WO2005012972A1 - Emetteur recepteur optique a base de circuit integre photonique - Google Patents

Emetteur recepteur optique a base de circuit integre photonique Download PDF

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Publication number
WO2005012972A1
WO2005012972A1 PCT/GB2004/003320 GB2004003320W WO2005012972A1 WO 2005012972 A1 WO2005012972 A1 WO 2005012972A1 GB 2004003320 W GB2004003320 W GB 2004003320W WO 2005012972 A1 WO2005012972 A1 WO 2005012972A1
Authority
WO
WIPO (PCT)
Prior art keywords
optical
waveband
receiver
optical transceiver
transmitter
Prior art date
Application number
PCT/GB2004/003320
Other languages
English (en)
Inventor
Yee Loy Lam
Yuen Chuen Chan
Keisuke Kojima
Original Assignee
Denselight Semiconductors Pte Ltd
Finnie, Peter, John
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Denselight Semiconductors Pte Ltd, Finnie, Peter, John filed Critical Denselight Semiconductors Pte Ltd
Publication of WO2005012972A1 publication Critical patent/WO2005012972A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/40—Transceivers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/122—Basic optical elements, e.g. light-guiding paths
    • G02B6/124—Geodesic lenses or integrated gratings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/122—Basic optical elements, e.g. light-guiding paths
    • G02B6/125—Bends, branchings or intersections
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4246—Bidirectionally operating package structures
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/25—Arrangements specific to fibre transmission
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details

Definitions

  • the present invention relates to a monolithic optical transceiver with improved isolation, and in particular to a transceiver with multiple filter components in a photonic integrated circuit.
  • PON Passive Optical Network
  • a laser light source, photodiodes, and the wavelength division multiplexing (WDM) filters need to be integrated into one compact package, while meeting the performance specifications defined in the international standards.
  • the mean transmitter output power from the laser source is around +2dBm, while the receiver sensitivity should be at least -30dBm.
  • the receiver sensitivity should be at least -30dBm.
  • the transceiver 20 comprises a laser diode packaged in a transistor outline (TO) can 21 with, a TO-packaged photodiode 22, a WDM filter (beam splitter 23), and a glass lens 24, all assembled together in a single package coupled to an optical fibre 25.
  • the WDM filter 23 separates the outgoing light from the incoming light, based on the difference of wavelengths.
  • the 1.3 ⁇ m transmission light is generated by a laser diode 32, coupled into an optical waveguide 33 and then passes through a WDM filter 34 before being coupled into a single mode optical fibre 35, which is overlaid with glass 36 and has a ferrule 37 for assembly.
  • the 1.55 ⁇ m light to be received exits the optical fibre 35, is coupled into the optical waveguide 33 and then reflected by the WDM filter 34 before being detected by the 1.55 ⁇ m photodiode 38, and the resulting signal amplified by a pre- amplifier 39.
  • optical coupling between the optical waveguide 33 and the optical fibre 35 or between the laser diode 32 and the optical waveguide 33 is not very high.
  • a further prior art system 40 utilizes even more compact monolithic integration, whereby a laser diode 41 having a grating rear reflector, a wavelength-selective absorbing section 42, and a photodiode 43, are monolithically integrated on the same Indium Phosphide (InP) substrate 44, and the whole assembly, including a preamplifier 45, is packaged into a small module 46, as shown in Figure 4(b).
  • InP Indium Phosphide
  • the 1.3 ⁇ m laser light is emitted directly from the laser facet, while the light exiting the laser section 41 in the other direction, via the grating reflector, is partially reflected by the grating and partially absorbed by the absorbing section 42, which comprises the same material as the laser diode 41.
  • the incoming 1.55 ⁇ m light is coupled into the laser first 41, passes through the absorber 42, and finally fed into the photodiode 43.
  • the absorbing section does not absorb very much of the 1.55 ⁇ m light.
  • a monolithic integrated optical transceiver comprises: an optical transmitter for generating an optical output signal at a first waveband in dependence on an electrical driving signal; an optical receiver for detecting an optical input signal at a second waveband, the optical receiver generating an electrical received signal in dependence on the optical input signal; and, a photonic integrated circuit optically coupled to the optical transmitter and the optical receiver, the integrated circuit comprising: an optical port for coupling optical output signals at the first waveband out of the optical transceiver and coupling optical input signals at the second waveband into the optical transceiver; and, a plurality of optically coupled filtering components disposed between the optical transmitter and the optical receiver, said components discriminating between the first waveband and the second waveband, wherein, in use, the optical receiver is substantially isolated from optical signals at the first waveband by the plurality of filtering components.
  • a monolithic integrated transceiver may be fabricated using photonic integrated circuit technology, in which the necessary high levels of optical isolation (and, indirectly, electrical isolation) between transmitter and receiver is achieved by a cascade of suitably designed filter components that discriminate between the wavelengths of the incoming and outgoing optical signals.
  • the filter chain may comprise a first stage WDM filter followed by a second stage filtering to isolate the receiver from light at the transmitter wavelength.
  • the second stage filter comprises a pair of wavelength-selective vertically coupled waveguides, or a waveguide grating.
  • the filter chain may comprise waveguide-based wavelength selective device with an embedded grating for additional wavelength discrimination and isolation.
  • the device comprises a directional coupler, or a Mach- Zehnder interferometer. It is preferred that any grating is reflective at the first waveband and transmissive at the second waveband.
  • the first waveband will typically lie within the wavelength range 1260- 1360nm and the second waveband within the wavelength range 1480-1600nm.
  • the whole transceiver will be formed on a common Indium Phosphide substrate, as this facilitates monolithic integration of a laser diode transmitter, photodiode receiver and intervening filter components.
  • a method for improving isolation in an optical transceiver between an optical transmitter generating an optical output signal at a first waveband and an optical receiver for detecting an optical input signal at a second waveband comprises the step of: disposing a photonic integrated circuit comprising a plurality of optically coupled filter components between the transmitter and the receiver, said filter components discriminating between the first waveband and the second waveband so as to substantially prevent optical signals at the first waveband from reaching the receiver.
  • Figure 1 illustrates bi-directional communication between the central office (OLT) and a customer premises (ONU);
  • Figure 2 shows a known transceiver system using bulk optics;
  • Figure 3 shows a known transceiver system utilizing hybrid integration on a Si optical bench;
  • Figure 4A shows a known transceiver system utilizing monolithic integration of a laser diode, an absorbing section and a photodiode;
  • Figure 4B shows a module incorporating the monolithically integrated chip shown in Fig 4A;
  • Figure 5 shows a schematic block diagram of an optical transceiver according to the present invention;
  • Figure 6 shows a side view of vertical coupled waveguides for enhanced optical isolation in a transceiver according to a first embodiment of the present invention;
  • Figure 7 shows a top view of a grating-patterned waveguide for enhanced optical isolation in a transceiver according to a second embodiment of the present invention;
  • Figure 8 shows a top view of
  • the present invention provides a new design for an optical transceiver, which achieves good electrical and optical isolation performance in a compact module, such that it could meet the requirements of PON with speeds of 1Gbps and above.
  • the description is focused on the optical transceiver at the customer premise, the ONU.
  • the same concept could equally be applied to that at the central office, at the OLT.
  • electrical and optical isolation of the two wavelengths of light propagating in an optical transceiver typically the 1310nm and 1490nm bands, is critical, especially at the receiver photodiode (PD).
  • the receiver PD should only be sensitive to the downstream 1490nm light, but not the 1310nm upstream light.
  • FIG. 5 shows a simple block schematic diagram of an optical transceiver 50, which employs this approach.
  • an optical transmitter 52 laser source with modulation means
  • an optical receiver 53 photodiode
  • the optical port is typically coupled to an optical communications fibre, which provides the long distance propagation medium for the transmitter and receiver signals.
  • the whole transceiver may be fabricated so as to form a single photonic integrated circuit, using planar waveguide technology. Individual components are coupled together by passive waveguides, and the components themselves may comprise active or passive waveguides, with appropriate structures and/or electrical driving signals to perform the required function.
  • filter component 55 provides the primary wavelength discrimination that routes light at wavelength ⁇ out from the transmitter to the optical port, whilst exhibiting transparency to light at wavelength ⁇ * ⁇ propagating from the optical port towards the receiver.
  • filter component 54 provides additional isolation, allowing light at wavelength ⁇ in to reach the receiver whilst preventing unwanted residual light at wavelength ⁇ out from doing so.
  • various configurations are possible for the filtering operation, including multiple cascaded optical filters.
  • one filter may be embedded within another filter, to provide the necessary level of discrimination and isolation.
  • a WDM filter provides a good means for separating the incoming and outgoing optical signals (cf. component 55 in Figure 5).
  • the passive output port waveguide from the WDM filter should ideally guide only the incoming 1490nm light into the receiver photodiode (PD).
  • a second stage isolation filter (cf. component 54 in Figure 5), located prior to the receiver PD, supplements the first stage WDM filter. It is assumed that the first stage WDM filter has largely performed the role of separating out the 1490nm and 1310nm light, and therefore we focus on enhancing the optical isolation by introducing a second stage isolation filtering before the receiver PD.
  • a first embodiment of this second stage filtering is shown in Figure 6.
  • the second stage wavelength selectivity is introduced through vertical coupling of two proximate waveguides 60, to improve upon the imperfect filtering operation of the first stage WDM filter.
  • the coupling length between the waveguide 61 and waveguide 62 is designed so that, of the light propagating from the WDM filter and into waveguide 62, only the 1490nm signal light is coupled into waveguide 61, which subsequently guides the 1490nm light into the receiver PD 63 for detection.
  • the unwanted residual 1310nm light is guided away in waveguide 62.
  • the optical isolation provided for by this vertical coupling scheme is around 20dB, and together with that realized at the first stage WDM filter, a net effective optical isolation of at least 40dB could be achieved.
  • a second embodiment of this second stage filtering is shown in Figure 7. Again, the same assumption is made of a first stage WDM filter in this arrangement of the optical transceiver.
  • second stage filtering 70 is achieved by introducing wavelength selectivity in the waveguide 71 leading to the receiver PD 73 by fabricating gratings 72 in the waveguide.
  • the diffractive gratings 72 are designed to reflect only the 1310nm and to allow the 1490nm light to be transmitted through to the receiver PD 73.
  • the optical isolation provided for by this grating scheme is also around 20dB, and together with the contribution by the first stage WDM filter, an overall effective optical isolation of at least 40dB could be achieved.
  • the gratings could be chirped to ensure that it reflects the whole 1310nm band of light, from 1260nm to 1360nm.
  • Figure 8 shows a third embodiment of an optical transceiver 80 according the present invention.
  • first- stage filtering is provided by a directional coupler 81, comprising two waveguides 82 and 83 located between the transmitter 84 and receiver 85, whilst a grating 86 embedded inside the directional coupler provides the "second-stage” filtering.
  • the directional coupler is designed such that its coupling length allows the 1490nm light to pass straight through as the bar state. As illustrated in Figure 8, the incoming 1490nm signal light enters into waveguide 82 via port P1 and leaves waveguide 82 of the directional coupler via port P3 and is guided towards the receiver PD 85.
  • chirped diffractive gratings 86 are introduced to waveguide 82 of the directional coupler to provide broad reflection to the 1310nm band of light, while offering good transmission to the 1490nm light.
  • Light output from the 1310nm FP laser diode 84 is launched into waveguide 83 via port P2. Some of this light is coupled across to the waveguide 82, but the wavelength selective gratings 86 reflect it towards the output port P1, where it is coupled into an optical fibre.
  • any stray 1310nm light propagating back from the optical fibre towards the receiver PD 85 will either be channeled towards waveguide 83 and on to port P4 or else be reflected back to port P1.
  • FIG. 9 shows a fourth embodiment of an optical transceiver 90 according the present invention.
  • first-stage filtering is provided by a Mach-Zehnder interferometer (MZI) 91, comprising two waveguides 92 and 93, and two beam splitters/combiners 94 and 95.
  • MZI 91 is located between the transmitter 96 and receiver 97 and a grating 98 embedded inside the MZI provides the second-stage filtering.
  • the MZI 91 can be implemented in planar waveguide form as part of the PIC, with broad area multimode interferometers (MMIs) providing the necessary beam splitters/combiners 94 and 95.
  • MMIs broad area multimode interferometers
  • the MZI is designed such that it couples the 1490nm light from port P1 and waveguide W1 to waveguide W3 and port P3, and finally into the receiver PD 97.
  • Chirped gratings 98 are patterned into waveguides 92 and 93 immediately after the MMI coupler 94 to provide for broad reflection of the 1310nm band light but good transmission for the 1490nm band light.
  • the light output from the 1310nm FP laser diode is coupled into port P2 of the MZI and then into waveguides 92 and 93 after traversing the MMI coupler 94.
  • the existence of the diffractive gratings 98 means that the 1310nm light will be reflected back towards the MMI coupler 94, and then channeled towards the upper waveguide W1 and into port P1 for launching into the optical fibre.
  • stray 1310nm light coming back from the optical fibre will also be reflected back and not propagate to the receiver PD 97.
  • the net optical isolation realizable from this grating-integrated Mach-Zehnder interferometer configuration will be at least 40dB, ensuring very low optical cross talk for the transceiver 90.
  • All of the embodiments described above realize a compact monolithic integrated optical transceiver, which exhibits the high level of optical (and electrical) isolation demanded by today's rigorous international standards. Accurate alignment of all constituent components is assured during fabrication of the photonic integrated circuit, negating the alignment problems associated with discrete components.
  • the cascaded or embedded filter components may be optimized individually and also in terms of the composite peformance, according to the specific application of the transceiver.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Electromagnetism (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optical Integrated Circuits (AREA)

Abstract

La présente invention concerne un émetteur récepteur optique intégré monolithique possédant un seul port pour les signaux optiques d'entrée et de sortie, cet émetteur récepteur comprenant un émetteur optique et un récepteur optique avec un circuit intégré photonique intermédiaire qui comprend une pluralité d'éléments de filtrage optique, lesquels font la distinction entre les longueurs d'onde des signaux optiques entrants et sortants et isole ainsi à haut niveau le récepteur des signaux générés par l'émetteur.
PCT/GB2004/003320 2003-07-30 2004-07-30 Emetteur recepteur optique a base de circuit integre photonique WO2005012972A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0317859A GB0317859D0 (en) 2003-07-30 2003-07-30 Photonic integrated circuit based optical transceiver
GB0317859.7 2003-07-30

Publications (1)

Publication Number Publication Date
WO2005012972A1 true WO2005012972A1 (fr) 2005-02-10

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WO (1) WO2005012972A1 (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7877016B2 (en) 2004-10-28 2011-01-25 Infinera Corporation Photonic integrated circuit (PIC) transceivers for an optical line terminal (OLT) and an optical network unit (ONU) in passive optical networks (PONs)
FR2965939A1 (fr) * 2010-10-12 2012-04-13 Commissariat Energie Atomique Duplexeur optique nanophotonique
CN101666893B (zh) * 2009-06-25 2012-05-30 浙江大学 一种基于蚀刻衍射光栅的单片集成单纤多向收发器
CN104638338A (zh) * 2015-02-16 2015-05-20 成都赛纳赛德科技有限公司 隔离段宽度变化定向耦合器
CN104638333A (zh) * 2015-02-16 2015-05-20 成都赛纳赛德科技有限公司 耦合段宽度变化定向耦合器
EP2614604A4 (fr) * 2010-09-06 2016-08-31 Huawei Tech Co Ltd Diminution de diaphonie dans un dispositif optoélectronique bidirectionnel
CN108732685A (zh) * 2017-04-25 2018-11-02 中兴光电子技术有限公司 一种基于亚波长光栅的定向耦合器

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19548547A1 (de) * 1995-12-23 1997-06-26 Hertz Inst Heinrich Sende- und Empfangseinheit für die Datenübertragung durch Lichtwellen in Lichtwellenleitern
US20030095737A1 (en) * 2001-10-09 2003-05-22 Welch David F. Transmitter photonic integrated circuits (TxPIC) and optical transport networks employing TxPICs

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19548547A1 (de) * 1995-12-23 1997-06-26 Hertz Inst Heinrich Sende- und Empfangseinheit für die Datenübertragung durch Lichtwellen in Lichtwellenleitern
US20030095737A1 (en) * 2001-10-09 2003-05-22 Welch David F. Transmitter photonic integrated circuits (TxPIC) and optical transport networks employing TxPICs

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7877016B2 (en) 2004-10-28 2011-01-25 Infinera Corporation Photonic integrated circuit (PIC) transceivers for an optical line terminal (OLT) and an optical network unit (ONU) in passive optical networks (PONs)
CN101666893B (zh) * 2009-06-25 2012-05-30 浙江大学 一种基于蚀刻衍射光栅的单片集成单纤多向收发器
EP2614604A4 (fr) * 2010-09-06 2016-08-31 Huawei Tech Co Ltd Diminution de diaphonie dans un dispositif optoélectronique bidirectionnel
FR2965939A1 (fr) * 2010-10-12 2012-04-13 Commissariat Energie Atomique Duplexeur optique nanophotonique
EP2442164A1 (fr) * 2010-10-12 2012-04-18 Commissariat à l'Énergie Atomique et aux Énergies Alternatives Duplexeur optique nanophotonique
US8693816B2 (en) 2010-10-12 2014-04-08 Commissariat A L'energie Atomique Et Aux Energies Alternatives Nanophotonic optical duplexer
CN104638338A (zh) * 2015-02-16 2015-05-20 成都赛纳赛德科技有限公司 隔离段宽度变化定向耦合器
CN104638333A (zh) * 2015-02-16 2015-05-20 成都赛纳赛德科技有限公司 耦合段宽度变化定向耦合器
CN108732685A (zh) * 2017-04-25 2018-11-02 中兴光电子技术有限公司 一种基于亚波长光栅的定向耦合器

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