WO2016192790A1 - Émetteur optique pour des communication par fibres optiques - Google Patents

Émetteur optique pour des communication par fibres optiques Download PDF

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Publication number
WO2016192790A1
WO2016192790A1 PCT/EP2015/062427 EP2015062427W WO2016192790A1 WO 2016192790 A1 WO2016192790 A1 WO 2016192790A1 EP 2015062427 W EP2015062427 W EP 2015062427W WO 2016192790 A1 WO2016192790 A1 WO 2016192790A1
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WO
WIPO (PCT)
Prior art keywords
optical
mirror
optical transmitter
phase
cavity
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Application number
PCT/EP2015/062427
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English (en)
Inventor
Silvano Donati
Valerio ANNOVAZZI LODI
Giuseppe Martini
Original Assignee
Universita' Degli Studi Di Pavia
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Publication date
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Priority to PCT/EP2015/062427 priority Critical patent/WO2016192790A1/fr
Publication of WO2016192790A1 publication Critical patent/WO2016192790A1/fr

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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
    • H04B10/50—Transmitters
    • H04B10/501—Structural aspects
    • H04B10/503—Laser transmitters
    • H04B10/504—Laser transmitters using direct modulation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
    • H01S5/14—External cavity lasers
    • H01S5/141—External cavity lasers using a wavelength selective device, e.g. a grating or etalon
    • H01S5/142—External cavity lasers using a wavelength selective device, e.g. a grating or etalon which comprises an additional resonator
    • 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
    • H04B10/50—Transmitters
    • H04B10/516—Details of coding or modulation
    • H04B10/5162—Return-to-zero modulation schemes
    • 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
    • H04B10/50—Transmitters
    • H04B10/516—Details of coding or modulation
    • H04B10/548—Phase or frequency modulation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/106—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/02—Structural details or components not essential to laser action
    • H01S5/022—Mountings; Housings
    • H01S5/023—Mount members, e.g. sub-mount members
    • H01S5/02325—Mechanically integrated components on mount members or optical micro-benches

Definitions

  • the present invention relates to the field of fiber optic communications.
  • the present invention relates to an optical transmitter for a network apparatus of a fiber optic communication network operating at high data rates (e.g. 100 Gbit/s and higher).
  • phase-shift-keying relies on changing the phase of an optical carrier generated by a coherent optical source, such as a laser, to encode digital data.
  • the quadrature phase-shift-keying (QPSK) scheme employs four transmission symbols on a constellation diagram equispaced around a circle.
  • the dual-polarization QPSK (DP- QPSK) scheme involves the polarization multiplexing of two QPSK signals.
  • Other modulation schemes are also used such as multi-level (e.g. 8-PSK, 16 PSK) modulation schemes.
  • phase-shift keying is achieved by employing a continuous wave (CW) laser and a phase modulator external with respect to the laser cavity.
  • the optical wave generated by the laser is coupled to a phase modulator to produce a PSK modulated signal at the desired bit rate.
  • phase modulators for the 1300 nm or 1550 nm windows are based on the linear electro- optic effect and include lithium niobate (LiNbOs) phase modulators or semiconductor based (e.g. indium phosphide, InP) phase modulators.
  • these modulators comprise a planar waveguide into which the optical signal is modulated by applying a voltage across the waveguide, the voltage inducing a variation of the refractive index due to electric field related effects, such as the known Pockels effect.
  • phase modulators may exploit other effects, like the quantum confined Stark effect (QCSE) in indium phosphide (InP) multi quantum well (MQW) modulators.
  • QCSE quantum confined Stark effect
  • InP indium phosphide
  • MQW multi quantum well
  • phase modulators such as those based on the linear electro-optic effect, are typically produced on separate chips, and typically have input and output fiber connectors. Therefore, the signal output by the laser must be injected into the modulator by coupling the modulator to the laser either directly by a lens or through a fiber. This operation usually introduces high coupling losses (typically ranging between 3 dB and 6 dB), resulting in an undesired reduction of the power available for transmission.
  • the Applicant has tackled the problem of providing an optical transmitter for a network apparatus of a fiber optic communication network which allows minimizing the coupling loss which is caused by the coupling of the optical source and the phase modulator in known optical transmitters.
  • the present invention provides an optical transmitter for a network apparatus of a fiber optic communication network, the optical transmitter comprising an optical source in turn comprising an optical cavity and a phase modulator inside the optical cavity, the optical transmitter further comprising an electrical signal generator configured to encode, according to a return-to-zero scheme, a sequence of bits to be transmitted as a multi-level electrical signal for driving the phase modulator to generate a multi-level phase modulated optical signal.
  • the phase modulator is configured to:
  • the fixed time duration, Tp is a fraction of a bit time, Tb.
  • the fixed time duration, Tp is comprised between 30% to 50% of the bit time, Tb
  • the phase modulator is configured to generate the multilevel phase modulated optical signal according to a QPSK modulation scheme.
  • the optical source is a laser comprising an active medium, a first mirror and a second mirror forming the optical cavity.
  • the first mirror has a reflectivity of about 100%.
  • the second mirror has a reflectivity of about 35%.
  • the optical transmitter further comprises an auxiliary optical source for injecting light into the optical cavity of the optical source.
  • the auxiliary optical source comprises a third mirror external to the optical cavity and a further active medium between the first mirror and the third mirror, for injecting light into the optical cavity.
  • the first mirror has a reflectivity of about 35% and the third mirror has a reflectivity comprised between about 50% and about 100%.
  • the optical transmitter further comprises a third mirror external to the optical cavity and a non- amplified propagation region between the first mirror and the third mirror, for re-injecting part of the light emitted by the optical source back into said optical cavity.
  • the first mirror has a reflectivity of about 35% and the third mirror has a reflectivity comprised between about 80% and about 95%.
  • the optical transmitter is implemented in a monolithic integrated implementation in a chip of a semiconductor material.
  • the semiconductor material is one of: InP, GaAIAs, InGaAsP.
  • the phase modulator is a planar waveguide phase modulator in InP, GaAIAs or InGaAsP.
  • the optical transmitter further comprises a variable optical attenuator, VOA.
  • VOA variable optical attenuator
  • FIG. 1 shows a block scheme of an optical transmitter according to an embodiment of the present invention
  • FIG. 2 shows exemplary time diagrams illustrating the operation of the optical transmitter according to the present invention
  • FIG. 3 schematically shows a semiconductor chip into which the functions of the blocks of Figure 1 are integrated;
  • FIG. 4 shows a block scheme of an optical transmitter according to an advantageous variant of the present invention
  • FIG. 5 schematically shows a semiconductor chip into which the functions of the blocks of Figure 4 are integrated.
  • Figure 1 shows a block scheme of an optical transmitter 1 according to an embodiment of the present invention.
  • the optical transmitter 1 comprises a coherent optical source 10, i.e. a laser.
  • the optical source 10 preferably comprises an active medium 1 1 , a first mirror 12 and a second mirror 13 connected in cascade.
  • the active medium 1 1 is, as known, a material adapted to amplify light by stimulated emission.
  • the first mirror 12 and the second mirror 13 form an optical cavity of length L providing feedback of the light.
  • the first mirror 12 has preferably a high reflectivity, namely about 100%.
  • the second mirror 13 is preferably partially transparent so that a portion of the light bouncing back and forth within the optical cavity exits the cavity and may be launched by the optical transmitter 1 into an optical fiber for transmission of data.
  • the second mirror 13 may have, for instance, a reflectivity of about 35%.
  • the optical cavity allows propagation of a number of longitudinal modes. These modes are such that the cavity length L is equal to an exact multiple of half the mode wavelength.
  • the optical source 10 comprises an optical path modulator 14 inside the optical cavity (which will be referred to in the present description and in the claims also as "phase modulator”).
  • the phase modulator 14 is preferably arranged between the active medium 1 1 and the second mirror 13.
  • the phase modulator 14 is preferably configured to introduce a phase variation superimposed to the optical signal generated by the optical source 10 in response to a driving electrical signal.
  • the phase variation is due to the fact that application of the driving electrical signal changes the optical path of the signal by changing the refractive index in correspondence of the modulator 14. This is a known effect and will not be described in greater detain herein after.
  • the optical transmitter 1 preferably comprises an electrical signal generator 15, which is connected to the phase modulator 14.
  • the electrical signal generator 15 is preferably configured to receive (from a bit generator that is not shown in the Figures) as input a sequence of bits (indicated by arrow A in Figure 1 ) to be transmitted by the optical transmitter 10.
  • the electrical signal generator 15 is configured to encode the bit sequences according to a return-to-zero (RZ) coding scheme and to generate a multi-level electrical signal adapted to drive the phase modulator 14.
  • the multi-level electrical signal driving the phase modulator 14 is a voltage signal and is applied to the phase modulator 14 to generate an electric field which induces the phase variation within the phase modulator 14, according, for example, to the known Pockels effect.
  • the electrical pulse generator 15 may provide a 4-level electrical signal with amplitudes equal to, e. g., -1 , 0, +1 , +2 V.
  • amplitude values may be -3, -1 , +1 , +3 if zero average on a long sequence of bits is desired.
  • Each amplitude value corresponds to a specific pair of bits which in its turn is represented by a given constellation point. For instance, value -1 may correspond to bits "10", value 0 may correspond to bits "00", value +1 may correspond to bits "01 ", and value +2 may correspond to bits "1 1 ".
  • the present invention provides for driving the phase modulator 14 with a return-to-zero driving electrical signal, as it will be described herein after, which allows obtaining, at the output of the optical transmitter, a multi-level phase modulated optical signal.
  • the driving electrical signal drives the phase modulator 14 in order to change the optical path inside the optical cavity, as already mentioned above. This produces a variation of the frequency of the optical source 10, since it depends on the optical path travelled by the optical signal inside the optical cavity. Then, the frequency variation is accumulated for a fixed time period, and produces a phase variation in the output optical signal, as it will be described in greater detail herein after.
  • optical transmitter 1 The operation of the optical transmitter 1 , and, in particular, of the electrical signal generator 15 and the phase modulator 14, according to the present invention will be described herein after with reference to an exemplary situation illustrated in Figure 2.
  • Figure 2 shows a first waveform (a) which represents a transmission clock of the optical transmitter 1 .
  • a bit time Tb is defined as half the period of the clock waveform.
  • the bit time Tb may be equal to 40 ps, which corresponds to a data rate equal to 25 GHz.
  • the QPSK modulation scheme one symbol (two bits) out of 4 possible symbols is transmitted in a bit time Tb thus the equivalent bit rate is 50 Gbit/s.
  • DP-QPSK two polarizations
  • the second waveform (b) represents the amplitude values of a non-return- to-zero (NRZ) electrical signal corresponding to the given sequence of bits, wherein value 0 is associated with bits "00", value +1 is associated with bits "01 " and value +2 is associated with bits "1 1 ".
  • This waveform visually represents the multi-level phase modulation which is to be superimposed to the optical signal for transmitting the given sequence of bits.
  • the third waveform (c) illustrates an exemplary sequence of electrical pulses at the output of the electrical pulse generator 15 when an RZ coding scheme is applied.
  • Each electrical pulse has a duration Tp which is a fraction of the bit time Tb, for instance 30%.
  • the duration Tp of the electrical pulse may be comprised between 30% to 50% of the bit time Tb.
  • an electrical pulse of amplitude value equal to +1 is generated in correspondence of a desired 90° phase shift, namely for transmitting bits "01 " after bits "00” and bits “1 1 " after bits "01 ".
  • a further electrical pulse of amplitude -2 is generated in correspondence of a desired -180° phase shift, namely for transmitting bits "00" after bits "1 1 ".
  • the fourth waveform (d) exemplarily represents the frequency variation which may be achieved when the signal of waveform (c) is applied to drive the phase modulator 14
  • the applied signal produces a phase variation ⁇ in the phase modulator 14 which results in a variation ⁇ of the frequency of the optical signal generated within the optical cavity, according to the following equation:
  • the spacing f M L of the longitudinal modes of the optical source corresponds to a variation of the phase equal to ⁇ within the optical cavity.
  • a phase variation ⁇ results in the frequency variation ⁇ of equation [1 ].
  • the variation ⁇ of the frequency produced by the phase modulator 14 within the optical cavity is cumulated, within the fixed time Tp of duration of the electrical pulse of the driving electrical signal (which, as mentioned above, is a fraction of the bit time Tb), in a phase variation ⁇ of the optical signal, according to the following equation:
  • the fifth waveform (e) of Figure 2 shows a resulting phase variation ⁇ that may be produced by the phase modulator 14 on the output optical signal for the exemplary bit sequence considered above.
  • the ratio G between the phase variation ⁇ of the output optical signal emitted by the optical source 10 and the phase variation ⁇ impressed by the phase modulator 14 on the optical signal oscillating within the optical cavity is greater than 1 .
  • the ratio G is indeed equal to 1 for known systems including a phase modulator which is external with respect to the optical cavity.
  • the gain G may be expressed by the following equation:
  • f M i_ is the spacing of the longitudinal modes of the optical source 10 within the optical cavity
  • G is equal to about 5.75.
  • the duration of the electrical pulse Tp is the time during which the frequency variation ⁇ is integrated to give the phase variation ⁇ of the output optical signal.
  • the optical transmitter according to the present invention achieves a larger output power with respect to known schemes adopting an external phase modulator, because the coupling losses between the optical source and the phase modulator are eliminated as the phase modulator is being incorporated into the optical cavity.
  • the power of the output optical signal is an important design parameter, as it indicates how much fiber loss can be tolerated and hence influences the optical reach. Generally, the greater the power, the greater the reach that can be achieved.
  • a gain in the amplitude of the modulated phase is obtained, because in the physical process of conversion between, firstly, optical path variation and frequency variation of the optical signal, and then between the frequency variation of the optical signal and the variation of the generated phase, an output phase variation is produced which is greater than the variation impressed to the optical path, which is in turn equal to the phase variation obtained with a known external modulator.
  • the driving electrical signal of the phase modulator is conformed as a return-to-zero signal, and the frequency variation is thus cumulated for a fixed time (namely for the time duration of the RZ electrical pulse) within the bit time, finally providing the output phase variation.
  • the gain in the amplitude of the phase variation which is obtained by the present invention advantageously results in a reduction of the power of the driving electrical signal with respect to known schemes for the phase modulation.
  • Figure 3 shows an exemplary monolithic integrated implementation of the optical transmitter 1 according to the present invention.
  • the functions indicated in the block scheme of Figure 1 are integrated in a chip of a semiconductor material.
  • the material may be indium phosphide (InP), aluminium gallium arsenide (GaAIAs) or indium gallium arsenide phosphide (InGaAsP) or another semiconductor material.
  • the optical cavity comprises the active medium 1 1 and the first and second mirrors 12, 13.
  • the material of the active medium 1 1 may be, for instance InP, GaAIAs or InGaAsP.
  • the first mirror 12 and the second mirror 13 may be, for instance, distributed mirrors (for instance, distributed Bragg reflectors, DBR), or, alternatively, they may be obtained by cleaving the end faces of the chip.
  • the phase modulator 14 may be a planar waveguide phase modulator in InP, GaAIAs or InGaAsP.
  • the optical transmitter 1 may comprise a variable optical attenuator (VOA) 17, if required, to control the emitted power.
  • VOA variable optical attenuator
  • the electrical signal generator 15 is not shown in Figure 3. In this integrated implementation, the electrical signal generator 15 is connected to the phase modulator 14 by means of a number of electrodes 141 .
  • Another advantage of the present invention is related to the behavior of the optical transmitter at the high frequency cutoff.
  • the phase modulator may suffer a reduction in efficiency.
  • the optical transmitter according to the present invention can be used at higher frequencies, because its monolithic structure is compatible with the implementation of bandwidth expansion techniques such as those described in E.K. Lau et al. "Enhanced Modulation Characteristics of Optical Injection-laser” Journal Selected Topics Quantum Electronics vol. 15, no. 3, (May/June 2009), pp. 618-633, and U. Troppenz, et al. "40 Gbit/s Directly Modulated Passive-Feedback Laser", in Proc. 20th International Conference on Indium Phosphide and Related Materials, 2008. IPRM 2008. DOI: 10.1 109 / ICIPRM.2008.4703053.
  • the bandwidth expansion techniques mentioned above are based on the fact that, by injecting into the (main) laser cavity the radiation of another (auxiliary) laser, or by re-injecting a part of the emission of the laser back into the laser itself by means of a mirror external with respect to the laser cavity, an increase of the carrier recombination rate within the laser cavity and thus an extension of the frequency bandwidth is obtained.
  • a power that is 3 times higher than the pre-existing power a widening of the bandwidth of about a factor of 2.5 has been obtained, as described in E.K. Lau et al. "Enhanced Modulation Characteristics of Optical Injection-laser" Journal Selected Topics Quantum Electronics vol. 15, no.
  • the bit rate may increase from about 25 Gbit/s to about 62.5 Gbit/s.
  • an external reflector located at a distance from the output mirror approximately equal to the length of the laser cavity, a widening of the modulation bandwidth from about 10 Gbit/s to about 35 Gbit/s has been obtained, i.e. of approximately a factor equal to 3.5, as described in U. Troppenz, et al. "40 Gbit/s Directly Modulated Passive-Feedback Laser", in Proc. 20th International Conference on Indium Phosphide and Related Materials, 2008. IPRM 2008. DOI: 10.1 109 / ICIPRM.2008.4703053.
  • FIG 4 shows a block scheme of an optical transmitter V according to an advantageous variant of the optical transmitter 1 of Figure 1 for implementing a bandwidth expansion technique.
  • the optical transmitter 1 ' preferably comprises, in addition to the components already described with reference to the block scheme of Figure 1 , an auxiliary active medium 18 arranged between the first mirror 12' and a third mirror 19 external to the optical cavity.
  • the first mirror 12' is partially transparent.
  • the first mirror 12' may have a reflectivity equal to about 35%.
  • the third mirror 19 is highly reflective.
  • the third mirror 19 may have a reflectivity ranging from about 50% up to about 100%.
  • This scheme comprises an auxiliary optical source consisting of the auxiliary active medium 18 between the first mirror 12' and the third mirror 19.
  • This auxiliary optical source injects light into the optical cavity of the (main) optical source 10 comprising the active medium 1 1 between the first mirror 12' and the second mirror 13.
  • the auxiliary active medium 18 may be replaced by a non-amplified propagation region (or a passive external waveguide). This scheme is typically known as "passive feedback”.
  • the third mirror 19 may have, for instance, a reflectivity within the range 80%-95%. In this way, part of the light emitted by the optical source 10 is re-injected back into the optical cavity by means of the third mirror 19.
  • Figure 5 schematically shows a monolithic integrated implementation of the functions of the blocks of Figure 4. Reference numbers correspond to those already used in the other Figures.
  • the two optical sources (main and auxiliary) and the optical path modulator 14 can be implemented on the same chip, in a technological approach known as PIC (Photonic Integrated Circuit).
  • PIC Photonic Integrated Circuit
  • the above-mentioned bandwidth extension in practice up to a factor of 2.5-3) may be achieved.
  • a bandwidth extension may also be achieved up to a factor of 3.5, which allows to reach a bit rate of about 350 Gbit/s with the DPQPSK modulation scheme.
  • optical transmitters 1 , 1 ' can be realized both in bulk optics (as schematically shown in Figures 1 and 4) and in monolithic integrated version as shown in Figures 3 and 5, where in a single chip of semiconductor (InAGaAsP on InP or GaAIAs on GaAs, or other materials typically employed in photonic applications), all the functions of the block schemes described above may be realized, including the optical source and the phase modulator.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optics & Photonics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Optical Communication System (AREA)

Abstract

L'invention concerne un émetteur optique destiné à un appareil de réseau d'un réseau de communication par fibres optiques. L'émetteur optique comprend une source optique contenant à son tour une cavité optique et un modulateur de phase à l'intérieur de la cavité optique. L'émetteur optique comprend en outre un générateur de signal électrique configuré de manière à coder, selon un schéma de retour à zéro, une séquence de bits devant être émise comme signal électrique multi-niveau pour attaquer le modulateur de phase afin de produire un signal optique à modulation de phase multi-niveau.
PCT/EP2015/062427 2015-06-03 2015-06-03 Émetteur optique pour des communication par fibres optiques WO2016192790A1 (fr)

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PCT/EP2015/062427 WO2016192790A1 (fr) 2015-06-03 2015-06-03 Émetteur optique pour des communication par fibres optiques

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1686706A1 (fr) * 2005-02-01 2006-08-02 Alcatel Alsthom Compagnie Generale D'electricite Emetteur optique et procédé de modulation d'un signal optique
US20090060526A1 (en) * 2002-12-03 2009-03-05 Finisar Corporation Optical fm source based on intra-cavity phase and amplitude modulation in lasers
US20090268765A1 (en) * 2008-04-28 2009-10-29 Daniel Mahgerefteh Intra-Cavity Phase Modulated Laser Based on Intra-Cavity Depletion-Edge-Translation Lightwave Modulators

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090060526A1 (en) * 2002-12-03 2009-03-05 Finisar Corporation Optical fm source based on intra-cavity phase and amplitude modulation in lasers
EP1686706A1 (fr) * 2005-02-01 2006-08-02 Alcatel Alsthom Compagnie Generale D'electricite Emetteur optique et procédé de modulation d'un signal optique
US20090268765A1 (en) * 2008-04-28 2009-10-29 Daniel Mahgerefteh Intra-Cavity Phase Modulated Laser Based on Intra-Cavity Depletion-Edge-Translation Lightwave Modulators

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
A. YARIV: "Quantum electronics", WILEY AND SONS, pages: 145
E.K. LAU ET AL.: "Enhanced Modulation Characteristics of Optical Injection-laser", JOURNAL SELECTED TOPICS QUANTUM ELECTRONICS, vol. 15, no. 3, May 2009 (2009-05-01), pages 618 - 633
U. TROPPENZ ET AL.: "40 Gbit/s Directly Modulated Passive-Feedback Laser", PROC. 20TH INTERNATIONAL CONFERENCE ON INDIUM PHOSPHIDE AND RELATED MATERIALS, 2008

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