Highly transmissive sensor for detecting the position of an optical signal

• US 6,429,417 B1
• Filed: 11/08/2000
• Issued: 08/06/2002
• Est. Priority Date: 11/08/2000
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Chua, Christopher L., Peeters, Eric, Street, Robert A., Lu, Jeng Ping, Rosa, Michel A.
• Primary Examiner(s): Allen, Stephone
• Assistant Examiner(s): HILL, BRADFORD K
• Application Number:
  US09/708,808
• Time in Patent Office: 636 Days
• Field of Search: 250/208.1, 250/214.1, 257/52, 257/53, 257/464
• US Class Current: 250/214.1
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 6/3518 the reflective optical element being an intrinsic part of a MEMS device, i.e. fabricated together with the MEMS device MEMS devices in general B81B; manufacture of MEM devices in general B81C; micromechanical devices controlling the direction of light G02B26/0833
• CPC Class Codes: G02B 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/356 in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001
• CPC Class Codes: G02B 6/3588 of the processed beams, i.e. controlling during switching of orientation, alignment, or beam propagation properties such as intensity, size or shape
• CPC Class Codes: H01L 31/1055 the devices comprising amorphous materials of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/108 the potential barrier being of the Schottky type
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/003 using switches based on microelectro-mechanical systems [MEMS]
• CPC Class Codes: H04Q 2011/0039 Electrical control

Abstract

A system to align optical components is described. The system utilizes a highly transmissive sensor positioned in the optical path of an optical signal to determine the precise position of the optical signal. A feedback loop uses output from the highly transmissive sensor to readjust elements that maintains the optical signal in a desired position. The current system is particularly suitable for use in an optical cross switch.

Claims

1. A highly transmissive sensor to determine the position of an optical beam comprising:

a highly transmissive sensor layer;

a highly transmissive conductor plate positioned over the sensor layer; and

a highly transmissive substrate supporting the highly transmissive sensor layer and highly transmissive conductor plate, the highly transmissive sensor layer to determine the position of an optical beam passing through the highly transmissive sensor.

2. The highly transmissive sensor of claim 1 wherein:

the highly transmissive sensor is segmented such that the width of a segment is approximately equal to the width of the optical beam.

3. The highly transmissive sensor of claim 1 further comprising:

a segmented second highly transmissive sensor layer superimposed over the first highly transmissive sensor layer, the first highly transmissive sensor layer also segmented to form a first segmented highly transmissive sensor layer such that the overlap region between the first segmented highly transmissive sensor layer and the second segmented highly transmissive layer forms a series of approximately rectangular overlap regions.

4. The highly transmissive sensor of claim 1 wherein the highly transmissive sensor layer is a thin film semiconductor.

5. The highly transmissive sensor of claim 4 wherein the thin film semiconductor includes one of a group consisting of amorphous silicon, amorphous silicon-germanium alloy, an organic photoconductor or polycrystalline silicon.

6. The highly transmissive sensor of claim 1 wherein the highly transmissive sensor layer is divided into an array of pixel detectors.

7. The highly transmissive sensor of claim 6 wherein the sensor includes a plurality of transistors that allows active matrix addressing of each individual pixel detectors in the highly transmissive sensor.

8. The highly transmissive sensor of claim 7 wherein each pixel detector is coupled to a corresponding transistor in the plurality of transistor with a highly transmissive conducting wire.

9. The highly transmissive sensor of claim 1 wherein the highly transmissive sensor includes an amorphous silicon p-i-n diode.

10. The highly transmissive sensor of claim 1 wherein the conducting plate is formed form ITO.

11. A highly transmissive sensor to detect the position of an optical signal comprising:

a highly transmissive substrate;

a highly transmissive conductor plate;

a first highly transmissive light detecting layer deposited over the highly transmissive substrate,

a second highly transmissive light detecting layer, the second light detecting layer separated from the first highly transmissive light detecting layer by the highly transmissive conductor plate, the highly transmissive conductor plate to bias the first light detecting layer and the second light detecting layer to detect the position of an optical signal passing through the first light detecting layer, the second light detecting layer and the highly transmissive substrate, the combination of the highly transmissive substrate and the highly transmissive light detecting layer attenuating the intensity of the optical signal by less than 10 percent.

12. The highly transmissive sensor of claim 11 further comprising:

a second conductor plate positioned on a second side of the first highly transmissive light detecting sensor layer, the second conductor to collect carriers generated by the optical signal passing through the light detecting layer and the highly transmissive substrate.

13. The highly transmissive sensor of claim 12 wherein the first and the second conductor plates are formed from indium tin oxide.

14. The highly transmissive sensor of claim 12 wherein the second conductor plate transports carriers to a set of parallel electrodes coupled to the second conductor.

15. The highly transmissive sensor of claim 12 further comprising:

a third conductor plate positioned on a second side of the second highly transmissive light detecting sensor layer, the third conductor plate to carry current generated by the optical signal in the second highly transmissive light detecting layer.

16. The highly transmissive sensor of claim 15 further comprising:

a first set of parallel electrodes coupled to the second conductor plate; and

a second set of parallel electrodes coupled to the third conductor plate, the second set of parallel electrodes approximately perpendicularly oriented to the first set of parallel electrodes.

17. The highly transmissive sensor of claim 15 wherein the second conducting plate has a thickness and the optical signal has a frequency with a corresponding wavelength, the thickness equal to approximately one quarter of the wavelength.

18. The highly transmissive sensor of claim 11 wherein the light detecting layer includes amorphous silicon.