Optical power meter drives over the rainbow

The Yokogawa TB200 is billed as the world's first optical power meter to support blue, red and near-infra-red measurements.

The Yokogawa TB200 is billed as the world's first optical power meter to support blue, red and near-infra-red measurements, allowing a single unit to be used for measurements on CDs, DVDs and next-generation optical disks such as Blu-ray and HD DVD and related developments.

Devices such as next-generation optical disk recorders that use blue lasers (with a shorter wavelength than the red laser for DVDs) are already on the market, and optical disks of this type are now becoming widespread.

As laser power is used to read and write to these optical disks, it is important to be able to measure the laser power magnitude during the optical disk development and production processes.

As next-generation optical disks proliferate, there will be increasing demand for equipment having just one pickup that can support all three disk generations: ie next-generation optical disks, DVDs and CDs.

And, as next-generation optical disk equipment enters production, there is a need for optical power meters with features such as removable sensor units and remote-control capabilities.

The TB200 optical power meter has been developed in response to these market trends and user needs.

Key features of the new instrument include a detachable optical sensor module for use on production lines, a large diameter light sensor ideal for picking up high NA (numerical aperture) light, and a USB interface to ease remote control and to transfer the measurement results to PC.

The TB200 has flat wavelength sensitivity characteristics for the three wavelengths - 405nm (blue), 660nm (red) and 785nm (near infra-red) - used with next-generation optical disks, DVDs and CDs.

Sensitivity is controlled to approximately 1% within +/-5nm of the centre wavelength in each band without the need to set the measurement wavelength.

As the sensor of the TB200 has an 18mm wide photodetection area, stable measurement even at high NA (0.85) is possible without the need for fine adjustment of the positions of the lens and sensor.

The instrument also carries out antireflection processing to eliminate the effects of multiple reflections.

The TB200 is equally suited to use in conventional R and D and production lines.

It is designed so that the cover outside the sensor can be removed to allow the optical sensor module alone to be attached to the production equipment.

This design gives more flexibility in installation and frees up space for the production equipment.

All TB200 functions can be fully remote-controlled at the high speeds essential for the manufacturing environment via the USB interface.

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