Optical transmitter and code conversion circuit used therefor

An optical transmitter, comprising:

• a code conversion circuit, including:
• a first serializer that generates a first signal having a first bit rate by simply bit-multiplexing a plurality of series of signals;
• a second serializer that generates a second signal having the first bit rate by simply bit-multiplexing another plurality of series of signals;
• a first arithmetic circuit that performs Exclusive-OR operation of the first signal and own Exclusive-OR output delayed for one cycle;
• a second arithmetic circuit that performs Exclusive-OR operation of the second signal and own Exclusive-OR output delayed for the one cycle;
• a third arithmetic circuit that performs Exclusive-OR operation of an output signal of said first arithmetic circuit and a signal obtained by delaying an output signal of said second arithmetic circuit for the one cycle so as to output a third signal;
• and
• a fourth arithmetic circuit that performs Exclusive-OR operation of the output signal of said first arithmetic circuit and the output signal of said second arithmetic circuit,
• wherein a signal obtained by delaying an output signal of said fourth arithmetic circuit for a ½ cycle is rendered to be a fourth signal;
• and
• an optical transmission circuit that performs optical modulation by a both-side electrode Mach-Zehnder type optical modulator using the third and fourth signals output by said code conversion circuit, and outputs an optical signal that is Exclusive-OR of the third and fourth signals.

An optical transmitter, comprising:

• a code conversion circuit, including:
• a first serializer that generates a first signal by simply bit-multiplexing a plurality of series of signals;
• a second serializer that generates a second signal by simply bit-multiplexing another plurality of series of signals;
• a first Exclusive-OR circuit that performs Exclusive-OR operation of the first signal and an output of a second flip flop;
• a first flip flop that delays the second signal for a ½ cycle in synchronization with an inverse clock;
• a second Exclusive-OR circuit that performs Exclusive-OR operation of an output signal of said first flip flop and an output of a third flip flop;
• said second flip flop that outputs an output signal of said second Exclusive-OR circuit by delaying for the ½ cycle in synchronization with a clock;
• and
• said third flip flop that outputs an output signal of said first Exclusive-OR circuit by delaying for the ½ cycle in synchronization with the inverse clock;
• and
• an optical transmission circuit that performs optical modulation by a both-side electrode Mach-Zehnder type optical modulator using third and fourth signals output by said code conversion circuit, and outputs an optical signal that is Exclusive-OR of the third and fourth signals.