Patent ID: 7495203

Claim:
An in-line monitoring apparatus to monitor input power of an optical signal received by an optical signal detector, said in-line monitoring apparatus comprising: an avalanche photodiode (“APD”) configured to receive said optical signal; an input configured to provide a bias for said APD; and a power monitoring stage coupled to said input in parallel with said APD and further configured to generate a measurement signal in-situ, wherein said power monitoring stage provides an extended range over which said power monitoring stage measures said input power as an extended input power range, said power monitoring stage comprising two or more power monitoring stages to establish said extended input power range, each individual power monitoring stage of said two or mote power monitoring stages being configured to measure input power values within a separate portion of said extended input power range, where a first power monitoring stage is configured to detect a low-powered optical signal as said input power and a second power monitoring stage is configured to provide a linear range of input optical power levels, wherein said measurement signal is representative of said input power.