Читать книгу VCSEL Industry - Babu Dayal Padullaparthi - Страница 42
1.4.2 Single‐Mode and Multi‐Mode Behavior
ОглавлениеSemiconductor lasers oscillate in different modes (power radiation patterns) that depend on the dimensions of the optical resonator. Especially for VCSELs, the mode structure or pattern depends on the size and shape of the oxide aperture (mode) diameter used for current and optical confinement [53, 54]. Several kinds of modes appear in the emission spectra, namely longitudinal, transverse, single, and multi‐modes. In Figure 1.16 we show how the behavior of VCSEL in single longitudinal and multi‐transverse (and longitudinal) operation. More details on the VCSEL mode structure will be discussed in Chapter 2.
Table 1.2 Milestones of surface emitting laser research and development.
| 1977 | Surface‐emitting laser concept proposed |
| 1979 | First device demonstrated (77 K, pulsed) |
| 1988 | First RT CW operation |
| 1988 | Semiconductor DBR |
| 1989 | QW VCSEL |
| 1989 | Micro‐post QW laser RT CW (Bell Labs) |
| 1989 | Periodic gain proposed (UCSB) |
| 1990 | AlGaAs hydro‐oxidization (UIUC) |
| 1992 | VCSEL mechanical tuning demonstrated |
| 1995‐ | Low threshold device competition Ith < 0.1 mA |
| 1995 | MEMS tunable VCSEL (USB) |
| 1996 | VCSEL commercialization (Honeywell) |
| 1999 | VCSEL LAN |
| 2000 | Oxide aperture device reliability |
| 2001 | VCSEL printer (Fuji, Xerox), |
| 2001 | Computer mouse (HP) |
| 2002 | 10G Ethernet standard IEEE802.3ae |
| 2003 | 4Gb/s VCSELs (Honeywell) |
| 2006 | High‐contrast grating for VCSEL (UC Berkeley) |
| 2010 | 100G Ethernet standard IEEE802.3ba |
| 2011‐ | VCSEL photonics |
| 2016 | VCSEL arrays for sensing |
| 2016 | VCSEL SWDM in datacom |
| 2017 | VCSEL face ID 3D sensor (iPhone X from Apple) |
| 2018 | 400G AOC (Finisar/II–VI) |
| 2020 | LiDAR scanner (iPhone 12 Pro, iPad Pro 11″/12″ from Apple) |
| 2021‐ | VCSEL Industry |
Italic: From K. Iga’s group.
RT CW: Room‐temperature continuous wave
QW: Quantum well.
Figure 1.16 Origin of single‐mode and multi‐mode behavior in VCSELs.
Source: [55, 8]. Figure by K. Iga [copyright reserved by author].
The origin of multi‐mode operation in a VCSEL is not from longitudinal mode behavior but multiple transverse mode oscillation. When the lateral extent of the optical resonator diameter is extended to larger than several microns, multi‐transverse with multispectral‐mode operation is achieved. On the other hand, small diameters lead to single‐transverse and single spectral‐mode operation.
