Polarization Independent Reflective Modulator

Patent metadata

Field	Value
Publication number	US-2016337041-A1
Application number	US-201615136396-A
Country	US
Kind code	A1
Filing date	Apr 22, 2016
Priority date	May 15, 2015
Publication date	Nov 17, 2016
Grant date	—

Abstract

An apparatus comprising an optical input configured to receive an optical carrier, an polarization beam splitter configured to forward a first polarized component of the optical carrier along a first light path, and forward a second polarized component of the optical carrier along a second light path, wherein the first polarized component comprises a first polarization that is perpendicular to a second polarization of the second polarized component upon exiting the optical splitter, and an optical modulator coupled to the first light path and the second light path, the modulator configured to modulate the first polarized component of the optical carrier and the second polarized component of the optical carrier.

First claim

What is claimed is:

1 . An apparatus comprising:
an optical input configured to receive an optical carrier; a polarization beam splitter optically coupled to the optical input, a first light path, and a second light path, wherein the polarization beam splitter is configured to:
forward a first polarized component of the optical carrier along the first light path; and
forward a second polarized component of the optical carrier along the second light path, wherein the first polarized component comprises a first polarization that is perpendicular to a second polarization of the second polarized component upon exiting the polarization beam splitter; and
an optical modulator with a proximate end coupled to the first light path and a distal end coupled to the second light path, wherein the optical modulator is configured to modulate the first polarized component of the optical carrier and the second polarized component of the optical carrier.

2 . The apparatus of claim 1 , wherein modulating the first polarized component and the second polarized component comprises:
receiving the first polarized component from the first light path via the proximate end; receiving the second polarized component from the second light path via the distal end; modulating the first polarized component to generate a first modulated component; modulating the second polarized component to generate a second modulated component; outputting the first modulated component to the second light path via the distal end; and outputting the second modulated component to the first light path via the proximate end.

3 . The apparatus of claim 2 , wherein the polarization beam splitter is further configured to:
combine the first modulated component and the second modulated component into a combined modulated signal; and forward the combined modulated signal via the optical input in an opposite direction to a direction of the optical carrier.

4 . The apparatus of claim 3 , wherein the first polarized component and the second polarized component are substantially simultaneously modulated by a common electrical signal.

5 . The apparatus of claim 1 , further comprising a polarization rotator positioned along the second light path and configured to rotate the second polarization of the second polarized component to be parallel to the first polarization of the first polarized component.

6 . The apparatus of claim 5 , wherein the polarization rotator comprises a Faraday rotator or mode convertor.

7 . The apparatus of claim 5 , wherein the first light path and the second light path comprise a silicon waveguide, and wherein the polarization beam splitter and the polarization rotator are comprised in a silicon based polarization splitter rotator (PSR).

8 . The apparatus of claim 1 , wherein the optical modulator comprises a silicon waveguide based modulator, a single lumped modulator, a Mach-Zehnder modulator, an Inphase Quadrature (IQ) modulator, a micro-ring resonator based modulator, an electro-absorption modulator, or combinations thereof.

9 . The apparatus of claim 5 , wherein the polarization beam splitter comprises a Yttrium Orthovanadate (YVO4) birefringence crystal, and wherein the polarization rotator comprises a glass wedge and a half wave plate.

10 . The apparatus of claim 5 , wherein the polarization beam splitter and the polarization rotator are comprised in a two-dimensional grating coupler.

11 . An apparatus comprising:
an optical port configured to receive an optical carrier from a remote device; a polarization independent reflective modulator (PIRM) coupled to the optical port, wherein the PIRM is configured to:
receive the optical carrier from the optical port;
split the optical carrier into a first polarized component and a second polarized component such that a first polarization of the first polarized component is perpendicular to a second polarization of the second polarized component;
modulate an electrical signal onto the first polarized component and the second polarized component; and
combine the modulated first polarized component and the modulated second polarized component to create a combined modulated signal.

12 . The apparatus of claim 11 , wherein the PIRM is further configured to rotate the second polarization to be parallel to the first polarization and substantially simultaneously modulate the first polarized component and the second polarized component.

13 . The apparatus of claim 11 , wherein the apparatus comprises a plurality of PIRMs, wherein the apparatus further comprises a wavelength division multiplexer coupled to the optical port and the PIRMs, wherein the optical carriers comprises a plurality of wavelengths, and wherein the wavelength division multiplexer is configured to distribute each wavelength to a corresponding PIRM to support wavelength division multiplexing.

14 . The apparatus of claim 11 , wherein the apparatus is a server positioned in a data center, wherein the remote device is an end-of-row (EOR) switch, and wherein the PIRM is further configured to transmit the combined modulated signal to the EOR switch via the optical port.

15 . The apparatus of claim 11 , wherein the apparatus further comprises a downstream optical port, and wherein the PIRM is further configured to transmit the combined modulated signal to a downstream device via the downstream optical port.

16 . The apparatus of claim 11 , wherein the apparatus is a remote radio unit (RRU), wherein the remote device is a baseband unit (BBU), wherein the apparatus comprises a wireless transceiver, and wherein the electrical signal is received from a mobile network via the wireless transceiver for modulation and re-transmission to the BBU via the optical port.

17 . A method comprising:
receiving an optical carrier from a remote device via an optical input port; splitting the optical carrier into a first polarized component and a second polarized component such that a first polarization of the first polarized component is perpendicular to a second polarization of the second polarized component; modulating an electrical signal onto the first polarized component and the second polarized component; and combining the modulated first polarized component and the modulated second polarized component to create a combined modulated signal.

18 . The method of claim 17 , further comprising transmitting the combined modulated signal via the optical input port over a common optical fiber with the optical carrier.

19 . The method of claim 18 , further comprising rotating the second polarization of the second polarized component to be parallel to the first polarization of the first polarized component prior to modulation.

20 . The method of claim 19 , wherein the electrical signal is substantially simultaneously modulated onto the first polarized component and the second polarized component by employing a single modulator, and wherein the first polarized component and the second polarized component traverse the single modulator in opposite directions.

Assignees

• Futurewei Technologies Inc

Inventors

• Wen Yangjing
• Zhu Fei
• Bai Yu Sheng

Classifications

• H04J14/0212

  using optical switches or wavelength selective switches [WSS] · CPC title

• H04Q11/0067

  Provisions for optical access or distribution networks, e.g. Gigabit Ethernet Passive Optical Network (GE-PON), ATM-based Passive Optical Network (A-PON), PON-Ring · CPC title

• H04J14/06 Primary

  Polarisation multiplex systems · CPC title

• H04B10/532 Primary

  Polarisation modulation · CPC title

• H04Q2011/0073

  Provisions for forwarding or routing, e.g. lookup tables · CPC title