Unipolar electrical to bipolar optical converter
OwnerJan Conradiinventor
Life of this patent
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Abstract
An optical amplitude modulator (16) has a first input (13) for receiving a continuous optical signal, a second input (17) for receiving a bipolar data encoded electrical signal, and a Mach-Zehnder interferometer transfer operation biased at Vπ for modulating the continuous signal based on the bipolar data encoded electrical signal for generating an AMI modulated optical signal having three electric field levels, +/−E and 0, and two power levels, 0 and P, such that the resultant modulated signal is both amplitude and phase modulated.
Claims20
An optical amplitude modulator comprising:
- a first input for receiving a continuous optical signal;
- a second input for receiving a bipolar data encoded electrical signal;
- and
- a Mach-Zehnder modulator biased at Vπ for modulating the continuous signal based on the bipolar data encoded electrical signal for generating an AMI modulated optical signal having three electric field levels, +/−E and 0, and two power levels, 0 and P, such that the resultant modulated signal is both amplitude and phase modulated.
A method of converting a unipolar voltage data stream into a bipolar optical data stream, the method comprising:
- supplying a continuous optical signal to a modulator, wherein the modulator has a maximum MARK optical power output at a first voltage driving level +V, a maximum MARK optical power output at a second voltage driving level −V, a minimum optical power output at a voltage level between the first and second voltage driving level and the phase of every maximum MARK optical output pulse is inverted alternately;
- encoding a unipolar voltage data stream to provide an encoded bipolar voltage data stream;
- and
- driving the modulator with the encoded bipolar voltage data stream to generate a bipolar optical data stream such that there will be a minimum optical power output when the encoded bipolar voltage data stream stays at a midlevel between the first and the second voltage level.
A unipolar electrical to bipolar optical converter, the converter comprising:
- a bipolar electrical coder for alternating the amplitude polarity of consecutive MARK pulses of a data encoded electrical signal to generate a bipolar data encoded electrical signal;
- and
- an electrical to optical modulator having an optical input for receiving a continuous optical signal, an electrical input for receiving the bipolar data encoded electrical signal, and an optical output for providing an AMI modulated optical signal having three optical electric field levels, +/−E and 0, and two optical power levels, 0 and P, when the bipolar data encoded electrical signal is applied to the electrical to optical modulator such that the resultant alternate electric fields of +/−E are in a form of phase shift keying.
Dependencies are inferred from the claim text.