Swept Light Sources

Littman-Metcalf Configuration; Center Wavelength 1310 to 1330 nm; Wavelength Span >100 nm; Energy ≥17 mW; Coherence Length >7 mm

NTT Advanced Technology’s 200 kHz swept light source for OCT imaging is currently the highest speed swept-wavelength light source in the world. Emitting wavelengths in the 1.3 μm band, the swept light source is ideally suited for OCT-based examination of the coronary arteries.

The device accelerates image acquisition and as a result reduces diagnosis time. This reduction in diagnosis time contributes to a great reduction of both the physical and the psychological impact on patients.

The total system cost can be reduced because the load on the image processing system is reduced and the linear frequency sweeping enables easy calculation of the relationship between time and wavelength.

The swept-wavelength light source with a KTN deflector is aiming at the usage in phase sensitive OCT systems (Doppler OCT and PS OCT: applications to new OCT diagnosis methods) because of its lower jitter than that of the more generally used MEMS-based light sources.

Core building block of the wavelength swept light source is a laser with an external resonator, the so-called Littman-Metcalf configuration. By optimizing the laser with a highly efficient diffraction grating and KTN light deflectors into a compact structure, high-speed operation, a wider wavelength sweep span, and sufficient coherence length are realized.

Key Features:

• High Speed (200 kHz Sweep Rate)
• Voltage-controlled Sweeping Formats (k-linear scan available)
• High Phase Stability (Low Trigger Jitter <78 ps)
• Coherence Length 7 mm at 200 kHz Scan
• High Reliability (No Moving Parts)
• Wavelength Sweep Span >100 nm
• Average Light Output ≥17 mW

Applications: OCT Imaging