Parallel optical receiver for optical systems

An optical receiver for receiving a high data rate signal transmitted in one WDM channel of an optical link, comprising:

• a splitter, splitting the incoming signal into N branches, the incoming signal consisting of N spectral bands being orthogonal to each other (N>1) and transmitted without guard bands between them, the incoming signal transmitting data via orthogonal frequency division multiplexing (OFDM);
• an optical hybrid, receiving the light of one branch and mixing it with a local oscillator beam having a wavelength within n-th spectral band (2≦n≦N);
• a balanced optical detector with a set of photosensitive elements, receiving output signals from the optical hybrid and converting them into electrical signals;
• an ADC digitizing the electrical signals;
• and
• a digital signal processor recovering data from the digital signals using Fast Fourier Transform (FFT).

An optical communications system transmitting light via multiple WDM channels, comprising:

• an optical transmitter, including a light source producing light of multiple WDM channel wavelengths;
• a spectral splitter selecting light of one wavelength corresponding to one channel of the WDM system;
• the light of one channel consisting of N spectral bands (N>1);
• the spectral bands being orthogonal to each other;
• a set of data modulators embedding data in M-PSK format in orthogonal frequency division multiplexed (OFDM) optical signals of N spectral bands;
• combiner for combining light of all spectral bands and all WDM channels together;
• the transmitter transmitting combined light via optical link;
• an optical receiver receiving the transmitted combined signal and spectrally separating it into different channels;
• a splitter splitting the light of one channel into N branches by intensity;
• an optical hybrid receiving the light of one branch and mixing it with a local oscillator signal having a wavelength from the n-th spectral band (2≦n≦N);
• a set of balanced photodetectors receiving outputs of the optical hybrid and transforming them into electrical signals;
• a set of ADCs digitizing the electrical signals;
• a digital signal processing unit recovering data from the digitized signals.