Method and system for equalizing transmission line loss of a laser drive signal
First Claim
1. A method for compensating transmission line loss of a laser drive signal, comprising:
- providing a transmission line between a laser driver circuit and a laser diode, the transmission line having coupled thereto a set of frequency dependent impedance circuits connected in series, each frequency dependent impedance circuit comprising a resistor, an inductor and a capacitor connected in parallel, and each frequency dependent impedance circuit is configured to produce a desired impedance at the corresponding frequency, the set of frequency dependent impedance circuits corresponding to a predefined set of operating frequencies of the laser drive signal, wherein each frequency dependent impedance circuit of the set of frequency dependent impedance circuits is configured to generate a frequency response that compensates for the laser drive signal loss of the transmission line at a distinct corresponding operating frequency, and wherein; and
driving the laser drive signal from the laser driver circuit to the laser diode through the transmission line, the laser drive signal operating within a range of frequencies associated with the predefined set of operating frequencies.
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Accused Products
Abstract
A circuit for equalizing transmission line loss of a laser drive signal includes a laser driver, a laser diode, and a transmission line for connecting the laser driver to the laser diode. The laser driver includes a differential pair of transistors, a modulation current source and two sets of source impedance circuits. Each set of source impedance circuits is configured to produce a frequency response for compensating the frequency response of the lossy transmission line at a distinct corresponding operating frequency. The set of source impedance circuits may be tuned to generate approximately zero impedance when the operating frequency is approximately zero. Hence a lower voltage power supply can be used to power both the laser driver and the laser diode, which in turn reduces the power consumption of the circuit.
35 Citations
20 Claims
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1. A method for compensating transmission line loss of a laser drive signal, comprising:
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providing a transmission line between a laser driver circuit and a laser diode, the transmission line having coupled thereto a set of frequency dependent impedance circuits connected in series, each frequency dependent impedance circuit comprising a resistor, an inductor and a capacitor connected in parallel, and each frequency dependent impedance circuit is configured to produce a desired impedance at the corresponding frequency, the set of frequency dependent impedance circuits corresponding to a predefined set of operating frequencies of the laser drive signal, wherein each frequency dependent impedance circuit of the set of frequency dependent impedance circuits is configured to generate a frequency response that compensates for the laser drive signal loss of the transmission line at a distinct corresponding operating frequency, and wherein; and driving the laser drive signal from the laser driver circuit to the laser diode through the transmission line, the laser drive signal operating within a range of frequencies associated with the predefined set of operating frequencies. - View Dependent Claims (2, 3, 4, 5)
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6. A circuit for compensating transmission line loss of a laser drive signal, comprising:
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a laser driver circuit; a laser diode; a transmission line connecting the laser driver circuit to the laser diode; and a set of frequency dependent impedance circuits connected in series, each frequency dependent impedance circuit comprising a resistor, an inductor and a capacitor connected in parallel, and each frequency dependent impedance circuit is configured to produce a desired impedance at the corresponding frequency, the set of frequency dependent impedance circuits, the set of frequency dependent impedance circuits having a first terminal coupled to a power supply and a second terminal coupled to the transmission line, wherein each frequency dependent impedance circuit of the set of frequency dependent impedance circuits is configured to generate a frequency response that compensates for laser drive signal loss of the transmission line at a distinct corresponding operating frequency. - View Dependent Claims (7, 8, 9, 10)
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11. A method for operating a laser driver circuit, wherein the laser driver circuit drives a laser drive signal to a laser diode through a transmission line, comprising:
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providing a laser driver circuit that comprises; a differential pair of transistors having each drain terminal coupled to a power supply through a set of source impedance circuits and gate terminals coupled to a pair of differential input signals, wherein the set of source impedance circuits produces a substantially zero impedance when the operating frequency is approximately zero and produces a predetermined non-zero impedance at each operating frequency of a predefined set of operating frequencies, and wherein the differential input signals operate within a range of frequencies associated with the predefined set of operating frequencies; a current source coupled between source terminals of the differential pair of transistors and a circuit ground; and a pair of output ports coupled to the drain terminals of the differential pair of transistors; and driving the laser driver circuit with an input signal, the input signal operating within a range of frequencies associated with the predefined set of operating frequencies. - View Dependent Claims (12, 13, 14, 15)
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16. A laser driver circuit, wherein the laser driver circuit drives a laser drive signal to a laser diode through a transmission line, comprising:
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a differential pair of transistors having each drain terminal coupled to a power supply through a set of source impedance circuits and gate terminals coupled to a pair of differential input signals, wherein the set of source impedance circuits produces a substantially zero impedance when the operating frequency is approximately zero and produces a predetermined non-zero impedance at each operating frequency of a predefined set of operating frequencies, and wherein the differential input signals operate within a range of frequencies associated with the predefined set of operating frequencies; a current source coupled between source terminals of the differential pair of transistors and a circuit ground; and a pair of output ports coupled to the drain terminals of the differential pair of transistors. - View Dependent Claims (17, 18, 19, 20)
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Specification