An actively stabilized laser is disclosed which includes a temperature tunable etalon in the laser cavity for single frequency operation. The operation of the laser is actively monitored to detect variations induced by changes in the length of the resonator. These changes tend to cause the frequency of the selected longitudinal mode to shift so that it is no longer aligned with the peak of the transmission curve of the etalon. When this misalignment occurs, operation deteriorates. By monitoring ...

A multi-stage optical fiber amplifier having a high gain, a high output power and a low noise figure, without limiting a gain bandwidth includes at least two stages of cascade connected optical fiber amplifiers. A synchronized etalon filter is disposed between the optical fiber amplifiers. The etalon filter has a resonant frequency matched with a standard frequency of a WDM (Wavelength Division Multiplexing) system using the optical fiber amplifiers.

A wavelength division demultiplexing device is presented utilizing a polarization-based filter or a multi-cavity etalon (e.g., a multi-cavity Fabry-Perot etalon) to obtain a flat-top filter response which can be utilized to create a flat-top slicer which separates out odd and even wavelengths, or upper and lower channels of an input WDM signal. The flat-top slicer can be used as the first stage of a cascaded network of wavelength demultiplexers in which following stages can be based on polarizat...

Wavelength reference apparatus for use in calibrating a tunable Fabry-Perot filter or a tunable VCSEL, whereby the device may be tuned to a precise, known wavelength, the wavelength reference apparatus comprising an LED, where the LED is chosen so as to have an emission profile which varies with wavelength; an etalon, where the etalon is chosen so as to have a transmission profile which comprises a comb of transmission peaks, with each transmission peak occurring at a precise, known wavelength; ...

A laser contains within its optical cavity a mode selector comprising a prism and a Fabry-Perot etalon. The etalon has two spaced parallel surfaces slightly inclined to a normal to the optical axis, one of the surfaces being formed by a face of the prism. The surfaces may be plane or spherical, and the mode selector may be used with gas or solid crystal lasers. The spacing of the etalon surfaces may be varied for tuning purposes.

There is disclosed a stabilized single-frequency arrangement for a broadband laser, such as a neodymium ion laser, in which a resonant etalon including birefringent material is disposed in the resonator in the path of the radiation and is tilted to select only one axial mode of oscillation in each of two orthogonal polarizations. In one specific embodiment, the resonator is tuned for maximum intensity of the mode of one polarization in response to a nearly linear intensity-frequency discriminant...

An incandescent lamp utilizing an etalon type transparent heat mirror on the lamp envelope for transmitting radiation in the visible range produced by the lamp filament and reflecting infrared thermal radiation back to the filament for increasing its temperature and thereby increasing its efficiency.

An air spaced etalon for wavelength selection including a spacer comprised of two hollow cylindrical members abutting each other in end-to-end aligned relation. A high degree of parallelism of two seconds or less can be easily obtained between the opposite end surfaces of the compound spacer by adjusting the relative angular position of the spacer members irrespective of the parallelism of the end surfaces of the individual spacer members. This enables production of high performance etalons with...

A grating-in-etalon wavelength division multiplexing device is disclosed. In one aspect the device includes an etalon structure with a single volume (or Bragg) diffraction grating, multiple superimposed volume diffraction gratings or a binary volume supergrating is interposed between the reflective opposed faces of the etalon. The etalon includes a tilt mechanism for tilting one or both of the reflective faces at a preselected angle with respect to each other from the parallel. A multiple wavele...

A high finesse holographic Fabry-Perot etalon and method of making a high finesse holographic Fabry-Perot etalon is disclosed. Particularly, a holographic Fabry-Perot etalon which achieves high finesse despite non-flat interfaces between the etalon media is presented. In a preferred method of fabricating a high finesse Fabry-Perot etalon, single step recording of both holograms simultaneously, with the spacer and substrates in place, is employed which preserves full phase synchronization between...