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US 12,191,913 B2Granted
Optical transmitter for passive optical networks
AssigneeNokia Solutions and Networks Oy
InventorsPatrick Iannone, Roland Ryf, Rene-Jean Essiambre
Life of this patent
Estimating the term…
Abstract
An apparatus includes an optical PSK transmitter configured to output carrier-suppressed optical signal phase-modulated according to a M-PSK constellation without substantial amplitude modulation. The apparatus includes an optical phase modulator, a driver configured to drive the modulator with a PAM-N electrical signal, N>M, and a signal encoder configured to map an input bit stream to the PAM-N electrical signal.
Claims20
An apparatus comprising:
- an optical transmitter for transmitting an optical carrier modulated according to an M-symbol phase shift keying (M-PSK) modulation format, M≥2, the optical transmitter comprising:
- an optical phase modulator (OPM);
- a driver for driving the OPM with an electrical driver signal;
- and
- a signal processor for mapping an input bit stream to levels of a PAM-N constellation, where N is an integer greater than M, such that each of the levels causes the driver to produce a corresponding electrical driver signal.
2 more elements
An apparatus comprising:
- an optical transmitter for transmitting an optical carrier modulated according to an M-symbol phase shift keying (M-PSK) modulation format, M≥2, the optical transmitter comprising:
- an optical phase modulator (OPM);
- a driver for driving the OPM with an electrical driver signal;
- and
- a signal processor for mapping an input bit stream to levels of a PAM-N constellation, where Nis an integer greater than M;
- wherein the signal processor is configured to cause the electrical driver signal to vary between N signal levels corresponding to the levels of the PAM-N constellation, and to map different instances of a same input digital value to two different ones of the N signal levels;
- and
- wherein the two different ones of the N signal levels correspond to a same phase shift of the optical carrier modulo 2π.
5 more elements
An apparatus comprising:
- an optical quadrature phase shift keying (QPSK) transmitter for transmitting an optical carrier modulated according to a QPSK modulation format, the optical QPSK transmitter comprising:
- an optical phase shifter (OPS);
- a driver for driving the OPS with a PAM-6 electrical signal to cause an optical phase shift to the optical carrier that alternates between six different phase levels spaced substantially by π/2 radian, the six different phase levels comprising two pairs of 2π spaced phase levels;
- and
- a signal processor for processing an input bit stream to map consecutive 2-bit sequences therein to symbols of a QPSK constellation, so that a first and a second of the symbols are each mapped to both phase levels of a corresponding pair of the 2π spaced phase levels.
2 more elements
Dependencies are inferred from the claim text.