lithium niobateLiNbO3
PPLN Λ = 6.82 µm · 1064 → 532 nm · 2 px/µm
lithium niobate / 07 History / 7.7

7.7 The internet's modulator

1985–2021

L1 Narrative

1985-2021 · 18 events

Long-distance fiber links need a modulator that imprints data on a steady laser without disturbing its color. The first commercial guided-wave LN modulator went on sale in 1985 [Becker 1988 rec]. Undersea routes were among the first to use external modulation [Leonberger et al. 1995 S]; by 1997 vendors described LN modulators for 10 Gb/s [Lin & Sanders 1997 S]; by 2000 a review written by JDS Uniphase engineers listed them for 2.5, 10 and 40 Gb/s systems and analog cable TV [Wooten et al. 2000 rec; affiliation P]. Commercial use depended on drift: the bias point wanders as charge moves in the crystal. In 1992 Fujitsu wrote that there had been “no report to guarantee the long-term reliability of Ti:LiNbO3 devices against DC drift” and showed a design assured for 15 years [Seino et al. 1992 rec].

In 2009 Fujitsu introduced what it called the first DP-QPSK LN modulator, which writes data on the phase of light in two polarizations for 100 Gb/s per wavelength [Fujitsu 2009 rec]. By 2021 it had shipped one million [Fujitsu 2021 rec]. The companies changed hands repeatedly: Crystal Technology to Gooch & Housego (2011) [Gooch & Housego 2026 rec], Lumentum's Italian LN line to Advanced Fiber Resources (2019) [Lightwave 2019 S].

Bit rate by decade — A chart (log or linear) of the line rates named in dated sources (1997 10 Gb/s; 1998 10 and 20 Gb/s; 2000 40 Gb/s; 2009 100 Gb/s DP-QPSK; 2022 1.96 Tb/s single wavelength, research); each point opens its source with status.
Line rate per wavelength named in dated sources
1101001k10k19851995200520152025Gb/s10 Gb/s20 Gb/s40 Gb/s100 Gb/s1.96 Tb/sproduct statement (vendor or press)research result
199710 Gb/sUTP: 10 Gb/s LN modulators Lin & Sanders 1997S
199820 Gb/sLucent X2600 family for 10 and 20 Gb/s Lightwave 1998S
200040 Gb/sWooten et al.: LN modulators for 2.5, 10 and 40 Gb/s systems Wooten et al. 2000rec
2009100 Gb/sFujitsu DP-QPSK LN modulator for 100 Gb/s (vendor claim) Fujitsu 2009rec
20221.96 Tb/sDual-polarization TFLN IQ modulator: 1.96 Tb/s net, single wavelength Xu et al. 2022rec
1101001k10k19851995200520152025Gb/s10 Gb/s20 Gb/s40 Gb/s100 Gb/s1.96 Tb/sproduct statement (vendor or press)research result
  1. 199710 Gb/sUTP: 10 Gb/s LN modulatorssecondary only Lin & Sanders 1997
  2. 199820 Gb/sLucent X2600 family for 10 and 20 Gb/ssecondary only Lightwave 1998
  3. 200040 Gb/sWooten et al.: LN modulators for 2.5, 10 and 40 Gb/s systemsverified record Wooten et al. 2000
  4. 2009100 Gb/sFujitsu DP-QPSK LN modulator for 100 Gb/s (vendor claim)verified record Fujitsu 2009
  5. 20221.96 Tb/sDual-polarization TFLN IQ modulator: 1.96 Tb/s net, single wavelengthverified record Xu et al. 2022

L2 Numbers and mechanisms

The internet's modulator

Device. A Mach-Zehnder modulator splits light into two Ti:LN waveguide arms under traveling-wave electrodes; with push-pull drive the transmission is T = cos2(π V / (2 Vπ)) with V measured from the transmission maximum, or T = (1 - sin(π V / Vπ)) / 2 about quadrature (closed form in chapter 06).

DC drift. Seino et al. (Fujitsu, OFC 1992 postdeadline): Ti:LN modulators were in transmission experiments and planned for commercial systems; a Si coating suppressed temperature and humidity drift; long-term DC drift “stable enough for use in commercial optical transmission systems” [Seino et al. 1992 rec]. Sumitomo Cement published DC-drift studies by 1993 [Nagata & Kiuchi 1993 rec]. Physics of drift: chapter 04.

Dated product statements. UTP: 10 Gb/s LN modulators (1997) [Lin & Sanders 1997 S]. Lucent X2600 family for 10 and 20 Gb/s (1998) [Lightwave 1998 S]. Wooten et al. (2000): 2.5, 10 and 40 Gb/s digital systems, CATV analog, and 10 Gb/s RZ pulse generation plus data modulation in one device [Wooten et al. 2000 rec]. Fujitsu (2009-09-14): DP-QPSK LN modulator, 25 GHz, maximum 3.5 V drive, shipping 2009-12-01, described by Fujitsu as a world first [Fujitsu 2009 rec]. Fujitsu (2021-03-31): more than one million coherent LN modulators shipped by the end of 2021-02 and a 70% market share in 2020 (vendor claims) [Fujitsu 2021 rec].

Corporate lineage (press-level unless marked): Crystal Technology, Palo Alto (oxide crystals from 1967 [optics.org 2026 rec]; first commercial guided-wave modulator 1985 [Becker 1988 rec]; acquired by G&H 2011-04-01 for USD 13.75 M [Gooch & Housego 2026 rec]). United Technologies Photonics to Uniphase 1995 [Lightwave 1995 S], JDS Uniphase 1999 with Ramar [RF Globalnet 2026 S]. Pirelli Milan components to Corning 2000 [Compound Semiconductor 2000 S]. Codeon to Covega 2003 [Lightwave 2003 S]. EOSPACE from Boeing integrated optics, late 1997 [EOSPACE 2026 rec]. Photline (Besancon, 2000) to iXblue 2013 [Photonics Online 2015 S] to Exail 2022 [Exail 2022 S]. Sumitomo Osaka Cement (formed 1994-10-01; Guangdong subsidiary 2011-11) [Sumitomo Osaka Cement 2026 rec]. Lumentum's San Donato LN lines to AFR, signed 2019-11-28 [Lightwave 2019 S].

L3 Sources and status

21 sources cited on this page
ClaimSourceStatus
External modulation first deployed on submarine routes (no year)Leonberger et al. 1995, vendor authorsS
Wooten 2000 authors all JDSUOpenAlex affiliationP
2.5/10/40 Gb/sWooten et al. 2000 abstract (OpenAlex)rec
15-year drift assurance 1992Seino et al. 1992 abstract and bylinerec
2009 DP-QPSK; 1 M units by 2021-02Fujitsu 2009, Fujitsu 2021 (archived releases)V (vendor claims)
Year Fujitsu or SOC first shipped Ti:LN modulatorsnot foundopen

References

  1. R.A. Becker, MRS Bulletin 13 21-23 (1988). Optical-Guided-Wave Modulators. Issued 1988-08. doi:10.1557/s0883769400064630
  2. F. J. Leonberger et al., Laser Focus World (1995). Optical modulators find wider use in CATV and telecommunications. Issued 1995-07-01. www.laserfocusworld.com/optics/article/16553605/optical-modulato…
  3. J. Lin & P. Sanders, Lightwave (1997). OC-192 lithium-niobate modulators spark fiber-optic network capacity. Issued 1997-02-01. www.lightwaveonline.com/optical-tech/electronics/article/1665277…
  4. Wooten et al., IEEE Journal of Selected Topics in Quantum Electronics 6 69-82 (2000). A review of lithium niobate modulators for fiber-optic communications systems. Issued 2000-01. doi:10.1109/2944.826874
  5. M. Seino et al., Digest of Conference on Optical Fiber Communication PD3 (1992). A low DC-drift Ti:LiNbO3 modulator assured over 15 years. Issued 1992. doi:10.1364/ofc.1992.pd3
  6. Fujitsu Introduces World's First DP-QPSK LN Modulator for 100Gbps Optical Networks (2009). Fujitsu Introduces World's First DP-QPSK LN Modulator for 100Gbps Optical Networks. Issued 2009-09-14. web.archive.org/web/20210620162454/https://www.fujitsu.com/jp/gr…
  7. Fujitsu Optical Components Ships One Millionth Coherent Lithium-Niobate Modulator (2021). Fujitsu Optical Components Ships One Millionth Coherent Lithium-Niobate Modulator. Issued 2021-03-31. web.archive.org/web/20230812112018/https://www.fujitsu.com/jp/gr…
  8. Gooch & Housego, our history (2026). Gooch & Housego, our history. Issued 2026. gandh.com/our-history
  9. Lightwave (2019). Lumentum to sell certain lithium niobate-based product lines to AFR. Issued 2019-12-02. www.lightwaveonline.com/business/mergers-acquisitions/article/14…
  10. Hirotoshi Nagata & Kazumasa Kiuchi, Journal of Applied Physics 73 4162-4164 (1993). Temperature dependence of dc drift of Ti:LiNbO3 optical modulators with sputter deposited SiO2 buffer layer. Issued 1993-05-01. doi:10.1063/1.352849
  11. Lightwave (1998). Lithium niobate modulators (Lucent X2600). Issued 1998-05-01. www.lightwaveonline.com/optical-tech/electronics/article/1665608…
  12. optics.org buyers guide: Crystal Technology, Inc. (2026). optics.org buyers guide: Crystal Technology, Inc.. Issued 2026. optics.org/buyers-guide/crystal-technology-inc
  13. Lightwave (1995). Business purchase (Uniphase acquires United Technologies Photonics). Issued 1995-07-01. www.lightwaveonline.com/business/market-research/article/1666211…
  14. referenceforbusiness.com (2026). JDS Uniphase Corporation (company history). Issued 2026. www.referenceforbusiness.com/history2/11/JDS-Uniphase-Corporatio…
  15. Compound Semiconductor (2000). Corning to acquire Pirelli's optical components and devices business for $3.6 billion. Issued 2000. compoundsemiconductor.net/article/80769/Corning_to_Acquire_Pirel…
  16. Lightwave (2003). Codeon Corp. and Quantum Photonics merge to form Covega Corp.. Issued 2003. lightwaveonline.com/business/article/16656427/codeon-corp-and-qu…
  17. EOSPACE technical management (2026). EOSPACE technical management. Issued 2026. www.eospace.com/technicalmanagement
  18. Photonics Online (2015). iXblue completes integration of iXFiber and Photline. Issued 2015-02-04. www.photonicsonline.com/doc/ixblue-completes-integration-of-ixfi…
  19. ECA Group and iXblue join forces and become Exail (2022). ECA Group and iXblue join forces and become Exail. Issued 2022-10-18. www.exail.com/eca-group-and-ixblue-join-forces-and-become-exail/
  20. Sumitomo Osaka Cement company history (2026). Sumitomo Osaka Cement company history. Issued 2026. www.soc.co.jp/company/history/
  21. Mengyue Xu et al., Optica 9 61 (2022). Dual-polarization thin-film lithium niobate in-phase quadrature modulators for terabit-per-second transmission. Issued 2022-01-20. doi:10.1364/optica.449691

Events of 7.7

18 events; status per event
DateEventWhoRefSt
1992-02Low DC-drift Ti:LiNbO3 modulator assured over 15 yearsM. Seino, T. Nakazawa +4DOIrec
1993-05-01DC drift of Ti:LiNbO3 modulators studied at Sumitomo CementHirotoshi Nagata, Kazumasa KiuchiDOIrec
1994-10-01Sumitomo Cement and Osaka Cement merge into Sumitomo Osaka CementURLrec
1995-07-01Uniphase buys United Technologies Photonics (LN integrated optics, Bloomfield CT)URLS
1995-07-01UTP engineers: external modulation first deployed in telecom on submarine routesF. J. Leonberger, S. W. Merritt +1URLS
1997EOSPACE formed in Redmond WA as a spin-out of Boeing integrated opticsSuwat ThaniyavarnURLrec
1997-02-01OC-192 (10 Gb/s) lithium niobate modulators described by UTP engineersJ. Lin, P. SandersURLS
1998-05-01Lucent X2600 LN modulator family for 10 and 20 Gb/sURLS
1999-06-28JDS Fitel and Uniphase merge into JDS Uniphase; Ramar (LN integrated optics) acquired 1999-10URLS
2000-01Review of lithium niobate modulators for fiber-optic communicationsE. L. Wooten, K. M. Kissa +9DOIrec
2000-09Photline Technologies founded in Besancon from FEMTO-STHenri Porte-S
2000-09-27Corning agrees to buy Pirelli's optical components unit (Milan), including LN modulators, for about $3.6 BURLS
2003-03-05Codeon (Mach-10 and Mach-40 LN modulators) merges with Quantum Photonics to form CovegaURLS
2009-09-14Fujitsu introduces a DP-QPSK LN modulator for 100 Gb/s networksURLrec
2011-04-01Gooch & Housego acquires Crystal Technology, LLC (Palo Alto LN and TeO2 growth)URLrec
2011-11Sumitomo Osaka Cement sets up an optical-communication parts subsidiary in GuangdongURLrec
2019-11-28Lumentum sells its LN modulator product lines (San Donato, Italy) to Advanced Fiber ResourcesURLS
2021-03-31Fujitsu Optical Components ships its one millionth coherent LN modulatorURLrec