Q8341 Advantest Optical Analyzer

Additional Features:

• Measures LDs with high speed and high accuracy
• High speed measurement option: 0.5 s
• Small, lightweight platform
• Coherence measurement resolution: 0.001 mm
• Wavelength resolution (at 650 nm): 0.05 nm (standard), 0.01 nm (option)
• The measured resolution of the peak wavelength is 0.001 nm
• Wavelength measurement accuracy: ±0.05 nm (standard), ±0.01 nm (option)
• Max. input level: ±10 dBm
• Max. Coherence measurement length: Approx. 10 mm (standard), Approx. 40 mm (option)
• Wavelength measurement range: 350 to 1000 nm

Specifications

Wavelength

• Measurement range: 350 to 1000 nm
• Accuracy: Standard: ±0.05 nm; Option: ±0.05 nm (Normal Resolution Mode); ±0.01 nm (High Resolution Mode)
• Resolution: Standard: 0.05 nm; Option: 0.05 nm (Normal Resolution Mode); 0.01 nm (High Resolution Mode)

Level

• Input sensitivity: –50 dBm or less (350 to 1000 nm); –55 dBm or less (400 to 900 nm)
• Maximum input power: +10 dBm
• Accuracy: ±1.0 dB (780nm, Input level of –10 dBm)
• Scale: 0.2, 0.5, 1.0, 2.0, 5.0, 10 dB/div and Linear
• Dynamic range: 30 dB or more

Coherence

• Max. analysis length
• Standard: 10.3 mm
• Option: 41.4 mm
• Measurement resolution: 0.001 mm

• Input return loss: 30 dB

Measurement time

• CW Mode: Standard: 2 s or less; Option: 0.5 s or less (Normal Resolution Mode); 1.0 s or less (High Resolution Mode)
• Pulse Mode: 2 s or less

Functions

• Operation/analysis: Spectral width measurement, Automatic peak search, Peak normalization, Averaging, Total Power, Pulse light measurement mode
• Display, Other functions: Superimpose display, List display, Cursor function, Accumulating operation time verify function
• Memory function: Internal CF memory (50 MB or more): Measurement data (Text), Screen Display data (Bmp), An external storage device is available via USB

Optical input

• Connector: FC type
• Applicable fiber: 50/125 GI fiber

I/O interface:

• GPIB (IEEE 488.2)
• Ethernet (10/100 Base)
• VGA output
• USB port
• PS/2 Mouse

• Display: 6.5-inch color LCD (640 x 480 dots)

General Specifications

• Operating environment: Ambient temperature: +10 to +40°C
• Relative humidity: 85% max. (no condensation)
• Storage environment: Ambient temperature: –10 to +50°C
• Relative humidity: 90% max. (no condensation)
• Power supply: 100 to 120 VAC/220 to 240 VAC, 50/60 Hz, 150 VA or less
• Automatic switching between 100 and 200 V systems
• Dimensions: Approx. 424 (H) x 132 (W) x 500 (D) mm

The Advantest Q8341 is an optical spectrum analyzer for visible radiation with a wavelength range of 350 nm to 1000 nm. Because it uses a Fourier spectrum system with a Michelson interferometer, the Q8341 can measure coherence. With its narrow wavelength resolution of 0.01 nm (with option), the Q8341 is very effective for the evaluation of not only CD/DVD laser diodes, but also for blue-violet laser diodes. In addition, the built-in He-Ne laser acts as a wavelength reference to ensure a high wavelength measurement accuracy of ±0.01nm (with option). Finally, with its fast 0.5 s (with option) measurement speed, the Q8341 is ideal for evaluating temperature characteristics of system components.

Measurement principle

The Q8341 uses a Michelson interferometer. In this arrangement, the light from the device-under-test is split and travels down two paths (with interference introduced between the two resulting light paths). From this, an interferogram is created. The horizontal axis represents the difference in length (i.e., time or phase) of the two light paths. In contrast, the vertical axis represents the interference light intensity. This is the autocorrelation of the device-under-test. Performing an FFT on this function then yields the power spectrum. To help with this, a He-Ne laser is used as the wavelength reference source.

High-speed measurement option: 0.5 s.

Ideal for manufacturing/production environments

The Q8341 measures a full span in approx. 0.5 seconds. This feature makes the Q8341 ideal for laser and light-emitting diode production lines. In addition, this fast measurement speed is ideal for high throughput environments.

Excellent coherence analysis length

• Analysis length: Approx. 40 mm, MAX (option)
• Approx. 10 mm, MAX (standard)
• Max. length resolution: 0.001 mm

The Q8341 also evaluates the laser diode's coherence for optical discs. With a long analysis length of up to 40 mm and a narrow resolution of 0.001 mm, the Q8341 is best suited to evaluate blue-violet laser diodes and other compact optical components.

High wavelength accuracy

• Wavelength accuracy: ±0.01 nm (option), ±0.05 nm (standard)

With its built-in Ne-He laser reference light source, the Q8341 measures spectrum with high wavelength accuracy.

Narrow-resolution to measure the oscillation mode of blue-violet laser diodes

• Wavelength resolution (at 650 nm): 0.01 nm (option), 0.05 nm (standard)

With its narrow resolution, the Q8341 separates the oscillation mode of blue-violet laser diodes. In addition, the measured resolution of the peak wavelength of 0.001 nm is ideal for monitoring measurement result affected by the ambient environment of the DUT.

For high-throughput measurement

Employing the large-capacity memory and high-performance calculation unit, the Q8341 quickly stores data. This data is then calculated by the unit to reveal the specified wavelength and span. For example, if the Q8341 analyzes the spectrums of two wavelength ranges (650 nm ±50 nm and 780 nm ±50 nm), it executes the spectrum analysis of the 2 separate LDs by changing only its display range. All of this is done without reconfiguring the system. Hence, the Q8341 reduces the index time for mass production system use.

Measurement Examples

Coherent measurement of DVD laser diode

One important coherence characteristic of DVD laser diodes is determining the interference ratio output of the peak to the 2nd peak. The Q8341 measures this by simply pressing a key. It also displays the coherence calculations as result data.

Automatic measurements: Peak wavelength, center wavelength and spectral width of laser diodes

The peak wavelength (λp), center wavelength (λo) and spectral width (Δλ) are fundamental spectrum measurement parameters for laser diodes. With one key, the Q8341 automatically calculates and displays these results on the CRT.

Wide dynamic range

With option 70, the Q8341 performs measurements with narrow resolution. This enables you to separate oscillation modes for 405 nm band LDs.