Measurement device
View Patent ↗A measurement device may include a bias source to provide a bias, a photodiode to provide a linear current based on an input optical power and the bias, a log amplifier to receive the linear current and to provide a voltage, and one or more processors to receive the voltage and to determine a measurement of the input optical power at an observed temperature. The measurement may be determined based on a photodiode current corresponding to the voltage, a dark current, and a calibration current. The calibration current may be determined, for a threshold power range, based on a first plurality of current measurements at a first temperature and at a plurality of optical powers, a second current measurement at a second temperature and at a first optical power, and a third current measurement at the second temperature and at a second optical power.
1. A measurement device, comprising:
a bias source to provide a bias;
a photodiode to provide a linear current based on an input optical power and the bias;
a log amplifier to receive the linear current and to provide a voltage;
a temperature sensor to determine an observed temperature; and
one or more processors to receive the voltage and to determine a measurement of the input optical power at the observed temperature,
wherein the measurement is determined based on:
a photodiode current corresponding to the voltage,
a dark current for the observed temperature, and
a calibration current for the observed temperature,
wherein the calibration current is determined, for a threshold power range, based on a first plurality of current measurements at a first temperature and at a plurality of optical powers, a second current measurement at a second temperature and at a first optical power, of the plurality of optical powers, and a third current measurement at the second temperature and at a second optical power, of the plurality of optical powers,
wherein a quantity of calibration temperatures used for calibrating the measurement device is two, including only the first temperature and the second temperature, for an optical power range of −9 decibel-milliWatts (dBm) to 2 dBm,
wherein the first temperature is different than the second temperature, and
wherein the first optical power is different than the second optical power.
2. The measurement device of claim 1 , wherein an accuracy of the measurement is within 0.5 decibel-milliWatts (dBm) for an optical power range of between −60 dBm and 2 dBm.
3. The measurement device of claim 1 , wherein an accuracy of the measurement is within 0.25 decibel-milliWatts (dBm) for an optical power range of between −55 dBm and 2 dBm.
4. The measurement device of claim 1 , wherein an accuracy of the measurement is within 2.5-milliWatts (dBm) for an optical power range of −68 dBm to 2 dBm.
5. The measurement device of claim 1 , wherein a step size of the plurality of optical powers is 1 decibel-milliWatts (dBm).
6. The measurement device of claim 1 , wherein the first optical power is less than −55 decibel milliWatts (dBm).
7. The measurement device of claim 1 , wherein the first optical power is 67 decibel milliWatts (dBm).
8. The measurement device of claim 1 , wherein the second optical power is greater than −45 decibel milliWatts (dBm).
9. The measurement device of claim 1 , wherein the second optical power is greater than −3 decibel milliWatts (dBm).
10. The measurement device of claim 1 , wherein the second optical power is between 1 decibel milliWatts (dBm) and 2 dBm.
11. A method, comprising:
determining, by a device, a first plurality of current measurements at a first temperature and at a plurality of optical powers;
determining, by the device, a second current measurement at a second temperature and at a first optical power, of the plurality of optical powers,
the first temperature being different than the second temperature;
determining, by the device, a third current measurement at the second temperature and at a second optical power, of the plurality of optical powers,
the first optical power being different than the second optical power;
determining, by the device, an observed temperature using a temperature sensor;
determining, by the device, a calibration current for the observed temperature and a threshold power range based on the first plurality of current measurements, the second current measurement, and the third current measurement,
wherein a quantity of calibration temperatures used for calibrating the device is two, including only the first temperature and the second temperature, for an optical power range of −9 decibel-milliWatts (dBm) to 2 dBm;
determining, by the device, a photodiode current for the observed temperature;
determining, by the device, a dark current for the observed temperature; and
determining a measurement of an input optical power at the observed temperature based on the calibration current, the photodiode current, and the dark current.
12. The method of claim 11 , further comprising:
receiving input identifying a measured voltage,
wherein the measured voltage corresponds to a linear current generated by a photodiode based on the input optical power and a bias; and
where determining the photodiode current comprises:
determining the photodiode current based on the measured voltage.
13. The method of claim 11 , wherein the threshold power range is between −33 decibel milliWatts (dBm) and 2 dBm.
14. A device, comprising:
a temperature sensor to determine an observed temperature; and
a processor to determine a measurement of an input optical power at the observed temperature and to output information identifying the measurement of the input optical power at the observed temperature,
wherein the measurement is determined based on:
a photodiode current corresponding to a voltage,
a dark current for an observed temperature, and
a calibration current for the observed temperature,
wherein the calibration current for the observed temperature is determined based on a plurality of current measurements performed at a plurality of optical powers and at a first temperature and a second temperature,
wherein a quantity of calibration temperatures used for calibrating the device is two, including only the first temperature and the second temperature, for an optical power range of −9 decibel-milliWatts (dBm) to 2 dBm, and
wherein the first temperature is different than the second temperature.
15. The device of claim 14 , further comprising:
a photodiode to provide a linear current based on the input optical power and a bias,
wherein the voltage is related to the linear current.
16. The device of claim 14 , further comprising:
an amplifier to receive a linear current and provide the voltage based on the linear current.
17. The device of claim 14 , wherein the processor is configured to determine the calibration current based on a responsivity of a photodiode that receives the input optical power.
18. The measurement device of claim 1 , wherein the measurement is determined based on a corrected power curve,
wherein a corrected slope value for the corrected power curve is based on a slope constant derived using two calibration temperatures, which include only the first temperature and the second temperature.
19. The measurement device of claim 1 , wherein the measurement is determined based on a corrected power curve,
wherein a corrected intercept value for the corrected power curve is based on an intercept constant derived using two calibration temperatures, which include only the first temperature and the second temperature.
20. The device of claim 14 , wherein the measurement is determined based on a corrected power curve,
wherein a corrected slope value for the corrected power curve is based on a slope constant derived using two calibration temperatures, which include only the first temperature and the second temperature, and
wherein a corrected intercept value for the corrected power curve is based on an intercept constant derived using two calibration temperatures, which include only the first temperature and the second temperature.