Wavelength division multiplex (wdm) signal monitor

• US 20030138250A1
• Filed: 09/26/2002
• Published: 07/24/2003
• Est. Priority Date: 04/06/2000
• Status: Abandoned Application

• Current Assignee: M A Mortenson Company (M A Mortenson Companies Incorporated)
• Original Assignee: M A Mortenson Company (M A Mortenson Companies Incorporated)
• Inventors: Glynn, Gerard James
• Application Number:
  US10/239,942
• Publication Number:
  US 20030138250A1
• Time in Patent Office: Days
• US Class Current: 398/34
• CPC Class Codes: G01J 1/4257 applied to monitoring the characteristics of a beam, e.g. laser beam, headlamp beam monitoring arrangements for lasers in general H01S3/0014
• CPC Class Codes: G01J 9/0246 Measuring optical wavelength
• CPC Class Codes: G01J 9/04 by beating two waves of a same source but of different frequency and measuring the phase shift of the lower frequency obtained
• CPC Class Codes: H04B 10/077 using a supervisory or additional signal
• CPC Class Codes: H04B 10/07955 Monitoring or measuring power

Abstract

A WDM signal monitor (4) for measuring optical power and/or wavelength of components of a WDM signal is disclosed. The monitor comprises: a wavelength selectable light source (20), preferably wavelength tuneable laser, which is operable to produce an optical output at known selectable wavelengths; an optical receiver (24) to which said optical output and WDM signal are applied and which is operable to produce an electrical signal whose frequency is representative of the difference in wavelength between a component of the WDM signal and optical output; means (22) for determining the power of the component of the WDM signal from the magnitude of said electrical signal; and means (22) for determining the wavelength of the component form the wavelength selected and the frequency of said electrical signal.

Claims

1. A WDM signal monitor (4) for measuring optical power of components of a WDM signal comprising:

a wavelength selectable light source (20) which is operable to produce an optical output at a known selectable wavelength;

an optical receiver (24) to which said optical output and WDM signal are applied and which is operable to produce an electrical signal whose frequency is representative of the difference in wavelength between a component of the WDM signal and optical output and;

means (22) for determining the power of the component of the WDM signal from the magnitude of said electrical signal.

5. A WDM signal monitor according to any preceding claim in which the wavelength selectable light source (20) comprises a wavelength tuneable laser (40).

6. A WDM signal monitor according to claim 5 and further comprising wavelength measuring means (44) for measuring the wavelength of the optical output produced by the laser (40) and control means (42) responsive to said wavelength measuring means (44) for controlling the laser (40) to maintain the optical output at the known wavelength.

7. A WDM signal monitor according to claim 6 and further comprising power monitoring means (52) for measuring the optical power produced by the laser (40).

8. A WDM signal monitor according to any preceding claim in which the optical receiver (24) comprises a balanced optical to electrical converter (36, 38).

9. A WDM signal monitor according to claim 8 and further comprising a matched 3 dB optical combiner (18) for respectively applying the optical output and WDM signals to respective inputs of the balanced optical to electrical converter (36, 38).

10. A WDM signal monitor according to any preceding claim and further comprising a bandpass filter (64) connected to the output of the optical receiver in which the passband of the filter (64) is selected such as to allow passage of electrical signals which correspond with one of the components of the WDM signal.

11. A plurality of WDM signal monitors according to any preceding claim which are operable with a single wavelength selectable light source.

2. A WDM signal monitor (14) for measuring wavelength of components of a WDM signal comprising:

a wavelength selectable light source (20) which is operable to produce an optical output at a known selectable wavelength;

an optical receiver (24) to which said optical output and WDM signal are applied and which is operable to produce an electrical signal whose frequency is representative of the difference in wavelength between a component of the WDM signal and optical output; and

means (22) for determining the wavelength of the component of the WDM signal from the wavelength selected and the frequency of said electrical signal.

3. A WDM signal monitor for measuring wavelength of components of a WDM signal comprising:

a wavelength selectable light source (20) which is operable to produce an optical output at a known selectable wavelength;

an optical receiver (24) to which said optical output and WDM signal are applied and which is operable to produce an electrical signal whose frequency is representative of the difference in wavelength between a component of the WDM signal and optical output; and

means (22) for detecting the presence of the electrical signal within a selected bandwidth indicating that the wavelength of the component of the optical WDM substantially corresponds with the wavelength selected.

4. A WDM signal monitor (4) for measuring optical power and wavelength of components of a WDM signal comprising:

a wavelength selectable light source (20) which is operable to produce an optical output at a known selectable wavelength;

an optical receiver (24) to which said optical output and WDM signal are applied and which is operable to produce an electrical signal whose frequency is representative of the difference in wavelength between a component of the WDM signal and optical output;

means (22) for determining the power of the component of the WDM signal from the magnitude of said electrical signal; and

means (22) for determining the wavelength of the component from the wavelength selected and the frequency of said electrical signal.

12. A WDM signal monitor for measuring optical power and/or wavelength of components of a WDM signal substantially as hereinbefore described with reference to or substantially as illustrated in the accompanying drawings.