Diffractive mems device

Patent metadata

Field	Value
Publication number	US-2017199374-A1
Application number	US-201715470423-A
Country	US
Kind code	A1
Filing date	Mar 27, 2017
Priority date	Jan 11, 2012
Publication date	Jul 13, 2017
Grant date	—

Abstract

A diffractive MEMS device has an in-plane binary reflective diffraction pattern formed in an outer surface of a tillable platform. The binary reflective diffraction pattern includes rectangular or trapezoidal ridges and valleys, or grooves, of a same depth. The binary reflective diffractive pattern has a high diffraction efficiency even though the surfaces of the “grooves” or “ridges” are not perpendicular to the incoming optical beam. The diffractive pattern is supported by a pair of torsional hinges and is tiltable by an electrostatic actuator. The electrostatic actuator can include at least one side electrode for linearization of dependence of tilt angle on the voltage applied to the actuator.

First claim

1 - 24 . (canceled)

25 . A device comprising:
a substrate; a platform supported over the substrate and tiltable about a first axis; and an electrostatic actuator comprising a stator and a rotor for tilting the platform about the first axis when a first control voltage is applied between the stator and the rotor, wherein
the stator comprises a first stator side electrode extending upwardly from the substrate for an electrostatic interaction with the platform,
the stator and the rotor are located above the substrate, a slope generated by the stator and the rotor increases with a tilt angle of the platform, and
a slope generated by the first stator side electrode decreases with the tilt angle of the platform, thereby providing for a linear dependence of a control voltage on the tilt angle.

26 . The device of claim 25 , wherein the platform comprises a binary diffractive surface relief pattern, comprising a binary diffraction grating, and a conforming reflective metal layer disposed over the binary diffractive surface relief pattern.

27 . The device of claim 26 , wherein
the binary diffractive surface relief pattern comprises ridges comprising sidewalls and separated by trenches, and the ridges have rectangular or trapezoidal cross-sections.

28 . The device of claim 27 , wherein the conforming reflective metal layer is disposed on the sidewalls of the ridges and in the trenches.

29 . The device of claim 25 , wherein the first stator side electrode extends to at least 50% to 150% of a distance between the substrate and the platform when no voltage is applied between the stator and the rotor.

30 . The device of claim 25 , wherein the platform further includes a flange that surrounds at least some of the first stator side electrode.

31 . The device of claim 25 , wherein
the stator further comprises a first stator comb extending from the substrate towards the platform, the rotor comprises a first rotor comb extending from the platform towards the substrate, and the first rotor comb is interdigitated with the first stator comb.

32 . The device of claim 31 , wherein
the stator further comprises a second stator comb extending from the substrate towards the platform, the rotor further comprises a second rotor comb extending from the platform towards the substrate, and the second rotor comb is interdigitated with the second stator comb.

33 . The device of claim 25 , wherein
the stator further comprises a second stator side electrode extending upwardly from the substrate for an electrostatic interaction with the platform, and

34 . The device of claim 33 , wherein the second stator side electrode extends to at least 50% to 150% of a distance between the substrate and the platform when no voltage is applied between the stator and the rotor.

35 . The device of claim 33 , wherein the platform comprises first and second flanges extending laterally therefrom and surrounding the first stator side electrode and the second stator side electrode, respectively.

36 . The device of claim 33 , wherein the stator further comprises a third stator side electrode and a fourth stator side electrode, each extending from the substrate on opposite sides of the platform, for an electrostatic interaction with the platform, such that a first flange is at least partially disposed between the first stator side electrode and the third stator side electrode and a second flange is at least partially disposed between the second stator side electrode and the fourth stator side electrode.

37 . The device of claim 36 , wherein the stator further comprises a fifth stator side electrode and a sixth stator side electrode, each extending from the substrate on opposite sides of the platform, for an electrostatic interaction with the platform.

38 . The device of claim 37 , wherein the fifth stator side electrode and the sixth stator side electrode each extend to at least 50% to 150% of a distance between the substrate and the platform when no voltage is applied between the stator and the rotor.

39 . The device of claim 37 , wherein the platform further comprises third and fourth flanges extending laterally therefrom and surrounding the fifth stator side electrode and the sixth stator side electrode, respectively.

40 . The device of claim 39 , wherein the stator further comprises a seventh stator side electrode and an eighth stator side electrode, each extending from the substrate on opposite sides of the platform, for an electrostatic interaction with the platform, such that the third flange is at least partially disposed between the fifth stator side electrode and the seventh stator side electrode and the fourth flange is at least partially disposed between the sixth stator side electrode and the eighth stator side electrode.

41 . A tunable semiconductor laser comprising:
a semiconductor chip for providing optical gain at a lasing wavelength; and the device of claim 25 , optically coupled to the semiconductor chip, for providing a wavelength selective optical feedback for tuning the lasing wavelength.

42 . The tunable semiconductor laser of claim 41 , wherein a pitch parameter is between 75% and 125% of the lasing wavelength.

43 . The tunable semiconductor laser of claim 41 , wherein the semiconductor chip includes a Mach Zehnder modulator, a semiconductor optical amplifier, a grating, a laser gain section, and a phase section.

44 . The tunable semiconductor laser of claim 41 , wherein the semiconductor chip includes two facets and each facet is coated with an anti-reflection coating and a translucent coating.

Assignees

• Lumentum Operations Llc

Inventors

• Miller John Michael
• Jin Wenlin

Classifications

• G02B26/0841

  the reflecting element being moved or deformed by electrostatic means · CPC title

• G02B26/0833

  the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD (G02B26/0825 takes precedence; micromechanical devices in general B81B) · CPC title

• G02B26/0808 Primary

  by means of one or more diffracting elements · CPC title

• G02B5/18

  Diffraction gratings {(holographic optical elements G02B5/32, G03H; integrally combined with optical fibres G02B6/02057; for coupling light guides G02B6/34; integrally combined with optical integrated light guides G02B6/12; grating systems G02B27/44)} · CPC title

• G02B5/1861 Primary

  Reflection gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials (G02B5/1809, G02B5/1828, G02B5/1833, G02B5/1838 and G02B5/1847 take precedence) · CPC title