High-speed optical wavelength meter

Manufacturer's part number :


Manufacturer Bristol Instruments

Bristol Instruments

Description :

The 828B system measures the absolute wavelength of WDM lasers to an accuracy of ± 0.65 parts per million (± 1 pm at 1550 nm). What makes the model 828B so special is that it measures wavelength at a rate of 1 kHz, which is 50 times faster than the next fastest system available. The system is traceable to an NIST standard. That is, all tests lasers used have a traceability path to the NIST Standard Reference Material SRM 2517a (Acetylene 12C2H2 Absorption Reference for 1510 nm to 1540 nm Wavelength Calibration). Repeatability, also known as precision, refers to the degree to which the wavelength measurements will show the same or similar results. This specification is for a 10 minute measurement period given at three times the standard deviation (3σ).

The 828B system uses a laser diode that is locked to an absorption of acetylene to ensure that the absolute accuracy specification is met. Absorptions of acetylene have been certified as a reference by NIST (NIST Special Publication 260-133). Calibration of the model 828B can be initiated manually or automatically at user-defined temperature or time intervals. The calibration process will interrupt the wavelength and power measurements for about 250 ms. Display Resolution indicates the minimum incremental change in the displayed measurement. The 828B system can measure wavelength (nm), wavenumber (cm-1), or frequency (THz). Since wavelength and wavenumber are dependent upon the value of the speed of light, which is a function of the medium in which the light is traveling, the measurement in these units are provided as values in vacuum. It is important that a standard condition such as vacuum is used to report wavelength and wavenumber values to ensure consistency regardless of the measurement conditions.

The 828B system measures wavelength at a rate as high as 1 kHz. If the highest measurement rate is not necessary, the frame rate of the photodetector can be changed to 500 Hz, 250 Hz, 100 Hz, or 20 Hz. The power measurement is limited to a rate of 500 Hz. As a result, a single power measurement value may be associated with several consecutive wavelength measurements when operating at the highest frame rate. In order to provide measurements at a rate of 1 kHz, the measurement data is streamed over an RS-422 serial interface. This eliminates timing issues associated with using SCPI commands over the USB, Ethernet, and GPIB interfaces. When using SCPI commands, the measurement time is dependent on the PC or network used, and is approximately 5 ms. The system uses a touch screen Front Panel Display to report measurement data and to control measurement parameters and instrument settings. Five display screens are available and are selected by the five Screen Selection buttons across the bottom of the Front Panel Display.

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Technical Data :

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  • Wavelegnth range: 1250 – 1650 nm (182 – 240 THz)
  • Wavelength measured to an accuracy of ± 1 pm
  • Automatic calibration with a built-in wavelength standard
  • Measurement confidence level of ≥ 99.7%
  • Traceable to an NIST standard
  • Measurement rate as high as 1 kHz for greater productivity
  • Measurement time as low as 1 ms for exceptional time resolution
  • Simultaneous measurement of total optical power to an accuracy of ± 0.5 dB
  • Input power requirement as low as -40 dBm
  • 1 kHz data rate (streaming or triggered) over RS-422 serial interface
  • SCPI interface via USB, Ethernet, or GPIB
  • Rugged design for manufacturing environments
  • Benefits

  • A 1 kHz measurement rate enables more efficient wavelength testing and therefore greater productivity when manufacturing WDM components.
  • Provides time resolution as short as 1 ms resulting in more detailed wavelength characterisation of components such as tunable WDM lasers.