Graviton provides optical to electrical (O/E) converters with eleven different series: SPD, SPA, SPS, LPD, LPS, DLP, MPR, MWL, WRU, WRTL, and WRU-NIM. Each series has different models depending on receivable wavelength range, reference wavelength, maximum light-receiving diameter, maximum NA, and convertible frequency bandwidth.
This selection guide offers the outline of each series. For details, please refer to each model.
** For 650nm standard model and 850nm standard model **
Photodetector, which is currently build in SPD-1、SPD-2, and SPA-2, has the wavelength dependency of a frequency characteristic, and the frequency characteristic of photodetector changes in the range of, approximately, 1MHz to 100MHz.
Therefore, a frequency characteristic of SPD-1_650nm, SPD-2_650nm, and SPA-2_650nm, is designed and tuned to be flat at 650 nm. Also, the frequency characteristic of SPD-1_850nm and for SPD-2_850nm is designed to be flat at 850 nm.
For customers who need several wavelengths measurements, it is recommend the use of SPD-3, SPD-4, SPA-3, SPA-4 with PD which has less frequency characteristic dependence on the wavelength.
** About the minimum fiber diameter **
The core diameter of the fiber, to be connected to the SPA-2_650nm, is 100um diameter or more. When a fiber with a thin fiber core diameter is used, the optical spot at the
photodetector becomes so small, that the frequency characteristics of the product is not maintained.