Claims
- 1. An electromagnetic energy filter comprising:
a carrier; and a plurality of electromagnetic energy filters mounted on the carrier.
- 2. The filter of claim 1 where each electromagnetic energy filter filters a different frequency.
- 3. The filter of claim 2 where each electromagnetic energy filter filters energy in the near infrared spectrum.
- 4. The filter of claim 1 where:
for each electromagnetic energy filter, when an electromagnetic energy beam strikes the filter at a given angle, the filter allows a certain portion of the frequencies in the electromagnetic energy beam striking the filter to pass through the electromagnetic energy filter and reflects other frequencies in the beam; and each filter in at least a subset of the plurality of electromagnetic energy filters allows a different set of frequencies to pass through it.
- 5. The filter of claim 4 where:
the carrier is a disk; each of the plurality of electromagnetic energy filters is located towards the periphery of the disk; and the frequencies filtered by the tunable filter are changed by rotating the disk.
- 6. The filter of claim 5 where each electromagnetic energy filter includes at least:
an intermediate portion having a first side and a second side; a first reflective layer mounted on the first side; and a second reflective layer mounted on the second side.
- 7. The filter of claim 6 where the carrier has a first side and a second side and where, at any given time, one of the plurality of the filters is a selected filter, further comprising:
a first output lens adjacent to the first side and capable of accepting a beam; a second output lens adjacent to the second side and capable of accepting a beam; a first input lens capable of providing an input beam to the carrier on the first side at a first angle so that a portion of the beam is reflected by the selected filter into the first output lens and a portion of the beam is transmitted by the selected filter to the second output lens; and a second input lens capable of providing an add beam to the carrier on the second side at the first angle so that at least a portion of the add beam is transmitted by the selected filter into the first output lens.
- 8. The filter of claim 1 where:
the carrier is a disk; each of the plurality of electromagnetic energy filters is located near the edge of the disk; and the frequency of the tunable filter is changed by rotating the disk.
- 9. The filter of claim 8 where each electromagnetic energy filter filters energy in the near infrared spectrum.
- 10. The filter of claim 9 where each electromagnetic energy filter is a Fabry-Perot interferometer.
- 11. A tunable filter comprising:
a holder having a first side and a second side; a plurality of filters disposed on the holder; a first output lens capable of accepting a beam; a second output lens capable of accepting a beam; a first input lens capable of providing an input beam to the holder on the first side at a first angle so that a portion of the beam is reflected by a selected filter of the plurality of filters into the first output lens and a portion of the beam is transmitted by the selected filter to the second output lens.
- 12. The tunable filter of claim 11 where, to change the frequency of the filter, the holder is moved to change which filter of the plurality of filters is in contact with the beam.
- 13. The tunable filter of claim 12 where each electromagnetic energy filter is a Fabry-Perot interferometer.
- 14. The tunable filter of claim 13 where the holder is a disk.
- 15. The tunable filter of claim 14, where the tunable filter filters energy in the near infrared spectrum.
- 16. An electromagnetic filter suitable for filtering a beam, comprising:
a holder; and a set of fixed frequency filters disposed on the holder; where the frequency filtered by the electromagnetic filter is altered by changing which section of the holder the beam strikes.
- 17. The electromagnetic filter of claim 16 where the frequency of the electromagnetic filter is changed by rotating the holder.
- 18. The electromagnetic filter of claim 17 where each of the fixed frequency filters is a Fabry-Perot interferometer.
- 19. The electromagnetic filter of claim 18 where each of the fixed frequency filters filters energy in the near infrared spectrum.
PRIOR PROVISIONAL PATENT APPLICATION
[0001] The present application claims the benefit of U.S. Provisional Application No. 60/113,922, entitled “Tunable Add/Drop Filter,” filed Dec. 28, 1998.
Provisional Applications (1)
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Number |
Date |
Country |
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60113922 |
Dec 1998 |
US |