HIGH-SPEED PHOTODETECTOR. Thorlabs item # SIR5-FC

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1 HIGH-SPEED PHOTODETECTOR Thorlabs item # SIR5-FC Serial #

2 SIR5-FC PHOTODETECTOR TECHNICAL DATA Wavelength Range Detector Material Detector Diameter Bandwidth (-3 db point) Rise and Fall Time Afterpulse Ringing Dark Current Junction Capacitance NEP Dynamic Range Fiber Input Receptacle Output Impedence Typical Peak Optical Input Power for a 2 V output (Okay to increase to achieve a full 2 V output) Maximum Safe Output Voltage Battery Power Supply Battery Shelf Life Dimensions nm InGaAs 80 μm >5 GHz <70 ps <20% of Maximum 2x10E-15 W/sqrt(Hz) Calculate from NEP and 1V maximum output into 50 Ω FC 50 Ω 20 mw 1 V 20 V 190 mah of stored charge, lifetime depends on signal rep-rate, 25 t x 25 x 38 mm

3 OPERATIONAL INSTRUCTIONS FOR THE PHOTODETECTORS SIR5-FC, SV2-FC, AND SUV7-FC Inject the radiation to be analyzed into a 50 μm fiber. Keep the energy and power of the radiation below the damage threshold of the fiber tip/volume. Attenuate the peak power of the optical pulse exiting the fiber to less than 20 mw. NOTE: If the photodetector input is greater than 20 mw, the detector may be damaged, and the warranty will not apply. Connect the photodetector to an oscilloscope using a high-bandwidth SMA adapter. Using cables or low-bandwidth adapters will significantly degrade the quality of the measurement. Slowly insert the FC fiber connector into the photodetector fiber receptacle while watching the electrical signal on the oscilloscope. The maximum value of the signal must be lower than 1V into 50 Ω. Attenuate at the fiber input until the fiber connector can be completely inserted into the receptacle without exceeding 1V. Upon completion of measurements, disconnect the fiber from the photodetector, or block the fiber input to prevent unnecessary drain on the batteries. Always use protective plastic caps for the fiber connectors and photodetector receptacles. Note about Battery Lifetime When using battery operated photodetector packages it is important to realize the limitations on the battery life. Photo detectors are current output devices, meaning that the output current is directly proportional to the light hitting incident on the detector. Most users will convert this to a voltage by applying a load terminating resistor. The resistance value is essentially the circuit gain. For very high speed detectors, such as the SIR5, SV2, and SUV7, it is very important to use a 50Ω terminating resistor to match the impedance of standard coax cables to reduce cable reflections and improve overall signal performance and integrity. Most high bandwidth scopes include this termination. Since the detector is a current device, this directly correlates to the battery usage lifetime. Most battery manufacturers provide a battery capacity in terms of ma hr. The battery used with these detectors is rated for 190mA hrs. this means that it will reliably operate for 190hr at a current draw of 1mA. Below is a quick example of how to determine batter lifetime: Let s assume a 1550nm light source with an average 1mW power is applied to an SIR5. The responsivity of a biased photodetector at this wavelength is 1.0 A/W as shown in the response curve above. From this the photo current can be calculated as 1.0 A/W * 1 mw, or 1.0 ma. If the battery used to power the biased photodetector has a specified capacity of 190 mahrs, as the SV2 does, then the battery will last 190 ma hrs / 1.0 ma, which equals 190 hrs (8 days) of continuous use. By reducing the average incident power of the light to 10 uw the

4 same battery would last for about 2 years when used continuously. For these high speed detectors a 50Ω terminating load is recommended for best performance. Continuing the example above, the 1.0mA photo current will be converted to a voltage as 1.0mA * 50Ω, or 50mV. The 10μW power level will produce on output voltage of 10μA * 50Ω, or 0.5mA. For some measurement devices this signal level may be too low and a compromise between battery lifetime and measurement accuracy will need to be made. As a result, when using a biased photodetector with a battery powered source it is beneficial to use as low of light intensity as is reasonable for the application. It is important to remember that a battery will not immediately cease producing a current after it has supplied its specified number of mahr; instead, the terminal voltage of the battery will drop below the rating of the battery. A drop in the terminal voltage of the battery will lower the electric potential being applied to the photodiode. This in turn will increase the response time of the detector (lower the bandwidth of the detector). As a result, it is important to make sure that the battery is operating within its specified parameters in order to ensure the proper functioning of the biased photodetector. The battery can be tested by following the procedure described in the specifications sheet for the detector. Another suggestion to increase the battery lifetime is to remove, or power down the light source illuminating the sensor. Without the light source the photodetector will continue to draw current equal to the photodetector dark current, however this will significantly increase the lifetime. The SIR5 has a dark current less than 1.5nA, will not significantly impact the battery life. For applications where a DET series photodetector is being continuously illuminated with a relatively highpower light source or if having to change the battery is not acceptable consider using the DET1A adapter for that allows the photodetector to be powered using the LDS2 power supply. The drawback to the DET1A is that noise in the line voltage will contribute to noise in the output signal of the DET series detector. Warranty Information and Technical Support All high-speed photodetectors are under warranty for 12 months. During this time, Thorlabs will accept return and repairs free of charge for all problems, provided the customer operates the unit within our specifications. Replacement batteries are available directly from Thorlabs, part # SBP20. The average time for repair and returns is 2 weeks. You may use any of the following methods to contact Thorlabs in case of difficulty or if you have questions regarding your photodetector. techsupport@thorlabs.com You can send a detailed message and one of our application engineers will respond promptly (within 1 business day). Fax: (973) Phone: (973)

5 3 STEPS TO CHANGE THE BATTERY PACK

6 Model Number: SIR5-FC Serial Number: Thorlabs does hereby certify that the above equipment meets or exceeds our published specifications for performance and accuracy. All test results specific to the above unit are shown below. Tested and Approved by: Date: