Patent ID: 7502565

Claim:
A laser filter circuit for filtering a laser signal, comprising: an input terminal configured to receive an input laser signal; a first filter chain configured to generate a filtered signal, wherein the first filter chain is coupled to the input terminal and has one or more filters connected in series and each filter comprises one or more adjustable capacitor networks; an adjustable capacitor controller configured to generate one or more capacitor switch control signals in accordance with an operating frequency of the input laser signal for adjusting the capacitance of the one or more adjustable capacitor networks in the first filter chain; one or more output terminals configured to output the filtered signal from the first filter chain; a bypass circuit coupled to the input terminal and configured to output an unfiltered signal, wherein the one or more output terminals include at least one bypass output terminal configured to output the unfiltered signal from the bypass circuit; and a feedback circuit coupled between an output terminal and an input terminal of a particular filter in the first filter chain, wherein the feedback circuit is configured to enhance the frequency response of the laser filter circuit in accordance with a predetermined set of application requirements, the feedback circuit comprising: a voltage sensor configured to produce a current in accordance with a voltage level sensed at the output terminal of the particular filter; and a current mirror having an input terminal coupled to the voltage sensor and an output terminal coupled to the corresponding input terminal of the particular filter, wherein the current mirror is configured to produce a current in proportion to the current generated by the voltage sensor.