Direct-coupled multimode WDM optical data links with monolithically-integrated multiple-channel VCSEL and photodetector

• US 6,195,485 B1
• Filed: 10/22/1999
• Issued: 02/27/2001
• Est. Priority Date: 10/26/1998
• Status: Expired due to Term

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Hu, Syn-Yem, Coldren, Larry A.
• Primary Examiner(s): Ullah, Akm E.
• Application Number:
  US09/425,542
• Time in Patent Office: 494 Days
• Field of Search: 385/14-15, 385/24, 385/33, 385/37, 385/4, 385/10, 372/45, 372/50, 372/96, 372/36, 438/47, 438/29, 438/46
• US Class Current: 385/49
• CPC Class Codes: G02B 6/4202 for coupling an active element with fibres without intermediate optical elements, e.g. fibres with plane ends, fibres with shaped ends, bundles
• CPC Class Codes: G02B 6/4239 Adhesive bonding; Encapsulation with polymer material
• CPC Class Codes: G02B 6/4246 Bidirectionally operating package structures
• CPC Class Codes: G02B 6/4249 comprising arrays of active devices and fibres
• CPC Class Codes: H01S 5/02251 using optical fibres
• CPC Class Codes: H01S 5/18358 containing spacer layers to adjust the phase of the light wave in the cavity
• CPC Class Codes: H01S 5/4087 emitting more than one wavelength
• CPC Class Codes: H01S 5/423 having a vertical cavity

Abstract

A low cost, high speed WDM optical link which employs a circular array of VCSEL emitters directly coupled to a multi-mode fiber through which multiple simultaneously optical transmissions are sent to an optical detector comprising a circular array of RCPD detectors receiving the multiple simultaneous transmissions. The emitters and detectors within each array are fabricated with a double-absorber design which avoids position sensitivity related to the cavity standing wave and eliminates the need for in-situ cavity-mode adjustment. In addition, a coupled-cavity structure is presented to achieve passbands with flat tops and steep sides to approach the ideal square-shape photoresponse and to ensure proper channel alignment.

Claims

1. An optical data link, comprising:

(a) an array of vertical cavity surface emitting laser (VCSEL) emitters, operating at predetermined wavelengths, fabricated within a substrate configured for simultaneous direct coupling of the VCSEL array to an optical fiber;

(b) an optical fiber capable of communicating multiple optical wavelengths; and

(c) an array of optical detectors coupled to a terminating end of said optical fiber, wherein a set of reception wavelengths generally match the wavelengths transmitted by the optical VCSEL emitters such that multiple optical wavelengths can be simultaneously communicated at high-speed from the emitters to the detectors across the optical fiber.

2. An optical data link as recited in claim 1, wherein said VCSEL emitters are selected from the group consisting of bottom-emitting VCSEL emitters and top-emitting VCSEL emitters.

3. An optical data link as recited in claim 1, wherein said optical detectors comprise resonant cavity photodetectors having a double-absorber design with a field²-absorption integral that is independent of absorber position relative to the cavity standing wave, and wherein each said optical detector includes two thin quantum well absorption layers spaced apart at an approximate quarter-wavelength spacing.

4. An optical data link as recited in claim 1, wherein the VCSEL array is configured as a circular array of VCSEL emitters.

5. An optical data link as recited in claim 1, wherein the VCSEL array is configured with “

pie-shaped”

optical elements arranged in a circle.

6. An optical data link as recited in claim 1, wherein said optical fiber is coupled to said VCSEL array by the use of a self-aligned Burrus-type fiber-coupling configuration.

7. An optical data link as recited in claim 1, wherein said array of optical detectors comprises a resonant-cavity photodetector array directly coupled to the optical fiber.

8. An optical data link as recited in claim 1, wherein the VCSEL emitters are wavelength adjustable.

9. An optical data link comprising:

(a) an array of vertical cavity surface emitting laser (VCSEL) emitters configured for direct coupling to an optical fiber, wherein the VCSEL emitters operate at various predetermined emission wavelengths;

(b) an array of resonant cavity photodetector (RCPD) detectors configured for direct coupling to an optical fiber, said RCPD detectors having reception wavelengths generally corresponding to the emission wavelengths of the VCSEL emitters;

(c) an optical fiber directly coupled between the VCSEL emitter array and RCPD array, wherein multiple optical wavelengths can be simultaneously communicated at high-speed from the emitters to the detectors across the optical fiber.

10. An optical data link, as recited in claim 9, wherein the VCSEL emitters are wavelength adjustable.

11. A method of creating a multiple band optical link, comprising the steps of:

(a) fabricating a vertical cavity surface emitting laser (VCSEL) emitter array on a substrate, wherein the VCSEL emitters are arranged in a circular pattern on the substrate and each VCSEL emitter is set for a different emissive wavelength;

(b) configuring the substrate with the VCSEL emitters for Burrus-type selfaligning fiber-coupling;

(c) fabricating a resonant-cavity photodetector (RCPD) detector array on a substrate, wherein the RCPD detectors are arranged in a circular pattern on the substrate and each RCPD is set to detect a different emissive wavelength;

(d) configuring the substrate of the RCPD detector array for Burrus-type self-aligning fiber-coupling;

(e) bonding the substrates of the VCSEL emitter array and RCPD detector array onto electronic circuits configured to receive the respective emitter and detector arrays; and

(f) bonding a multi-mode fiber between the VCSEL emitter and RCPD detector, wherein said bonding is created by means of Burrus-style coupling.