Abstract: An optical transmitter includes: a controller that generates a multi-level amplitude modulated signal based on transmission data that is binary data; a driver that generates a drive signal in accordance with the multi-level amplitude modulated signal; and a light emitter that generates an optical signal in accordance with the drive signal. The controller selects one of a first encoding method and a second encoding method in accordance with a switching signal. The controller generates the multi-level amplitude modulated signal by converting a bit string of M (M is an integer of 2 or more) bits included in the transmission data into a pulse signal having 2M logic levels using a selected encoding method. The controller sets voltage values of the 2M logic levels depending on the selected encoding method.

Abstract: An optical receiver that receives a wavelength-multiplexed optical signal is disclosed. The optical receiver implements two or more PD elements each receiving an optical signal contained in the wavelength-multiplexed optical signal, a switch that selects one of photocurrents output from the PD elements, an I/V converter that converts the photocurrent into a voltage signal by a variable resistor whose resistance is adjusted for respective photocurrent, and a digital-to-analog converter. The optical receiver estimates the power of the optical signals from look-up-tables correlating the power of the optical signals with the digitally converted photocurrents at the selected resistance of the variable resistor.

Abstract: An optical transceiver that provides an optical module, a circuit board, and a housing, where the housing encloses the optical module and the circuit board therein. The optical module provides lead terminals connected with circuits on the circuit board through a flexible printed circuit (FPC) board. The FPC board is bent at a bent portion corresponding to an end of the optical module as the top surface thereof becomes inner. The bent portion of the FPC board provides a bared portion in the back surface thereof, where the bared portion removes a ground pattern.

Abstract: An optical transceiver that provides an optical module, a circuit board, and a housing, where the housing encloses the optical module and the circuit board therein. The optical module provides lead terminals connected with circuits on the circuit board through a flexible printed circuit (FPC) board. The FPC board is bent at a bent portion corresponding to an end of the optical module as the top surface thereof becomes inner. The bent portion of the FPC board provides a bared portion in the back surface thereof, where the bared potion removes a ground pattern.

Abstract: An optical transceiver that provides a receiver optical module including a plurality photodiodes (PDs) each biased through internal bias lines, signal lines carrying driving signals to an optical transmitter module, and external bias lines each connected to the internal bias lines. One of the internal bias lines connected to one of the external bias lines arranged closest to the signal lines has a length shorter than lengths of the other internal bias lines so as not to affect EMI noises induced from the signal lines to the other internal bias lines.

Abstract: An optical receiver that receives a wavelength-multiplexed optical signal is disclosed. The optical receiver implements two or more PD elements each receiving an optical signal contained in the wavelength-multiplexed optical signal, a switch that selects one of photocurrents output from the PD elements, an I/V converter that converts the photocurrent into a voltage signal by a variable resistor whose resistance is adjusted for respective photocurrent, and a digital-to-analog converter. The optical receiver estimates the power of the optical signals from look-up-tables correlating the power of the optical signals with the digitally converted photocurrents at the selected resistance of the variable resistor.

Abstract: An optical transceiver that provides a receiver optical module including a plurality photodiodes (PDs) each biased through internal bias lines, signal lines carrying driving signals to an optical transmitter module, and external bias lines each connected to the internal bias lines. One of the internal bias lines connected to one of the external bias lines arranged closest to the signal lines has a length shorter than lengths of the other internal bias lines so as not to affect EMI noises induced from the signal lines to the other internal bias lines.

Abstract: Disclosed is an optical transceiver 1 including a phase locked loop circuit 3a configured to receive a reference clock CL1 and remove a jitter component of the reference clock CL1; a second phase locked loop circuit 3b configured to receive an output of the first phase locked loop circuit, generate a multiplied clock CL3 synchronized with the output, and when the frequency of the output deviates from a predetermined range and is in an abnormal state, output an alarm signal ALM1; and an optical transmitter module 5 configured to output an optical output signal modulated based on the multiplied clock CL3 and electrical signals D1, D2, D3, and D4 from the outside.

Abstract: Disclosed is an optical transceiver 1 including a phase locked loop circuit 3a configured to receive a reference clock CL1 and remove a jitter component of the reference clock CL1; a second phase locked loop circuit 3b configured to receive an output of the first phase locked loop circuit, generate a multiplied clock CL3 synchronized with the output, and when the frequency of the output deviates from a predetermined range and is in an abnormal state, output an alarm signal ALM1; and an optical transmitter module 5 configured to output an optical output signal modulated based on the multiplied clock CL3 and electrical signals D1, D2, D3, and D4 from the outside.