Patent ID: 6979810

Claim:
An optical module comprising: a photodiode or avalanche photodiode for converting a light signal into an electric signal; a transimpedance amplifier for current/voltage conversion; a voltage amplifier; and a clock and data recovery IC, the clock and data recovery IC having a phase locked loop, the phase locked loop comprising: a voltage-controlled oscillator; a +45° phase shifter which causes the phase of one branched output signal from the voltage-controlled oscillator to lead 45°; a −45° phase shifter which causes the phase of the other branched output signal from the voltage-controlled oscillator to lag 45°; a selector for selecting either data provided from a data input pad or an output from the −45° phase shifter; a phase detector which compares the phase of an output selected by the selector with the phase of an output from the +45° phase shifter; and a filter circuit which receives an output signal from the phase detector and which provides an output signal to the voltage-controlled oscillator.