does not indicate a physical change in the laser, only a difference in how the wavelength is referenced.