OPTICAL ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING RECEIVER AND OPTICAL SIGNAL RECEIVING METHOD THEREOF

• US 20110135319A1
• Filed: 05/04/2010
• Published: 06/09/2011
• Est. Priority Date: 12/04/2009
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Choi, Kwang-Seong, Kwon, Yong-Hwan, Nam, Eun Soo, Choe, Joong-Seon, Kim, Jong-Hoi, YOUN, Chun Ju
• Granted Patent: US 8,521,040 B2
• Time in Patent Office: Days
• US Class Current: 398/202
• CPC Class Codes: H04B 10/6971 using equalisation
• CPC Class Codes: H04J 14/00 Optical multiplex systems
• CPC Class Codes: H04L 2025/03375 Passband transmission
• CPC Class Codes: H04L 27/2096 Arrangements for directly or externally modulating an optical carrier optical modulation H04B10/503
• CPC Class Codes: H04L 27/2649 Demodulators
• CPC Class Codes: H04L 27/2697 in combination with other modulation techniques

Abstract

Provided is an optical OFDM receiver. The optical OFDM receiver receives an optical signal dependent on the nonlinearity of a transmitter. The optical OFDM receives includes an optical down converter, a nonlinearity compensator, and an OFDM demodulator. The optical down converter converts the optical signal into an electrical signal. The nonlinearity compensator filters the electrical signal, for compensating distortion which is added to the optical signal when the transmitter performs optical modulation. The OFDM demodulator demodulates the distortion-compensated electrical signal in an OFDM scheme.

Claims

1. An optical Orthogonal Frequency Division Multiplexing (OFDM) receiver which receives an optical signal dependent on a nonlinearity of a transmitter, the optical OFDM receiver comprising:

an optical down converter converting the optical signal into an electrical signal;

a nonlinearity compensator filtering the electrical signal, for compensating distortion which is added to the optical signal when the transmitter performs optical modulation; and

an OFDM demodulator demodulating the distortion-compensated electrical signal in an OFDM scheme.

2. The optical OFDM receiver of claim 1, wherein the distortion is caused by a nonlinearity of an optical modulator which is comprised in the transmitter.

3. The optical OFDM receiver of claim 2, wherein the nonlinearity compensator comprises an A/D converter converting the electrical signal into a digital signal, wherein transfer characteristic of the A/D converter and transfer characteristic of the optical modulator have complementary relationship.

4. The optical OFDM receiver of claim 3, wherein the A/D converter comprises:

a sampler sampling the electrical signal to output a discrete signal;

a quantizer mapping the discrete signal at a predetermined quantization level according to a nonuniform quantization scheme for compensating the nonlinearity; and

an encoder encoding the discrete signal, which is mapped at the quantization level, into a binary code.

5. The optical OFDM receiver of claim 2, wherein the nonlinearity compensator comprises:

an equalizer compensating distortion, which is caused by the nonlinearity, from the electrical signal being an analog signal; and

an A/D converter converting an output of the equalizer into a digital signal.

6. The optical OFDM receiver of claim 2, wherein the nonlinearity compensator comprises:

an A/D converter converting the electrical signal into a digital signal; and

a digital filter compensating distortion, which is caused by the nonlinearity, from the digital signal.

7. A reception method in an optical Orthogonal Frequency Division Multiplexing (OFDM) receiver which receives an optical signal dependent on a nonlinearity of a transmitter, the reception method comprising:

receiving the optical signal to convert the optical signal into an electrical signal;

compensating distortion, which is caused by a nonlinearity of an optical modulator in the transmitter, from the electrical signal; and

demodulating the distortion-compensated signal in an OFDM scheme.

8. The reception method of claim 7, wherein the compensating of distortion comprises converting the electrical signal being an analog signal into a digital signal,

wherein the converting of the electrical signal comprises a nonuniform quantization operation having complementary input/output characteristic with respect to transfer characteristic of the optical modulator.

9. The reception method of claim 7, wherein the compensating of distortion comprises:

compensating distortion, which is caused by the nonlinearity, from the electrical signal being an analog signal; and

converting the distortion-compensated electrical signal into a digital signal.

10. The reception method of claim 9, wherein the converting of the distortion-compensated electrical signal comprises a uniform quantization operation which maps the electrical signal at a uniform quantization level.

11. The reception method of claim 7, wherein the compensating of distortion comprises:

converting the electrical signal being an analog signal into a digital signal; and

compensating distortion, which is caused by the nonlinearity, from the digital signal.

12. The reception method of claim 11, wherein the converting of the electrical signal comprises a uniform quantization operation which maps the electrical signal at a uniform quantization level.