| 摘要 |
An optical power monitoring device is provided for monitoring the power of an optical signal supplied along a waveguide 2 substantially independently of the polarisation of the optical signal. At least one tap-off coupler 5, 10 is provided for purpose of monitoring the power of the optical signal with a view to providing respective signals of different optical modes within two intermediate waveguides 6, 14 incorporating respective attenuators 11 and 12. The optical mode signal in at least one of the waveguides 6, 14 is controlled by the attenuators in such a way that the sum of the mode signals detected by a single photodiode 7 produces an electrical output signal which is substantially independent of the polarisation of the optical signal monitored. Such an arrangement enables the desired low polarisation-dependence monitoring signal to be obtained using phototonics of relaxed specification, and in particular using only one monitoring photodiode.
|
