230 has been eliminated in particular embodiments of the invention lookup table 277 is included as part of or directly coupled to memory device 235 in the optical measurement system summing circuit 289 receives vector phase 283 and vector phase 287 position value 295 represents the desired true measurement value that a properly calibrated and compensated optical receiver 230 would measure and output phase error of optical receiver 230 is stored in lookup table 277 phase error data is selectively accessed in accordance with frequency information and is applied from the data output 279 of lookup table 277 to summing circuit 275 process blocks previously described such as blocks 255 260 265 270 281 285 and 291 can be performed by application specific integrated circuits asic or similar hardware firmware or software based related devices it is also contemplated that the various process blocks and circuits can be integrated with one another or have similar logical process blocks perform similar functions referring now to fig3 illustrated is a block diagram of a more or less conventional optical receiver design optical receiver receives optical or light signal 300 optical receiver includes photodiode 305 coupled to transimpedance amplifier 310 transimpedance amplifier 310 includes feedback resistor r 315 coupled from transimpedance amplifier 310 output to transimpedance amplifier 310 input optical receiver also includes high pass filter 320 at the output of transimpedance amplifier 310.