Optical demultiplexer

• US 5,760,937 A
• Filed: 01/16/1997
• Issued: 06/02/1998
• Est. Priority Date: 08/02/1994
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Ooi, Hiroki, Ishikawa, George, Nishimoto, Hiroshi, Tomofuji, Hiroaki, Sekiya, Motoyoshi
• Primary Examiner(s): NEGASH, KINFE MICHAEL
• Application Number:
  US08/784,441
• Time in Patent Office: 502 Days
• Field of Search: 359/115, 359/128, 359/135, 359/139, 359/158
• US Class Current: 398/98
• CPC Class Codes: G02F 2203/21 Thermal instability, i.e. DC drift, of an optical modulator; Arrangements or methods for the reduction thereof
• CPC Class Codes: H04B 10/0795 Performance monitoring; Measurement of transmission parameters
• CPC Class Codes: H04B 10/07957 Monitoring or measuring wavelength
• CPC Class Codes: H04B 10/0797 Monitoring line amplifier or line repeater equipment
• CPC Class Codes: H04B 10/0799 Monitoring line transmitter or line receiver equipment
• CPC Class Codes: H04B 10/25133 including a lumped electrical or optical dispersion compensator H04B10/2519, H04B10/2525 takes precedence
• CPC Class Codes: H04B 10/25137 using pulse shaping at the transmitter, e.g. pre-chirping or dispersion supported transmission [DST]
• CPC Class Codes: H04B 10/2525 using dispersion-compensating fibres
• CPC Class Codes: H04B 10/255 Self-phase modulation [SPM]
• CPC Class Codes: H04B 10/2563 Four-wave mixing [FWM]
• CPC Class Codes: H04B 10/66 Non-coherent receivers, e.g. using direct detection
• CPC Class Codes: H04B 10/67 Optical arrangements in the receiver
• CPC Class Codes: H04B 10/675 for controlling the optical bandwidth of the input signal, e.g. spectral filtering
• CPC Class Codes: H04B 2210/252 after the transmission line, i.e. post-compensation
• CPC Class Codes: H04B 2210/254 before the transmission line, i.e. pre-compensation
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems
• CPC Class Codes: H04J 14/0298 with sub-carrier multiplexing [SCM]
• CPC Class Codes: H04J 14/08 Time-division multiplex systems
• CPC Class Codes: H04J 14/086 Medium access H04J3/16 takes precedence
• CPC Class Codes: H04L 7/0037 Delay of clock signal
• CPC Class Codes: H04L 7/0075 : with photonic or optical means
• CPC Class Codes: H04L 7/027 : extracting the synchronising or clock signal from the received signal spectrum, e.g. by using a resonant or bandpass circuit
• CPC Class Codes: H04L 7/06 : the synchronisation signals differing from the information signals in amplitude, polarity or frequency or length
• CPC Class Codes: H04Q 11/0001 : using optical switching

Abstract

An optical demultiplexer comprises a clock regenerating circuit for regenerating a clock signal for each optical signal channel from an optical multiplexed signal. An optical switch separates each optical signal channel from the optical multiplexed signal in accordance with the clock signal regenerated by the clock regenerating circuit. An identification information extraction circuit extracts identification information contained in each optical signal channel separated by the optical switch. A control circuit changes output destinations so that each optical signal channel is output to a designated destination in accordance with the identification information extracted by the identification information extraction circuit. The identification information is appended as identification data to a data signal represented by the optical signal, and the identification information extraction circuit extracts the identification data contained in the data signal reconstructed from each optical signal channel. A signal switching circuit is provided between outputs of the optical switch and output destinations, wherein the control circuit changes output destinations by changing connection relationships in the signal switching circuit between the outputs of the optical switch and the output destinations, for example, by changing the phase of the clock signal supplied to the optical switch.

Claims

1. An optical demultiplexer comprising:

a clock regenerating circuit for regenerating a clock signal for each optical signal channel from an optical multiplexed signal;

an optical switch for separating each optical signal channel from the optical multiplexed signal in accordance with the clock signal regenerated by the clock regenerating circuit;

an identification information extraction circuit for extracting the identification information contained in the optical signal channel separated by the optical switch; and

a control circuit for changing output destinations so that each optical signal channel is output on a designated destination in accordance with the identification information extracted by the identification information extraction circuit.

2. An optical demultiplexer according to claim 1, wherein

the identification information is appended as identification data to a data signal represented by the optical signal, and

the identification information extraction circuit extracts the identification data contained in the data signal reconstructed from each optical signal channel.

3. An optical demultiplexer according to claim 2, further comprising a signal switching circuit provided between outputs of the optical switch and output destinations, wherein the control circuit changes output destinations by changing in the signal switching circuit connection relationships between the outputs of the optical switch and the output destinations.

4. An optical demultiplexer according to claim 2, wherein the control circuit changes output destinations by changing the phase of the clock signal supplied to the optical switch.

5. An optical demultiplexer according to claim 2, wherein the control circuit changes output destinations by delaying or advancing the optical multiplexed signal input to the optical switch.

6. An optical demultiplexer according to claim 1, wherein

the identification information is superimposed as a low-frequency signal on the optical multiplexed signal in a time slot designated for a specific optical signal channel, and

the identification information extraction circuit extracts the identification information by detecting the low-frequency signal superimposed on the optical multiplexed signal.

7. An optical demultiplexer according to claim 6, wherein the identification information extraction circuit detects the low-frequency signal from an electrical signal converted from each optical signal channel separated by the optical switch.

8. An optical demultiplexer according to claim 6, wherein the identification information extraction circuit detects the low-frequency signal from a current flowing to an optical/electrical converting device for converting each optical signal channel separated by the optical switch into an electrical signal.

9. An optical demultiplexer according to claim 6, further comprising a signal switching circuit provided between outputs of the optical switch and output destinations, wherein the control circuit changes output destinations by changing in the signal switching circuit connection relationships between the outputs of the optical switch and the output destinations.

10. An optical demultiplexer according to claim 6, wherein the control circuit changes output destinations by changing the phase of the clock signal supplied to the optical switch.

11. An optical receiver according to claim 6, wherein the control circuit changes output destinations by delaying or advancing the optical multiplexed signal input to the optical switch.