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Si Fiber-Coupled Amplified Photodetectors
Menlo Systems' high-sensitivity Silicon (Si) PIN photodetectors are easy-to-use photodetectors with an integrated high-gain, low-noise RF (FPD310-FC-VIS) or transimpedance (FPD510-FC-VIS and FPD610-FC-VIS) amplifier.
The FPD310-FC-VIS is optimized for high gain, high bandwidths, extremely short rise times, and high signal-to-noise ratio. The gain can be switched between two settings, which allows optimal performance for many applications. The 3 dB bandwidth of this AC-coupled device is 5 - 1000 MHz.
The FPD510-FC-VIS and FPD610-FC-VIS photodetectors are optimized for maximum signal-to-noise-ratio for detection of low-level optical beat signals and pulse shapes at frequencies up to 250 MHz and 600 MHz, respectively. Both detectors have a fixed gain. The FPD510-FC-VIS has a rise time of 2 ns, while the FPD610-FC-VIS has a 1 ns rise time. The 3 dB bandwidth of these DC-coupled devices is 200 MHz for the FPD510-FC-VIS and 500 MHz for the FPD610-FC-VIS.
The compact design of these detectors allows for easy OEM integration. These detectors feature a FC/PC input for fiber-coupled applications and include a power supply that has a universal AC input. To view Si detectors with free-space input, click here.
Signal Out- SMA Female (Photodetector)
For connection to a suitable monitoring device, e.g. oscilloscope or RF-spectrum-analyzer, with 50 Ω impedance.
Female (Power Cables)
Male Power IN (Photodetector)
Pulsed Laser Emission: Power and Energy Calculations
Determining whether emission from a pulsed laser is compatible with a device or application can require referencing parameters that are not supplied by the laser's manufacturer. When this is the case, the necessary parameters can typically be calculated from the available information. Calculating peak pulse power, average power, pulse energy, and related parameters can be necessary to achieve desired outcomes including:
Pulsed laser radiation parameters are illustrated in Figure 1 and described in the table. For quick reference, a list of equations are provided below. The document available for download provides this information, as well as an introduction to pulsed laser emission, an overview of relationships among the different parameters, and guidance for applying the calculations.
Click to Enlarge
Figure 1: Parameters used to describe pulsed laser emission are indicated in the plot (above) and described in the table (below). Pulse energy (E) is the shaded area under the pulse curve. Pulse energy is, equivalently, the area of the diagonally hashed region.
Is it safe to use a detector with a specified maximum peak optical input power of 75 mW to measure the following pulsed laser emission?
The energy per pulse:
seems low, but the peak pulse power is:
It is not safe to use the detector to measure this pulsed laser emission, since the peak power of the pulses is >5 orders of magnitude higher than the detector's maximum peak optical input power.