A system and method including multi-dimensional coded modulation wherein symbols within successive blocks of symbols are mapped using at least two different constellations to differentiate the symbols from each other. At least one data bit is encoded by an order of the symbols within each block of symbols. The receiver decodes the data by decoding at least one bit from the order of the symbols mapped with the first and second constellations.

A system and method including multi-dimensional coded modulation wherein symbols within successive blocks of symbols are mapped using at least two different constellations to differentiate the symbols from each other. At least one data bit is encoded by an order of the symbols within each block of symbols. The receiver decodes the data by decoding at least one bit from the order of the symbols mapped with the first and second constellations.

Methods and systems for tuning a resonant modulator are disclosed. One method includes receiving a carrier signal modulated by the resonant modulator with a stream of data having an approximately equal number of high and low bits, determining an average power of the modulated carrier signal, comparing the average power to a predetermined threshold, and operating a tuning device coupled to the resonant modulator based on the comparison of the average power and the predetermined threshold. One system includes an input structure, a plurality of processing elements, and a digital control element. The input structure is configured to receive, from the resonant modulator, a modulated carrier signal. The plurality of processing elements are configured to determine an average power of the modulated carrier signal. The digital control element is configured to operate a tuning device coupled to the resonant modulator based on the average power of the modulated carrier signal.

Methods and systems for tuning a resonant modulator are disclosed. One method includes receiving a carrier signal modulated by the resonant modulator with a stream of data having an approximately equal number of high and low bits, determining an average power of the modulated carrier signal, comparing the average power to a predetermined threshold, and operating a tuning device coupled to the resonant modulator based on the comparison of the average power and the predetermined threshold. One system includes an input structure, a plurality of processing elements, and a digital control element. The input structure is configured to receive, from the resonant modulator, a modulated carrier signal. The plurality of processing elements are configured to determine an average power of the modulated carrier signal. The digital control element is configured to operate a tuning device coupled to the resonant modulator based on the average power of the modulated carrier signal.

A second optical modulator is provided between a semiconductor laser and a first optical modulator. Further, a second optical waveguide branched from a first optical waveguide is provided between the semiconductor laser and the second optical modulator, and a light receiving element which converts received laser light into a second electrical signal is provided at an end of the second optical waveguide. Furthermore, the second optical modulator adjusts a light intensity of the laser light entering the first optical modulator to a fixed light intensity, based on data transmitted as the second electrical signal. Still further, the first optical modulator modulates the laser light based on data transmitted as a first electrical signal, and converts the first electrical signal into an optical signal.

An object is to output an optical signal accurately corresponding to a data signal. A pluggable optical module (100) includes a pluggable electric connector (11), a control unit (12), an optical signal output unit (13), and a pluggable optical receptor (14). The pluggable electric connector (11) can communicate a modulation signal (MOD) and a control signal (CON1) with an optical communication apparatus (92). The optical signal output unit (13) outputs an optical signal (LS) modulated by the modulation scheme by the control signal (CON1) in response to the modulation signal (MOD). The pluggable optical receptor (14) is configured in such a manner that an optical fiber (91) is insertable into and removable from the pluggable optical receptor (14). The pluggable optical receptor (14) can output the optical signal (LS) output from the optical signal output unit (13). The control unit (12) controls the optical signal output unit (13) to output the optical signal (LS) of a modulation amplitude set corresponding to the modulation signal (MOD) in the modulation scheme specified by the control signal (CON1).

An object is to output an optical signal accurately corresponding to a data signal. A pluggable optical module (100) includes a pluggable electric connector (11), a control unit (12), an optical signal output unit (13), and a pluggable optical receptor (14). The pluggable electric connector (11) can communicate a modulation signal (MOD) and a control signal (CON1) with an optical communication apparatus (92). The optical signal output unit (13) outputs an optical signal (LS) modulated by the modulation scheme by the control signal (CON1) in response to the modulation signal (MOD). The pluggable optical receptor (14) is configured in such a manner that an optical fiber (91) is insertable into and removable from the pluggable optical receptor (14). The pluggable optical receptor (14) can output the optical signal (LS) output from the optical signal output unit (13). The control unit (12) controls the optical signal output unit (13) to output the optical signal (LS) of a modulation amplitude set corresponding to the modulation signal (MOD) in the modulation scheme specified by the control signal (CON1).

Techniques are described for characterizing a receiver front end of a pluggable optical module. The pluggable optical module receives an optical signal that includes a first portion having a first polarization and a second portion having a second polarization. The first portion and second portion are not coherent with one another and the power of the first portion and second portion is equal.

Techniques are described for characterizing a receiver front end of a pluggable optical module. The pluggable optical module receives an optical signal that includes a first portion having a first polarization and a second portion having a second polarization. The first portion and second portion are not coherent with one another and the power of the first portion and second portion is equal.

An apparatus comprises: a first input tap; a first optical modulator coupled to the first input tap; a first output tap coupled to the first optical modulator so that the first optical modulator is positioned between the first input tap and the first output tap; and a controller indirectly coupled to the first input tap and the first output tap.