Elementary matrix based optical signal/network analyzer
View Patent ↗A method for characterizing a device under test includes propagating multiple optical signals through the device under test and combining the multiple optical signals with a reference optical signal. The multiple optical signals are mixed with the reference optical signal and a relative perturbation between the multiple optical signals from the mixing of the multiple optical signals with the reference optical signal is determined. In another embodiment a modulated optical signal is provided from a local oscillator and the modulated optical signal is combined with the input optical signal. The modulated optical signal is mixed with the input signal to provide a mixed signal and at least one polarization-resolved parameter of the input optical signal is extracted from the mixed signal.
1. A method for characterizing a device under test, comprising:
propagating multiple optical signals through the device under test, the multiple optical signals including multiple sideband pairs, each sideband pair having a positive sideband and a negative sideband, and the positive sideband and the negative sideband of a particular sideband pair having a substantially same polarization state;
combining the multiple optical signals with a reference optical signal;
mixing the multiple optical signals with the reference optical signal; and
for each of at least one sideband pair, determining a relative perturbation between the positive sideband and the negative sideband of the sideband pair, from the mixing of the multiple optical signals with the reference optical signal.
2. The method of claim 1 , further comprising determining at least one elementary parameter from the determined relative perturbation, the at least one elementary parameter including at least one of the following:
a group delay, a 0° component of the differential group delay, a 45° component of the differential group delay, a circular component of the differential group delay, an absorption change per unit frequency, a frequency derivative of a 0° component of the polarization dependent loss, a frequency derivative of a 45° component of the polarization dependent loss, and a frequency derivative of a circular component of the polarization dependent loss.
3. The method of claim 1 , wherein different sideband pairs have different polarization states.
4. The method of claim 1 , further comprising modulating an optical signal to create the multiple optical signals.
5. The method of claim 1 , further comprising:
providing a local oscillator signal; and
modulating the local oscillator signal to provide a set of at least one reference optical signal.
6. The method of claim 5 , wherein the set of at least one reference optical signal includes a plurality of reference optical signal pairs, and wherein the mixing of the multiple optical signals with the reference optical signal includes mixing the multiple sideband pairs with corresponding ones of the reference optical signal pairs.
7. The method of claim 5 , further comprising providing first sinusoidal modulation of the local oscillator signal.
8. The method of claim 7 , further comprising providing second sinusoidal modulation of the local oscillator signal.
9. The method of claim 5 , wherein the set of at least one reference optical signals includes a plurality of reference optical signal pairs having different polarization states.