Controlled multi-wavelength etalon

A multi-wavelength air-gap etalon comprising:

• first and second body components separated by a gap and being transparent at least in a predetermined range of wavelengths;
• the first body component having a first outwardly facing side and a first inwardly facing side;
• the second body component having a second outwardly facing side and a second inwardly facing side;
• the first inwardly facing side having a plurality of steps, each step having a surface substantially parallel to the second inwardly facing side, the surface of the second inwardly facing side and the surfaces of the steps of the first inwardly facing side being at least partially reflective;
• the second inwardly facing side and the surface of a particular one of the plurality of steps of the first inwardly facing side being separated by a gap distance d;
• the difference between the gap distances separating the second side and the surfaces of a pair of adjacent steps of the first inwardly facing side defining a step size Δd;
• the gap distance d being selected such that a transmission intensity curve of light transmitted through the etalon in the region of the particular step in response to light being applied substantially normal to the second inwardly facing side of the etalon is at a first relative peak when the applied light is of a first wavelength λ, is at a second adjacent relative peak when the applied light is of a second wavelength λ+cs;
• and
• wherein the step size Δd is less than cs.

A stepped etalon for use in stabilizing the wavelength of a laser light source producing light for use in an optical communication system, the optical communication system having a first communication channel wavelength of λ and a channel spacing of cs, the etalon comprising:

• a transparent body having an index of refraction r and first and second opposing sides, the first side having a surface, the second side having a plurality of steps, each step having a surface substantially parallel to the first side, the surface of the first side and the surfaces of the steps being partially reflective;
• the body having a nominal thickness d separating the first side and the surface of a particular one of the plurality of steps equal to approximately (λ2+λ*cs)/(2*r*cs);
• and
• the difference between the thicknesses separating the first side and the surfaces of a pair of adjacent steps defining a step size Δd, wherein the step size Δd for each pair of adjacent steps is approximately equal to λ/(2*r*n), where n is the number of said plurality of steps.

A multi-wavelength etalon comprising:

• a body which is transparent at least in a predetermined range of wavelengths and having first and second outwardly facing and opposing sides, the first side having a surface, the second side having a plurality of steps, each step having a surface substantially parallel to the surface of the first side, the surface of the first side and the surfaces of the steps being at least partially reflective;
• the first side and the surface of a particular one of the plurality of steps being separated by a thickness d;
• the difference between the thicknesses separating the first side and the surfaces of a pair of adjacent steps defining a step size Δd;
• the distance d being selected such that a reflection intensity curve of light reflected by the etalon in the region of the particular step in response to light being applied substantially normal to the first side of the etalon is at a first relative peak when the applied light is of a first wavelength λ, is at a second adjacent relative peak when the applied light is of a second wavelength λ+cs;
• and
• wherein the step size Δd is less than cs.